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| versions
list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0707.1630 | Tim Schulze | T. F. Schulze (1), P. S. H\"afliger (1), C. Niedermayer (2), K.
Mattenberger (1), S. Bubenhofer (1), B. Batlogg (1) ((1) Laboratory for Solid
State Physics, ETH Z\"urich, Switzerland, (2) Laboratory for Neutron
Scattering, Paul-Scherrer-Institut (PSI) and ETH Z\"urich, Switzerland) | Direct link between low temperature magnetism and high temperature
sodium order in NaxCoO2 | 4 pages, 4 figures, to appear in PRL | null | 10.1103/PhysRevLett.100.026407 | null | cond-mat.str-el cond-mat.mtrl-sci | null | We prove the direct link between low temperature magnetism and high
temperature sodium ordering in NaxCoO2 using the example of a heretofore
unreported magnetic transition at 8 K which involves a weak ferromagnetic
moment. The 8 K feature is characterized in detail and its dependence on a
diffusive sodium rearrangement around 200 K is demonstrated. Applying muons as
local probes this process is shown to result in a reversible phase separation
into distinct magnetic phases that can be controlled by specific cooling
protocols. Thus the impact of ordered sodium Coulomb potential on the CoO2
physics is evidenced opening new ways to experimentally revisit the NaxCoO2
phase diagram.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 15:00:35 GMT"
},
{
"version": "v2",
"created": "Thu, 22 Nov 2007 13:08:39 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Schulze",
"T. F.",
""
],
[
"Häfliger",
"P. S.",
""
],
[
"Niedermayer",
"C.",
""
],
[
"Mattenberger",
"K.",
""
],
[
"Bubenhofer",
"S.",
""
],
[
"Batlogg",
"B.",
""
]
] |
0707.1631 | Fabricio Macedo de Souza | Fabricio M. Souza | Spin-Dependent Ringing and Beats in a Quantum Dot System | published version: reference added, typos corrected, minor changes in
the text | Phys. Rev. B 76, 205315 (2007) | 10.1103/PhysRevB.76.205315 | null | cond-mat.mes-hall | null | We report spin-dependent quantum coherent oscillations (ringing) and beats of
the total and spin currents flowing through a quantum dot with Zeeman split
levels. The spin dependent transport is calculated via nonequilibrium Green
function in the transient after a bias voltage is turned on at t=0. The dot is
coupled to two electrodes that can be ferromagnetic or nonmagnetic. In the
ferromagnetic case both parallel and antiparallel alignments are considered.
The coherent oscillation and beat frequencies are controlled via the Zeeman
energy E_Z. In particular, for E_Z=0 no beats are observed and the spin current
is zero for nonmagnetic leads. In the ferromagnetic case a finite spin current
is found for E_Z=0. The effects of temperature are also analyzed. We observe
that with increasing temperature the ringing response and the beats tend to
disappear. Additionally, the spin current goes to zero for nonmagnetic leads,
remaining finite in the ferromagnetic case. The tunnel magnetoresistance (TMR)
also reveals quantum coherent oscillations and beats, and it attains negative
values for small enough temperatures and short times.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 14:32:57 GMT"
},
{
"version": "v2",
"created": "Wed, 21 Nov 2007 12:45:44 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Souza",
"Fabricio M.",
""
]
] |
0707.1632 | Adriana Elizabeth Nuncio Quiroz | A. Geiser and A. E. Nuncio Quiroz | The FMNRxPYTHIA interface for Heavy Quark production at HERA | 10 pages, 9 figures | J.Phys.Conf.Ser.110:022036,2008 | 10.1088/1742-6596/110/2/022036 | null | hep-ph | null | A method to calculate heavy flavor visible-level cross sections at
Next-to-Leading Order (NLO) in Quantum Chromodynamics (QCD), based on an
interface of the FMNR program to PYTHIA, is described. It uses the NLO
prediction at quark level provided by FMNR, with a statistical reduction
procedure (REDSTAT) that allows a link to PYTHIA 6.2 to be made, from where the
description of the full hadron fragmentation and decay chain is obtained. The
method is applied to ep -> b bbar X -> D* mu X and mu+ mu- X final states at
HERA. Comparisons of the data and NLO cross sections at visible and b-quark
level were found to be consistent.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 14:33:32 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Geiser",
"A.",
""
],
[
"Quiroz",
"A. E. Nuncio",
""
]
] |
0707.1633 | Woochun Park | The BABAR Collaboration, B. Aubert, et al | Search for Prompt Production of $\chi_{c}$ and X(3872) in e^+e^-
Annihilations | 8 pages 1 figure submitted to Phys. Rev. D (Rapid Communications) | Phys.Rev.D76:071102,2007 | 10.1103/PhysRevD.76.071102 | BABAR-PUB-07/028, SLAC-PUB-12660 | hep-ex | null | We have searched for prompt production of $\chi_{c1}$, $\chi_{c2}$ and
X(3872) in continuum e^+e^- annihilations using a 386 fb^{-1} data sample
collected around $\sqrt{s} = 10.6$ GeV with the BABAR detector using the
$\gamma J/\psi$ decay mode. After accounting for the feed-down from
$\psi(2S)\to\gamma\chi_{c1,2}$, no significant signal for prompt $\chi_{c1,2}$
production is observed. We present improved upper limits on the cross-section,
with the rest of the event consisting of more than two charged tracks, to be 77
fb for $\chi_{c1}$ and 79 fb for $\chi_{c2}$ with $e^+e^-$ center-of-mass frame
$\chi_c$ momentum greater than 2.0 GeV at 90% confidence level. These limits
are consistent with NRQCD predictions. We also set an upper limit on the prompt
production of X(3872) through the decay $X(3872)\to \gamma J/\psi$.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 14:41:46 GMT"
}
] | 2010-04-12T00:00:00 | [
[
"The BABAR Collaboration",
"",
""
],
[
"Aubert",
"B.",
""
]
] |
0707.1634 | Raffaele Romano | Raffaele Romano, Alessio Del Fabbro | Optimal generation of entanglement under local control | 4 pages | Phys. Rev. A 76, 044302 (2007) | 10.1103/PhysRevA.76.044302 | null | quant-ph | null | We study the optimal generation of entanglement between two qubits subject to
local unitary control. With the only assumptions of linear control and unitary
dynamics, by means of a numerical protocol based on the variational approach
(Pontryagin's Minimum Principle), we evaluate the optimal control strategy
leading to the maximal achievable entanglement in an arbitrary interaction
time, taking into account the energy cost associated to the controls. In our
model we can arbitrarily choose the relative weight between a large
entanglement and a small energy cost.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 14:42:48 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Romano",
"Raffaele",
""
],
[
"Del Fabbro",
"Alessio",
""
]
] |
0707.1635 | Evgeny Mukhin | B. Feigin, E. Feigin, M. Jimbo, T. Miwa and E. Mukhin | Principal $\hat{sl}(3)$ subspaces and quantum Toda Hamiltonian | Latex, 42 pages | null | null | null | math.QA math-ph math.MP | null | We study a class of representations of the Lie algebra of Laurent polynomials
with values in the nilpotent subalgebra of sl(3). We derive Weyl-type (bosonic)
character formulas for these representations. We establish a connection between
the bosonic formulas and the Whittaker vector in the Verma module for the
quantum group $U_v sl(3)$. We also obtain a fermionic formula for an
eigenfunction of the sl(3) quantum Toda Hamiltonian.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 14:42:56 GMT"
},
{
"version": "v2",
"created": "Mon, 27 Aug 2007 14:29:06 GMT"
}
] | 2007-08-27T00:00:00 | [
[
"Feigin",
"B.",
""
],
[
"Feigin",
"E.",
""
],
[
"Jimbo",
"M.",
""
],
[
"Miwa",
"T.",
""
],
[
"Mukhin",
"E.",
""
]
] |
0707.1636 | Sa\v{s}a Iliji\'c | Dubravko Horvat and Sasa Ilijic | Gravastar energy conditions revisited | LaTeX/IOP-style, 16 pages, 2 figures, changes wrt v1: motivation for
eq. (6) clarified, several referecnes added (to appear in Class. Quantum
Grav.) | Class.Quant.Grav.24:5637-5649,2007 | 10.1088/0264-9381/24/22/022 | null | gr-qc | null | We consider the gravastar model where the vacuum phase transition between the
de Sitter interior and the Schwarzschild or Schwarzschild-de Sitter exterior
geometries takes place at a single spherical delta-shell. We derive sharp
analytic bounds on the surface compactness (2m/r) that follow from the
requirement that the dominant energy condition (DEC) holds at the shell. In the
case of Schwarzschild exterior, the highest surface compactness is achieved
with the stiff shell in the limit of vanishing (dark) energy density in the
interior. In the case of Schwarzschild-de Sitter exterior, in addition to the
gravastar configurations with the shell under surface pressure, gravastar
configurations with vanishing shell pressure (dust shells), as well as
configurations with the shell under surface tension, are allowed by the DEC.
Respective bounds on the surface compactness are derived for all cases. We also
consider the speed of sound on the shell as derived from the requirement that
the shell is stable against the radial perturbations. The causality requirement
(sound speed not exceeding that of light) further restricts the space of
allowed gravastar configurations.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 14:44:38 GMT"
},
{
"version": "v2",
"created": "Fri, 28 Sep 2007 08:00:35 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Horvat",
"Dubravko",
""
],
[
"Ilijic",
"Sasa",
""
]
] |
0707.1637 | Mikael Vejdemo-Johansson | Mikael Vejdemo-Johansson | A partial $A_\infty$-structure on the cohomology of $C_n\times C_m$ | 11 pages, updated to official JHRS version. | Journal of Homotopy and Related Structures, 3:1 (2008) pp. 1-11 | null | null | math.KT math.AT math.RT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Suppose k is a field of characteristic 2, and $n,m\geq 4$ powers of 2. Then
the $A_\infty$-structure of the group cohomology algebras $H^*(C_n,k)$ and
$(H^*(C_m,k)$ are well known. We give results characterizing an
$A_\infty$-structure on $H^*(C_n\times C_m,k)$ including limits on
non-vanishing low-arity operations and an infinite family of non-vanishing
higher operations.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 14:46:29 GMT"
},
{
"version": "v2",
"created": "Fri, 18 Jan 2008 15:16:08 GMT"
},
{
"version": "v3",
"created": "Thu, 13 May 2010 04:41:50 GMT"
}
] | 2010-05-14T00:00:00 | [
[
"Vejdemo-Johansson",
"Mikael",
""
]
] |
0707.1638 | Elias Gyftopoulos | Elias P. Gyftopoulos | Quantum Limits in Nanomechanical Systems | 2 pages | null | null | null | physics.gen-ph | null | In two articles, the authors claim that the Heisenberg uncertainty principle
limits the precision of simultaneous measurements of the position and velocity
of a particle and refer to experimental evidence that supports their claim.
It is true that ever since the inception of quantum mechanics, the
uncertainty relation that corresponds to a pair of observables represented by
non-commuting operators is interpreted by many scientists and engineers,
including Heisenberg himself, as a limitation on the accuracy with which
observables can be measured. However, such a limitation cannot be deduced from
the postulates and theorems of quantum thermodynamics.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 14:46:42 GMT"
}
] | 2007-07-12T00:00:00 | [
[
"Gyftopoulos",
"Elias P.",
""
]
] |
0707.1639 | Alban Ponse | Jan A. Bergstra and Alban Ponse | Interface groups and financial transfer architectures | 22 pages | null | null | PRG0702 | cs.SE | null | Analytic execution architectures have been proposed by the same authors as a
means to conceptualize the cooperation between heterogeneous collectives of
components such as programs, threads, states and services. Interface groups
have been proposed as a means to formalize interface information concerning
analytic execution architectures. These concepts are adapted to organization
architectures with a focus on financial transfers. Interface groups (and
monoids) now provide a technique to combine interface elements into interfaces
with the flexibility to distinguish between directions of flow dependent on
entity naming.
The main principle exploiting interface groups is that when composing a
closed system of a collection of interacting components, the sum of their
interfaces must vanish in the interface group modulo reflection. This certainly
matters for financial transfer interfaces.
As an example of this, we specify an interface group and within it some
specific interfaces concerning the financial transfer architecture for a part
of our local academic organization.
Financial transfer interface groups arise as a special case of more general
service architecture interfaces.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 14:55:26 GMT"
}
] | 2007-07-12T00:00:00 | [
[
"Bergstra",
"Jan A.",
""
],
[
"Ponse",
"Alban",
""
]
] |
0707.1640 | Jean Bertoin | Jean Bertoin (PMA, Dma) | Asymptotic regimes for the occupancy scheme of multiplicative cascades | null | null | null | null | math.PR | null | In the classical occupancy scheme, one considers a fixed discrete probability
measure ${\bf p}=(p_i: {i\in{\cal I}})$ and throws balls independently at
random in boxes labeled by ${\cal I}$, such that $p_i$ is the probability that
a given ball falls into the box $i$. In this work, we are interested in
asymptotic regimes of this scheme in the situation induced by a refining
sequence $({\bf p}(k) : k\in\N)$ of random probability measures which arise
from some multiplicative cascade. Our motivation comes from the study of the
asymptotic behavior of certain fragmentation chains
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 15:00:34 GMT"
},
{
"version": "v2",
"created": "Tue, 9 Oct 2007 18:30:22 GMT"
}
] | 2007-10-09T00:00:00 | [
[
"Bertoin",
"Jean",
"",
"PMA, Dma"
]
] |
0707.1641 | Timothy J. Dennis | Timothy J. Dennis (1), Andrew J. Cunningham (1), Adam Frank (1), Bruce
Balick (2), Eric G. Blackman (1), Sorin Mitran (3) ((1) University of
Rochester (2) University of Washington (3) University of North Carolina) | PPN as Explosions: Bullets vs Jets and Nebular Shaping | 25 pages, 9 figures | null | 10.1086/587730 | null | astro-ph | null | Many proto-planetary nebulae (PPN) appear as narrow collimated structures
sometimes showing multiple, roughly aligned lobes. In addition, many PPN flows
have been shown to have short acceleration times. In this paper we explore
whether jet or ``bullet'' (a massive clump) models fit the observations of
individual collimated lobes adequately by comparing simulations of both
radiatively cooled (stable) jets and bullets. We find that the clump model is
somewhat favored over jets because (1) it leads to greater collimation of
outflows (2) it accounts better and more naturally for ring-like structures
observed in the PPN CRL 618, and (3) it is more successful in reproducing the
Hubble-flow character of observed kinematics in some PPN. In addition, bullets
naturally account for observed multipolar flows, since the likely MHD launch
mechanisms required to drive outflows make multiple non-aligned jets unlikely.
Thus we argue that PPN outflows may be driven by explosive MHD launch
mechanisms such as those discussed in the context of supernovae (SNe) and
gamma-ray bursts(GRB).
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 15:08:59 GMT"
},
{
"version": "v2",
"created": "Thu, 12 Jul 2007 15:34:07 GMT"
},
{
"version": "v3",
"created": "Fri, 13 Jul 2007 15:24:31 GMT"
}
] | 2018-01-17T00:00:00 | [
[
"Dennis",
"Timothy J.",
""
],
[
"Cunningham",
"Andrew J.",
""
],
[
"Frank",
"Adam",
""
],
[
"Balick",
"Bruce",
""
],
[
"Blackman",
"Eric G.",
""
],
[
"Mitran",
"Sorin",
""
]
] |
0707.1642 | Olaf Kittel | Herbert K. Dreiner, Olaf Kittel, and Ulrich Langenfeld | Polarization aspects in radiative neutralino production | 4 pages, 2 figures, Proceedings for the LCWS/ILC 2007 workshop at
DESY, Hamburg, Germany | ECONF C0705302:SUS05-POL01,2007 | null | BONN-TH-2007-04 | hep-ph | null | We study the impact of beam polarization on radiative neutralino production
e+e- \to \chi^0_1 \chi^0_1 photon at the International Linear Collider. We show
that longitudinal polarized beams significantly enhance the signal and
simultaneously reduce the Standard Model background from radiative neutrino
production e+e- \to \nu \bar\nu photon. We point out that the radiative
production of neutralinos could be the only accessible SUSY particles, if
neutralinos, charginos, sleptons, as well as squarks and gluinos are too heavy
to be pair-produced in the first stage of the ILC at sqrt{s} = 500 GeV.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 15:03:22 GMT"
}
] | 2009-02-16T00:00:00 | [
[
"Dreiner",
"Herbert K.",
""
],
[
"Kittel",
"Olaf",
""
],
[
"Langenfeld",
"Ulrich",
""
]
] |
0707.1643 | Yukinobu Toda | Yukinobu Toda | Birational Calabi-Yau 3-folds and BPS state counting | Some explanations and proofs are added. To appear in Communications
in Number Theory and Physics | null | null | null | math.AG | null | This paper contains some applications of Bridgeland-Douglas stability
conditions on triangulated categories, and Joyce's work on counting invariants
of semistable objects, to the study of birational geometry. We introduce the
notion of motivic Gopakumar-Vafa invariants as counting invariants of
D2-branes, and show that they are invariant under birational transformations
between Calabi-Yau 3-folds. The result is similar to the fact that birational
Calabi-Yau 3-folds have the same betti numbers or Hodge numbers.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 15:11:18 GMT"
},
{
"version": "v2",
"created": "Thu, 12 Jul 2007 10:57:57 GMT"
},
{
"version": "v3",
"created": "Sun, 16 Mar 2008 15:36:54 GMT"
}
] | 2008-03-16T00:00:00 | [
[
"Toda",
"Yukinobu",
""
]
] |
0707.1644 | Dan Olteanu | Lyublena Antova, Thomas Jansen, Christoph Koch, Dan Olteanu | Fast and Simple Relational Processing of Uncertain Data | 12 pages, 14 figures | null | null | null | cs.DB cs.PF | null | This paper introduces U-relations, a succinct and purely relational
representation system for uncertain databases. U-relations support
attribute-level uncertainty using vertical partitioning. If we consider
positive relational algebra extended by an operation for computing possible
answers, a query on the logical level can be translated into, and evaluated as,
a single relational algebra query on the U-relation representation. The
translation scheme essentially preserves the size of the query in terms of
number of operations and, in particular, number of joins. Standard techniques
employed in off-the-shelf relational database management systems are effective
for optimizing and processing queries on U-relations. In our experiments we
show that query evaluation on U-relations scales to large amounts of data with
high degrees of uncertainty.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 15:13:39 GMT"
}
] | 2007-07-12T00:00:00 | [
[
"Antova",
"Lyublena",
""
],
[
"Jansen",
"Thomas",
""
],
[
"Koch",
"Christoph",
""
],
[
"Olteanu",
"Dan",
""
]
] |
0707.1645 | Fernando C. Lombardo | Paula I. Villar and Fernando C. Lombardo | Decoherence in a Two Slit Diffraction Experiment with Massive Particles | 6 pages, 3 figures | J.Phys.Conf.Ser.67:012041,2007 | 10.1088/1742-6596/67/1/012041 | null | quant-ph cond-mat.other hep-ph | null | Matter-wave interferometry has been largely studied in the last few years.
