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list | update_date
timestamp[s] | authors_parsed
sequence |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0707.2830 | Boris Gershgorin | Boris Gershgorin | Characterization of thermalized Fermi-Pasta-Ulam chains | null | null | null | null | math-ph math.DS math.MP | null | The Fermi-Pasta-Ulam (FPU) chains of particles in \textit{thermal
equilibrium} are studied from both wave-interaction and particle-interaction
points of view. It is shown that, even in a strongly nonlinear regime, the
chain in thermal equilibrium can be effectively described by a system of weakly
interacting \textit{renormalized} nonlinear waves. These waves possess (i) the
Rayleigh-Jeans distribution and (ii) zero correlations between waves, just as
noninteracting free waves would. This renormalization is achieved through a set
of canonical transformations. The renormalized linear dispersion of these
renormalized waves is obtained and shown to be in excellent agreement with
numerical experiments. Moreover, a dynamical interpretation of the
renormalization of the dispersion relation is provided via a self-consistency,
mean-field argument. It turns out that this renormalization arises mainly from
the trivial resonant wave interactions, i.e., interactions with no momentum
exchange. Furthermore, using a multiple time-scale, statistical averaging
method, we show that the interactions of near-resonant waves give rise to the
broadening of the resonance peaks in the frequency spectrum of renormalized
modes. The theoretical prediction for the resonance width for the thermalized
$\beta$-FPU chain is found to be in very good agreement with its numerically
measured value. Moreover, we show that the dynamical scenario for thermalized
$\beta$-FPU chains is spatially highly localized discrete breathers riding
chaotically on spatially extended, renormalized waves. We present numerical
evidence of existence of discrete breathers in thermal equilibrium.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 02:19:12 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Gershgorin",
"Boris",
""
]
] |
0707.2831 | Stephen Jordan | Peter W. Shor and Stephen P. Jordan | Estimating Jones polynomials is a complete problem for one clean qubit | 29 pages, 12 figures. Improved presentation and removed typos | Quantum Information and Computation Vol. 8 pg. 681 (2008) | null | null | quant-ph math.GT | null | It is known that evaluating a certain approximation to the Jones polynomial
for the plat closure of a braid is a BQP-complete problem. That is, this
problem exactly captures the power of the quantum circuit model. The one clean
qubit model is a model of quantum computation in which all but one qubit starts
in the maximally mixed state. One clean qubit computers are believed to be
strictly weaker than standard quantum computers, but still capable of solving
some classically intractable problems. Here we show that evaluating a certain
approximation to the Jones polynomial at a fifth root of unity for the trace
closure of a braid is a complete problem for the one clean qubit complexity
class. That is, a one clean qubit computer can approximate these Jones
polynomials in time polynomial in both the number of strands and number of
crossings, and the problem of simulating a one clean qubit computer is
reducible to approximating the Jones polynomial of the trace closure of a
braid.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 02:30:49 GMT"
},
{
"version": "v2",
"created": "Mon, 10 Dec 2007 18:55:01 GMT"
},
{
"version": "v3",
"created": "Fri, 1 Feb 2008 17:44:31 GMT"
}
] | 2011-06-03T00:00:00 | [
[
"Shor",
"Peter W.",
""
],
[
"Jordan",
"Stephen P.",
""
]
] |
0707.2832 | W. H. Zurek | Wojciech Hubert Zurek | Relative States and the Environment: Einselection, Envariance, Quantum
Darwinism, and the Existential Interpretation | null | null | null | Los Alamos preprint LAUR 07-4568 | quant-ph | null | Starting with basic axioms of quantum theory I revisit "Relative State
Interpretation'' set out 50 years ago by Hugh Everett.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 03:59:22 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Zurek",
"Wojciech Hubert",
""
]
] |
0707.2833 | Damien Chablat | Damien Chablat (IRCCyN), Philippe Wenger (IRCCyN), Jean-Pierre Merlet
(INRIA Sophia Antipolis) | A Comparative Study between Two Three-DOF Parallel Kinematic Machines
using Kinetostatic Criteria and Interval Analysis | null | 11th World Congress in Mechanism and Machine Science (04/2004) 1-6 | null | null | cs.RO | null | This paper addresses the workspace analysis of two 3-DOF translational
parallel mechanisms designed for machining applications. The two machines
features three fixed linear joints. The joint axes of the first machine are
orthogonal whereas these of the second are parallel. In both cases, the mobile
platform moves in the Cartesian $x-y-z$ space with fixed orientation. The
workspace analysis is conducted on the basis of prescribed kinetostatic
performances. Interval analysis based methods are used to compute the dextrous
workspace and the largest cube enclosed in this workspace.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 04:44:06 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Chablat",
"Damien",
"",
"IRCCyN"
],
[
"Wenger",
"Philippe",
"",
"IRCCyN"
],
[
"Merlet",
"Jean-Pierre",
"",
"INRIA Sophia Antipolis"
]
] |
0707.2834 | Nathael Gozlan | Nathael Gozlan (LAMA) | Poincar\'e inequality for non euclidean metrics and transportation cost
inequalities on $\mathbb{R}^d$ | null | Ann. Inst. Henri Poincar\'e Probab. Stat. 46 (2010), no. 3,
708-739 | 10.1214/09-AIHP209 | null | math.PR | null | In this paper, we consider Poincar\'e inequalities for non euclidean metrics
on $\mathbb{R}^d$. These inequalities enable us to derive precise dimension
free concentration inequalities for product measures. This technique is
appropriate for a large scope of concentration rate: between exponential and
gaussian and beyond. We give different equivalent functional forms of these
Poincar\'e type inequalities in terms of transportation-cost inequalities and
infimum convolution inequalities. Workable sufficient conditions are given and
a comparison is made with generalized Beckner-Latala-Oleszkiewicz inequalities.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 04:48:24 GMT"
}
] | 2012-03-05T00:00:00 | [
[
"Gozlan",
"Nathael",
"",
"LAMA"
]
] |
0707.2835 | Gregory Eskin | Gregory Eskin | Optical Aharonov-Bohm effect: an inverse hyperbolic problems approach | 34 pages. Minor changes, references added | Comm. Math. Phys. 284 (2008) no. 2, 317-343 | 10.1007/s00220-008-0647-6 | null | math-ph math.AP math.MP | null | We describe the general setting for the optical Aharonov-Bohm effect based on
the inverse problem of the identification of the coefficients of the governing
hyperbolic equation by the boundary measurements. We interpret the inverse
problem result as a possibility in principle to detect the optical
Aharonov-Bohm effect by the boundary measurements.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 05:07:25 GMT"
},
{
"version": "v2",
"created": "Thu, 18 Oct 2007 05:41:20 GMT"
}
] | 2015-07-06T00:00:00 | [
[
"Eskin",
"Gregory",
""
]
] |
0707.2836 | Inanc Inan | Inanc Inan, Feyza Keceli, Ender Ayanoglu | Multimedia Capacity Analysis of the IEEE 802.11e Contention-based
Infrastructure Basic Service Set | null | null | null | null | cs.IT cs.MM math.IT | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We first propose a simple mathematical analysis framework for the Enhanced
Distributed Channel Access (EDCA) function of the recently ratified IEEE
802.11e standard. Our analysis considers the fact that the distributed random
access systems exhibit cyclic behavior. The proposed model is valid for
arbitrary assignments of AC-specific Arbitration Interframe Space (AIFS) values
and Contention Window (CW) sizes and is the first that considers an arbitrary
distribution of active Access Categories (ACs) at the stations. Validating the
theoretical results via extensive simulations, we show that the proposed
analysis accurately captures the EDCA saturation performance. Next, we propose
a framework for multimedia capacity analysis of the EDCA function. We calculate
an accurate station- and AC-specific queue utilization ratio by appropriately
weighing the service time predictions of the cycle time model for different
number of active stations. Based on the calculated queue utilization ratio, we
design a simple model-based admission control scheme. We show that the proposed
call admission control algorithm maintains satisfactory user-perceived quality
for coexisting voice and video connections in an infrastructure BSS and does
not present over- or under-admission problems of previously proposed models in
the literature.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 05:16:53 GMT"
},
{
"version": "v2",
"created": "Mon, 30 Jul 2007 18:08:46 GMT"
},
{
"version": "v3",
"created": "Tue, 12 Aug 2008 05:55:21 GMT"
}
] | 2008-08-12T00:00:00 | [
[
"Inan",
"Inanc",
""
],
[
"Keceli",
"Feyza",
""
],
[
"Ayanoglu",
"Ender",
""
]
] |
0707.2837 | Richard L. Hall | Nasser Saad, Richard L Hall, Hakan Ciftci | Solutions for certain classes of Riccati differential equation | 10 pages | J. Phys. A 40, 10903 - 10914 (2007) | 10.1088/1751-8113/40/35/012 | CUQM-123 | math-ph math.MP | null | We derive some analytic closed-form solutions for a class of Riccati equation
y'(x)-\lambda_0(x)y(x)\pm y^2(x)=\pm s_0(x), where \lambda_0(x), s_0(x) are
C^{\infty}-functions. We show that if \delta_n=\lambda_n
s_{n-1}-\lambda_{n-1}s_n=0, where \lambda_{n}=
\lambda_{n-1}^\prime+s_{n-1}+\lambda_0\lambda_{n-1} and
s_{n}=s_{n-1}^\prime+s_0\lambda_{k-1}, n=1,2,..., then The Riccati equation has
a solution given by y(x)=\mp s_{n-1}(x)/\lambda_{n-1}(x). Extension to the
generalized Riccati equation y'(x)+P(x)y(x)+Q(x)y^2(x)=R(x) is also
investigated.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 15:20:04 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Saad",
"Nasser",
""
],
[
"Hall",
"Richard L",
""
],
[
"Ciftci",
"Hakan",
""
]
] |
0707.2838 | Seungwon Baek | Seungwon Baek | A solution to B --> pi pi puzzle and B --> K K | 12 pages, 2 figures, minor changes, references added | Phys.Lett.B659:265-269,2008 | 10.1016/j.physletb.2007.11.029 | null | hep-ph | null | The large ratio of color-suppressed tree amplitude to color-allowed one in $B
\to \pi \pi$ decays is difficult to understand within the Standard Model, which
is known as the "$B \to \pi\pi$ puzzle". The two tree diagrams contain the up-
and charm-quark component of penguin amplitude, $P_{uc}$, which cannot be
separated by measuring $B \to \pi \pi$ decays alone. We show that the
measurements of the branching ratio and direct CP asymmetry of $B^+ \to K^+
\bar{K^0}$ decay enable one to disentangle the $P_{uc}$ with two-fold
ambiguity. One of the two degenerate solutions of the $P_{uc}$ can solve the $B
\to \pi \pi$ puzzle by giving $|C/T|\sim 0.3$ which is consistent with the
expectation in the Standard Model. We also show that the two solutions can be
discriminated by the measurement of the indirect CP-asymmetry of $B^0 \to K^0
\ol{K^0}$. We point out that if the $B \to \pi \pi$ puzzle is solved in this
way, the corresponding puzzle in $B \to \pi K$ decays should have a different
origin.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 06:36:56 GMT"
},
{
"version": "v2",
"created": "Thu, 26 Jul 2007 12:22:46 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Baek",
"Seungwon",
""
]
] |
0707.2839 | Asaf Nachmias | Asaf Nachmias and Yuval Peres | Critical percolation on random regular graphs | 47 pages | null | null | null | math.PR math.CO | null | We describe the component sizes in critical independent p-bond percolation on
a random d-regular graph on n vertices, where d \geq 3 is fixed and n grows. We
prove mean-field behavior around the critical probability p_c=1/(d-1).