Usually, the main problem in the analysis of the diffraction experiments is to
establish the causes for the loss of coherence observed in the interference
pattern. In this work, we use different type of environmental couplings to
model a two slit diffraction experiment with massive particles. For each model,
we study the effects of decoherence on the interference pattern and define a
visibility function that measures the loss of contrast of the interference
fringes on a distant screen. Finally, we apply our results to the experimental
reported data on massive particles $C_{70}$.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 19:31:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Villar",
"Paula I.",
""
],
[
"Lombardo",
"Fernando C.",
""
]
] |
0707.1646 | Tam\'as Nepusz | Tam\'as Nepusz, Andrea Petr\'oczi, L\'aszl\'o N\'egyessy, F\"ul\"op
Bazs\'o | Fuzzy communities and the concept of bridgeness in complex networks | 13 pages, 9 figures. Quality of Fig. 4 reduced due to file size
considerations | Phys Rev E, 77:016107, 2008 | 10.1103/PhysRevE.77.016107 | null | physics.soc-ph | null | We consider the problem of fuzzy community detection in networks, which
complements and expands the concept of overlapping community structure. Our
approach allows each vertex of the graph to belong to multiple communities at
the same time, determined by exact numerical membership degrees, even in the
presence of uncertainty in the data being analyzed. We created an algorithm for
determining the optimal membership degrees with respect to a given goal
function. Based on the membership degrees, we introduce a new measure that is
able to identify outlier vertices that do not belong to any of the communities,
bridge vertices that belong significantly to more than one single community,
and regular vertices that fundamentally restrict their interactions within
their own community, while also being able to quantify the centrality of a
vertex with respect to its dominant community. The method can also be used for
prediction in case of uncertainty in the dataset analyzed. The number of
communities can be given in advance, or determined by the algorithm itself
using a fuzzified variant of the modularity function. The technique is able to
discover the fuzzy community structure of different real world networks
including, but not limited to social networks, scientific collaboration
networks and cortical networks with high confidence.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 15:34:00 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Jul 2007 17:39:39 GMT"
},
{
"version": "v3",
"created": "Wed, 28 Nov 2007 18:34:41 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Nepusz",
"Tamás",
""
],
[
"Petróczi",
"Andrea",
""
],
[
"Négyessy",
"László",
""
],
[
"Bazsó",
"Fülöp",
""
]
] |
0707.1647 | Ian G. Moss | Ian G Moss and Chris M Graham | Testing models of inflation with CMB non-gaussianity | 13 pages, 5 figures in ReVTeX | JCAP 0711:004,2007 | 10.1088/1475-7516/2007/11/004 | null | astro-ph | null | Two different predictions for the primordial curvature fluctuation bispectrum
are compared through their effects on the Cosmic Microwave Background
temperature fluctuations. The first has a local form described by a single
parameter f_{NL}. The second is based on a prediction from the warm
inflationary scenario, with a different dependence on wavenumber and a
parameter f_{WI}. New expressions are obtained for the angular bispectra of the
temperature fluctuations and for the estimators used to determine $f_{NL}$ and
f_{WI}. The standard deviation of the estimators in an ideal experiment is
roughly 5 times larger for f_{WI} than for f_{NL}. Using 3 year WMAP data gives
limits -375<f_{WI}<36.8, but there is a possibility of detecting a signal for
f_{WI} from the Planck satellite.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 15:25:51 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Moss",
"Ian G",
""
],
[
"Graham",
"Chris M",
""
]
] |
0707.1648 | Tetiana Berger Hryn'ova | The BABAR Collaboration, B. Aubert, et al | Evidence for the B0->ppbarK*0 and B+->eta_cK*+ decays and Study of the
Decay Dynamics of B Meson Decays into ppbarh Final States | 16 pages, 6 postscript figures, submitted to Phys Rev D | Phys.Rev.D76:092004,2007 | 10.1103/PhysRevD.76.092004 | BABAR-PUB-07/031, SLAC-PUB-12661 | hep-ex | null | With a sample of 232x10^6 Upsilon(4S)->BBbar events collected with the BaBar
detector, we study the decays of B mesons to ppbarh final states, where
h=pi+,Ks,K*0 or K*+. We report evidence for the B->ppbarK*0 decay, with a
branching fraction (1.5+/-0.5(stat)+/-0.4(syst))x10^-6, and for the
B+->eta_cK*+ decay, with the branching fraction of
Br(B+->eta_cK*+)xBr(eta_c->ppbar)=(1.57^{+0.56}_{-0.45}(stat)^{+0.46}_{-0.36}(syst))x10^-6,
and provide improved measurements of the branching fractions of the other modes
of this type. We also report the measurements of the charge asymmetry
consistent with zero in the B+->ppbarpi+, B0->ppbarK*0 and B+->ppbarK*+ modes.
No evidence is found for the pentaquark candidate Theta+ in the mass range 1.52
to 1.55 GeV/c^2, decaying into pKs, or the glueball candidate fJ(2220) in the
mass range 2.2<mppbar<2.4GeV/c^2, and branching fraction limits are established
for both at the 10^-7 level.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 19:27:28 GMT"
}
] | 2010-04-12T00:00:00 | [
[
"The BABAR Collaboration",
"",
""
],
[
"Aubert",
"B.",
""
]
] |
0707.1649 | Sadhan Adhikari K | Sadhan K. Adhikari and Luca Salasnich | One-dimensional superfluid Bose-Fermi mixture: mixing, demixing and
bright solitons | 11 pages, 11 figures | Phys. Rev. A 76 (2007) 023612 (p1-11) | 10.1103/PhysRevA.76.023612 | null | cond-mat.other nlin.PS | null | We study a ultra-cold and dilute superfluid Bose-Fermi mixture confined in a
strictly one-dimensional atomic waveguide by using a set of coupled nonlinear
mean-field equations obtained from the Lieb-Liniger energy density for bosons
and the Gaudin-Yang energy density for fermions. We consider a finite
Bose-Fermi inter-atomic strength g_{bf} and both periodic and open boundary
conditions. We find that with periodic boundary conditions, i.e. in a quasi-1D
ring, a uniform Bose-Fermi mixture is stable only with a large fermionic
density. We predict that at small fermionic densities the ground state of the
system displays demixing if g_{bf}>0 and may become a localized Bose-Fermi
bright soliton for g_{bf}<0. Finally, we show, using variational and numerical
solution of the mean-field equations, that with open boundary conditions, i.e.
in a quasi-1D cylinder, the Bose-Fermi bright soliton is the unique ground
state of the system with a finite number of particles, which could exhibit a
partial mixing-demixing transition. In this case the bright solitons are
demonstrated to be dynamically stable. The experimental realization of these
Bose-Fermi bright solitons seems possible with present setups.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 19:19:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Adhikari",
"Sadhan K.",
""
],
[
"Salasnich",
"Luca",
""
]
] |
0707.1650 | Romain Bachelard | Romain Bachelard, Duccio Fanelli | Short-time dynamics in presence of wave-particles interactions: a
perturbative approach | 12 pages, 6 figures | Communications in Nonlinear Science and Numerical Simulation 50,
40 (2010) | 10.1016/j.cnsns.2008.07.023 | null | math-ph math.MP | null | The self-consistent interaction between a beam of charged particles and a
wave is considered, within a Vlasov picture. The model is discussed with
reference to the case of a Free Electron Laser. Starting with a spatially
bunched waterbag distribution, we derive, via perturbative methods, closed
analytical expressions for the time evolution of the main macroscopic
observables. Predictions of the theory are shown to agree with direct numerical
simulations.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 16:08:08 GMT"
}
] | 2015-03-31T00:00:00 | [
[
"Bachelard",
"Romain",
""
],
[
"Fanelli",
"Duccio",
""
]
] |
0707.1651 | Christoph L\"udeling | W. Buchm\"uller, C. L\"udeling, J. Schmidt | Local SU(5) Unification from the Heterotic String | 38 pages. v2: Typos corrected | JHEP0709:113,2007 | 10.1088/1126-6708/2007/09/113 | DESY-07-072, HD-THEP-07-14 | hep-ph hep-th | null | We construct a 6D supergravity theory which emerges as intermediate step in
the compactification of the heterotic string to the supersymmetric standard
model in four dimensions. The theory has N=2 supersymmetry and a gravitational
sector with one tensor and two hypermultiplets in addition to the supergravity
multiplet. Compactification to four dimensions occurs on a T^2/Z_2 orbifold
which has two inequivalent pairs of fixed points with unbroken SU(5) and
SU(2)xSU(4) symmetry, respectively. All gauge, gravitational and mixed
anomalies are cancelled by the Green-Schwarz mechanism. The model has partial
6D gauge-Higgs unification. Two quark-lepton generations are localized at the
SU(5) branes, the third family is composed of split bulk hypermultiplets. The
top Yukawa coupling is given by the 6D gauge coupling, all other Yukawa
couplings are generated by higher-dimensional operators at the SU(5) branes.
The presence of the SU(2)xSU(4) brane breaks SU(5) and generates split gauge
and Higgs multiplets with N=1 supersymmetry in four dimensions. The third
generation is obtained from two split \bar{5}-plets and two split 10-plets,
which together have the quantum numbers of one \bar{5}-plet and one 10-plet.
This avoids unsuccessful SU(5) predictions for Yukawa couplings of ordinary 4D
SU(5) grand unified theories.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 16:15:38 GMT"
},
{
"version": "v2",
"created": "Fri, 16 Nov 2007 15:28:44 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Buchmüller",
"W.",
""
],
[
"Lüdeling",
"C.",
""
],
[
"Schmidt",
"J.",
""
]
] |
0707.1652 | Thomas Paul | S. Argiro, S.L.C. Barroso, J. Gonzalez, L. Nellen, T. Paul, T.A.
Porter, L. Prado Jr., M. Roth, R. Ulrich, D. Veberic | The Offline Software Framework of the Pierre Auger Observatory | 23 pages, 6 figures. Accepted for publication in NIMA | Nucl.Instrum.Meth.A580:1485-1496,2007 | 10.1016/j.nima.2007.07.010 | NUB-3260 | astro-ph | null | The Pierre Auger Observatory is designed to unveil the nature and the origins
of the highest energy cosmic rays. The large and geographically dispersed
collaboration of physicists and the wide-ranging collection of simulation and
reconstruction tasks pose some special challenges for the offline analysis
software. We have designed and implemented a general purpose framework which
allows collaborators to contribute algorithms and sequencing instructions to
build up the variety of applications they require. The framework includes
machinery to manage these user codes, to organize the abundance of
user-contributed configuration files, to facilitate multi-format file handling,
and to provide access to event and time-dependent detector information which
can reside in various data sources. A number of utilities are also provided,
including a novel geometry package which allows manipulation of abstract
geometrical objects independent of coordinate system choice. The framework is
implemented in C++, and takes advantage of object oriented design and common
open source tools, while keeping the user side simple enough for C++ novices to
learn in a reasonable time. The distribution system incorporates unit and
acceptance testing in order to support rapid development of both the core
framework and contributed user code.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 17:16:51 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Argiro",
"S.",
""
],
[
"Barroso",
"S. L. C.",
""
],
[
"Gonzalez",
"J.",
""
],
[
"Nellen",
"L.",
""
],
[
"Paul",
"T.",
""
],
[
"Porter",
"T. A.",
""
],
[
"Prado",
"L.",
"Jr."
],
[
"Roth",
"M.",
""
],
[
"Ulrich",
"R.",
""
],
[
"Veberic",
"D.",
""
]
] |
0707.1653 | Tania Monteiro Prof. | J. Reslen, C.E. Creffield, and T.S. Monteiro | Dynamical instability in kicked Bose-Einstein condensates: Bogoliubov
resonances | 8 pages | null | 10.1103/PhysRevA.77.043621 | null | quant-ph | null | Bose-Einstein condensates subject to short pulses (`kicks') from standing
waves of light represent a nonlinear analogue of the well-known chaos paradigm,
the quantum kicked rotor. Previous studies of the onset of dynamical
instability (ie exponential proliferation of non-condensate particles)
suggested that the transition to instability might be associated with a
transition to chaos. Here we conclude instead that instability is due to
resonant driving of Bogoliubov modes. We investigate the excitation of
Bogoliubov modes for both the quantum kicked rotor (QKR) and a variant, the
double kicked rotor (QKR-2). We present an analytical model, valid in the limit
of weak impulses which correctly gives the scaling properties of the resonances
and yields good agreement with mean-field numerics.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 16:00:38 GMT"
},
{
"version": "v2",
"created": "Thu, 2 Aug 2007 17:10:50 GMT"
},
{
"version": "v3",
"created": "Thu, 6 Dec 2007 17:28:59 GMT"
},
{
"version": "v4",
"created": "Fri, 7 Dec 2007 12:33:24 GMT"
},
{
"version": "v5",
"created": "Tue, 12 Feb 2008 15:33:08 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Reslen",
"J.",
""
],
[
"Creffield",
"C. E.",
""
],
[
"Monteiro",
"T. S.",
""
]
] |
0707.1654 | R. S. Mackintosh | R. S. Mackintosh (Open University) and N. Keeley (Saclay) | Strong pickup-channel coupling effects in proton scattering: the case of
p + Be-10 | 14 pages, 4 figures, RevTeX4, accepted by Phys Rev C | Phys.Rev.C81:034612,2010; Phys.Rev.C83:057601,2011 | 10.1103/PhysRevC.81.034612 10.1103/PhysRevC.83.057601 | null | nucl-th | null | The dynamic polarization potential (DPP) contribution to the effective
proton-nucleus interaction, that is due to the coupling of deuteron channels,
is evaluated by applying $S_{lj} \to V(r)$ inversion to the elastic channel
$S$-matrix from coupled reaction channel calculations of proton elastic
scattering. This was done for protons scattering from $^{10}$Be at 12, 13, 14,
15, and 16 MeV; non-orthogonality corrections were included. We find a
consistent pattern of a repulsive real and an absorptive imaginary DPP, with
the absorption shifted to a larger radius. This is consistent with what has
been found for proton scattering from the neutron skin nucleus $^8$He. The DPP
is not of a form that can be represented by a renormalization of the bare
potential, and has properties suggesting an underlying non-local process. We
conclude that deuteron channels cannot be omitted from a full theoretical
description of the proton-nucleus interaction (optical potential).
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 16:06:55 GMT"
}
] | 2011-06-21T00:00:00 | [
[
"Mackintosh",
"R. S.",
"",
"Open University"
],
[
"Keeley",
"N.",
"",
"Saclay"
]
] |
0707.1655 | Michael C. Ogilvie | Peter N. Meisinger and Michael C. Ogilvie | PT-symmetric Models with O(N) Symmetry | 8 pages, no figures | null | null | null | hep-th | null | We construct PT-symmetric quantum mechanical models with an O(N)-symmetric
interaction term of the form $-g(\vec{x}^{2})^{2}/N$. Using functional integral
methods, we find the equivalent Hermitian model, which has several unusual
features. The effective potential obtained in the large-N limit of the
Hermitian form is shown to be identical to the form obtained from the original
PT-symmetric model using familiar constraint field methods. The analogous
constraint field prescription in four dimensions suggests that
$-g(\vec{\phi}^{2})^{2}/N$ PT-symmetric scalar field theories are
asymptotically free.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 16:07:01 GMT"
}
] | 2007-07-12T00:00:00 | [
[
"Meisinger",
"Peter N.",
""
],
[
"Ogilvie",
"Michael C.",
""
]
] |
0707.1656 | Sami Amasha | S. Amasha, K. MacLean, Iuliana P. Radu, D. M. Zumbuhl, M. A. Kastner,
M. P. Hanson, A. C. Gossard | Electrical control of spin relaxation in a quantum dot | 4 pages, 3 figures | Phys. Rev. Lett. 100 046803 (2008) | 10.1103/PhysRevLett.100.046803 | null | cond-mat.mes-hall | null | We demonstrate electrical control of the spin relaxation time T_1 between
Zeeman split spin states of a single electron in a lateral quantum dot. We find
that relaxation is mediated by the spin-orbit interaction, and by manipulating
the orbital states of the dot using gate voltages we vary the relaxation rate
W= (T_1)^-1 by over an order of magnitude. The dependence of W on orbital
confinement agrees with theoretical predictions and from these data we extract
the spin-orbit length. We also measure the dependence of W on magnetic field
and demonstrate that spin-orbit mediated coupling to phonons is the dominant
relaxation mechanism down to 1T, where T_1 exceeds 1s.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 17:03:59 GMT"
}
] | 2010-09-28T00:00:00 | [
[
"Amasha",
"S.",
""
],
[
"MacLean",
"K.",
""
],
[
"Radu",
"Iuliana P.",
""
],
[
"Zumbuhl",
"D. M.",
""
],
[
"Kastner",
"M. A.",
""
],
[
"Hanson",
"M. P.",
""
],
[
"Gossard",
"A. C.",
""
]
] |
0707.1657 | Ratnakar Palai | R Palai, H Huhtinen, R.S. Katiyar and J.F. Scott | Observation of Spin-glass-like Behavior in SrRuO3 Epitaxial Thin Films | 5 pages, 5 Figures | Physical Review B, 79, 104413 (2009) | 10.1103/PhysRevB.79.104413 | null | cond-mat.mtrl-sci cond-mat.other | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We report the observation of spin-glass-like behavior and strong magnetic
anisotropy in extremely smooth (~1-3 \AA) roughness) epitaxial (110) and (010)
SrRuO3 thin films. The easy axis of magnetization is always perpendicular to
the plane of the film (unidirectional) irrespective of crystallographic
orientation. An attempt has been made to understand the nature and origin of
spin-glass behavior, which fits well with Heisenberg model.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 16:19:50 GMT"
},
{
"version": "v2",
"created": "Wed, 2 Sep 2009 16:30:25 GMT"
}
] | 2009-09-02T00:00:00 | [
[
"Palai",
"R",
""
],
[
"Huhtinen",
"H",
""
],
[
"Katiyar",
"R. S.",
""
],
[
"Scott",
"J. F.",
""
]
] |
0707.1658 | Gabriel A. Gonzalez-Sprinberg | G. A. Gonz\'alez-Sprinberg, J. Bernab\'eu and J. Vidal | $\tau$ electric dipole moment with polarized beams | 8 pages, 1 figure, contributed paper to Lepton Photon 2007 | null | null | null | hep-ph | null | High luminosity Super B/Flavor factories, near and on top of the $\Upsilon$
resonances, allow for a detailed investigation of CP-violation in $\tau$
physics. In particular, bounds on the $\tau$ electric dipole moment can be
obtained from CP-odd observables. We perform an independent analysis from other
low and high energy data. For polarized electron beam a CP-odd asymmetry,
associated to the normal polarization term, can be used to set stringent bounds
on the $\tau$ electric dipole moment.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 16:40:39 GMT"
}
] | 2007-07-12T00:00:00 | [
[
"González-Sprinberg",
"G. A.",
""
],
[
"Bernabéu",
"J.",
""
],
[
"Vidal",
"J.",
""
]
] |
0707.1659 | Sakuntala Chatterjee | Sakuntala Chatterjee and Mustansir Barma | Shock probes in a one-dimensional Katz-Lebowitz-Spohn model | Accepted in Physical Review E | Phys. Rev. E, vol. 77, 061124 (2008) | 10.1103/PhysRevE.77.061124 | null | cond-mat.stat-mech | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We consider shock probes in a one-dimensional driven diffusive medium with
nearest neighbor Ising interaction (KLS model). Earlier studies based on an
approximate mapping of the present system to an effective zero-range process
concluded that the exponents characterising the decays of several static and
dynamical correlation functions of the probes depend continuously on the
strength of the Ising interaction. On the contrary, our numerical simulations
indicate that over a substantial range of the interaction strength, these
exponents remain constant and their values are the same as in the case of no
interaction (when the medium executes an ASEP). We demonstrate this by
numerical studies of several dynamical correlation functions for two probes and
also for a macroscopic number of probes. Our results are consistent with the
expectation that the short-ranged correlations induced by the Ising interaction
should not affect the large time and large distance properties of the system,
implying that scaling forms remain the same as in the medium with no
interactions present.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 16:41:18 GMT"
},
{
"version": "v2",
"created": "Tue, 1 Jul 2008 13:56:29 GMT"
}
] | 2008-07-01T00:00:00 | [
[
"Chatterjee",
"Sakuntala",
""
],
[
"Barma",
"Mustansir",
""
]
] |
0707.1660 | Claudio Pita-Ruiz | Lenin A. Echavarria Cepeda, Claudio Pita Ruiz, Stephen B. Sontz | Accardi complementarity for -1/2 < mu < 0 and related results | 13 pages | null | null | null | math-ph math.MP | null | We show (an earlier conjecture of the last two authors) that the momentum and
position operators of mu-deformed quantum mechanics for -1/2 < mu < 0 are not
Accardi complementary. We also prove some related formulas that were
conjectured by the same authors.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 16:57:47 GMT"
},
{
"version": "v2",
"created": "Thu, 12 Jul 2007 15:12:38 GMT"
},
{
"version": "v3",
"created": "Tue, 24 Jul 2007 18:11:17 GMT"
},
{
"version": "v4",
"created": "Fri, 27 Jul 2007 17:59:49 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Cepeda",
"Lenin A. Echavarria",
""
],
[
"Ruiz",
"Claudio Pita",
""
],
[
"Sontz",
"Stephen B.",
""
]
] |
0707.1661 | Mauro M. Doria | Mauro M. Doria, Antonio R. de C. Romaguera, and S. Salem-Sugui Jr | Vanishing of the upper critical field in Bi_2Sr_2CaCu_2O_{8+\delta} from
Landau-Ott scaling | 3 figures | null | 10.1103/PhysRevB.76.052504 | null | cond-mat.supr-con | null | We apply Landau-Ott scaling to the reversible magnetization data of
Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ published by Y. Wang et al. [\emph{Phys.
Rev. Lett. \textbf{95} 247002 (2005)}] and find that the extrapolation of the
Landau-Ott upper critical field line vanishes at a critical temperature
parameter, T^*_c, a few degrees above the zero resistivity critical
temperature, T_c. Only isothermal curves below and near to T_c were used to
determine this transition temperature. This temperature is associated to the
disappearance of the mixed state instead of a complete suppression of
superconductivity in the sample.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 16:51:56 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Doria",
"Mauro M.",
""
],
[
"Romaguera",
"Antonio R. de C.",
""
],
[
"Salem-Sugui",
"S.",
"Jr"
]
] |
0707.1662 | J. D. Kurk | Jaron D. Kurk (MPIA Heidelberg), Fabian Walter, Xiaohui Fan, Linhua
Jiang, Dominik A. Riechers, Hans-Walter Rix, Laura Pentericci, Michael A.
Strauss, Chris Carilli, Stefan Wagner | Black hole masses and enrichment of z ~ 6 SDSS quasars | Accepted by ApJ, 15 pages, 8 figures | Astrophys.J.669:32-44,2007 | 10.1086/521596 | null | astro-ph | null | We present sensitive near-infrared spectroscopic observations for a sample of
five z ~ 6 quasars. These are amongst the most distant, currently known quasars
in the universe. The spectra have been obtained using ISAAC at the VLT and
include the CIV, MgII and FeII lines. We measure the FeII/MgII line ratio, as
an observational proxy for the Fe/alpha element ratio. We derive a ratio of
2.7+/-0.8 for our sample, which is similar to that found for lower redshift
quasars, i.e., we provide additional evidence for the lack of evolution in the
FeII/MgII line ratio of quasars up to the highest redshifts. This result
demonstrates that the sample quasars must have undergone a major episode of
iron enrichment in less than one Gyr and star formation must have commenced at
z > 8. The linewidths of the MgII and CIV lines give two estimates for the
black hole masses. A third estimate is given by assuming that the quasars emit
at their Eddington luminosity. The derived masses using these three methods
agree well, implying that the quasars are not likely to be strongly lensed. We
derive central black hole masses of 0.3-5.2 10^9 solar masses. We use the
difference between the redshift of MgII (a proxy for the systemic redshift of
the quasar) and the onset of the Gunn Peterson trough to derive the extent of
the ionized Stromgren spheres around our target quasars. The derived physical
radii are about five Mpc. Using a simple ionization model, the emission of the
central quasars would need of order 10^6-10^8 year to create these cavities in
a surrounding intergalactic medium with a neutral fraction between 0.1 and 1.0.
As the e-folding time scale for the central accreting black hole is on the
order of a few times 10^7 year, it can grow by one e-folding or less within
this time span.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 16:53:08 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Kurk",
"Jaron D.",
"",
"MPIA Heidelberg"
],
[
"Walter",
"Fabian",
""
],
[
"Fan",
"Xiaohui",
""
],
[
"Jiang",
"Linhua",
""
],
[
"Riechers",
"Dominik A.",
""
],
[
"Rix",
"Hans-Walter",
""
],
[
"Pentericci",
"Laura",
""
],
[
"Strauss",
"Michael A.",
""
],
[
"Carilli",
"Chris",
""
],
[
"Wagner",
"Stefan",
""
]
] |
0707.1663 | Linhua Jiang | Linhua Jiang, Xiaohui Fan, Marianne Vestergaard, Jaron D. Kurk, Fabian
Walter, Brandon C. Kelly, and Michael A. Strauss | Gemini Near-infrared Spectroscopy of Luminous z~6 Quasars: Chemical
Abundances, Black Hole Masses, and MgII Absorption | 33 pages (including 7 figures and 6 tables), AJ in press | Astron.J.134:1150-1161,2007 | 10.1086/520811 | null | astro-ph | null | We present Gemini near-infrared spectroscopic observations of six luminous
quasars at z=5.8$\sim$6.3. Five of them were observed using Gemini-South/GNIRS,
which provides a simultaneous wavelength coverage of 0.9--2.5 $\mu$m in cross
dispersion mode. The other source was observed in K band with
Gemini-North/NIRI. We calculate line strengths for all detected emission lines
and use their ratios to estimate gas metallicity in the broad-line regions of
the quasars. The metallicity is found to be supersolar with a typical value of
$\sim$4 Z_{\sun}, and a comparison with low-redshift observations shows no
strong evolution in metallicity up to z$\sim$6. The FeII/MgII ratio of the
quasars is 4.9+/-1.4, consistent with low-redshift measurements. We estimate
central BH masses of 10^9 to 10^{10} M_{\sun} and Eddington luminosity ratios
of order unity. We identify two MgII $\lambda\lambda$2796,2803 absorbers with
rest equivalent width W_0^{\lambda2796}>1 \AA at 2.2<z<3 and three MgII
absorbers with W_0^{\lambda2796}>1.5 \AA at z>3 in the spectra, with the two
most distant absorbers at z=4.8668 and 4.8823, respectively. The redshift
number densities (dN/dz) of MgII absorbers with W_0^{\lambda2796}>1.5 \AA are
consistent with no cosmic evolution up to z>4.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 16:59:52 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Jiang",
"Linhua",
""
],
[
"Fan",
"Xiaohui",
""
],
[
"Vestergaard",
"Marianne",
""
],
[
"Kurk",
"Jaron D.",
""
],
[
"Walter",
"Fabian",
""
],
[
"Kelly",
"Brandon C.",
""
],
[
"Strauss",
"Michael A.",
""
]
] |
0707.1664 | Alexei Litvinov | V. A. Fateev and A. V. Litvinov | Multipoint correlation functions in Liouville field theory and minimal
Liouville gravity | Contribution to the proceedings of the International Workshop on
Classical and Quantum Integrable Systems, Dubna, Russia, January 22-25, 2007,
18 pages | Theor.Math.Phys.154:454-472,2008 | 10.1007/s11232-008-0038-3 | null | hep-th | null | We study n+3-point correlation functions of exponential fields in Liouville
field theory with n degenerate and 3 arbitrary fields. An analytical expression
for these correlation functions is derived in terms of Coulomb integrals. The
application of these results to the minimal Liouville gravity is considered.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 17:29:32 GMT"
},
{
"version": "v2",
"created": "Thu, 13 Sep 2007 15:34:45 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Fateev",
"V. A.",
""
],
[
"Litvinov",
"A. V.",
""
]
] |
0707.1665 | Kunihiko Yamauchi | Kunihiko Yamauchi, Biplab Sanyal and Silvia Picozzi | Interface effects at a half-metal/ferroelectric junction | 4 pages, 3figures, accepted for publication in Appl. Phys. Lett | null | 10.1063/1.2767776 | null | cond-mat.mtrl-sci | null | Magnetoelectric effects are investigated ab-initio at the interface between
half-metallic and ferroelectric prototypes: Heusler Co$_2$MnSi and perovskite
BaTiO$_3$. For the Co-termination ferroelectricity develops in BaTiO$_3$ down
to nanometer thicknesses, whereas for the MnSi-termination a paraelectric and a
ferroelectric state energetically compete, calling for a full experimental
control over the junction atomic configuration whenever a ferroelectric barrier
is needed. Switch of the electric polarization largely affects magnetism in
Co$_2$MnSi, with magnetoelectric coupling due to electronic hybridization at
the MnSi termination and to structural effects at the Co-termination.
Half-metallicity is lost at the interface, but recovered already in the
subsurface layer.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 17:08:31 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yamauchi",
"Kunihiko",
""
],
[
"Sanyal",
"Biplab",
""
],
[
"Picozzi",
"Silvia",
""
]
] |
0707.1666 | Cheol-Hwan Park | Cheol-Hwan Park, Feliciano Giustino, Marvin L. Cohen, and Steven G.