In particular, we show that there is a scaling window of width n^{-1/3}
around p_c in which the sizes of the largest components are roughly n^{2/3} and
we describe their limiting joint distribution. We also show that for the
subcritical regime, i.e. p = (1-eps(n))p_c where eps(n)=o(1) but \eps(n)n^{1/3}
tends to infinity, the sizes of the largest components are concentrated around
an explicit function of n and eps(n) which is of order o(n^{2/3}). In the
supercritical regime, i.e. p = (1+\eps(n))p_c where eps(n)=o(1) but
eps(n)n^{1/3} tends to infinity, the size of the largest component is
concentrated around the value (2d/(d-2))\eps(n)n and a duality principle holds:
other component sizes are distributed as in the subcritical regime.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 06:49:09 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jul 2007 22:05:05 GMT"
}
] | 2007-07-24T00:00:00 | [
[
"Nachmias",
"Asaf",
""
],
[
"Peres",
"Yuval",
""
]
] |
0707.2840 | Remco Zegers | R.G.T Zegers, T. Adachi, H. Akimune, Sam M. Austin, A.M. van den Berg,
B.A. Brown, Y. Fujita, M. Fujiwara, S. Gales, C.J. Guess, M.N. Harakeh, H.
Hashimoto, K. Hatanaka, R. Hayami, G.W. Hitt, M.E. Howard, M. Itoh, T.
Kawabata, K. Kawase, M. Kinoshita, M. Matsubara, K. Nakanishi, S. Nakayama,
S. Okumura, T. Ohta, Y. Sakemi, Y. Shimbara, Y. Shimizu, C. Scholl, C.
Simenel, Y. Tameshige, A. Tamii, M. Uchida, T. Yamagata, M. Yosoi | On the extraction of weak transition strengths via the (3He,t) reaction
at 420 MeV | 4 pages, 2 figures | Phys. Rev. Lett. 99, 202501 (2007) | 10.1103/PhysRevLett.99.202501 | null | nucl-ex | null | Differential cross sections for transitions of known weak strength were
measured with the (3He,t) reaction at 420 MeV on targets of 12C, 13C, 18O,
26Mg, 58Ni, 60Ni, 90Zr, 118Sn, 120Sn and 208Pb. Using this data, it is shown
the proportionalities between strengths and cross sections for this probe
follow simple trends as a function of mass number. These trends can be used to
confidently determine Gamow-Teller strength distributions in nuclei for which
the proportionality cannot be calibrated via beta-decay strengths. Although
theoretical calculations in distorted-wave Born approximation overestimate the
data, they allow one to understand the main experimental features and to
predict deviations from the simple trends observed in some of the transitions.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:21:28 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Mar 2008 13:45:25 GMT"
}
] | 2008-03-27T00:00:00 | [
[
"Zegers",
"R. G. T",
""
],
[
"Adachi",
"T.",
""
],
[
"Akimune",
"H.",
""
],
[
"Austin",
"Sam M.",
""
],
[
"Berg",
"A. M. van den",
""
],
[
"Brown",
"B. A.",
""
],
[
"Fujita",
"Y.",
""
],
[
"Fujiwara",
"M.",
""
],
[
"Gales",
"S.",
""
],
[
"Guess",
"C. J.",
""
],
[
"Harakeh",
"M. N.",
""
],
[
"Hashimoto",
"H.",
""
],
[
"Hatanaka",
"K.",
""
],
[
"Hayami",
"R.",
""
],
[
"Hitt",
"G. W.",
""
],
[
"Howard",
"M. E.",
""
],
[
"Itoh",
"M.",
""
],
[
"Kawabata",
"T.",
""
],
[
"Kawase",
"K.",
""
],
[
"Kinoshita",
"M.",
""
],
[
"Matsubara",
"M.",
""
],
[
"Nakanishi",
"K.",
""
],
[
"Nakayama",
"S.",
""
],
[
"Okumura",
"S.",
""
],
[
"Ohta",
"T.",
""
],
[
"Sakemi",
"Y.",
""
],
[
"Shimbara",
"Y.",
""
],
[
"Shimizu",
"Y.",
""
],
[
"Scholl",
"C.",
""
],
[
"Simenel",
"C.",
""
],
[
"Tameshige",
"Y.",
""
],
[
"Tamii",
"A.",
""
],
[
"Uchida",
"M.",
""
],
[
"Yamagata",
"T.",
""
],
[
"Yosoi",
"M.",
""
]
] |
0707.2841 | Damien Chablat | Damien Chablat (IRCCyN), Philippe D\'epinc\'e, Eric No\"el,
Peer-Oliver Woelk (IFW) | The Virtual Manufacturing concept: Scope, Socio-Economic Aspects and
Future Trends | null | Design Engineering Technical Conferences (09/2004) 1-6 | null | null | cs.RO | null | The research area "Virtual Manufacturing (VM)'' is the use of information
technology and computer simulation to model real world manufacturing processes
for the purpose of analysing and understanding them. As automation technologies
such as CAD/CAM have substantially shortened the time required to design
products, Virtual Manufacturing will have a similar effect on the manufacturing
phase thanks to the modelling, simulation and optimisation of the product and
the processes involved in its fabrication. After a description of Virtual
Manufacturing (definitions and scope), we present some socio-economic factors
of VM and finaly some "hot topics'' for the future are proposed.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 07:15:53 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Chablat",
"Damien",
"",
"IRCCyN"
],
[
"Dépincé",
"Philippe",
"",
"IFW"
],
[
"Noël",
"Eric",
"",
"IFW"
],
[
"Woelk",
"Peer-Oliver",
"",
"IFW"
]
] |
0707.2842 | Damien Chablat | Maher Baili (IRCCyN), Philippe Wenger (IRCCyN), Damien Chablat
(IRCCyN) | A Classification of 3R Orthogonal Manipulators by the Topology of their
Workspace | null | Proc. IEEE Int. Conf. Rob. and Automation (04/2004) 1-6 | null | null | cs.RO | null | A classification of a family of 3-revolute (3R) positining manipulators is
established. This classification is based on the topology of their workspace.
The workspace is characterized in a half-cross section by the singular curves.
The workspace topology is defined by the number of cusps and nodes that appear
on these singular curves. The design parameters space is shown to be divided
into nine domains of distinct workspace topologies, in which all manipulators
have similar global kinematic properties. Each separating surface is given as
an explicit expression in the DH-parameters.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 07:20:26 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Baili",
"Maher",
"",
"IRCCyN"
],
[
"Wenger",
"Philippe",
"",
"IRCCyN"
],
[
"Chablat",
"Damien",
"",
"IRCCyN"
]
] |
0707.2843 | Silvano Tosi | The BABAR Collaboration, B. Aubert, et al | A study of B-meson decays to eta_c K* and eta_c gamma K(*) | 8 pages, 9 figures | null | null | SLAC-PUB-12665 | hep-ex | null | We present preliminary results of a study of the two-body B-meson decays to a
charmonium state (ccbar) and a K+ or K*0(892) meson using a sample of about 349
fb-1 of data collected with the BABAR detector at the PEP-II asymmetric-energy
B Factory at SLAC. Here ccbar indicates either the eta_c state, reconstructed
in the K_S K+- pi-+ and K+K-pi0 decay channels, or the h_c state, reconstructed
in its decay to eta_c gamma. We measure BR(B0 -> eta_c K*0)=(6.1+-0.8_stat +-
1.1_syst) * 10-4, BR(B+ -> h_c K+) * BR(h_c -> eta_c gamma)<5.2 * 10-5 and
BR(B0 -> h_c K*0) * BR(h_c -> eta_c gamma)<2.41 * 10^-4, at the 90% C.L.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 07:55:34 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"The BABAR Collaboration",
"",
""
],
[
"Aubert",
"B.",
""
]
] |
0707.2844 | C. A. Dominguez | C.A. Dominguez, M. Loewe, J.C. Rojas | Heavy-light quark pseudoscalar and vector mesons at finite temperature | null | JHEP0708:040,2007 | 10.1088/1126-6708/2007/08/040 | UCT-TP-268/07 | hep-ph | null | The temperature dependence of the mass, leptonic decay constant, and width of
heavy-light quark peseudoscalar and vector mesons is obtained in the framework
of thermal Hilbert moment QCD sum rules. The leptonic decay constants of both
pseudoscalar and vector mesons decrease with increasing $T$, and vanish at a
critical temperature $T_c$, while the mesons develop a width which increases
dramatically and diverges at $T_c$, where $T_c$ is the temperature for
chiral-symmetry restoration. These results indicate the disappearance of
hadrons from the spectral function, which then becomes a smooth function of the
energy. This is interpreted as a signal for deconfinement at $T=T_c$. In
contrast, the masses show little dependence on the temperature, except very
close to $T_c$, where the pseudoscalar meson mass increases slightly by 10-20
%, and the vector meson mass decreases by some 20-30 %
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 08:24:33 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Dominguez",
"C. A.",
""
],
[
"Loewe",
"M.",
""
],
[
"Rojas",
"J. C.",
""
]
] |
0707.2845 | Henning Vahlbruch | Henning Vahlbruch, Simon Chelkowski, Karsten Danzmann and Roman
Schnabel | Quantum engineering of squeezed states for quantum communication and
metrology | 12 pages, 3 figures | New Journal of Physics 9 (2007) 371 | 10.1088/1367-2630/9/10/371 | null | quant-ph | null | We report the experimental realization of squeezed quantum states of light,
tailored for new applications in quantum communication and metrology. Squeezed
states in a broad Fourier frequency band down to 1 Hz has been observed for the
first time. Nonclassical properties of light in such a low frequency band is
required for high efficiency quantum information storage in electromagnetically
induced transparency (EIT) media. The states observed also cover the frequency
band of ultra-high precision laser interferometers for gravitational wave
detection and can be used to reach the regime of quantum non-demolition
interferometry. And furthermore, they cover the frequencies of motions of
heavily macroscopic objects and might therefore support the attempts to observe
entanglement in our macroscopic world.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 07:55:41 GMT"
}
] | 2007-12-04T00:00:00 | [
[
"Vahlbruch",
"Henning",
""
],
[
"Chelkowski",
"Simon",
""
],
[
"Danzmann",
"Karsten",
""
],
[
"Schnabel",
"Roman",
""
]
] |
0707.2846 | Ping Zhang | Zi-Gang Yuan, Ping Zhang, Shu-Shen Li | Disentanglement of two qubits coupled to an XY spin chain: Role of
quantum phase transition | 17 pages, 5 figures | null | 10.1103/PhysRevA.76.042118 | null | quant-ph | null | We study the disentanglement of two spin qubits which interact with a general
XY spin-chain environment. The dynamical process of the disentanglement is
numerically and analytically investigated in the vicinity of quantum phase
transition (QPT) of the spin chain in both weak and strong coupling cases. We
find that the disentanglement of the two qubits is in general enhanced greatly
when the environmental spin chain is exposed to QPT. We give a detailed