Louie | Velocity Renormalization and Carrier Lifetime in Graphene from
Electron-Phonon Interaction | 4 pages, 4 figures; reference 22 added, numerical error corrected | Phys. Rev. Lett. 99, 086804 (2007) | 10.1103/PhysRevLett.99.086804 | null | cond-mat.mtrl-sci | null | We present a first-principles investigation of the phonon-induced electron
self-energy in graphene. The energy dependence of the self-energy reflects the
peculiar linear bandstructure of graphene and deviates substantially from the
usual metallic behavior. The effective band velocity of the Dirac fermions is
found to be reduced by 4-8%, depending on doping, by the interaction with
lattice vibrations. Our results are consistent with the observed linear
dependence of the electronic linewidth on the binding energy in photoemission
spectra.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 17:12:49 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Jul 2007 23:48:29 GMT"
}
] | 2007-08-23T00:00:00 | [
[
"Park",
"Cheol-Hwan",
""
],
[
"Giustino",
"Feliciano",
""
],
[
"Cohen",
"Marvin L.",
""
],
[
"Louie",
"Steven G.",
""
]
] |
0707.1667 | Sergiu Vacaru I. | Sergiu I. Vacaru | Deformation Quantization of Nonholonomic Almost Kahler Models and
Einstein Gravity | latex 2e, 11pt, 15 pages, v4 accepted by Phys. Lett. A | Phys.Lett.A372:2949-2955,2008 | 10.1016/j.physleta.2008.01.044 | null | gr-qc hep-th math-ph math.MP math.SG | null | Nonholonomic distributions and adapted fame structures on (pseudo) Riemannian
manifolds of even dimension are employed to build structures equivalent to
almost Kahler geometry and which allows to perform a Fedosov-like quantization
of gravity. The nonlinear connection formalism that was formally elaborated for
Lagrange and Finsler geometry is implemented in classical and quantum Einstein
gravity.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 17:13:20 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Jul 2007 17:45:11 GMT"
},
{
"version": "v3",
"created": "Thu, 19 Jul 2007 20:23:25 GMT"
},
{
"version": "v4",
"created": "Thu, 10 Jan 2008 20:58:07 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Vacaru",
"Sergiu I.",
""
]
] |
0707.1668 | Adrian Vasiu | Adrian Vasiu | Good reductions of Shimura varieties of Hodge type in arbitrary
unramified mixed characteristic. Part I | 87 pages. Final version, to appear in Mathematische Nachrichten (most
alignment issues kept loose to match with the layout of the journal) | Mathematische Nachrichten Volume 293, Issue12, December 2020,
Pages 2399-2448 | 10.1002/mana.201700415 | null | math.NT math.AG | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We prove the existence of good smooth integral models of Shimura varieties of
Hodge type in arbitrary unramified mixed characteristic $(0,p)$. As a first
application we provide a smooth solution (answer) to a conjecture (question) of
Langlands for Shimura varieties of Hodge type. As a second application we prove
the existence in arbitrary unramified mixed characteristic $(0,p)$ of integral
canonical models of projective Shimura varieties of Hodge type with respect to
h--hyperspecial subgroups as pro-\'etale covers of N\'eron models; this forms
progress towards the proof of conjectures of Milne and Reimann. Though the
second application was known before in some cases, its proof is new and more of
a principle.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 17:21:37 GMT"
},
{
"version": "v2",
"created": "Tue, 24 Jul 2012 17:04:17 GMT"
},
{
"version": "v3",
"created": "Thu, 8 Sep 2016 07:36:54 GMT"
},
{
"version": "v4",
"created": "Fri, 21 Aug 2020 12:25:11 GMT"
}
] | 2023-04-27T00:00:00 | [
[
"Vasiu",
"Adrian",
""
]
] |
0707.1669 | Andrew Neitzke | Murat Gunaydin, Andrew Neitzke, Oleksandr Pavlyk and Boris Pioline | Quasi-conformal actions, quaternionic discrete series and twistors:
SU(2,1) and G_2(2) | 83 pages; v4: Directors' cut edition: misprints corrected, improved
figures, improved notations for quaternionic vielbein | null | 10.1007/s00220-008-0563-9 | LPTENS-07-25 | hep-th math.RT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Quasi-conformal actions were introduced in the physics literature as a
generalization of the familiar fractional linear action on the upper half
plane, to Hermitian symmetric tube domains based on arbitrary Jordan algebras,
and further to arbitrary Freudenthal triple systems. In the mathematics
literature, quaternionic discrete series unitary representations of real
reductive groups in their quaternionic real form were constructed as degree 1
cohomology on the twistor spaces of symmetric quaternionic-Kahler spaces. These
two constructions are essentially identical, as we show explicitly for the two
rank 2 cases SU(2,1) and G_{2(2)}. We obtain explicit results for certain
principal series, quaternionic discrete series and minimal representations of
these groups, including formulas for the lowest K-types in various
polarizations. We expect our results to have applications to topological
strings, black hole micro-state counting and to the theory of automorphic
forms.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 17:32:09 GMT"
},
{
"version": "v2",
"created": "Sun, 22 Jul 2007 08:17:50 GMT"
},
{
"version": "v3",
"created": "Sat, 23 Aug 2008 22:28:08 GMT"
},
{
"version": "v4",
"created": "Thu, 19 Feb 2009 13:23:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Gunaydin",
"Murat",
""
],
[
"Neitzke",
"Andrew",
""
],
[
"Pavlyk",
"Oleksandr",
""
],
[
"Pioline",
"Boris",
""
]
] |
0707.1670 | William Detmold | Silas R. Beane, William Detmold, Martin J. Savage | n-Boson Energies at Finite Volume and Three-Boson Interactions | null | Phys.Rev.D76:074507,2007 | 10.1103/PhysRevD.76.074507 | NT@UW-07-11, UNH-07-02 | hep-lat hep-ph nucl-th | null | We calculate the volume dependence of the ground-state energy of n identical
bosons with short-range repulsive interactions in a periodic spatial volume of
side L, up to and including terms of order 1/L^6. With this result, Lattice QCD
calculations of the ground-state energies of three or more pions will allow for
a systematic extraction of the three-pion interaction at this order in the
volume expansion.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 17:33:10 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Beane",
"Silas R.",
""
],
[
"Detmold",
"William",
""
],
[
"Savage",
"Martin J.",
""
]
] |
0707.1671 | Sergey Kozyrev | S.M.Kozyrev | Comment about the "Gravity coupled to a scalar field in extra
dimensions" paper | null | null | null | null | gr-qc | null | Wehus and Ravndal have argued that in d + 1 dimensions the general solution
for gravity minimally coupled to a scalar field can not be explicitly written
in Schwarzschild coordinates. We contest these objections.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 17:42:15 GMT"
}
] | 2007-07-12T00:00:00 | [
[
"Kozyrev",
"S. M.",
""
]
] |
0707.1672 | Jesus Gomez-Gardenes | J. Gomez-Gardenes, V. Latora, Y. Moreno and E.V. Profumo | Spreading of sexually transmitted diseases in heterosexual populations | 7 pages, 3 figures and 2 tables | Proceedings of the National Academy of Sciences (USA) 105, 1399
(2008) | 10.1073/pnas.0707332105 | null | physics.soc-ph physics.bio-ph q-bio.OT | null | The spread of sexually transmitted diseases (e.g. Chlamydia, Syphilis,
Gonorrhea, HIV) across populations is a major concern for scientists and health
agencies. In this context, both data collection on sexual contact networks and
the modeling of disease spreading, are intensively contributing to the search
for effective immunization policies. Here, the spreading of sexually
transmitted diseases on bipartite scale-free graphs, representing heterosexual
contact networks, is considered. We analytically derive the expression for the
epidemic threshold and its dependence with the system size in finite
populations. We show that the epidemic outbreak in bipartite populations, with
number of sexual partners distributed as in empirical observations from
national sex surveys, takes place for larger spreading rates than for the case
in which the bipartite nature of the network is not taken into account.
Numerical simulations confirm the validity of the theoretical results. Our
findings indicate that the restriction to crossed infections between the two
classes of individuals (males and females) has to be taken into account in the
design of efficient immunization strategies for sexually transmitted diseases.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 18:03:02 GMT"
},
{
"version": "v2",
"created": "Thu, 7 Feb 2008 14:56:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Gomez-Gardenes",
"J.",
""
],
[
"Latora",
"V.",
""
],
[
"Moreno",
"Y.",
""
],
[
"Profumo",
"E. V.",
""
]
] |
0707.1673 | Vito Latora | Arturo Buscarino, Luigi Fortuna, Mattia Frasca, Vito Latora | Disease spreading in populations of moving agents | 4 pages, 4 figures | null | 10.1209/0295-5075/82/38002 | null | physics.soc-ph physics.bio-ph | null | We study the effect of motion on disease spreading in a system of random
walkers which additionally perform long-distance jumps. A small percentage of
jumps in the agent motion is sufficient to destroy the local correlations and
to produce a large drop in the epidemic threshold, well explained in terms of a
mean-field approximation. This effect is similar to the crossover found in
static small-world networks, and can be furthermore linked to the structural
properties of the dynamical network of agent interactions.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 18:07:03 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Buscarino",
"Arturo",
""
],
[
"Fortuna",
"Luigi",
""
],
[
"Frasca",
"Mattia",
""
],
[
"Latora",
"Vito",
""
]
] |
0707.1674 | James Sparks | Dario Martelli, James Sparks | Resolutions of non-regular Ricci-flat Kahler cones | 41 pages, 1 figure, v2: cosmetic changes to some equations | J.Geom.Phys.59:1175-1195,2009 | 10.1016/j.geomphys.2009.06.005 | null | math.DG hep-th | null | We present explicit constructions of complete Ricci-flat Kahler metrics that
are asymptotic to cones over non-regular Sasaki-Einstein manifolds. The metrics
are constructed from a complete Kahler-Einstein manifold (V,g_V) of positive
Ricci curvature and admit a Hamiltonian two-form of order two. We obtain
Ricci-flat Kahler metrics on the total spaces of (i) holomorphic C^2/Z_p
orbifold fibrations over V, (ii) holomorphic orbifold fibrations over weighted
projective spaces WCP^1, with generic fibres being the canonical complex cone
over V, and (iii) the canonical orbifold line bundle over a family of Fano
orbifolds. As special cases, we also obtain smooth complete Ricci-flat Kahler
metrics on the total spaces of (a) rank two holomorphic vector bundles over V,
and (b) the canonical line bundle over a family of geometrically ruled Fano
manifolds with base V. When V=CP^1 our results give Ricci-flat Kahler orbifold
metrics on various toric partial resolutions of the cone over the
Sasaki-Einstein manifolds Y^{p,q}.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 18:09:22 GMT"
},
{
"version": "v2",
"created": "Fri, 12 Oct 2007 13:40:52 GMT"
}
] | 2009-07-22T00:00:00 | [
[
"Martelli",
"Dario",
""
],
[
"Sparks",
"James",
""
]
] |
0707.1675 | L. V. Bogdanov | L.V. Bogdanov, V.S. Dryuma, S.V. Manakov | Dunajski generalization of the second heavenly equation: dressing method
and the hierarchy | 13 pages | Journal of Physics A, 40 (2007) 14383-14393 | 10.1088/1751-8113/40/48/005 | null | nlin.SI | null | Dunajski generalization of the second heavenly equation is studied. A
dressing scheme applicable to Dunajski equation is developed, an example of
constructing solutions in terms of implicit functions is considered. Dunajski
equation hierarchy is described, its Lax-Sato form is presented. Dunajsky
equation hierarchy is characterized by conservation of three-dimensional volume
form, in which a spectral variable is taken into account.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 18:13:06 GMT"
}
] | 2010-11-03T00:00:00 | [
[
"Bogdanov",
"L. V.",
""
],
[
"Dryuma",
"V. S.",
""
],
[
"Manakov",
"S. V.",
""
]
] |
0707.1676 | Erik Tonni | Sergio Benvenuti, Erik Tonni | Near-flat space limit and Einstein manifolds | 30 pages, 1 figure | JHEP 0802:022,2008 | 10.1088/1126-6708/2008/02/022 | null | hep-th | null | We study the near-flat space limit for strings on AdS(5)xM(5), where the
internal manifold M(5) is equipped with a generic metric with U(1)xU(1)xU(1)
isometry. In the bosonic sector, the limiting sigma model is similar to the one
found for AdS(5)xS(5), as the global symmetries are reduced in the most general
case. When M(5) is a Sasaki-Einstein space like T(1,1), Y(p,q) and L(p,q,r),
whose dual CFT's have N=1 supersymmetry, the near-flat space limit gives the
same bosonic sector of the sigma model found for AdS(5)xS(5). This indicates
the generic presence of integrable subsectors in AdS/CFT.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 18:13:55 GMT"
}
] | 2009-04-30T00:00:00 | [
[
"Benvenuti",
"Sergio",
""
],
[
"Tonni",
"Erik",
""
]
] |
0707.1677 | Paulo A. Faria da Veiga | Paulo A. Faria da Veiga and Michael O'Carroll | Dynamical Eightfold Way in Strongly Coupled Lattice QCD | 6 pages | null | null | null | hep-lat hep-th nucl-th | null | We obtain from the quark-gluon dynamics, the Gell'Mann-Ne'eman eightfold way
baryons in an imaginary-time functional integral formulation of 3+1 lattice QCD
in the strong coupling regime (small hopping parameter $\kappa>0$). The model
has ${\rm SU}(3)_c$ gauge and global ${\rm SU}(3)_f$ flavor symmetries. In the
subspace of the physical Hilbert space of vectors with an odd number of quarks,
the baryons are associated with isolated dispersion curves in the
energy-momentum spectrum. The spin 1/2 octet and spin 3/2 decuplet baryons have
asymptotic mass $-3\ln\kappa$ and for each baryon there is an antibaryon with
identical spectral properties. All the masses have the form
$M=-3\ln\kappa-3\kappa^3/4+\kappa^6 r(\kappa)$, with $r(\kappa)$ real analytic.
For each member of the octet $r(\kappa)$ is the same; for each member of the
decuplet, $r(0)$ is the same. So, there is no mass splitting within the octet,
and within the decuplet up to and including ${\cal O}(\kappa^6)$. However,
there is an octet-decuplet mass difference of $3\kappa^6/4+{\cal O}(\kappa^7)$.
The baryon and antibaryon spectrum is the only one up to near the meson-baryon
threshold of nearly $-5\ln\kappa$. A decoupling of hyperplane method is used to
naturally unveil the form of the baryon composite fields (no a priori
guesswork), to show the existence of particles and their multiplicities using a
spectral representation for the two-baryon correlation. We also obtain the
(anti-)baryon dispersion curves which admit the representation $w(\kappa,\vec
p)= -3\ln\kappa -3\kappa^3/4+\kappa^3\sum_{j=1,2,3} (1-\cos ^j)/4+r(\kappa,\vec
p)$, where $r(\kappa,\vec p)$ is of ${\cal O}(\kappa^6)$.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 18:23:47 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"da Veiga",
"Paulo A. Faria",
""
],
[
"O'Carroll",
"Michael",
""
]
] |
0707.1678 | A. Perez-Lorenzana | Abdel P\'erez-Lorenzana, Merced Montesinos and Tonatiuh Matos | Unification of cosmological scalar fields | Title slightly changed to match published version. Typos corrected
and references added. Five pages, no figures | Phys.Rev.D77:063507,2008 | 10.1103/PhysRevD.77.063507 | null | astro-ph gr-qc hep-ph hep-th | null | We present a model where early inflation and late accelerating expansion of
the Universe are driven by the real and imaginary parts of a single complex
scalar field, which we identified as inflaton and phantom field, respectively.
This inflaton-phantom unification is protected by an internal SO(1,1) symmetry,
with the two cosmological scalars appearing as the degrees of freedom of a sole
fundamental representation. The unification symmetry allows to build successful
potentials. We observe that our theory provides a matter-phantom duality, which
transforms scalar matter cosmological solutions into phantom solutions and vice
versa. We also suggest that a complete unification of all scalar fields of
cosmological interest is yet possible under a similar footing.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 18:29:09 GMT"
},
{
"version": "v2",
"created": "Wed, 12 Mar 2008 16:43:35 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Pérez-Lorenzana",
"Abdel",
""
],
[
"Montesinos",
"Merced",
""
],
[
"Matos",
"Tonatiuh",
""
]
] |
0707.1679 | Michael Tannenbaum | M. J. Tannenbaum (for the PHENIX Collaboration) | Measurements of Hard-Scattering by PHENIX at RHIC | 6 pages, 12 figures, Proceedings of Hadron Collider Physics Symposium
2007, La Biodola, Isola d'Elba (Italy), May 20-26, 2007 | Nucl.Phys.Proc.Suppl.177-178:150-155,2008 | 10.1016/j.nuclphysbps.2007.11.101 | null | nucl-ex | null | Hard-scattering in p-p collisions was discovered in 1972 at the CERN-ISR, the
first hadron collider. Techniques were developed and several hard-processes
were discovered which form the basis for many of the measurements made in p-p
and Au+Au collisions at RHIC. Recent measurements of hard-scattering and
related reactions by the PHENIX experiment at RHIC are presented in this
context.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 18:36:14 GMT"
}
] | 2019-08-13T00:00:00 | [
[
"Tannenbaum",
"M. J.",
"",
"for the PHENIX Collaboration"
]
] |
0707.1680 | Nic Cade | T. Ritman-Meer, N. I. Cade, D. Richards | Spatial imaging of modifications to fluorescence lifetime and intensity
by individual Ag nanoparticles | 3 pages, 2 figures, submitted Applied Physics Letters | null | 10.1063/1.2789700 | null | cond-mat.other cond-mat.mtrl-sci | null | Highly ordered periodic arrays of silver nanoparticles have been fabricated
which exhibit surface plasmon resonances in the visible spectrum. We
demonstrate the ability of these structures to alter the fluorescence
properties of vicinal dye molecules by providing an additional radiative decay
channel. Using fluorescence lifetime imaging microscopy (FLIM), we have created
high resolution spatial maps of the molecular lifetime components; these show
an order of magnitude increase in decay rate from a localized volume around the
nanoparticles, resulting in a commensurate enhancement in the fluorescence
emission intensity.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 19:19:08 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ritman-Meer",
"T.",
""
],
[
"Cade",
"N. I.",
""
],
[
"Richards",
"D.",
""
]
] |
0707.1681 | Luca Dall'Asta | Luca Dall'Asta, Claudio Castellano, Matteo Marsili | Statistical physics of the Schelling model of segregation | 4 pages, 3 figures | null | 10.1088/1742-5468/2008/07/L07002 | null | physics.soc-ph | null | We investigate the static and dynamic properties of a celebrated model of
social segregation, providing a complete explanation of the mechanisms leading
to segregation both in one- and two-dimensional systems. Standard statistical
physics methods shed light on the rich phenomenology of this simple model,
exhibiting static phase transitions typical of kinetic constrained models,
nontrivial coarsening like in driven-particle systems and percolation-related
phenomena.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 18:43:44 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Dall'Asta",
"Luca",
""
],
[
"Castellano",
"Claudio",
""
],
[
"Marsili",
"Matteo",
""
]
] |
0707.1682 | Jacob Ruff | J.P.C. Ruff, B.D. Gaulin, J.P. Castellan, K.C. Rule, J.P. Clancy, J.