analysis to facilitate the understanding of the QPT-enhanced decaying behavior
of the disentanglement factor. Furthermore, the scaling behavior in the
disentanglement dynamics is also revealed and analyzed.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 08:16:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Yuan",
"Zi-Gang",
""
],
[
"Zhang",
"Ping",
""
],
[
"Li",
"Shu-Shen",
""
]
] |
0707.2847 | Hugues Sana | H. Sana, E. Gosset, Y. Naze, G. Rauw, N. Linder | The massive star binary fraction in young open clusters I. NGC 6231
revisited | 16 pages, 14 figures. Accepted by MNRAS | MNRAS, 386, 447-460 (2008) | 10.1111/j.1365-2966.2008.13037.x | null | astro-ph | null | We present the results of a long-term high-resolution spectroscopy campaign
on the O-type stars in NGC 6231. We revise the spectral classification and
multiplicity of these objects and we constrain the fundamental properties of
the O-star population. Almost three quarters of the O-type stars in the cluster
are members of a binary system. The minimum binary fraction is 0.63, with half
the O-type binaries having an orbital period of the order of a few days. The
eccentricities of all the short-period binaries are revised downward, and
henceforth match a normal period-eccentricity distribution. The mass-ratio
distribution shows a large preference for O+OB binaries, ruling out the
possibility that, in NGC 6231, the companion of an O-type star is randomly
drawn from a standard IMF. Obtained from a complete and homogeneous population
of O-type stars, our conclusions provide interesting observational constraints
to be confronted with the formation and early-evolution theories of O stars.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 08:18:37 GMT"
},
{
"version": "v2",
"created": "Thu, 31 Jan 2008 13:22:45 GMT"
}
] | 2020-12-09T00:00:00 | [
[
"Sana",
"H.",
""
],
[
"Gosset",
"E.",
""
],
[
"Naze",
"Y.",
""
],
[
"Rauw",
"G.",
""
],
[
"Linder",
"N.",
""
]
] |
0707.2848 | Shinji Tsujikawa | Sudhakar Panda, M. Sami, Shinji Tsujikawa | Prospects of inflation in delicate D-brane cosmology | 12 pages, 8 figures, version to appear in Physical Review D | Phys.Rev.D76:103512,2007 | 10.1103/PhysRevD.76.103512 | null | hep-th astro-ph gr-qc hep-ph | null | We study D-brane inflation in a warped conifold background that includes
brane-position dependent corrections for the nonperturbative superpotential.
Instead of stabilizing the volume modulus chi at instantaneous minima of the
potential and studying the inflation dynamics with an effective single field
(radial distance between a brane and an anti-brane) phi, we investigate the
multi-field inflation scenario involving these two fields. The two-field
dynamics with the potential V(phi,chi) in this model is significantly different
from the effective single-field description in terms of the field phi when the
field chi is integrated out. The latter picture underestimates the total number
of e-foldings even by one order of magnitude. We show that a correct
single-field description is provided by a field psi obtained from a rotation in
the two-field space along the background trajectory. This model can give a
large number of e-foldings required to solve flatness and horizon problems at
the expense of fine-tunings of model parameters. We also estimate the spectra
of density perturbations and show that the slow-roll parameter eta_{psi
psi}=M_{pl}^2 V_{,psi psi}/V in terms of the rotated field psi determines the
spectral index of scalar metric perturbations. We find that it is generally
difficult to satisfy, simultaneously, both constraints of the spectral index
and the COBE normalization, while the tensor to scalar ratio is sufficiently
small to match with observations.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 08:23:20 GMT"
},
{
"version": "v2",
"created": "Mon, 29 Oct 2007 08:39:53 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Panda",
"Sudhakar",
""
],
[
"Sami",
"M.",
""
],
[
"Tsujikawa",
"Shinji",
""
]
] |
0707.2849 | Taekyun Kim | Yilmaz Simsek | Complete sums of products of (h,q)-extension of Euler numbers and
polynomials | 10 pages | null | null | null | math.NT | null | In this paper we investigate some interesting of the (h,q)-extension of Euler
numbers and polynomials. Finally, we will give some relations between these
numbers anf polynomials
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 08:35:04 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Simsek",
"Yilmaz",
""
]
] |
0707.2850 | J. Marvin Herndon | J. Marvin Herndon | Nuclear Georeactor Generation of Earth's Geomagnetic Field | Submitted to Current Science | null | null | null | physics.geo-ph physics.gen-ph physics.space-ph | null | The purpose of this communication is to suggest that the mechanism for
generating the geomagnetic field and the energy source for powering it are one
and the same, a nuclear georeactor at the center of the Earth. Toward this end,
I: i) Present evidence that the nuclear georeactor fission-product sub-shell is
fluid; ii)Suggest that the geomagnetic field is generated within the georeactor
sub-shell, rather than within Earth's iron-alloy fluid core; iii) Describe why
convection appears more feasible within the georeactor sub-shell than within
the iron-alloy core; iv) Disclose additional relative physical advantages for
georeactor sub-shell dynamo operation; and, v) Outline briefly the research
that should be conducted to advance the state of knowledge of
georeactor-geomagnetic field generation. The concept of geomagnetic field
production by the nuclear georeactor is presented specifically for the Earth.
The concepts and principles, however, are generally applicable to planetary
magnetic field production.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:15:26 GMT"
},
{
"version": "v2",
"created": "Mon, 23 Jul 2007 22:00:00 GMT"
},
{
"version": "v3",
"created": "Wed, 25 Jul 2007 16:44:36 GMT"
},
{
"version": "v4",
"created": "Tue, 28 Aug 2007 20:54:39 GMT"
}
] | 2007-08-28T00:00:00 | [
[
"Herndon",
"J. Marvin",
""
]
] |
0707.2851 | Hugh R. Morton | H. R. Morton and P. M. G. Manchon | Geometrical relations and plethysms in the Homfly skein of the annulus | 28 pages, 15 figures | J. London Math. Soc. 78 (2008), 305-328. | 10.1112/jlms/jdn026 | null | math.GT | null | The oriented framed Homfly skein C of the annulus provides the natural
parameter space for the Homfly satellite invariants of a knot. It contains a
submodule C+ isomorphic to the algebra of the symmetric functions.
We collect and expand formulae relating elements expressed in terms of
symmetric functions to Turaev's geometrical basis of C+. We reformulate the
formulae of Rosso and Jones for quantum sl(N) invariants of cables in terms of
plethysms of symmetric functions, and use the connection between quantum sl(N)
invariants and C+ to give a formula for the satellite of a cable as an element
of C+. We then analyse the case where a cable is decorated by the pattern which
corresponds to a power sum in the symmetric function interpretation of C+ to
get direct relations between the Homfly invariants of some diagrams decorated
by power sums.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:17:45 GMT"
}
] | 2014-02-26T00:00:00 | [
[
"Morton",
"H. R.",
""
],
[
"Manchon",
"P. M. G.",
""
]
] |
0707.2852 | Alexander V. Milovanov Dr. | F. Zonca (1), P. Buratti (1), A. Cardinali (1), L. Chen (2,3), J.-Q.
Dong (4), Y.-X. Long (4), A.V. Milovanov (1,5,6), F. Romanelli (1), P.
Smeulders (1), L. Wang (7), Z.-T. Wang (4), C. Castaldo (1), R. Cesario (1),
E. Giovannozzi (1), M. Marinucci (1) and V. Pericoli Ridolfini (1) ((1)
Associazione Euratom-ENEA sulla Fusione, Frascati, Italy (2) Department of
Physics and Astronomy, University of California, Irvine CA, USA (3) Institute
for Fusion Theory and Simulation, Zhejiang University, Hangzhou, PRC (4)
Southwestern Institute of Physics, Chengdu, PRC (5) Department of Physics and
Technology, University of Tromso, Tromso, Norway (6) Department of Space
Plasma Physics, Space Research Institute, Russian Academy of Sciences,
Moscow, Russia (7) Institute of Physics, Chinese Academy of Sciences,
Beijing, PRC) | Electron fishbones: Theory and experimental evidence | 28 pages 8 figures | null | 10.1088/0029-5515/47/11/022 | null | physics.plasm-ph | null | We discuss the processes underlying the excitation of fishbone-like internal
kink instabilities driven by supra-thermal electrons generated experimentally
by different means: Electron Cyclotron Resonance Heating (ECRH) and by Lower
Hybrid (LH) power injection. The peculiarity and interest of exciting these
electron fishbones by ECRH only or by LH only is also analyzed. Not only the
mode stability is explained, but also the transition between steady state
nonlinear oscillations to bursting (almost regular) pulsations, as observed in
FTU, is interpreted in terms of the LH power input. These results are directly
relevant to the investigation of trapped alpha particle interactions with
low-frequency MHD modes in burning plasmas: in fact, alpha particles in reactor
relevant conditions are characterized by small dimensionless orbits, similarly
to electrons; the trapped particle bounce averaged dynamics, meanwhile, depends
on energy and not mass.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:00:01 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Zonca",
"F.",
""
],
[
"Buratti",
"P.",
""
],
[
"Cardinali",
"A.",
""
],
[
"Chen",
"L.",
""
],
[
"Dong",
"J. -Q.",
""
],
[
"Long",
"Y. -X.",
""
],
[
"Milovanov",
"A. V.",
""
],
[
"Romanelli",
"F.",
""
],
[
"Smeulders",
"P.",
""
],
[
"Wang",
"L.",
""
],
[
"Wang",
"Z. -T.",
""
],
[
"Castaldo",
"C.",
""
],
[
"Cesario",
"R.",
""
],
[
"Giovannozzi",
"E.",
""
],
[
"Marinucci",
"M.",
""
],
[
"Ridolfini",
"V. Pericoli",
""
]
] |
0707.2853 | Kazuhito Shida | Kazuhito Shida | Phase transition in the maximum clique problem: the case of Erdos-Renyi
graphs | About 12pages, 1 tables, 4 figures, | null | null | null | cond-mat.stat-mech | null | A phase transition, like the one already found on Boolean satisfiability
problem by Kirkpatrick and Selman, is found on max clique problem on ER graphs.
Although number of the datapoints is limited, the transition seems to obey
finite size scaling. The transition also shows concentration of the graph
instances which need particularly large CPU time to solve.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:04:08 GMT"
},
{
"version": "v2",
"created": "Sat, 12 Jan 2008 11:51:45 GMT"
}
] | 2008-01-12T00:00:00 | [
[
"Shida",
"Kazuhito",
""
]
] |
0707.2854 | Francesco Cianfrani dr | Francesco Cianfrani, Giovanni Montani | Boost invariance of the gravitational field dynamics: quantization
without time gauge | 9 pages, accepted for publication on Classical and Quantum Gravity | Class.Quant.Grav.24:4161-4168,2007 | 10.1088/0264-9381/24/16/011 | null | gr-qc | null | We perform a canonical quantization of gravity in a second-order formulation,
taking as configuration variables those describing a 4-bein, not adapted to the
space-time splitting. We outline how, neither if we fix the Lorentz frame
before quantizing, nor if we perform no gauge fixing at all, is invariance
under boost transformations affected by the quantization.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:14:55 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Cianfrani",
"Francesco",
""
],
[
"Montani",
"Giovanni",
""
]
] |
0707.2855 | Andrei Kataev | A.L.Kataev (INR, Moscow) | Non-planar structure of analytical QCD predictions for the Gottfried sum
rule | 12 pages, based on the talk at the Parralel Session of XI
International Workshop on Advanced Computing and Analysis Techniques in
Physics Research (ACAT07), April 23-27, 2007, Amsterdam; submitted to the
Proceedings | PoSACAT2007:072,2007 | null | null | hep-ph hep-ex hep-th | null | It is stressed that within large N_c-expansion {\bf analytical calculations}
of the $(\alpha_s/\pi)^2$ QCD contributions to the valence part of the
Gottfried sum rule for F_2 structure function of charged leptons-nucleon
deep-inelastic scattering reveals the existence of the $O(1/N_c^2)$ {\bf
non-planar} corrections only and the disappearance of the {\bf planar} O(N_c^0)
perturbative terms. The relation between Gottfried and Adler sum rule for
neutino-nucleon DIS is established and the proposal that the differebce between
corresponding QCD corrections to higher non-singlet moments in charged-lepton
and neutrino DIS are {\bf suppressed by 1/N_c^2} is made. The possible
consequence of the cancellation of {\bf perturbative planar} graphs in the
considered perturbative series, namely the existence of light-quark flavour
asymmetry $\bar{u}(x)<\bar{d}(x)$, is mentioned. The effect of the similar
origin, i.e. the relation of {\bf ``light-by-light-type''-type structure} in
DIS characteristics at the $\alpha_s^3$-level to the generation of light
quark-antiquark asymmetry, is also commented.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:16:35 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Kataev",
"A. L.",
"",
"INR, Moscow"
]
] |
0707.2856 | Leonid Pilyugin | L. S. Pilyugin, T. X. Thuan | The Oxygen Abundance of Nearby Galaxies from Sloan Digital Sky Survey
Spectra | 39 pages, 10 figures, 4 tables, accepted for publication in the
Astrophysical Journal | null | 10.1086/521597 | null | astro-ph | null | We have derived the oxygen abundance for a sample of nearby galaxies in the
Data Release 5 of the Sloan Digital Sky Survey (SDSS) which possess at least
two independent spectra of one or several HII regions with a detected
[OIII]4363 auroral line. Since, for nearby galaxies, the [OII]3727 nebular line
is out of the observed wavelength range, we propose a method to derive (O/H)_ff
abundances using the classic Te method coupled with the ff relation. (O/H)_7325
abundances have also been determined, based on the [OII]7320,7330 line
intensities, and using a small modification of the standard Te method. The
(O/H)_ff and (O/H)_7325 abundances have been derived with both the one- and
two-dimensional t_2 - t_3 relations. It was found that the (O/H)_ff abundances
derived with the parametric two-dimensional t_2 - t_3 relation are most
reliable. Oxygen abundances have been determined in 29 nearby galaxies, based
on 84 individual abundance determinations in HII regions. Because of our
selection methods, the metallicity of our galaxies lies in the narrow range 8.2
< 12 + log (O/H) < 8.4. The radial distribution of oxygen abundances in the
disk of the spiral galaxy NGC 4490 is determined for the first time.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:17:24 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pilyugin",
"L. S.",
""
],
[
"Thuan",
"T. X.",
""
]
] |
0707.2857 | Luigi Scelsi | L. Scelsi (1 and 2), A. Maggio (2), G. Micela (2), K. Briggs (3), M.
Guedel (3) ((1) Dipartimento di Scienze Fisiche ed Astronomiche, Universita
di Palermo, Italy, (2) INAF-Osservatorio Astronomico di Palermo, Italy, (3)
Paul Scherrer Institut, Villigen, Switzerland) | Coronal abundances of X-ray bright pre-main sequence stars in the Taurus
Molecular Cloud | 14 pages, 11 figures, to be published in Astronomy & Astrophysics | null | 10.1051/0004-6361:20077792 | null | astro-ph | null | We studied the thermal properties and chemical composition of the X-ray
emitting plasma of a sample of bright members of the Taurus Molecular Cloud to
investigate possible differences among classical and weak-lined T Tauri stars
and possible dependences of the abundances on the stellar activity level and/or
on the presence of accretion/circumstellar material. We used medium-resolution
X-ray spectra obtained with the sensitive EPIC/PN camera in order to analyse
the possible sample. The PN spectra of 20 bright (L_X ~ 10^30 - 10^31 erg/s)
Taurus members, with at least ~ 4500 counts, were fitted using thermal models
of optically thin plasma with two components and variable abundances of O, Ne,
Mg, Si, S, Ar, Ca, and Fe. Extensive preliminary investigations were employed
to study the performances of the PN detectors regarding abundance
determinations, and finally to check the results of the fittings. We found that
the observed X-ray emission of the studied stars can be attributed to coronal
plasma having similar thermal properties and chemical composition both in the
classical and in the weak-lined T Tauri stars. The results of the fittings did
not show evidence for correlations of the abundance patterns with activity or
accretion/disk presence. The iron abundance of these active stars is
significantly lower than (~ 0.2 of) the solar photospheric value. An indication
of slightly different coronal properties in stars with different spectral type
is found from this study. G-type and early K-type stars have, on average,
slightly higher Fe abundances (Fe ~ 0.24 solar) with respect to stars with
later spectral type (Fe ~ 0.15 solar), confirming previous findings from
high-resolution X-ray spectroscopy; stars of the former group are also found to
have, on average, hotter coronae.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:20:44 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Scelsi",
"L.",
"",
"1 and 2"
],
[
"Maggio",
"A.",
""
],
[
"Micela",
"G.",
""
],
[
"Briggs",
"K.",
""
],
[
"Guedel",
"M.",
""
]
] |
0707.2858 | John Hartnett | John G. Hartnett | Spheroidal and elliptical galaxy radial velocity dispersion determined
from Cosmological General Relativity | 10 pages, 3 figures | Int. J. Theor. Phys. 47(5): 1252-1260, 2008 | 10.1007/s10773-007-9558-0 | null | physics.gen-ph | null | Radial velocity dispersion in spheroidal and elliptical galaxies, as a
function of radial distance from the center of the galaxy, has been derived
from Cosmological Special Relativity. For velocity dispersions in the outer
regions of spherical galaxies, the dynamical mass calculated for a galaxy using
Carmelian theory may be 10 to 100 times less than that calculated from standard
Newtonian physics. This means there is no need to include halo dark matter. The
velocity dispersion is found to be approximately constant across the galaxy
after falling from an initial high value at the center.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:26:55 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hartnett",
"John G.",
""
]
] |
0707.2859 | Hendrik De Bie | Hendrik De Bie, Frank Sommen | A Clifford analysis approach to superspace | 15 pages, accepted for publication in Annals of Physics | null | 10.1016/j.aop.2007.04.012 | null | hep-th math-ph math.MP | null | A new framework for studying superspace is given, based on methods from
Clifford analysis. This leads to the introduction of both orthogonal and
symplectic Clifford algebra generators, allowing for an easy and canonical
introduction of a super-Dirac operator, a super-Laplace operator and the like.
This framework is then used to define a super-Hodge coderivative, which,
together with the exterior derivative, factorizes the Laplace operator. Finally
both the cohomology of the exterior derivative and the homology of the Hodge
operator on the level of polynomial-valued super-differential forms are
studied. This leads to some interesting graphical representations and provides
a better insight in the definition of the Berezin-integral.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:29:39 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"De Bie",
"Hendrik",
""
],
[
"Sommen",
"Frank",
""
]
] |
0707.2860 | Jeff Greensite | J. Greensite and S. Olejnik | Dimensional Reduction and the Yang-Mills Vacuum State in 2+1 Dimensions | 14 pages, 9 figures. v2: Typos corrected. v3: added a new section
discussing alternative (new variables) approaches, and fixed a problem with
the appearance of figures in the pdf version. Version to appear in Phys Rev D | Phys.Rev.D77:065003,2008 | 10.1103/PhysRevD.77.065003 | null | hep-lat hep-th | null | We propose an approximation to the ground state of Yang-Mills theory,
quantized in temporal gauge and 2+1 dimensions, which satisfies the Yang-Mills
Schrodinger equation in both the free-field limit, and in a strong-field zero
mode limit. Our proposal contains a single parameter with dimensions of mass;
confinement via dimensional reduction is obtained if this parameter is
non-zero, and a non-zero value appears to be energetically preferred. A method
for numerical simulation of this vacuum state is developed. It is shown that if
the mass parameter is fixed from the known string tension in 2+1 dimensions,
the resulting mass gap deduced from the vacuum state agrees, to within a few
percent, with known results for the mass gap obtained by standard lattice Monte
Carlo methods.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:57:02 GMT"
},
{
"version": "v2",
"created": "Thu, 9 Aug 2007 11:12:23 GMT"
},
{
"version": "v3",
"created": "Fri, 1 Feb 2008 00:14:57 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Greensite",
"J.",
""
],
[
"Olejnik",
"S.",
""
]
] |
0707.2861 | Dimitri Frantzeskakis | P. Niarchou, G. Theocharis, P.G. Kevrekidis, P. Schmelcher, and D.J.