Rodriguez, and H.A. Dabkowska | Structural Fluctuations in the Spin Liquid State of Tb2Ti2O7 | 5 pages, 4 figures, submitted for publication | null | 10.1103/PhysRevLett.99.237202 | null | cond-mat.dis-nn cond-mat.stat-mech | null | High resolution X-ray scattering measurements on single crystal Tb2Ti2O7
reveal finite structural correlations at low temperatures. This geometrically
frustrated pyrochlore is known to exhibit a spin liquid, or cooperative
paramagnetic state, at temperatures below ~ 20 K. Parametric studies of
structural Bragg peaks appropriate to the Fd$\bar{3}$m space group of Tb2Ti2O7
reveal substantial broadening and peak intensity reduction in the temperature
regime 20 K to 300 mK. We also observe a small, anomalous lattice expansion on
cooling below a density maximum at ~ 18 K. These measurements are consistent
with the development of fluctuations above a cooperative Jahn-Teller,
cubic-tetragonal phase transition at very low temperatures.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 18:51:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Ruff",
"J. P. C.",
""
],
[
"Gaulin",
"B. D.",
""
],
[
"Castellan",
"J. P.",
""
],
[
"Rule",
"K. C.",
""
],
[
"Clancy",
"J. P.",
""
],
[
"Rodriguez",
"J.",
""
],
[
"Dabkowska",
"H. A.",
""
]
] |
0707.1683 | Francois Demontoux | Fran\c{c}ois Demontoux (LPIOM), Jean-Louis Miane (LPIOM) | Travaux pratiques sur les r\'eseaux locaux de type WIFI utilisant des
simulations num\'eriques des ph\'enom\`enes de propagation des ondes
\'electromagn\'etiques | null | J3EA Volume 5 (2006) hors s\'erie no. 2 | null | null | physics.ed-ph | null | The wireless network technology WiFi finds more and more applications in the
industrial field as for the exchange of information between the people or the
equipment. It has the advantage of allowing a great flexibility of the network
but requires precautions of installation to be effective (flow,
reliability...). The fitter of such a network must have knowledge to install
and configure the materials (access points, wifi interface) but also of
knowledge in propagation of electromagnetic waves which is the support of the
transmission of data. The teaching of this technology requires practical works
which must make it possible for the student to implement this knowledge. This
article presents the various means of calculations which we implemented within
the framework of practical works to allow the student to visualize and thus to
better control the phenomena of propagation existing in a WiFI network.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 19:05:00 GMT"
}
] | 2007-07-12T00:00:00 | [
[
"Demontoux",
"François",
"",
"LPIOM"
],
[
"Miane",
"Jean-Louis",
"",
"LPIOM"
]
] |
0707.1684 | M. Rosenau da Costa | M. Rosenau da Costa, I.A. Shelykh, and N.T. Bagraev | Fractional quantization of ballistic conductance in 1D hole systems | 4 pages, 3 figures | null | 10.1103/PhysRevB.76.201302 | null | cond-mat.mes-hall | null | We analyze the fractional quantization of the ballistic conductance
associated with the light and heavy holes bands in Si, Ge and GaAs systems. It
is shown that the formation of the localized hole state in the region of the
quantum point contact connecting two quasi-1D hole leads modifies drastically
the conductance pattern. Exchange interaction between localized and propagating
holes results in the fractional quantization of the ballistic conductance
different from those in electronic systems. The value of the conductance at the
additional plateaux depends on the offset between the bands of the light and
heavy holes, \Delta, and the sign of the exchange interaction constant. For
\Delta=0 and ferromagnetic exchange interaction, we observe additional plateaux
around the values 7e^{2}/4h, 3e^{2}/h and 15e^{2}/4h, while antiferromagnetic
interaction plateaux are formed around e^{2}/4h, e^{2}/h and 9e^{2}/4h. For
large \Delta, the single plateau is formed at e^2/h.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 19:22:23 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"da Costa",
"M. Rosenau",
""
],
[
"Shelykh",
"I. A.",
""
],
[
"Bagraev",
"N. T.",
""
]
] |
0707.1685 | Juan C. Gallardo | A. Hershcovitch, W. Weng, M. Diwan, J. Gallardo, H. Kirk, B. Johnson,
S. Kahn, E. Garate, A. Van Drie | Plasma Lens for Us Based Super Neutrino Beam at Either FNAL or BNL | 4 pages, 4 figures submitted to Particle Accelerators Conference 2007
(PAC07) | Conf.Proc.C070625:3184,2007 | null | null | physics.acc-ph | null | The plasma lens concept is examined as an alternative to focusing horns and
solenoids for a neutrino beam facility. The concept is based on a combined
high-current lens/target configuration. Current is fed at an electrode located
downstream from the beginning of the target where pion capturing is needed. The
current is carried by plasma outside the target. A second plasma lens section,
with an additional current feed, follows the target. The plasma is immersed in
a relatively small solenoidal magnetic field to facilitate its current profile
shaping to optimize pion capture. Simulations of the not yet fully optimized
configuration yielded a 25% higher neutrino flux at a detector situated at 3 km
from the target than the horn system for the entire energy spectrum and a
factor of 2.5 higher flux for neutrinos with energy larger than 3 GeV. A major
advantage of plasma lenses is in background reduction. In antineutrino
operation, neutrino background is reduced by a factor of close to 3 for the
whole spectrum, and for energy larger than 3 GeV, neutrino background is
reduced by a factor of 3.6. Plasma lenses have additional advantages: larger
axial currents, high signal purity: minimal neutrino background in antineutrino
runs. The lens medium consists of plasma, consequently, particle absorption and
scattering is negligible. Withstanding high mechanical and thermal stresses in
a plasma is not an issue.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 19:13:56 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Hershcovitch",
"A.",
""
],
[
"Weng",
"W.",
""
],
[
"Diwan",
"M.",
""
],
[
"Gallardo",
"J.",
""
],
[
"Kirk",
"H.",
""
],
[
"Johnson",
"B.",
""
],
[
"Kahn",
"S.",
""
],
[
"Garate",
"E.",
""
],
[
"Van Drie",
"A.",
""
]
] |
0707.1686 | Raymond Ashoori | O.E. Dial, R.C. Ashoori, L.N. Pfeiffer, K.W. West | High Resolution Spectroscopy of Two-Dimensional Electron Systems | There are formatting and minor textual differences between this
version and the published version in Nature (follow the DOI link below) | Nature 448, 176-179 (2007) | 10.1038/nature05982 | null | cond-mat.mes-hall cond-mat.str-el | null | Spectroscopic methods involving the sudden injection or ejection of electrons
in materials are a powerful probe of electronic structure and interactions.
These techniques, such as photoemission and tunneling, yield measurements of
the "single particle" density of states (SPDOS) spectrum of a system. The SPDOS
is proportional to the probability of successfully injecting or ejecting an
electron in these experiments. It is equal to the number of electronic states
in the system able to accept an injected electron as a function of its energy
and is among the most fundamental and directly calculable quantities in
theories of highly interacting systems. However, the two-dimensional electron
system (2DES), host to remarkable correlated electron states such as the
fractional quantum Hall effect, has proven difficult to probe
spectroscopically. Here we present an improved version of time domain
capacitance spectroscopy (TDCS) that now allows us to measure the SPDOS of a
2DES with unprecedented fidelity and resolution. Using TDCS, we perform
measurements of a cold 2DES, providing the first direct measurements of the
single-particle exchange-enhanced spin gap and single particle lifetimes in the
quantum Hall system, as well as the first observations of exchange splitting of
Landau levels not at the Fermi surface. The measurements reveal the difficult
to reach and beautiful structure present in this highly correlated system far
from the Fermi surface.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 19:14:41 GMT"
}
] | 2007-07-12T00:00:00 | [
[
"Dial",
"O. E.",
""
],
[
"Ashoori",
"R. C.",
""
],
[
"Pfeiffer",
"L. N.",
""
],
[
"West",
"K. W.",
""
]
] |
0707.1687 | Fernando Delgado Acosta | F. Delgado, Y.-P. Shim, M. Korkusinski, and P. Hawrylak | Theory of spin, electronic and transport properties of the lateral
triple quantum dot molecule in a magnetic field | 30 pages (one column), 9 figures | Phys. Rev. B 76, 115332 (2007) | 10.1103/PhysRevB.76.115332 | null | cond-mat.str-el cond-mat.other | null | We present a theory of spin, electronic and transport properties of a
few-electron lateral triangular triple quantum dot molecule in a magnetic
field. Our theory is based on a generalization of a Hubbard model and the
Linear Combination of Harmonic Orbitals combined with Configuration Interaction
method (LCHO-CI) for arbitrary magnetic fields. The few-particle spectra
obtained as a function of the magnetic field exhibit Aharonov-Bohm
oscillations. As a result, by changing the magnetic field it is possible to
engineer the degeneracies of single-particle levels, and thus control the total
spin of the many-electron system. For the triple dot with two and four
electrons we find oscillations of total spin due to the singlet-triplet
transitions occurring periodically in the magnetic field. In the three-electron
system we find a transition from a magnetically frustrated to the
spin-polarized state. We discuss the impact of these phase transitions on the
addition spectrum and the spin blockade of the lateral triple quantum dot
molecule.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 19:16:01 GMT"
}
] | 2010-03-11T00:00:00 | [
[
"Delgado",
"F.",
""
],
[
"Shim",
"Y. -P.",
""
],
[
"Korkusinski",
"M.",
""
],
[
"Hawrylak",
"P.",
""
]
] |
0707.1688 | V. J. Goldman | F. E. Camino, Wei Zhou, and V. J. Goldman | Quantum transport in electron Fabry-Perot interferometers | null | Phys. Rev. B 76 155305 (2007) | 10.1103/PhysRevB.76.155305 | null | cond-mat.mes-hall | null | We report experiments on Fabry-Perot electron interferometers in the integer
quantum Hall regime. The GaAs/AlGaAs heterostructure devices consist of two
constrictions defined by etch trenches in 2D electron layer, enclosing an
approximately circular island. The interferometer is formed by
counterpropagating chiral edge channels coupled by tunneling in the two
constrictions. Interference fringes are observed as conductance oscillations,
similar to the Aharonov-Bohm effect. Front gates deposited in etch trenches
allow to fine-tune the device and to change the constriction filling f relative
to the bulk filling. Quantum-coherent conductance oscillations are observed on
the f = 1 - 4 plateaus. On plateau f we observe f conductance oscillations per
fundamental flux period h/e. This is attributed to the dominance of the
electron-electron Coulomb interaction, effectively mixing Landau level
occupation. On the other hand, the back-gate charge period is the same (one
electron) on all plateaus, independent of filling. This is attributed to the
self-consistent electrostatics in the large electron island. We also report
dependence of the oscillation period on front-gate voltage for f = 1, 2 and 4
for three devices. We find a linear dependence, with the slope inversely
proportional to f for f = 1 and 2.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 20:15:46 GMT"
}
] | 2007-10-08T00:00:00 | [
[
"Camino",
"F. E.",
""
],
[
"Zhou",
"Wei",
""
],
[
"Goldman",
"V. J.",
""
]
] |
0707.1689 | Khangulyan Dmitry | Dmitry Khangulyan, Felix Aharonian, Valenti Bosch-Ramon | On the formation of TeV radiation in LS 5039 | 14 pages, 26 figures, accepted for publication in MNRAS, submitted on
July 11, 2007 | null | 10.1111/j.1365-2966.2007.12572.x | null | astro-ph | null | The recent detections of TeV gamma-rays from compact binary systems show that
relativistic outflows (jets or winds) are sites of effective acceleration of
particles up to multi-TeV energies. In this paper, we discuss the conditions of
acceleration and radiation of ultra-relativistic electrons in LS 5039, the
gamma-ray emitting binary system for which the highest quality TeV data are
available. Assuming that the gamma-ray emitter is a jet-like structure, we
performed detailed numerical calculations of the energy spectrum and
lightcurves accounting for the acceleration efficiency, the location of the
accelerator, the speed of the emitting flow, the inclination angle of the
system, as well as specific features related to anisotropic inverse Compton
scattering and pair production. We conclude that the accelerator should not be
deep inside the binary system unless we assume a very efficient acceleration
rate. We show that within the IC scenario both the gamma-ray spectrum and flux
are strongly orbital phase dependent. Formally, our model can reproduce, for
specific sets of parameter values, the energy spectrum of gamma-rays reported
by HESS for wide orbital phase intervals. However, the physical properties of
the source can be constrained only by observations capable of providing
detailed energy spectra for narrow orbital phase intervals ($\Delta\phi\ll
0.1$).
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 20:10:16 GMT"
},
{
"version": "v2",
"created": "Wed, 10 Oct 2007 20:11:29 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Khangulyan",
"Dmitry",
""
],
[
"Aharonian",
"Felix",
""
],
[
"Bosch-Ramon",
"Valenti",
""
]
] |
0707.1690 | Jounghun Lee | Jounghun Lee (Seoul Natl U.), Ue-Li Pen (CITA) | The Nonlinear Evolution of Galaxy Intrinsic Alignments | ApJ in press, revised version, mistakes and typos corrected,
discussion improved, 29 pages, 11 figures | Astrophys.J. 681 (2008) 798-806 | 10.1086/588646 | null | astro-ph | null | The non-Gaussian contribution to the intrinsic halo spin alignments is
analytically modeled and numerically detected. Assuming that the growth of
non-Gaussianity in the density fluctuations caused the tidal field to have
nonlinear-order effect on the orientations of the halo angular momentum, we
model the intrinsic halo spin alignments as a linear scaling of the density
correlations on large scales, which is different from the previous
quadratic-scaling model based on the linear tidal torque theory. Then, we
analyze the halo catalogs from the recent high-resolution Millennium Run
simulation at four different redshifts (z=0,0.5,1 and 2) and measure
quantitatively the degree of the nonlinear effect on the halo spin alignments
and its changes with redshifts. A clear signal of spin correlations is found on
scales as large as 10 Mpc/h at z=0, which marks a detection of the nonlinear
tidal effect on the intrinsic halo alignments. We also investigate how the
nonlinear effect depends on the intrinsic properties of the halos. It is found
that the degree of the nonlinear tidal effect increases as the halo mass scale
decreases, the halo specific angular momentum increases, and the halo peculiar
velocity decreases. We discuss implication of our result on the weak
gravitational lensing.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 20:08:18 GMT"
},
{
"version": "v2",
"created": "Sat, 29 Mar 2008 12:40:18 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Lee",
"Jounghun",
"",
"Seoul Natl U."
],
[
"Pen",
"Ue-Li",
"",
"CITA"
]
] |
0707.1691 | Annarita Margiotta | G. Giacomelli and A. Margiotta (Dipartimento di Fisica
dell'Universita' di Bologna and INFN, Bologna, Italy) | The MACRO Experiment at Gran Sasso | Talk given for Charles Peck - Fest, Caltech, 2005 | null | null | null | hep-ex | null | In this overview of the MACRO experiment we recall the structure of the
detector and discuss several physics topics: atmospheric neutrinos and neutrino
oscillations, high energy neutrino astronomy, searches for WIMPs and for low
energy stellar gravitational collapse neutrinos, stringent upper limits on GUT
magnetic monopoles, high energy downgoing muons, primary cosmic ray composition
and shadowing of primary cosmic rays by the Moon and the Sun.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 20:05:12 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Giacomelli",
"G.",
"",
"Dipartimento di Fisica\n dell'Universita' di Bologna and INFN, Bologna, Italy"
],
[
"Margiotta",
"A.",
"",
"Dipartimento di Fisica\n dell'Universita' di Bologna and INFN, Bologna, Italy"
]
] |
0707.1692 | Charles Kane | Liang Fu and C.L. Kane | Superconducting proximity effect and Majorana fermions at the surface of
a topological insulator | 4 pages, 3 figures, published version | Phys. Rev. Lett. 100, 096407 (2008) | 10.1103/PhysRevLett.100.096407 | null | cond-mat.mes-hall cond-mat.str-el | null | We study the proximity effect between an s-wave superconductor and the
surface states of a strong topological insulator. The resulting two dimensional
state resembles a spinless p_x+ip_y superconductor, but does not break time
reversal symmetry. This state supports Majorana bound states at vortices. We
show that linear junctions between superconductors mediated by the topological
insulator form a non chiral 1 dimensional wire for Majorana fermions, and that
circuits formed from these junctions provide a method for creating,
manipulating and fusing Majorana bound states.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 20:00:07 GMT"
},
{
"version": "v2",
"created": "Mon, 16 Jul 2007 16:46:31 GMT"
},
{
"version": "v3",
"created": "Mon, 28 Apr 2008 19:01:53 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Fu",
"Liang",
""
],
[
"Kane",
"C. L.",
""
]
] |
0707.1693 | Christoph Pfrommer | Christoph Pfrommer (CITA) | Simulating cosmic rays in clusters of galaxies - III. Non-thermal
scaling relations and comparison to observations | 15 pages, 4 figures, to be published by MNRAS, added concept of
minimum gamma-ray emission from clusters in the hadronic model and improved
discussion on hard X-ray emission, full resolution version available at
http://www.cita.utoronto.ca/~pfrommer/Publications/CRs_scaling.pdf | null | 10.1111/j.1365-2966.2008.12957.x | null | astro-ph | null | Complementary views of galaxy clusters in the radio synchrotron, hard X-ray
inverse Compton, and high-energy gamma-ray regimes are critical in calibrating
them as high-precision cosmological probes. We present predictions for scaling
relations between cluster mass and these non-thermal observables. To this end,
we use high-resolution simulations of a sample of galaxy clusters spanning a
mass range of almost two orders of magnitudes, and follow self-consistent
cosmic ray physics on top of the radiative hydrodynamics. Calibrating the
magnetic fields of our model with Faraday rotation measurements (RM), the
synchrotron emission of our relativistic electron populations matches the radio
synchrotron luminosities and morphologies of observed giant radio halos and
mini-halos surprisingly well. Using the complete sample of the brightest X-ray
clusters observed by ROSAT in combination with our gamma-ray scaling relation,
we predict GLAST will detect about ten clusters allowing for Eddington bias due
to the scatter in the scaling relation. The brightest gamma-ray clusters are
Ophiuchus, Fornax, Coma, A3627, Perseus, and Centaurus. We provide an absolute
lower flux limit for the gamma-ray emission of Coma in the hadronic model which
can be made tighter for magnetic field values derived from RM values to match
the GLAST sensitivity, providing thus a unique test for the possible hadronic
origin of radio halos. Our predicted hard X-ray emission, due to inverse
Compton emission of shock accelerated and hadronically produced relativistic
electrons, falls short of the detections in Coma and Perseus by a factor of 50.