Frantzeskakis | Soliton oscillations in collisionally inhomogeneous attractive
Bose-Einstein condensates | null | null | 10.1103/PhysRevA.76.023615 | null | cond-mat.other | null | We investigate bright matter-wave solitons in the presence of a spatially
varying nonlinearity. It is demonstrated that a translation mode is excited due
to the spatial inhomogeneity and its frequency is derived analytically and also
studied numerically. Both cases of purely one-dimensional and ``cigar-shaped''
condensates are studied by means of different mean-field models, and the
oscillation frequencies of the pertinent solitons are found and compared with
the results obtained by the linear stability analysis.Numerical results are
shown to be in very good agreement with the corresponding analytical
predictions.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:38:20 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Niarchou",
"P.",
""
],
[
"Theocharis",
"G.",
""
],
[
"Kevrekidis",
"P. G.",
""
],
[
"Schmelcher",
"P.",
""
],
[
"Frantzeskakis",
"D. J.",
""
]
] |
0707.2862 | Hendrik De Bie | Hendrik De Bie, Frank Sommen | Fundamental solutions for the super Laplace and Dirac operators and all
their natural powers | 12 pages, accepted for publication in J. Math. Anal. Appl | null | 10.1016/j.jmaa.2007.06.015 | null | math.AP hep-th | null | The fundamental solutions of the super Dirac and Laplace operators and their
natural powers are determined within the framework of Clifford analysis.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:41:40 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"De Bie",
"Hendrik",
""
],
[
"Sommen",
"Frank",
""
]
] |
0707.2863 | Hendrik De Bie | Hendrik De Bie, Frank Sommen | Hermite and Gegenbauer polynomials in superspace using Clifford analysis | 18 pages, accepted for publication in J. Phys. A | J.Phys.A40:10441-10456,2007 | 10.1088/1751-8113/40/34/004 | null | hep-th math.CA | null | The Clifford-Hermite and the Clifford-Gegenbauer polynomials of standard
Clifford analysis are generalized to the new framework of Clifford analysis in
superspace in a merely symbolic way. This means that one does not a priori need
an integration theory in superspace. Furthermore a lot of basic properties,
such as orthogonality relations, differential equations and recursion formulae
are proven. Finally, an interesting physical application of the super
Clifford-Hermite polynomials is discussed, thus giving an interpretation to the
super-dimension.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:48:04 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"De Bie",
"Hendrik",
""
],
[
"Sommen",
"Frank",
""
]
] |
0707.2864 | Pedrame Bargassa | D0 Collaboration: V. Abazov, et al | Search for the lightest scalar top quark in events with two leptons in
p-pbar collisions at sqrt(s) = 1.96 TeV | 9 pages, 11 figures. Selection-cut layouts slightly different than in
PLB | Phys.Lett.B659:500-508,2008 | 10.1016/j.physletb.2007.11.086 | FERMILAB-PUB-07-352-E | hep-ex | null | Data collected by the D0 detector at a p-pbar center-of-mass energy of 1.96
TeV at the Fermilab Tevatron Collider have been used to search for pair
production of the lightest supersymmetric partner of the top quark decaying
into $b \ell \tilde{\nu}$. The search is performed in the $\ell\ell' = e\mu$
and $\mu \mu$ final states. No evidence for this process has been found in data
samples of approximately 400 pb^-1. The domain in the
[$M(\tilde{t}_1),M(\tilde{\nu})$] plane excluded at the 95% C.L. is
substantially extended by this search.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 09:58:11 GMT"
},
{
"version": "v2",
"created": "Sat, 5 Jan 2008 13:54:45 GMT"
}
] | 2010-04-08T00:00:00 | [
[
"D0 Collaboration",
"",
""
],
[
"Abazov",
"V.",
""
]
] |
0707.2865 | Martin Hardcastle | M. J. Hardcastle, J. H. Croston and R. P. Kraft | A Chandra study of particle acceleration in the multiple hotspots of
nearby radio galaxies | Accepted for ApJ. 33 pages, 8 figures inc. 2 in color | null | 10.1086/521696 | null | astro-ph | null | We present Chandra observations of a small sample of nearby classical double
radio galaxies which have more than one radio hotspot in at least one of their
lobes. The X-ray emission from the hotspots of these comparatively low-power
objects is expected to be synchrotron in origin, and therefore to provide
information about the locations of high-energy particle acceleration. In some
models of the relationship between the jet and hotspot the hotspots that are
not the current jet termination point should be detached from the energy supply
from the active nucleus and therefore not capable of accelerating particles to
high energies. We find that in fact some secondary hotspots are X-ray sources,
and thus probably locations for high-energy particle acceleration after the
initial jet termination shock. In detail, though, we show that the spatial
structures seen in X-ray are not consistent with naive expectations from a
simple shock model: the current locations of the acceleration of the
highest-energy observable particles in powerful radio galaxies need not be
coincident with the peaks of radio or even optical emission.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 10:01:33 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Hardcastle",
"M. J.",
""
],
[
"Croston",
"J. H.",
""
],
[
"Kraft",
"R. P.",
""
]
] |
0707.2866 | Ettore Vicari | M. Hasenbusch, F. Parisen Toldin, A. Pelissetto, E. Vicari | Magnetic-glassy multicritical behavior of the three-dimensional +- J
Ising model | 17 pages | Phys. Rev. B 76 (2007), 184202 | 10.1103/PhysRevB.76.184202 | null | cond-mat.dis-nn | null | We consider the three-dimensional $\pm J$ model defined on a simple cubic
lattice and study its behavior close to the multicritical Nishimori point where
the paramagnetic-ferromagnetic, the paramagnetic-glassy, and the
ferromagnetic-glassy transition lines meet in the T-p phase diagram (p
characterizes the disorder distribution and gives the fraction of ferromagnetic
bonds). For this purpose we perform Monte Carlo simulations on cubic lattices
of size $L\le 32$ and a finite-size scaling analysis of the numerical results.
The magnetic-glassy multicritical point is found at $p^*=0.76820(4)$, along the
Nishimori line given by $2p-1={\rm Tanh}(J/T)$. We determine the
renormalization-group dimensions of the operators that control the
renormalization-group flow close to the multicritical point, $y_1 = 1.02(5)$,
$y_2 = 0.61(2)$, and the susceptibility exponent $\eta = -0.114(3)$. The
temperature and crossover exponents are $\nu=1/y_2=1.64(5)$ and $\phi=y_1/y_2 =
1.67(10)$, respectively. We also investigate the model-A dynamics, obtaining
the dynamic critical exponent $z = 5.0(5)$.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 10:05:20 GMT"
}
] | 2007-11-13T00:00:00 | [
[
"Hasenbusch",
"M.",
""
],
[
"Toldin",
"F. Parisen",
""
],
[
"Pelissetto",
"A.",
""
],
[
"Vicari",
"E.",
""
]
] |
0707.2867 | Yunhe Sheng | Qian Lin, Zhangju Liu and Yunhe Sheng | Quadratic Deformations of Lie-Poisson Structures | 14 pages, no figure | Lett. Math. Phys. (2008) 83:217-229 | 10.1007/s11005-008-0221-3 | null | math.DG math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | In this letter, first we give a decomposition for any Lie-Poisson structure
$\pi_g$ associated to the modular vector. In particular, $\pi_g$ splits into
two compatible Lie-Poisson structures if $dim{g} \leq 3$. As an application, we
classified quadratic deformations of Lie-Poisson structures on $\mathbb R^3$ up
to linear diffeomorphisms.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 10:10:47 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Aug 2007 15:04:51 GMT"
},
{
"version": "v3",
"created": "Tue, 25 Mar 2008 18:11:10 GMT"
},
{
"version": "v4",
"created": "Wed, 14 Jul 2010 11:44:41 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Lin",
"Qian",
""
],
[
"Liu",
"Zhangju",
""
],
[
"Sheng",
"Yunhe",
""
]
] |
0707.2868 | Azhar Iqbal | Azhar Iqbal and Taksu Cheon | Constructing quantum games from non-factorizable joint probabilities | Revised in light of referee's comments, submitted to Physical Review
E | Physical Review E 76, 061122 (2007) | 10.1103/PhysRevE.76.061122 | null | quant-ph | null | A probabilistic framework is developed that gives a unifying perspective on
both the classical and the quantum games. We suggest exploiting peculiar
probabilities involved in Einstein-Podolsky-Rosen (EPR) experiments to
construct quantum games. In our framework a game attains classical
interpretation when joint probabilities are factorizable and a quantum game
corresponds when these probabilities cannot be factorized. We analyze how
non-factorizability changes Nash equilibria in two-player games while
considering the games of Prisoner's Dilemma, Stag Hunt, and Chicken. In this
framework we find that for the game of Prisoner's Dilemma even non-factorizable
EPR joint probabilities cannot be helpful to escape from the classical outcome
of the game. For a particular version of the Chicken game, however, we find
that the two non-factorizable sets of joint probabilities, that maximally
violates the Clauser-Holt-Shimony-Horne (CHSH) sum of correlations, indeed
result in new Nash equilibria.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 10:15:43 GMT"
},
{
"version": "v2",
"created": "Wed, 25 Jul 2007 05:33:56 GMT"
},
{
"version": "v3",
"created": "Wed, 10 Oct 2007 06:55:20 GMT"
},
{
"version": "v4",
"created": "Fri, 2 Nov 2007 08:44:49 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Iqbal",
"Azhar",
""
],
[
"Cheon",
"Taksu",
""
]
] |
0707.2869 | Alan McRae | Alan McRae | Clifford Algebras and Possible Kinematics | Published in SIGMA (Symmetry, Integrability and Geometry: Methods and
Applications) at http://www.emis.de/journals/SIGMA/ | SIGMA 3 (2007), 079, 29 pages | 10.3842/SIGMA.2007.079 | null | math-ph math.MP math.RT | null | We review Bacry and Levy-Leblond's work on possible kinematics as applied to
2-dimensional spacetimes, as well as the nine types of 2-dimensional
Cayley-Klein geometries, illustrating how the Cayley-Klein geometries give
homogeneous spacetimes for all but one of the kinematical groups. We then
construct a two-parameter family of Clifford algebras that give a unified
framework for representing both the Lie algebras as well as the kinematical
groups, showing that these groups are true rotation groups. In addition we give
conformal models for these spacetimes.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 10:49:32 GMT"
}
] | 2008-04-24T00:00:00 | [
[
"McRae",
"Alan",
""
]
] |
0707.2870 | Sheng Yunhe | Yunhe Sheng | Linear Poisson structures on R^4 | 14 pages, no figure | J. Geom. Phys. 57 (2007), 2398-2410 | 10.1016/j.geomphys.2007.08.008 | null | math.DG math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We classify all of the 4-dimensional linear Poisson structures of which the
corresponding Lie algebras can be considered as the extension by a derivation
of 3-dimensional unimodular Lie algebras. The affine Poisson structures on R^3
are totally classified.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 10:50:55 GMT"
},
{
"version": "v2",
"created": "Thu, 16 Aug 2007 15:16:31 GMT"
},
{
"version": "v3",
"created": "Tue, 25 Mar 2008 18:43:19 GMT"
},
{
"version": "v4",
"created": "Wed, 14 Jul 2010 11:41:32 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Sheng",
"Yunhe",
""
]
] |
0707.2871 | Muhammad Tahir | M. Tahir and K. Sabeeh | Theory of Weiss oscillations in the magnetoplasmon spectrum of Dirac
electrons in graphene | 9 pages, 1 figure Phys. Rev. B (accepted for publication) | null | 10.1103/PhysRevB.76.195416 | null | cond-mat.mes-hall | null | We present the collective excitations spectrum (magnetoplasmon spectrum) of
Dirac electrons in a weakly modulated single graphene layer in the presence
of a uniform magnetic field. We consider electric modulation in one-dimension
and the magnetic field applied perpendicular to graphene.We derive analytical
results for the intra-Landau band plasmon spectrum within the
self-consistent-field approach. We find Weiss oscillations in the
magnetoplasmon spectrum which is the primary focus of this work. Results are
presented for the intra-Landau band magnetoplasmon spectrum as a function of
inverse magnetic field. These results are also compared with those of
conventional 2DEG. We have found that the Weiss oscillations in the
magnetoplasmon spectrum are larger in amplitude compared to those in
conventional 2DEG for the same modulation strength, period of modulation and
electron density.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 11:02:32 GMT"
},
{
"version": "v2",
"created": "Thu, 23 Aug 2007 13:06:31 GMT"
},
{
"version": "v3",
"created": "Fri, 19 Oct 2007 11:50:07 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tahir",
"M.",
""
],
[
"Sabeeh",
"K.",
""
]
] |
0707.2872 | Ulli Wolff | Ulli Wolff | Cluster simulation of relativistic fermions in two space-time dimensions | 24 pages, 3 figures: tiny changes, mainly typos | Nucl.Phys.B789:258-276,2008 | 10.1016/j.nuclphysb.2007.08.006 | HU-EP-07/25, SFB/CCP-07-38 | hep-lat cond-mat.stat-mech hep-th | null | For Majorana-Wilson lattice fermions in two dimensions we derive a dimer
representation. This is equivalent to Gattringer's loop representation, but is
made exact here on the torus. A subsequent dual mapping leads to yet another
representation in which a highly efficient Swendsen-Wang type cluster algorithm
is constructed. It includes the possibility of fluctuating boundary conditions.
It also allows for improved estimators and makes interesting new observables
accessible to Monte Carlo. The algorithm is compatible with the Gross-Neveu as
well as an additional Z(2) gauge interaction. In this article numerical
demonstrations are reported for critical free fermions.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 11:03:50 GMT"
},
{
"version": "v2",
"created": "Thu, 6 Sep 2007 16:53:25 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Wolff",
"Ulli",
""
]
] |
0707.2873 | K\'aroly Podoski | Zoltan Halasi, Karoly Podoski | On the Orbits of Solvable Linear Groups | null | null | null | null | math.GR | null | Let $G$ be a solvable linear group acting on the finite vectorpace $V$ and
assume that $(|G|,|V|)=1$. In this paper we find $x,y\in V$ such that
$C_G(x)\cap C_G(y)=1$. In particular, this answers a question of I. M. Isaacs.
We complete some results of S. Dolphi, A. Seress and T. R. Wolf.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 11:12:32 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Halasi",
"Zoltan",
""
],
[
"Podoski",
"Karoly",
""
]
] |
0707.2874 | Domitille Anache | D. Anache-Menier and B. A. van Tiggelen | Giant fluctuations of topological charge in a disordered wave guide | 8 pages 5 figures, submitted to Waves in Random and Complex Media | null | 10.1080/17455030701788870 | null | cond-mat.other | null | We study the fluctuations of the total topological charge of a scalar wave
propagating in a hollow conducting wave guide filled with scatterers inside. We
investigate the dependence of the screening on the scattering mean free path
and on the presence of boundaries. Near the cut-off frequencies of the wave
guide, screening is strongly suppressed near the boundaries. The resulting huge
fluctuations of the total topological charge are very sensitive to the
disorder.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 11:15:37 GMT"
}
] | 2015-05-13T00:00:00 | [
[
"Anache-Menier",
"D.",
""
],
[
"van Tiggelen",
"B. A.",
""
]
] |
0707.2875 | Jacob Linder | J. Linder and A. Sudb\o | Quantum transport in noncentrosymmetric superconductors and
thermodynamics of ferromagnetic superconductors | 19 pages, 15 figures (high quality figures available in published
version). Accepted for publication in Phys. Rev. B | Phys. Rev. B 76, 054511 (2007) | 10.1103/PhysRevB.76.054511 | null | cond-mat.supr-con | null | We consider a general Hamiltonian describing coexistence of itinerant
ferromagnetism, spin-orbit coupling and mixed spin-singlet/triplet
superconducting pairing in the context of mean-field theory. The Hamiltonian is
diagonalized and exact eigenvalues are obtained, thus allowing us to write down
the coupled gap equations for the different order parameters. Our results may
then be applied to any model describing coexistence of any combination of these
three phenomena. As a specific application of our results, we consider
tunneling between a normal metal and a noncentrosymmetric superconductor with
mixed singlet and triplet gaps. The conductance spectrum reveals information
about these gaps in addition to how the influence of spin-orbit coupling is
manifested. We also consider the coexistence of itinerant ferromagnetism and
triplet superconductivity as a model for recently discovered ferromagnetic
superconductors. The coupled gap equations are solved self-consistently, and we
study the conditions necessary to obtain the coexistent regime of
ferromagnetism and superconductivity. Analytical expressions are presented for
the order parameters, and we provide an analysis of the free energy to identify
the preferred system state. Moreover, we make specific predictions concerning
the heat capacity for a ferromagnetic superconductor. In particular, we report
a nonuniversal relative jump in the specific heat, depending on the
magnetization of the system, at the uppermost superconducting phase transition.
[Shortened abstract due to arXiv submission.]
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 11:27:44 GMT"
},
{
"version": "v2",
"created": "Thu, 21 Feb 2008 08:35:09 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Linder",
"J.",
""
],
[
"Sudbø",
"A.",
""
]
] |
0707.2876 | Alastair Basden Dr | Alastair Basden, Deli Geng, Dani Guzman, Tim Morris, Richard Myers,
Chris Saunter | Shack-Hartmann sensor improvement using optical binning | Accepted for publication in Applied Optics | null | 10.1364/AO.46.006136 | null | physics.optics physics.ins-det | null | We present a design improvement for a recently proposed type of
Shack-Hartmann wavefront sensor that uses a cylindrical (lenticular) lenslet
array. The improved sensor design uses optical binning and requires
significantly fewer detector pixels than the corresponding conventional or
cylindrical Shack-Hartmann sensor, and so detector readout noise causes less
signal degradation. Additionally, detector readout time is significantly
reduced, which reduces the latency for closed loop systems, and data processing
requirements. We provide simple analytical noise considerations and Monte-Carlo
simulations, and show that the optically binned Shack-Hartmann sensor can offer
better performance than the conventional counterpart in most practical
situations, and our design is particularly suited for use with astronomical
adaptive optics systems.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 11:34:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Basden",
"Alastair",
""
],
[
"Geng",
"Deli",
""
],
[
"Guzman",
"Dani",
""
],
[
"Morris",
"Tim",
""
],
[
"Myers",
"Richard",
""
],
[
"Saunter",
"Chris",
""
]
] |
0707.2877 | Rien van de Weygaert | Rien van de Weygaert (Kapteyn Institute, University of Groningen, the
Netherlands) | Voronoi Tessellations and the Cosmic Web: Spatial Patterns and
Clustering across the Universe | 10 pages, 9 figures, accepted for publication as long paper in
proceedings Fourth International Symposium on Voronoi Diagrams in Science and
Engineering (ISVD 2007), ed. C. Gold, IEEE Computer Society, July 2007. For
high-res version see
http://www.astro.rug.nl/~weygaert/tim1publication/vorwey.isvd07.pdf | null | null | null | astro-ph | null | The spatial cosmic matter distribution on scales of a few up to more than a
hundred Megaparsec displays a salient and pervasive foamlike pattern. Voronoi
tessellations are a versatile and flexible mathematical model for such weblike
spatial patterns. They would be the natural asymptotic result of an evolution
in which low-density expanding void regions dictate the spatial organization of
the Megaparsec Universe, while matter assembles in high-density filamentary and
wall-like interstices between the voids. We describe the results of ongoing
investigations of a variety of aspects of cosmologically relevant spatial
distributions and statistics within the framework of Voronoi tessellations.
Particularly enticing is the finding of a profound scaling of both clustering
strength and clustering extent for the distribution of tessellation nodes,
suggestive for the clustering properties of galaxy clusters. Cellular patterns
may be the source of an intrinsic ``geometrically biased'' clustering.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 12:02:35 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"van de Weygaert",
"Rien",
"",
"Kapteyn Institute, University of Groningen, the\n Netherlands"
]
] |
0707.2878 | Saurabh D. Rindani | P.S. Bhupal Dev, A. Djouadi, R.M. Godbole, M.M. M\"uhlleitner, S.D.
Rindani | Determining the CP properties of the Higgs boson | 4 pages, revtex, uses axodraw (style file included in the submission) | Phys.Rev.Lett.100:051801,2008 | 10.1103/PhysRevLett.100.051801 | IISc-CHEP/7/07, CERN-PH-TH/2007-115, LPT-ORSAY-07-49, LAPTH-1194/07 | hep-ph | null | The search and the probe of the fundamental properties of Higgs boson(s) and,
in particular, the determination of their charge conjugation and parity (CP)
quantum numbers, is one of the main tasks of future high-energy colliders. We
demonstrate that the CP properties of a Standard Model-like Higgs particle can
be unambiguously assessed by measuring just the total cross section and the top
polarization in associated Higgs production with top quark pairs in e+e-
collisions.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 12:19:41 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Dev",
"P. S. Bhupal",
""
],
[
"Djouadi",
"A.",
""
],
[
"Godbole",
"R. M.",
""
],
[
"Mühlleitner",
"M. M.",
""
],
[
"Rindani",
"S. D.",
""
]
] |
0707.2879 | Vladislav Korenivski | N. Poli, J. P. Morten, M. Urech, Arne Brataas, D. B. Haviland and V.