This casts doubts on the inverse Compton interpretation and reinforces the
known discrepancy of magnetic field estimates from Faraday RM values and those
obtained by combining synchrotron and inverse Compton emission. [abridged]
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 21:41:10 GMT"
},
{
"version": "v2",
"created": "Wed, 6 Feb 2008 17:36:37 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pfrommer",
"Christoph",
"",
"CITA"
]
] |
0707.1694 | Frank Tackmann | Zoltan Ligeti and Frank J. Tackmann | Precise predictions for B -> Xs l+ l- in the large q^2 region | 7 pages, 4 figures, v2: corrected Eq. (6), journal version | Phys.Lett.B653:404-410,2007 | 10.1016/j.physletb.2007.07.070 | null | hep-ph | null | The inclusive B -> Xs l+ l- decay rate in the large q^2 region (q^2 >
m_{\psi'}^2) receives significant nonperturbative corrections. The resulting
uncertainties can be drastically reduced by normalizing the rate to the B -> Xu
l nu rate with the same q^2 cut, which allows for much improved tests of short
distance physics. We calculate this ratio, including the order 1/m_b^3
nonperturbative corrections and the analytically known NNLO perturbative
corrections. Since in the large q^2 region an inclusive measurement may be
feasible via a sum over exclusive states, our results could be useful for
measurements at LHCb and possibly for studies of B -> Xd l+ l-.
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 19:49:43 GMT"
},
{
"version": "v2",
"created": "Wed, 5 Sep 2007 20:56:14 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Ligeti",
"Zoltan",
""
],
[
"Tackmann",
"Frank J.",
""
]
] |
0707.1695 | Russell J. Smith | Russell J. Smith (Durham), John R. Lucey (Durham), Michael J. Hudson
(Waterloo) | A deep AAOmega survey of low-luminosity galaxies in the Shapley
Supercluster: Stellar population trends | 20 pages, 11 figures. MNRAS accepted | 2007, MNRAS, 381, 1035 | 10.1111/j.1365-2966.2007.12226.x | null | astro-ph | null | We present new optical spectroscopy for 342 R<18 galaxies in the Shapley
Supercluster obtained with the AAOmega facility at the Anglo-Australian
Telescope. We describe the observations and measurements of central velocity
dispersion, emission line equivalent widths and absorption line indices. The
distinguishing characteristic of the survey is its coverage of a very wide
baseline in velocity dispersion (30-300 km/s), while achieving high
signal-to-noise ratio throughout (median 60 per Ang). Significant emission at
H-alpha was detected in ~20 per cent of red-sequence Shapley members. Using
line-ratio diagnostics, we find that the emission is LINER-like at high
luminosity, but driven by star-formation in low-luminosity galaxies. We use
Lick indices to characterise the absorption spectra. We define a subset of
galaxies with very low emission contamination, and fit the index-sigma
relations for this subset. Comparing the index-sigma slopes against predictions
from single-burst stellar population models, we infer the scaling relations of
age, total metallicity, [Z/H], and alpha-element abundance ratio, [a/Fe]. To
reproduce the observed index-sigma slopes, all three parameters must increase
with increasing velocity dispersion. Specifically, we recover: Age \propto
sigma^0.52+/-0.10, Z/H \propto sigma^0.34+/-0.07, and a/Fe \propto
sigma^0.23+/-0.06 (error reflects systematic effects), derived over a decade
baseline in velocity dispersion. The recovered age-sigma relation is shown to
be consistent with the observed evolution in the giant-to-dwarf galaxy ratio in
clusters at redshifts z=0.4-0.8. A companion paper will analyse the
distribution of age, [Z/H] and [a/Fe] for individual galaxies. (Abridged.)
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 10:03:25 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Smith",
"Russell J.",
"",
"Durham"
],
[
"Lucey",
"John R.",
"",
"Durham"
],
[
"Hudson",
"Michael J.",
"",
"Waterloo"
]
] |
0707.1696 | Martin Rocek | Ulf Lindstrom, Martin Rocek, Itai Ryb, Rikard von Unge, Maxim Zabzine | T-duality and Generalized Kahler Geometry | 14 pages; published version: some conventions improved, minor
clarifications | JHEP 0802:056,2008 | 10.1088/1126-6708/2008/02/056 | UUITP-12/07,Nordita-2007-22,YITP-SB-07-22 | hep-th | null | We use newly discovered N = (2, 2) vector multiplets to clarify T-dualities
for generalized Kahler geometries. Following the usual procedure, we gauge
isometries of nonlinear sigma-models and introduce Lagrange multipliers that
constrain the field-strengths of the gauge fields to vanish. Integrating out
the Lagrange multipliers leads to the original action, whereas integrating out
the vector multiplets gives the dual action. The description is given both in N
= (2, 2) and N = (1, 1) superspace.
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 01:09:30 GMT"
},
{
"version": "v2",
"created": "Wed, 30 Jan 2008 14:26:09 GMT"
}
] | 2009-04-30T00:00:00 | [
[
"Lindstrom",
"Ulf",
""
],
[
"Rocek",
"Martin",
""
],
[
"Ryb",
"Itai",
""
],
[
"von Unge",
"Rikard",
""
],
[
"Zabzine",
"Maxim",
""
]
] |
0707.1697 | Willie Merrell II | Willie Merrell and Diana Vaman | T-duality, quotients and generalized Kahler geometry | 18 pages | Phys.Lett.B665:401-408,2008 | 10.1016/j.physletb.2008.06.031 | null | hep-th | null | In this paper we reopen the discussion of gauging the two-dimensional
off-shell (2,2) supersymmetric sigma models written in terms of semichiral
superfields. The associated target space geometry of this particular sigma
model is generalized Kahler (or bi-hermitean with two non-commuting complex
structures). The gauging of the isometries of the sigma model is now done by
coupling the semichiral superfields to the new (2,2) semichiral vector
multiplet. We show that the two moment maps together with a third function form
the complete set of three Killing potentials which are associated with this
gauging. We show that the Killing potentials lead to the generalized moment
maps defined in the context of twisted generalized Kahler geometry. Next we
address the question of the T-duality map, while keeping the (2,2)
supersymmetry manifest. Using the new vector superfield in constructing the
duality functional, under T-duality we swap a pair of left and right semichiral
superfields by a pair of chiral and twisted chiral multiplets. We end with a
discussion on quotient construction.
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 19:38:05 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Merrell",
"Willie",
""
],
[
"Vaman",
"Diana",
""
]
] |
0707.1698 | Laura Parker | Laura C. Parker (1,2), Henk Hoekstra (3), Michael J. Hudson (2),
Ludovic Van Waerbeke (4), Yannick Mellier (5) ((1) ESO, Garching (2)
University of Waterloo (3) University of Victoria (4) University of British
Columbia (5) Institut d'Astrophysique de Paris) | The Masses and Shapes of Dark Matter Halos from Galaxy-Galaxy Lensing in
the CFHTLS | 12 pages, 11 figures, accepted to ApJ, uses emulateapj | null | 10.1086/521541 | null | astro-ph | null | We present the first galaxy-galaxy weak lensing results using early data from
the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). These results are
based on ~22 sq. deg. of i' data. From this data, we estimate the average
velocity dispersion for an L* galaxy at a redshift of 0.3 to be 137 +- 11 km/s,
with a virial mass, M_{200}, of 1.1 +- 0.2 \times 10^{12} h^{-1} Msun and a
rest frame R-band mass-to-light ratio of 173 +- 34 h Msun/Lsun. We also
investigate various possible sources of systematic error in detail.
Additionally, we separate our lens sample into two sub-samples, divided by
apparent magnitude, thus average redshift. From this early data we do not
detect significant evolution in galaxy dark matter halo mass-to-light ratios
from a redshift of 0.45 to 0.27. Finally, we test for non-spherical galaxy dark
matter halos. Our results favor a dark matter halo with an ellipticity of ~0.3
at the 2-sigma level when averaged over all galaxies. If the sample of
foreground lens galaxies is selected to favor ellipticals, the mean halo
ellipticity and significance of this result increase.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 20:04:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Parker",
"Laura C.",
""
],
[
"Hoekstra",
"Henk",
""
],
[
"Hudson",
"Michael J.",
""
],
[
"Van Waerbeke",
"Ludovic",
""
],
[
"Mellier",
"Yannick",
""
]
] |
0707.1699 | Joel N. Bregman | Joel N. Bregman and Edward J. Lloyd-Davies (University of Michigan,
and University of Sussex) | X-Ray Absorption from the Milky Way Halo and the Local Group | 32 pages (14 figures); ApJ, in press | null | 10.1086/521321 | null | astro-ph | null | Million degree gas is present at near-zero redshift and is due either to a
gaseous Galactic Halo or a more diffuse but very massive Local Group medium. We
can discriminate between these models because the column densities should
depend on location in the sky, either relative to the Galaxy bulge or to the
M31-Milky Way axis. To search for these signatures, we measured the OVII Kalpha
absorption line strength toward 25 bright AGNs, plus LMC X-3, using XMM-Newton
RGS archival data. The data are in conflict with a purely Local Group model,
but support the Galactic Halo model. The strongest correlation is between the
OVII equivalent widths and the ROSAT background emission measurement in the R45
band (0.4-1 keV), for which OVII emission makes the largest single
contribution. This suggests that much of the OVII emission and absorption are
cospatial, from which the radius of a uniform halo appears to lie the range
15-110 kpc. The present data do not constrain the type of halo gas model and an
equally good fit is obtained in a model where the gas density decreases as a
power-law, such as r^(-3/2). For a uniform halo with a radius of 20 kpc, the
electron density would be 9E-4 cm^(-3), and the gas mass is 4E8 Msolar. The
redshift of the four highest S/N OVII measurements is consistent with a Milky
Way origin rather than a Local Group origin.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 20:14:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bregman",
"Joel N.",
"",
"University of Michigan,\n and University of Sussex"
],
[
"Lloyd-Davies",
"Edward J.",
"",
"University of Michigan,\n and University of Sussex"
]
] |
0707.1700 | Stephan Frank | S. Frank (The Ohio State University), S. Mathur (The Ohio State
University), M. Pieri (The Ohio State University) and D. G. York (University
of Chicago) | A Survey of Metal Lines at High-redshift (I) : SDSS Absorption Line
Studies - The Methodology and First Search Results for OVI | 41 pages, 10 figures, 2 tables, accepted by AJ. This is a
substantially altered version, including an appendix with details on the
validity of the search algorithm on one pixel rather than binning. Also note
that M. Pieri was added as author | null | null | null | astro-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We report the results of a systematic search for signatures of metal lines in
quasar spectra of the Sloan Digital Sky Survey (SDSS) Data Release 3(DR3),
focusing on finding intervening absorbers via detection of their OVI doublet.
Here we present the search algorithm, and criteria for distinguishing
candidates from spurious Lyman $\alpha${} forest lines. In addition, we compare
our findings with simulations of the Lyman $\alpha${} forest in order to
estimate the detectability of OVI doublets over various redshift intervals. We
have obtained a sample of 1756 OVI doublet candidates with rest-frame
equivalent width > 0.05 \AA{} in 855 AGN spectra (out of 3702 objects with
redshifts in the accessible range for OVI detection). This sample is further
subdivided into 3 groups according to the likelihood of being real and the
potential for follow-up observation of the candidate. The group with the
cleanest and most secure candidates is comprised of 145 candidates. 69 of these
reside at a velocity separation > 5000 km/s from the QSO, and can therefore be
classified tentatively as intervening absorbers. Most of these absorbers have
not been picked up by earlier, automated QSO absorption line detection
algorithms. This sample increases the number of known OVI absorbers at
redshifts beyond z$_{abs} > 2.7 substantially.
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 03:32:10 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Jul 2007 16:31:13 GMT"
},
{
"version": "v3",
"created": "Thu, 10 Jun 2010 10:24:30 GMT"
}
] | 2010-06-11T00:00:00 | [
[
"Frank",
"S.",
"",
"The Ohio State University"
],
[
"Mathur",
"S.",
"",
"The Ohio State\n University"
],
[
"Pieri",
"M.",
"",
"The Ohio State University"
],
[
"York",
"D. G.",
"",
"University\n of Chicago"
]
] |
0707.1701 | Lucas Labadie | L. Labadie (MPIA/Laog), P. Kern (LAOG), P. Labeye (CEA Leti), E. Le
Coarer (LAOG), C. Vigreux-Bercovici (LPMC), A. Pradel (LPMC), J.-E. Broquin
(IMEP), V. Kirschner (ESA/Estec) | Technology challenges for space interferometry: the option of
mid-infrared integrated optics | Accepted in Adv. in Space Research | Adv.Space Res.41:1975-1982,2008 | 10.1016/j.asr.2007.07.013 | null | astro-ph | null | Nulling interferometry is a technique providing high angular resolution which
is the core of the space missions Darwin and the Terrestrail Planet Finder. The
first objective is to reach a deep degree of starlight cancelation in the range
6 -- 20 microns, in order to observe and to characterize the signal from an
Earth-like planet. Among the numerous technological challenges involved in
these missions, the question of the beam combination and wavefront filtering
has an important place. A single-mode integrated optics (IO) beam combiner
could support both the functions of filtering and the interferometric
combination, simplifying the instrumental design. Such a perspective has been
explored in this work within the project Integrated Optics for Darwin (IODA),
which aims at developing a first IO combiner in the mid-infrared. The solutions
reviewed here to manufacture the combiner are based on infrared dielectric
materials on one side, and on metallic conductive waveguides on the other side.
With this work, additional inputs are offered to pursue the investigation on
mid-infrared photonics devices.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 20:53:12 GMT"
}
] | 2009-06-23T00:00:00 | [
[
"Labadie",
"L.",
"",
"MPIA/Laog"
],
[
"Kern",
"P.",
"",
"LAOG"
],
[
"Labeye",
"P.",
"",
"CEA Leti"
],
[
"Coarer",
"E. Le",
"",
"LAOG"
],
[
"Vigreux-Bercovici",
"C.",
"",
"LPMC"
],
[
"Pradel",
"A.",
"",
"LPMC"
],
[
"Broquin",
"J. -E.",
"",
"IMEP"
],
[
"Kirschner",
"V.",
"",
"ESA/Estec"
]
] |
0707.1702 | Greg L. Bryan | Maria J. Pereira, Greg L. Bryan and Stuart P. D. Gill (Columbia) | Radial Alignment in Simulated Clusters | v2: 13 pages, 10 figures, ApJ in press. Revisions include a new
section (4.2) comparing our results with observations, and a few added
references | 2008ApJ...672..825P | 10.1086/523830 | null | astro-ph | null | Observational evidence for the radial alignment of satellites with their dark
matter host has been accumulating steadily in the past few years. The effect is
seen over a wide range of scales, from massive clusters of galaxies down to
galaxy-sized systems, yet the underlying physical mechanism has still not been
established. To this end, we have carried out a detailed analysis of the shapes
and orientations of dark matter substructures in high-resolution N-body
cosmological simulations. We find a strong tendency for radial alignment of the
substructure with its host halo: the distribution of halo major axes is very
anisotropic, with the majority pointing towards the center of mass of the host.
The alignment peaks once the sub-halo has passed the virial radius of the host
for the first time, but is not subsequently diluted, even after the halos have
gone through as many as four pericentric passages. This evidence points to the
existence of a very rapid dynamical mechanism acting on these systems and we
argue that tidal torquing throughout their orbits is the most likely candidate.