Korenivski | Spin injection and relaxation in a mesoscopic superconductor | 5 pages, 5 figures | null | 10.1103/PhysRevLett.100.136601 | null | cond-mat.mes-hall cond-mat.supr-con | null | We study spin accumulation and spin relaxation in a superconducting nanowire.
Spins are injected and detected by using a set of magnetic tunnel contact
electrodes, closely spaced along the nanowire. We observe a giant enhancement
of the spin accumulation of up to five orders of magnitude on transition into
the superconducting state, consistent with the expected changes in the density
of states. The spin relaxation length decreases by an order of magnitude from
its value in the normal state. These measurements combined with our theoretical
model, allow us to distinguish the individual spin flip mechanisms present in
the transport channel. Our conclusion is that magnetic impurities rather than
spin-orbit coupling dominate spin-flip scattering in the superconducting state.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 12:39:54 GMT"
},
{
"version": "v2",
"created": "Tue, 11 Dec 2007 17:08:46 GMT"
},
{
"version": "v3",
"created": "Wed, 12 Dec 2007 12:01:23 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Poli",
"N.",
""
],
[
"Morten",
"J. P.",
""
],
[
"Urech",
"M.",
""
],
[
"Brataas",
"Arne",
""
],
[
"Haviland",
"D. B.",
""
],
[
"Korenivski",
"V.",
""
]
] |
0707.2880 | Andrew G. White | B. P. Lanyon, T. J. Weinhold, N. K. Langford, J. L. O'Brien, K. J.
Resch, A. Gilchrist, and A. G. White | Manipulating biphotonic qutrits | 4 pages, 4 figures | Phys. Rev. Lett. 100, 060504 (2008) | 10.1103/PhysRevLett.100.060504 | null | quant-ph | null | Quantum information carriers with higher dimension than the canonical qubit
offer significant advantages. However, manipulating such systems is extremely
difficult. We show how measurement induced non-linearities can be employed to
dramatically extend the range of possible transforms on biphotonic qutrits; the
three level quantum systems formed by the polarisation of two photons in the
same spatio-temporal mode. We fully characterise the biphoton-photon
entanglement that underpins our technique, thereby realising the first instance
of qubit-qutrit entanglement. We discuss an extension of our technique to
generate qutrit-qutrit entanglement and to manipulate any bosonic encoding of
quantum information.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 11:56:15 GMT"
},
{
"version": "v2",
"created": "Tue, 16 Oct 2007 05:57:36 GMT"
}
] | 2010-05-28T00:00:00 | [
[
"Lanyon",
"B. P.",
""
],
[
"Weinhold",
"T. J.",
""
],
[
"Langford",
"N. K.",
""
],
[
"O'Brien",
"J. L.",
""
],
[
"Resch",
"K. J.",
""
],
[
"Gilchrist",
"A.",
""
],
[
"White",
"A. G.",
""
]
] |
0707.2881 | Fabio Bresolin | Fabio Bresolin (IfA, Hawaii), Miguel A. Urbaneja (IfA, Hawaii),
Wolfgang Gieren (Concepcion), Grzegorz Pietrzynski (Concepcion) and
Rolf-Peter Kudritzki (IfA, Hawaii) | VLT spectroscopy of blue supergiants in IC 1613 | 17 pages, accepted for publication in the Astrophysical Journal | null | 10.1086/522571 | null | astro-ph | null | We present multi-object spectroscopy of young, massive stars in the Local
Group galaxy IC 1613. We provide the spectral classification and a detailed
spectral catalog for 54 OBA stars in this galaxy. The majority of the
photometrically selected sample is composed of B- and A-type supergiants. The
remaining stars include early O-type dwarfs and the only Wolf-Rayet star known
in this galaxy. Among the early B stars we have serendipitously uncovered 6 Be
stars, the largest spectroscopically confirmed sample of this class of objects
beyond the Magellanic Clouds. We measure chemical abundances for 9 early-B
supergiants, and find a mean oxygen abundance of 12+log(O/H)=7.90 +/- 0.08.
This value is consistent with the result we obtain for two HII regions in which
we detect the temperature-sensitive [OIII]4363 auroral line.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 11:59:14 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Bresolin",
"Fabio",
"",
"IfA, Hawaii"
],
[
"Urbaneja",
"Miguel A.",
"",
"IfA, Hawaii"
],
[
"Gieren",
"Wolfgang",
"",
"Concepcion"
],
[
"Pietrzynski",
"Grzegorz",
"",
"Concepcion"
],
[
"Kudritzki",
"Rolf-Peter",
"",
"IfA, Hawaii"
]
] |
0707.2882 | Rogerio Rosenfeld | L. R. Abramo, R. C. Batista, L. Liberato and R. Rosenfeld | Structure formation in the presence of dark energy perturbations | 21 pages, 8 figures. Matches published version, with caption of Fig.
6 corrected | JCAP0711:012,2007 | 10.1088/1475-7516/2007/11/012 | null | astro-ph hep-ph | null | We study non-linear structure formation in the presence of dark energy. The
influence of dark energy on the growth of large-scale cosmological structures
is exerted both through its background effect on the expansion rate, and
through its perturbations as well. In order to compute the rate of formation of
massive objects we employ the Spherical Collapse formalism, which we generalize
to include fluids with pressure. We show that the resulting non-linear
evolution equations are identical to the ones obtained in the Pseudo-Newtonian
approach to cosmological perturbations, in the regime where an equation of
state serves to describe both the background pressure relative to density, and
the pressure perturbations relative to the density perturbations as well. We
then consider a wide range of constant and time-dependent equations of state
(including phantom models) parametrized in a standard way, and study their
impact on the non-linear growth of structure. The main effect is the formation
of dark energy structure associated with the dark matter halo: non-phantom
equations of state induce the formation of a dark energy halo, damping the
growth of structures; phantom models, on the other hand, generate dark energy
voids, enhancing structure growth. Finally, we employ the Press-Schechter
formalism to compute how dark energy affects the number of massive objects as a
function of redshift.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 11:50:14 GMT"
},
{
"version": "v2",
"created": "Mon, 13 Aug 2007 15:10:11 GMT"
},
{
"version": "v3",
"created": "Wed, 28 Nov 2007 12:50:12 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Abramo",
"L. R.",
""
],
[
"Batista",
"R. C.",
""
],
[
"Liberato",
"L.",
""
],
[
"Rosenfeld",
"R.",
""
]
] |
0707.2883 | Manuel J. Schmidt | R. Oppermann and M.J. Schmidt | Construction and purpose of effective field theories for frustrated
magnetic order | Published online in Physica Status Solidi C (June 4 2007) | null | 10.1002/pssc.200775418 | null | cond-mat.dis-nn | null | This article reviews recent years' progress in the low temperature analysis
of standard models of spin glass order such as the Sherrington-Kirkpatrick (SK)
model. Applications to CdTe/CdMnTe layered systems and explanation of glassy
antiferromagnetic order at lowest temperatures stimulated us to study in detail
the beautifully complex physical effects of replica symmetry breaking (RSB).We
discuss analytical ideas based on highly precise numerical data which lead to
the construction of relatively simple effective field theories for the SK model
and help to understand the mysterious features of its exact solution. The goal
is to find construction principles for the theory of interplay between
frustrated magnetic order and various relevant physical degrees of freedom. The
emphasis in this article is on the role of Parisi's RSB, which surprisingly
creates critical phenomena in the low temperature limit despite the absence of
a standard phase transition.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 12:44:52 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Oppermann",
"R.",
""
],
[
"Schmidt",
"M. J.",
""
]
] |
0707.2884 | Tam\'{a}s Antal | Tam\'as Antal | On multidimensional item response theory -- a coordinate free approach | Published at http://dx.doi.org/10.1214/07-EJS016 in the Electronic
Journal of Statistics (http://www.i-journals.org/ejs/) by the Institute of
Mathematical Statistics (http://www.imstat.org) | Electronic Journal of Statistics 2007, Vol. 1, 290-306 | 10.1214/07-EJS016 | IMS-EJS-EJS_2007_16 | math.ST stat.TH | null | A coordinate system free definition of complex structure multidimensional
item response theory (MIRT) for dichotomously scored items is presented. The
point of view taken emphasizes the possibilities and subtleties of
understanding MIRT as a multidimensional extension of the ``classical''
unidimensional item response theory models. The main theorem of the paper is
that every monotonic MIRT model looks the same; they are all trivial extensions
of univariate item response theory.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 12:16:01 GMT"
}
] | 2009-09-29T00:00:00 | [
[
"Antal",
"Tamás",
""
]
] |
0707.2885 | Sudhir R. Ghorpade | Sudhir R. Ghorpade and Balmohan V. Limaye | Sylvester's Minorant Criterion, Lagrange-Beltrami Identity, and
Nonnegative Definiteness | 6 pages | The Mathematics Student. Special Centenary Volume (2007),
123--130. | null | null | math.HO math.GM | null | We consider the characterizations of positive definite as well as nonnegative
definite quadratic forms in terms of the principal minors of the associated
symmetric matrix. We briefly review some of the known proofs, including a
classical approach via the Lagrange-Beltrami identity. For quadratic forms in
up to 3 variables, we give an elementary and self-contained proof of
Sylvester's Criterion for positive definiteness as well as for nonnegative
definiteness. In the process, we obtain an explicit version of
Lagrange-Beltrami identity for ternary quadratic forms.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 12:27:22 GMT"
}
] | 2008-08-17T00:00:00 | [
[
"Ghorpade",
"Sudhir R.",
""
],
[
"Limaye",
"Balmohan V.",
""
]
] |
0707.2886 | Laurent Romary | Laurent Romary (MPDL) | OA@MPS - a colourful view | null | Zeitschrift f\"ur Bibliothekswesen und Bibliographie (15/08/2007)
7 pages | null | null | cs.DL | null | The open access agenda of the Max Planck Society, initiator of the Berlin
Declaration, envisions the support of both the green way and the golden way to
open access. For the implementation of the green way the Max Planck Society
through its newly established unit (Max Planck Digital Library) follows the
idea of providing a centralized technical platform for publications and a local
support for editorial issues. With regard to the golden way, the Max Planck
Society fosters the development of open access publication models and
experiments new publishing concepts like the Living Reviews journals.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 12:30:42 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Romary",
"Laurent",
"",
"MPDL"
]
] |
0707.2887 | Manuel Perucho Pla | M. Perucho and A. P. Lobanov | Kelvin-Helmholtz modes revealed by the transversal structure of the jet
in 0836+710 | 7 pages, to be published in the proceedings of: Extragalactic Jets,
Theory and Observation from Radio to Gamma Ray | null | null | null | astro-ph | null | Studying transversal structure in extragalactic jets is crucial for
understanding their physics. The Japanese led space VLBI project VSOP has