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 16:53:49 GMT"
},
{
"version": "v2",
"created": "Wed, 23 Jan 2008 20:52:34 GMT"
}
] | 2008-01-23T00:00:00 | [
[
"Pereira",
"Maria J.",
"",
"Columbia"
],
[
"Bryan",
"Greg L.",
"",
"Columbia"
],
[
"Gill",
"Stuart P. D.",
"",
"Columbia"
]
] |
0707.1703 | P. W. H. Pinkse | T. Rieger, P. Windpassinger, S.A. Rangwala, G. Rempe, P.W.H. Pinkse | Trapping of Neutral Rubidium with a Macroscopic Three-Phase Electric
Trap | 4 pages, 4 figures | Phys. Rev. Lett. 99, 063001 (2007) | 10.1103/PhysRevLett.99.063001 | null | physics.atom-ph | null | We trap neutral ground-state rubidium atoms in a macroscopic trap based on
purely electric fields. For this, three electrostatic field configurations are
alternated in a periodic manner. The rubidium is precooled in a magneto-optical
trap, transferred into a magnetic trap and then translated into the electric
trap. The electric trap consists of six rod-shaped electrodes in cubic
arrangement, giving ample optical access. Up to 10^5 atoms have been trapped
with an initial temperature of around 20 microkelvin in the three-phase
electric trap. The observations are in good agreement with detailed numerical
simulations.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 20:38:46 GMT"
}
] | 2011-11-10T00:00:00 | [
[
"Rieger",
"T.",
""
],
[
"Windpassinger",
"P.",
""
],
[
"Rangwala",
"S. A.",
""
],
[
"Rempe",
"G.",
""
],
[
"Pinkse",
"P. W. H.",
""
]
] |
0707.1704 | Vasily Vakorin | Vitaly A. Bulatov | Non-spectral methods of analysis of the internal gravity waves
measurements in ocean | 31 pages, 15 figures | null | null | null | physics.ao-ph physics.flu-dyn | null | The paper is devoted to the presentation of the non-spectral methods of
analysis of the natural measurements of the internal gravity waves in the ocean
with the purpose to determine characteristics of the wave-trains composing the
measured field, the forms and parameters of the ocean along the pass of these
wave-trains propagation. The problem of the analysis of the data of the natural
measurements of the internal waves with the purpose to separate the single
wave-trains from the measured field, and on this basis to determine the
characteristics of these wave-trains, to receive the information on the sources
of excitation of the waves, and the information on the properties of the ocean
along the pass of the waves propagation, is directly connected with the
problems of the wave dynamics. The basis of the offered algorithms of the
analysis is the supposition, that the measured wave field represents the sum of
the plane wave-trains having the certain speed and directions of propagation.
Transformation of the packages of the internal waves, which can be determined
by the given methods, may testify about the passage of the wave-trains through
the big-size oceanic formations, that makes it possible to remotely determine
the characteristics of these formations.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 20:39:56 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Bulatov",
"Vitaly A.",
""
]
] |
0707.1705 | Young-Wook Lee | Young-Wook Lee, Hansung B. Gim, and Chul Chung | Globular clusters with the extended horizontal-branch as remaining cores
of galaxy building blocks | Invited paper presented at the conference "New Quests in Stellar
Astrophysics II: Ultraviolet Properties of Evolved Stellar Populations", M.
Chavez, E. Bertone, D. Rosa-Gonzalez, & L. H. Rodriguez-Merino eds | null | null | null | astro-ph | null | The relics of building blocks that made stellar halo and bulge are yet to be
discovered unless they were completely disrupted throughout the history of the
Galaxy. Here we suggest that about 25% of the Milky Way globular clusters have
characteristics of the remaining cores of these early building blocks rather
than genuine star clusters. They are clearly distinct from other normal
globular clusters in the presence of extended horizontal-branch and multiple
stellar populations, in mass (brightness), and most importantly in orbital
kinematics. Based on this result, a three-stage formation picture of the Milky
Way is suggested, which includes early mergers, collapse, and later accretion.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 20:56:00 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Lee",
"Young-Wook",
""
],
[
"Gim",
"Hansung B.",
""
],
[
"Chung",
"Chul",
""
]
] |
0707.1706 | Michael Tannenbaum | M. J. Tannenbaum | Hard-scattering and Jets from RHIC to LHC: a critical review | 23 pages, 20 figures, Proceedings of High-pT physics at LHC,
Department of Physics, University of Jyvaskyla, Finland, March 23-27, 2007.
After referee report made minor changes to text, added new Fig. 2, enlarged
Fig. 10 | PoS LHC07:004,2007 | null | null | nucl-ex | null | Jets in hadron collisions are very complicated with a long learning curve
replete with errors. In relativistic heavy ion (RHI) collisions, it is likely
that jets will be much more complicated with an even longer and more difficult
learning curve. Hard scattering is more easily observed via single particle and
few particle correlation measurements. The main advantage of jets is higher
rate at large $p_T$, plus the possibility of detailed studies of soft
fragmentation if the soft fragments can be separated from the background. A
critical review of the possibility of using jets as a probe of hard-scattering
in RHI collisions is presented along with other probes and measurements which
the author considers much more likely to reveal the interesting physics in
Pb+Pb collisions at the LHC. Finally, a list of unanswered questions raised by
results at RHIC is presented.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 19:47:28 GMT"
},
{
"version": "v2",
"created": "Fri, 24 Aug 2007 15:05:09 GMT"
}
] | 2009-11-05T00:00:00 | [
[
"Tannenbaum",
"M. J.",
""
]
] |
0707.1707 | Christoph Pfrommer | Christoph Pfrommer (CITA), Torsten A. Ensslin (MPA), Volker Springel
(MPA) | Simulating cosmic rays in clusters of galaxies - II. A unified scheme
for radio halos and relics with predictions of the gamma-ray emission | 32 pages, 19 figures, small changes to match the version to be
published by MNRAS, full resolution version available at
http://www.cita.utoronto.ca/~pfrommer/Publications/CRs_non-thermal.pdf | null | 10.1111/j.1365-2966.2008.12956.x | null | astro-ph | null | The thermal plasma of galaxy clusters lost most of its information on how
structure formation proceeded as a result of dissipative processes. In
contrast, non-equilibrium distributions of cosmic rays (CR) preserve the
information about their injection and transport processes and provide thus a
unique window of current and past structure formation processes. This
information can be unveiled by observations of non-thermal radiative processes,
including radio synchrotron, hard X-ray, and gamma-ray emission. To explore
this, we use high-resolution simulations of a sample of galaxy clusters
spanning a mass range of about two orders of magnitudes, and follow
self-consistent CR physics on top of the radiative hydrodynamics. We model CR
electrons that are accelerated at cosmological structure formation shocks and
those that are produced in hadronic interactions of CRs with ambient gas
protons. We find that CR protons trace the time integrated non-equilibrium
activities of clusters while shock-accelerated CR electrons probe current
accretion and merging shock waves. The resulting inhomogeneous synchrotron
emission matches the properties of observed radio relics. We propose a unified
model for the generation of radio halos. Giant radio halos are dominated in the
centre by secondary synchrotron emission with a transition to the synchrotron
radiation emitted from shock-accelerated electrons in the cluster periphery.
This model is able to explain the observed correlation of mergers with radio
halos, the larger peripheral variation of the spectral index, and the large
scatter in the scaling relation between cluster mass and synchrotron emission.
Future low-frequency radio telescopes (LOFAR, GMRT, MWA, LWA) are expected to
probe the accretion shocks of clusters. [abridged]
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 14:06:10 GMT"
},
{
"version": "v2",
"created": "Wed, 6 Feb 2008 16:12:47 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pfrommer",
"Christoph",
"",
"CITA"
],
[
"Ensslin",
"Torsten A.",
"",
"MPA"
],
[
"Springel",
"Volker",
"",
"MPA"
]
] |
0707.1708 | A. Raghuram | A. Raghuram and Freydoon Shahidi | On certain period relations for cusp forms on GL_n | 40 pages. This preprint is also up on preprint server of the Erwin
Schrodinger Institute as preprint number 1928. The URL is
http://www.esi.ac.at/Preprint-shadows/esi1928.html | null | null | null | math.NT math.RT | null | Let $\pi$ be a regular algebraic cuspidal automorphic representation of ${\rm
GL}_n({\mathbb A}_F)$ for a number field $F$. We consider certain periods
attached to $\pi$. These periods were originally defined by Harder when $n=2$,
and later by Mahnkopf when $F = {\mathbb Q}$. In the first part of the paper we
analyze the behaviour of these periods upon twisting $\pi$ by algebraic Hecke
characters. In the latter part of the paper we consider Shimura's periods
associated to a modular form. If $\phi_{\chi}$ is the cusp form associated to a
character $\chi$ of a quadratic extension, then we relate the periods of
$\phi_{\chi^n}$ to those of $\phi_{\chi}$, and as a consequence give another
proof of Deligne's conjecture on the critical values of symmetric power
$L$-functions associated to dihedral modular forms. Finally, we make some
remarks on the symmetric fourth power $L$-functions.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 21:08:53 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Raghuram",
"A.",
""
],
[
"Shahidi",
"Freydoon",
""
]
] |
0707.1709 | David Waters | D. S. Waters (for the CDF and D0 Collaborations) | W and Z Production and Asymmetries at the Tevatron | Proceedings of the Symposium on Hadron Collider Physics 2006 (HCP
2006) | null | null | FERMILAB-PUB-06-538-E | hep-ex | null | An overview of W and Z production in high energy hadron collisions is given.
W and Z cross section and asymmetry measurements from CDF and DO are described,
with particular emphasis on recent results. The current status of precision W
mass and width measurements is reported. The fundamental physics parameters
that can be extracted from these measurements are described, and the relevance
of W and Z production studies for the LHC is pointed out.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 21:10:08 GMT"
}
] | 2019-08-14T00:00:00 | [
[
"Waters",
"D. S.",
"",
"for the CDF and D0 Collaborations"
]
] |
0707.1710 | Valentin Deaconu | Valentin Deaconu | Iterating the Pimsner construction | null | null | null | null | math.OA | null | For $A$ a $C^*$-algebra, $E_1, E_2$ two Hilbert bimodules over $A$, and a
fixed isomorphism $\chi : E_1\otimes_AE_2\to E_2\otimes_AE_1$, we consider the
problem of computing the $K$-theory of the Cuntz-Pimsner algebra ${\mathcal
O}_{E_2\otimes_A{\mathcal O}_{E_1}}$ obtained by extending the scalars and by
iterating the Pimsner construction.
The motivating examples are a commutative diagram of Douglas and Howe for the
Toeplitz operators on the quarter plane, and the Toeplitz extensions associated
by Pimsner and Voiculescu to compute the $K$-theory of a crossed product. The
applications are for Hilbert bimodules arising from rank two graphs and from
commuting endomorphisms of abelian $C^*$-algebras.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 22:09:29 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Deaconu",
"Valentin",
""
]
] |
0707.1711 | Sean Raymond | Sean N. Raymond (1), John Scalo (2), Victoria Meadows (3) ((1) CASA,
University of Colorado, Boulder, (2) Dept. of Astronomy, University of Texas,
Austin, TX, (3) IPAC, California Institute of Technology, Pasadena, CA) | A decreased probability of habitable planet formation around low-mass
stars | Accepted to ApJ. 11 pages, 6 figures | null | 10.1086/521587 | null | astro-ph | null | Smaller terrestrial planets (< 0.3 Earth masses) are less likely to retain
the substantial atmospheres and ongoing tectonic activity probably required to
support life. A key element in determining if sufficiently massive "sustainably
habitable" planets can form is the availability of solid planet-forming
material. We use dynamical simulations of terrestrial planet formation from
planetary embryos and simple scaling arguments to explore the implications of
correlations between terrestrial planet mass, disk mass, and the mass of the
parent star. We assume that the protoplanetary disk mass scales with stellar
mass as Mdisk ~ f Mstar^h, where f measures the relative disk mass, and 1/2 < h
< 2, so that disk mass decreases with decreasing stellar mass. We consider
systems without Jovian planets, based on current models and observations for M
stars. We assume the mass of a planet formed in some annulus of a disk with
given parameters is proportional to the disk mass in that annulus, and show
with a suite of simulations of late-stage accretion that the adopted
prescription is surprisingly accurate. Our results suggest that the fraction of
systems with sufficient disk mass to form > 0.3 Earth mass habitable planets
decreases for low-mass stars for every realistic combination of parameters.
This "habitable fraction" is small for stellar masses below a mass in the
interval 0.5 to 0.8 Solar masses, depending on disk parameters, an interval
that excludes most M stars. Radial mixing and therefore water delivery are
inefficient in lower-mass disks commonly found around low-mass stars, such that
terrestrial planets in the habitable zones of most low-mass stars are likely to
be small and dry.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 21:17:42 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Raymond",
"Sean N.",
""
],
[
"Scalo",
"John",
""
],
[
"Meadows",
"Victoria",
""
]
] |
0707.1712 | Thomas Wright | T. Wright (for the CDF and D{\O} Collaborations) | B-Tagging at CDF and DO, Lessons for LHC | Proceedings of Hadron Collider Physics 2006; 6 pages, 8 figures | null | null | FERMILAB-CONF-06-313-E | hep-ex | null | The identification of jets resulting from the fragmentation and hadronization
of b quarks is an important part of high-pT collider physics. The methods used
by the CDF and DO collaborations to perform this identification are described,
including the calibration of the efficiencies and fake rates. Some thoughts on
the application of these methods in the LHC environment are also presented.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 21:37:19 GMT"
}
] | 2019-08-14T00:00:00 | [
[
"Wright",
"T.",
"",
"for the CDF and DØ Collaborations"
]
] |
0707.1713 | David Hasler | D. Hasler, I. Herbst | On the self-adjointness and domain of Pauli-Fierz type Hamiltonians | null | null | 10.1142/S0129055X08003389 | null | math-ph math.MP | null | We prove a general theorem about the self-adjointness and domain of
Pauli-Fierz type Hamiltonians. Our proof is based on commutator arguments which
allow us to treat fields with non-commuting components. As a corollary it
follows that the domain of the Hamiltonian of non-relativistic QED with Coulomb
interactions is independent of the coupling constant.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 21:45:15 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Hasler",
"D.",
""
],
[
"Herbst",
"I.",
""
]
] |
0707.1714 | Michael Mahoney | Anirban Dasgupta, Petros Drineas, Boulos Harb, Ravi Kumar, and Michael
W. Mahoney | Sampling Algorithms and Coresets for Lp Regression | 19 pages, 1 figure | null | null | null | cs.DS | null | The Lp regression problem takes as input a matrix $A \in \Real^{n \times d}$,
a vector $b \in \Real^n$, and a number $p \in [1,\infty)$, and it returns as
output a number ${\cal Z}$ and a vector $x_{opt} \in \Real^d$ such that ${\cal
Z} = \min_{x \in \Real^d} ||Ax -b||_p = ||Ax_{opt}-b||_p$. In this paper, we
construct coresets and obtain an efficient two-stage sampling-based
approximation algorithm for the very overconstrained ($n \gg d$) version of
this classical problem, for all $p \in [1, \infty)$. The first stage of our
algorithm non-uniformly samples $\hat{r}_1 = O(36^p d^{\max\{p/2+1, p\}+1})$
rows of $A$ and the corresponding elements of $b$, and then it solves the Lp
regression problem on the sample; we prove this is an 8-approximation. The
second stage of our algorithm uses the output of the first stage to resample
$\hat{r}_1/\epsilon^2$ constraints, and then it solves the Lp regression
problem on the new sample; we prove this is a $(1+\epsilon)$-approximation. Our
algorithm unifies, improves upon, and extends the existing algorithms for
special cases of Lp regression, namely $p = 1,2$. In course of proving our
result, we develop two concepts--well-conditioned bases and subspace-preserving
sampling--that are of independent interest.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 22:04:18 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Dasgupta",
"Anirban",
""
],
[
"Drineas",
"Petros",
""
],
[
"Harb",
"Boulos",
""
],
[
"Kumar",
"Ravi",
""
],
[
"Mahoney",
"Michael W.",
""
]
] |
0707.1715 | Seth Pettie | Seth Pettie | Sources of Superlinearity in Davenport-Schinzel Sequences | null | null | null | null | cs.DM | null | A generalized Davenport-Schinzel sequence is one over a finite alphabet that
contains no subsequences isomorphic to a fixed forbidden subsequence. One of
the fundamental problems in this area is bounding (asymptotically) the maximum
length of such sequences. Following Klazar, let Ex(\sigma,n) be the maximum
length of a sequence over an alphabet of size n avoiding subsequences
isomorphic to \sigma. It has been proved that for every \sigma, Ex(\sigma,n) is
either linear or very close to linear; in particular it is O(n
2^{\alpha(n)^{O(1)}}), where \alpha is the inverse-Ackermann function and O(1)
depends on \sigma. However, very little is known about the properties of \sigma
that induce superlinearity of \Ex(\sigma,n).
In this paper we exhibit an infinite family of independent superlinear
forbidden subsequences. To be specific, we show that there are 17 prototypical
superlinear forbidden subsequences, some of which can be made arbitrarily long
through a simple padding operation. Perhaps the most novel part of our
constructions is a new succinct code for representing superlinear forbidden
subsequences.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 22:16:58 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Pettie",
"Seth",
""
]
] |
0707.1716 | Luis Antonio da Mota | B.O.Rodrigues, L.A.C.P.da Mota and L.G.S.Duarte | Numerical Calculation With Arbitrary Precision | contribution to X hadron Physics - 2007 to appear on International
Journal of Modern Physics E | null | 10.1142/S0218301307009014 | null | cs.NA cs.MS | null | The vast use of computers on scientific numerical computation makes the
awareness of the limited precision that these machines are able to provide us
an essential matter. A limited and insufficient precision allied to the
truncation and rounding errors may induce the user to incorrect interpretation
of his/hers answer. In this work, we have developed a computational package to
minimize this kind of error by offering arbitrary precision numbers and
calculation. This is very important in Physics where we can work with numbers
too small and too big simultaneously.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 22:24:48 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rodrigues",
"B. O.",
""
],
[
"da Mota",
"L. A. C. P.",
""
],
[
"Duarte",
"L. G. S.",
""
]
] |
0707.1717 | Kathrin Bringmann | Kathrin Bringmann | On the explicit construction of higher deformations of partition
statistics | 29 pages, Duke J. accepted for publication | null | null | null | math.NT | null | The modularity of the partition generating function has many important
consequences, for example asymptotics and congruences for $p(n)$. In a series
of papers the author and Ono \cite{BO1,BO2} connected the rank, a partition
statistic introduced by Dyson, to weak Maass forms, a new class of functions
which are related to modular forms and which were first considered in
\cite{BF}. Here we do a further step towards understanding how weak Maass forms
arise from interesting partition statistics by placing certain 2-marked Durfee
symbols introduced by Andrews \cite{An1} into the framework of weak Maass
forms. To do this we construct a new class of functions which we call quasiweak
Maass forms because they have quasimodular forms as components. As an
application we prove two conjectures of Andrews. It seems that this new class
of functions will play an important role in better understanding weak Maass
forms of higher weight themselves, and also their derivatives. As a side
product we introduce a new method which enables us to prove transformation laws
for generating functions over incomplete lattices.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 22:44:54 GMT"
},
{
"version": "v2",
"created": "Wed, 8 Aug 2007 00:16:54 GMT"
},
{
"version": "v3",
"created": "Tue, 4 Dec 2007 23:06:35 GMT"
}
] | 2007-12-05T00:00:00 | [
[
"Bringmann",
"Kathrin",
""
]
] |
0707.1718 | Mat\'ias Luis del Hoyo | Matias Luis del Hoyo | On the subdivision of small categories | 15 pages | Topology and its Applications 155 (2008) 1189--1200 | 10.1016/j.topol.2008.02.006 | null | math.AT | null | We present an intrinsic and concrete development of the subdivision of small
categories, give some simple examples and derive its fundamental properties. As
an application, we deduce an alternative way to compare the homotopy categories
of spaces and small categories, by using partially ordered sets. This yields a
new conceptual proof to the well-known fact that these two homotopy categories
are equivalent.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 23:08:06 GMT"
},
{
"version": "v2",
"created": "Fri, 22 Feb 2008 19:50:05 GMT"
}
] | 2018-07-10T00:00:00 | [
[
"del Hoyo",
"Matias Luis",
""
]
] |
0707.1719 | Byron K. Jennings | B.K. Jennings | The Scientific Method | null | null | null | null | physics.hist-ph physics.ed-ph physics.soc-ph | null | The nature of the scientific method is controversial with claims that a
single scientific method does not even exist. However the scientific method
does exist. It is the building of logical and self consistent models to
describe nature. The models are constrained by past observations and judged by
their ability to correctly predict new observations and interesting phenomena.
The observations exist independent of the models but acquire meaning from their
context within a model. Observations must be carefully done and reproducible to
minimize errors. Models assumptions that do not lead to testable predictions
are rejected as unnecessary.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 23:16:00 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Jennings",
"B. K.",
""
]
] |
0707.1720 | Hugues Vasseur | Hugues Vasseur | Cell Dissociation : A Cohesive Force of Hydrodynamic Origin | null | null | null | null | physics.bio-ph | null | When an experimentalist or a biological mechanism applies an external force
onto a cell chemically sticking to its substrate, a reacting 'suction' force,
due to the slow penetration of the surrounding fluid between the cell and the
substrate, opposes to the dissociation. This force can overcome other known
adhesive forces when the process is sufficiently violent (typically 100000pN).
Its maximal contribution to the total adhesive energy of the cell can then be
estimated to 0.002 J/m2. The physical origin of this effect is quite simple,
and it may be compared with that leaning a 'suction-cup' against a bathroom
wall. We address the consequences of this effect on (i) the dissociation
energy, (ii) the motion of the fluid surrounding the cell, more especially, on
the pumping of the fluid by moving cells, and (iii) the inhibition of cell
motion.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 23:20:31 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Vasseur",
"Hugues",
""
]
] |
0707.1721 | Matthew Thrasher | Matthew Thrasher, Sunghwan Jung, Yee Kwong Pang, Chih-Piao Chuu, Harry
L. Swinney | The Bouncing Jet: A Newtonian Liquid Rebounding off a Free Surface | 9 pages, 7 figures. submitted to Physical Review E | Phys. Rev. E 76, 056319 (2007) | 10.1103/PhysRevE.76.056319 | null | physics.flu-dyn | null | We find that a liquid jet can bounce off a bath of the same liquid if the
bath is moving horizontally with respect to the jet. Previous observations of
jets rebounding off a bath (e.g. Kaye effect) have been reported only for
non-Newtonian fluids, while we observe bouncing jets in a variety of Newtonian
fluids, including mineral oil poured by hand. A thin layer of air separates the
bouncing jet from the bath, and the relative motion replenishes the film of
air. Jets with one or two bounces are stable for a range of viscosity, jet flow
rate and velocity, and bath velocity. The bouncing phenomenon exhibits
hysteresis and multiple steady states.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 23:31:56 GMT"
}
] | 2008-02-06T00:00:00 | [
[
"Thrasher",
"Matthew",
""
],
[
"Jung",
"Sunghwan",
""
],
[
"Pang",
"Yee Kwong",
""
],
[
"Chuu",
"Chih-Piao",
""
],
[
"Swinney",
"Harry L.",
""
]
] |
0707.1722 | Spyridon Michalakis | Spyridon Michalakis | Multiplicativity of the maximal output 2-norm for depolarized
Werner-Holevo channels | 3 pages | J. Math. Phys., 48, Issue 12 (2007). | 10.1063/1.2818737 | null | quant-ph | null | We study the multiplicativity of the output 2-norm for depolarized
Werner-Holevo channels and show that multiplicativity holds for a product of
two identical channels in this class. Moreover, it shown that the depolarized
Werner-Holevo channels do not satisfy the entrywise positivity condition
introduced by C. King and M.B. Ruskai, which suggests that the main result is
non-trivial.
| [
{
"version": "v1",
"created": "Wed, 11 Jul 2007 23:37:45 GMT"
}
] | 2009-12-03T00:00:00 | [
[
"Michalakis",
"Spyridon",
""
]
] |
0707.1723 | Pomita Ghoshal | Raj Gandhi, Pomita Ghoshal, Srubabati Goswami, Poonam Mehta, S Uma
Sankar, Shashank Shalgar | Mass Hierarchy Determination via future Atmospheric Neutrino Detectors | 36 pages, 13 figures, revised version accepted in Physical Review D | Phys.Rev.D76:073012,2007 | 10.1103/PhysRevD.76.073012 | null | hep-ph hep-ex | null | We study the problem of determination of the sign of Delta m^2_{31}, or the
neutrino mass hierarchy, through observations of atmospheric neutrinos in
future detectors. We consider two proposed detector types :
(a) Megaton sized water Cerenkov detectors, which can measure the survival
rates of nu_\mu + \bar{\nu}_\mu and nu_e + \bar{\nu}_e and (b) 100 kton sized
magnetized iron detectors, which can measure the survival rates of \nu_\mu and
\bar{\nu}_\mu. For energies and path-lengths relevant to atmospheric neutrinos,
these rates obtain significant matter contributions from P_{\mu e}, P_{\mu \mu}
and P_{ee}, leading to an appreciable sensitivity to the hierarchy. We do a
binned \chi^2 analysis of simulated data in these two types of detectors which
includes the effect of smearing in neutrino energy and direction and
incorporates detector efficiencies and relevant statistical, theoretical and
systematic errors. We also marginalize the \chi^2 over the allowed ranges of
neutrino parameters in order to accurately account for their uncertainties.
Finally, we compare the performance of both types of detectors vis a vis the
hierarchy determination.
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 00:32:01 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Sep 2007 13:02:31 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Gandhi",
"Raj",
""
],
[
"Ghoshal",
"Pomita",
""
],
[
"Goswami",
"Srubabati",
""
],
[
"Mehta",
"Poonam",
""
],
[
"Sankar",
"S Uma",
""
],
[
"Shalgar",
"Shashank",
""
]
] |
0707.1724 | Jack Harris | J. D. Thompson, B. M. Zwickl, A. M. Jayich, Florian Marquardt, S. M.
Girvin, and J. G. E. Harris | Strong dispersive coupling of a high finesse cavity to a micromechanical
membrane | 25 pages (including supplementary material), 3 figures, 1 table | null | 10.1038/nature06715 | null | quant-ph cond-mat.mes-hall physics.optics | null | Macroscopic mechanical objects and electromagnetic degrees of freedom couple
to each other via radiation pressure. Optomechanical systems with sufficiently
strong coupling are predicted to exhibit quantum effects and are a topic of
considerable interest. Devices reaching this regime would offer new types of
control of the quantum state of both light and matter and would provide a new
arena in which to explore the boundary between quantum and classical physics.
Experiments to date have achieved sufficient optomechanical coupling to
laser-cool mechanical devices but have not yet reached the quantum regime. The
outstanding technical challenge in this field is integrating sensitive
micromechanical elements (which must be small, light, and flexible) into high
finesse cavities (which are typically much more rigid and massive) without
compromising the mechanical or optical properties of either. A second, and more
fundamental, challenge is to read out the mechanical element's quantum state:
displacement measurements (no matter how sensitive) cannot determine the energy
eigenstate of an oscillator, and measurements which couple to quantities other
than displacement have been difficult to realize. Here we present a novel
optomechanical system which seems to resolve both these challenges. We
demonstrate a cavity which is detuned by the motion of a thin dielectric
membrane placed between two macroscopic, rigid, high-finesse mirrors. This
approach segregates optical and mechanical functionality to physically distinct
structures and avoids compromising either. It also allows for direct
measurement of the square of the membrane's displacement, and thus in principle
the membrane's energy eigenstate. We estimate it should be practical to use
this scheme to observe quantum jumps of a mechanical system.
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 00:14:34 GMT"
},
{
"version": "v2",
"created": "Fri, 13 Jul 2007 19:29:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Thompson",
"J. D.",
""
],
[
"Zwickl",
"B. M.",
""
],
[
"Jayich",
"A. M.",
""
],
[
"Marquardt",
"Florian",
""
],
[
"Girvin",
"S. M.",
""
],
[
"Harris",
"J. G. E.",
""
]
] |
0707.1725 | Bernd Berg | Bernd A. Berg and Wei Yang | Numerical calculation of the combinatorial entropy of partially ordered
ice | Extended version: 7 pages, 10 figures (v1 is letter-type version) | J. Chem. Phys. 127, 224502 (2007) | 10.1063/1.2800002 | null | cond-mat.stat-mech cond-mat.mtrl-sci physics.chem-ph | null | Using a one-parameter case as an example, we demonstrate that multicanonical
simulations allow for accurate estimates of the residual combinatorial entropy
of partially ordered ice. For the considered case corrections to an
(approximate) analytical formula are found to be small, never exceeding 0.5%.
The method allows one as well to calculate combinatorial entropies for many
other systems.
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 00:39:31 GMT"
},
{
"version": "v2",
"created": "Thu, 20 Sep 2007 17:08:10 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Berg",
"Bernd A.",
""
],
[
"Yang",
"Wei",
""
]
] |
0707.1726 | Jun Cheng | Jun Cheng (1), Wang Yao (3), Xiaodong Xu (1), D. G. Steel (1), A. S.
Bracker (2), D. Gammon (2), and L. J. Sham (3) ((1) The H. M. Randall
Laboratory of Physics, The University of Michigan, Ann Arbor, MI (2) The
Naval Research Laboratory, Washington D. C. (3) Department of Physics, The
University of California-San Diego, La Jolla, CA) | Stimulated Raman spin coherence and spin-flip induced hole burning in
charged GaAs quantum dots | 5 pages, 5 figures | Phys. Rev. B 77, 115315 (2008) | 10.1103/PhysRevB.77.115315 | null | cond-mat.mes-hall | null | High-resolution spectral hole burning (SHB) in coherent nondegenerate
differential transmission spectroscopy discloses spin-trion dynamics in an
ensemble of negatively charged quantum dots. In the Voigt geometry, stimulated
Raman spin coherence gives rise to Stokes and anti-Stokes sidebands on top of
the trion spectral hole. The prominent feature of an extremely narrow spike at
zero detuning arises from spin population pulsation dynamics. These SHB
features confirm coherent electron spin dynamics in charged dots, and the
linewidths reveal spin spectral diffusion processes.
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 00:57:02 GMT"
},
{
"version": "v2",
"created": "Wed, 12 Mar 2008 21:46:15 GMT"
}
] | 2008-04-01T00:00:00 | [
[
"Cheng",
"Jun",
""
],
[
"Yao",
"Wang",
""
],
[
"Xu",
"Xiaodong",
""
],
[
"Steel",
"D. G.",
""
],
[
"Bracker",
"A. S.",
""
],
[
"Gammon",
"D.",
""
],
[
"Sham",
"L. J.",
""
]
] |
0707.1727 | Pui Tang Leung | J. Wu and P.T. Leung | Generalised Inverse-Cowling Approximation for Polar $w$-mode
Oscillations of Neutron Stars | 11 pages, 4 figures, accepted for publication in MNRAS | null | 10.1111/j.1365-2966.2007.12211.x | null | astro-ph | null | Adopting the Lindblom-Detweiler formalism for polar oscillations of neutron
stars, we study the $w$-mode oscillation and find that the Lagrangian change in
pressure, measured by the physical quantity $X$, is negligibly small. Based on
this observation, we develop the generalised inverse-Cowling approximation
(GICA) with the approximation $X=X'=0$, where $X'$ is the derivative of $X$
with respect to the circumferential radius, for $w$-mode oscillations of
neutron stars. Under GICA, $w$-mode oscillations are described by a
second-order differential system, which can yield accurate frequencies and
damping rates of quasi-normal modes.
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 02:28:34 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Wu",
"J.",
""
],
[
"Leung",
"P. T.",
""
]
] |
0707.1728 | Hiroshi Imai | Hiroshi Imai (Kagoshima University), Raghvendra Sahai (NASA/JPL), Mark
Morris (UCLA) | The spatio-kinematical structure and distance of the pre-planetary
nebula IRAS 19134+2131 | 17 pages, 5 figures, to appear in the Astrophysical Journal, October
20 issue | null | 10.1086/521350 | null | astro-ph | null | Using the VLBA, we have observed H2O maser emission in the pre-planetary
nebula IRAS 19134+2131(I19134), in which the H2O maser spectrum has two groups
of emission features separated in radial velocity by ~100 km/s. We also
obtained optical images of I19134 with the HST to locate the bipolar reflection
nebula in this source for the first time. The spatio-kinematical structure of
the H2O masers indicates the existence of a fast, collimated (precessing) flow
having a projected extent of ~140 mas and an expansion rate of ~1.9 mas/yr on
the sky plane, which gives a dynamical age of only ~40 yr. The two detected
optical lobes are also separated by ~150 mas in almost the same direction as
that of the collimated flow. The good agreement between the extent and
orientation of the H2O maser outflow and optical lobes suggests that the lobes
have been recently formed along the collimated fast flow. The positions of all
of the detected maser features have been measured with respect to the reference
source J1925+2106 over one year. Therefore we analyzed maser feature motions
that consist of the combination of an annual parallax, a secular motion
following Galactic rotation, and the intrinsic motions within the flow. We
obtain an annual-parallax distance to I19134 of D~8 kpc kpc and estimate its
location in the Galaxy to be (R, theta, z)=(7.4 kpc, 62 deg, 0.65 kpc). From
the mean motion of the blue-shifted and red-shifted clusters of maser features,
we estimate the 3-D secular motion of I19134 to be (V_{R}, V_{theta},
V_{z})=(3, 125, 8) [km/s]. From the height from the Galactic plane, z, and the
velocity component perpendicular to the Galactic plane, V_{z}, we estimate a
rough upper limit of ~9 M_{sun} to the stellar mass of I19134's progenitor.
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 02:43:51 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Imai",
"Hiroshi",
"",
"Kagoshima University"
],
[
"Sahai",
"Raghvendra",
"",
"NASA/JPL"
],
[
"Morris",
"Mark",
"",
"UCLA"
]
] |
0707.1729 | Rahul Jain | Richard Cleve, Dmitry Gavinsky, Rahul Jain | Entanglement-Resistant Two-Prover Interactive Proof Systems and
Non-Adaptive Private Information Retrieval Systems | 8 pages | null | null | null | quant-ph | null | We show that, for any language in NP, there is an entanglement-resistant
constant-bit two-prover interactive proof system with a constant completeness
vs. soundness gap. The previously proposed classical two-prover constant-bit
interactive proof systems are known not to be entanglement-resistant. This is
currently the strongest expressive power of any known constant-bit answer
multi-prover interactive proof system that achieves a constant gap. Our result
is based on an "oracularizing" property of certain private information
retrieval systems, which may be of independent interest.
| [
{
"version": "v1",
"created": "Thu, 12 Jul 2007 02:54:15 GMT"
}
] | 2007-07-13T00:00:00 | [
[
"Cleve",
"Richard",
""
],
[
"Gavinsky",
"Dmitry",
""
],
[
"Jain",
"Rahul",
""
]
] |
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