offered arguably the best opportunity for such studies, by reaching baseline
lengths of up to 36,000 km and resolving structures down to an angular size of
0.3 mas at 5 GHz. VSOP observations of the jet in 0836+710 at 1.6 and 5 GHz
have enabled tracing the radial structure of the flow on scales from 2 mas to
200 mas and determining the wavelengths of individual oscillatory modes
responsible for the formation of the structure observed. We conclude that these
modes are produced by Kelvin-Helmholtz instability in a sheared relativistic
flow. Our results point towards the stratification of the jet and the growth of
different modes at different jet radii. We also discuss the implications of the
driving frequency on the physics of the active nucleus of the quasar.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 12:48:02 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Perucho",
"M.",
""
],
[
"Lobanov",
"A. P.",
""
]
] |
0707.2888 | Enrico Perfetto | E. Perfetto, J. Gonzalez, F. Guinea, S. Bellucci and P. Onorato | Quantum Hall effect in carbon nanotubes and curved graphene strips | To appear in Phys. Rev. B | null | 10.1103/PhysRevB.76.125430 | null | cond-mat.mes-hall | null | We develop a long wavelength approximation in order to describe the
low-energy states of carbon nanotubes in a transverse magnetic field. We show
that, in the limit where the square of the magnetic length $l = \sqrt{\hbar c
/e B}$ is much larger than the $C$-$C$ distance times the nanotube radius $R$,
the low-energy theory is given by the linear coupling of a two-component Dirac
spinor to the corresponding vector potential. We investigate in this regime the
evolution of the band structure of zig-zag nanotubes for values of $R/l > 1$,
showing that for radius $R \approx 20$ nm a clear pattern of Landau levels
start to develop for magnetic field strength $B \gtrsim 10$ T. The levels tend
to be four-fold degenerate, and we clarify the transition to the typical
two-fold degeneracy of graphene as the nanotube is unrolled to form a curved
strip. We show that the dynamics of the Dirac fermions leads to states which
are localized at the flanks of the nanotube and that carry chiral currents in
the longitudinal direction. We discuss the possibility to observe the
quantization of the Hall conductivity in thick carbon nanotubes, which should
display steps at even multiples of $2 e^2/h$, with values doubled with respect
to those in the odd-integer quantization of graphene.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 12:42:20 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Perfetto",
"E.",
""
],
[
"Gonzalez",
"J.",
""
],
[
"Guinea",
"F.",
""
],
[
"Bellucci",
"S.",
""
],
[
"Onorato",
"P.",
""
]
] |
0707.2889 | David Coupier | David Coupier | Geography of local configurations | Published in at http://dx.doi.org/10.1214/09-AAP630 the Annals of
Applied Probability (http://www.imstat.org/aap/) by the Institute of
Mathematical Statistics (http://www.imstat.org) | Annals of Applied Probability 2010, Vol. 20, No. 3, 806-840 | 10.1214/09-AAP630 | IMS-AAP-AAP630 | math.PR math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | A $d$-dimensional binary Markov random field on a lattice torus is
considered. As the size $n$ of the lattice tends to infinity, potentials
$a=a(n)$ and $b=b(n)$ depend on $n$. Precise bounds for the probability for
local configurations to occur in a large ball are given. Under some conditions
bearing on $a(n)$ and $b(n)$, the distance between copies of different local
configurations is estimated according to their weights. Finally, a sufficient
condition ensuring that a given local configuration occurs everywhere in the
lattice is suggested.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 12:43:19 GMT"
},
{
"version": "v2",
"created": "Tue, 12 Oct 2010 11:15:32 GMT"
}
] | 2010-10-13T00:00:00 | [
[
"Coupier",
"David",
""
]
] |
0707.2890 | Leo van Iersel | Leo van Iersel, Judith Keijsper, Steven Kelk, Leen Stougie | Constructing level-2 phylogenetic networks from triplets | null | null | null | null | q-bio.PE | null | Jansson and Sung showed that, given a dense set of input triplets T
(representing hypotheses about the local evolutionary relationships of triplets
of species), it is possible to determine in polynomial time whether there
exists a level-1 network consistent with T, and if so to construct such a
network. They also showed that, unlike in the case of trees (i.e. level-0
networks), the problem becomes NP-hard when the input is non-dense. Here we
further extend this work by showing that, when the set of input triplets is
dense, the problem is even polynomial-time solvable for the construction of
level-2 networks. This shows that, assuming density, it is tractable to
construct plausible evolutionary histories from input triplets even when such
histories are heavily non-tree like. This further strengthens the case for the
use of triplet-based methods in the construction of phylogenetic networks. We
also show that, in the non-dense case, the level-2 problem remains NP-hard.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 12:58:57 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"van Iersel",
"Leo",
""
],
[
"Keijsper",
"Judith",
""
],
[
"Kelk",
"Steven",
""
],
[
"Stougie",
"Leen",
""
]
] |
0707.2891 | Miroslav Pozek | M. Pozek, I. Kupcic, A. Dulcic, A. Hamzic, D. Paar, M. Basletic, E.
Tafra, G. V. M. Williams | Transport, magnetic and superconducting properties of RuSr2RCu2O8 (R=
Eu, Gd) doped with Sn | 10 pages, 9 figures | Phys. Rev. B 77, 214514 (2008) | 10.1103/PhysRevB.77.214514 | null | cond-mat.supr-con cond-mat.str-el | null | Ru{1-x}Sn{x}Sr2EuCu2O8 and Ru{1-x}Sn{x}Sr2GdCu2O8 have been comprehensively
studied by microwave and dc resistivity and magnetoresistivity and by the dc
Hall measurements. The magnetic ordering temperature T_m is considerably
reduced with increasing Sn content. However, doping with Sn leads to only
slight reduction of the superconducting critical temperature T_c accompanied
with the increase of the upper critical field B_c2, indicating an increased
disorder in the system and a reduced scattering length of the conducting holes
in CuO2 layers. In spite of the increased scattering rate, the normal state
resistivity and the Hall resistivity are reduced with respect to the pure
compound, due to the increased number of itinerant holes in CuO2 layers, which
represent the main conductivity channel. Most of the electrons in RuO2 layers
are presumably localized, but the observed negative magnetoresistance and the
extraordinary Hall effect lead to the conclusion that there exists a small
number of itinerant electrons in RuO$_2$ layers that exhibit colossal
magnetoresistance.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 16:21:09 GMT"
}
] | 2012-01-10T00:00:00 | [
[
"Pozek",
"M.",
""
],
[
"Kupcic",
"I.",
""
],
[
"Dulcic",
"A.",
""
],
[
"Hamzic",
"A.",
""
],
[
"Paar",
"D.",
""
],
[
"Basletic",
"M.",
""
],
[
"Tafra",
"E.",
""
],
[
"Williams",
"G. V. M.",
""
]
] |
0707.2892 | Eran Sela | Eran Sela, H.S.Sim, Yuval Oreg, M.E. Raikh and Felix von Oppen | Electron Pair Resonance in the Coulomb Blockade | 5 pages, 4 figures | Phys. Rev. Lett. 100, 056809 (2008) | 10.1103/PhysRevLett.100.056809 | null | cond-mat.mes-hall cond-mat.str-el | null | We study many-body corrections to the cotunneling current via a localized
state with energy $\epsilon_d$ at large bias voltages $V$. We show that the
transfer of {\em electron pairs}, enabled by the Coulomb repulsion in the
localized level, results in ionization resonance peaks in the third derivative
of the current with respect to $V$, centered at $eV=\pm 2\epsilon_d/3$. Our
results predict the existence of previously unnoticed structure within
Coulomb-blockade diamonds.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 13:11:06 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sela",
"Eran",
""
],
[
"Sim",
"H. S.",
""
],
[
"Oreg",
"Yuval",
""
],
[
"Raikh",
"M. E.",
""
],
[
"von Oppen",
"Felix",
""
]
] |
0707.2893 | Yuri Gartstein | Yu.N. Gartstein and V.M. Agranovich | Excitons in long molecular chains near the reflecting interface | null | null | 10.1103/PhysRevB.76.115329 | null | cond-mat.other | null | We discuss coherent exciton-polariton states in long molecular chains that
are formed due to the interaction of molecular excitations with both vacuum
photons and surface excitations of the neighboring reflecting substrate. The
resonance coupling with surface plasmons (or surface polaritons) of the
substrate can substantially contribute to the retarded intermolecular
interactions leading to an efficient channel of the decay of one-dimensional
excitons with small momenta via emission of surface excitations. The interface
also modifies the radiative decay of excitons into vacuum photons. In an
idealized system, excitons with higher momenta would not emit photons nor
surface waves. For a dissipative substrate, additional exciton quenching takes
place owing to Joule losses as the electric field of the exciton polarization
penetrates the substrate. We discuss how these effects depend on the
polarization of molecular excitations, their frequency and on the distance of
the chain from the substrate.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 13:11:17 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Gartstein",
"Yu. N.",
""
],
[
"Agranovich",
"V. M.",
""
]
] |
0707.2894 | Nicola Bartolo | G. D'Amico (SISSA, Trieste, Italy), N. Bartolo (Physics Dept. and
INFN, Padova, Italy), S. Matarrese (Physics Dept. and INFN, Padova, Italy),
A. Riotto (Dep. de Physique Theorique, Geneva, Switzerland and INFN Padova,
Italy) | CMB temperature anisotropies from third order gravitational
perturbations | 19 pages, LateX file; typos corrected; some corrections made and
several consistency checks performed regarding Eqs.(2.18); (2.28)-(2.29) and
Eqs.(3.8)-(3.24) and Eq.(4.2). Version accepted for publication in JCAP | JCAP0801:005,2008 | 10.1088/1475-7516/2008/01/005 | null | astro-ph | null | In this paper we present a complete computation of the Cosmic Microwave
Background (CMB) anisotropies up to third order from gravitational
perturbations accounting for scalar, vector and tensor perturbations. We then
specify our results to the large scale limit, providing the evolution of the
gravitational potentials in a flat universe filled with matter and cosmological
constant which characterizes the Integrated Sachs-Wolfe effect. As a byproduct
in the large scale approximation we are able to give non-perturbative solutions
for the photon geodesic equations. Our results are the first step to provide a
complete theoretical prediction for cubic non-linearities which are
particularly relevant for characterizing the level of non-Gaussianity in the
CMB through the detection of the four-point angular connected correlation
function (trispectrum). For this purpose we also allow for generic initial
conditions due to primordial non-Gaussianity.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 13:21:54 GMT"
},
{
"version": "v2",
"created": "Fri, 14 Dec 2007 13:53:56 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"D'Amico",
"G.",
"",
"SISSA, Trieste, Italy"
],
[
"Bartolo",
"N.",
"",
"Physics Dept. and\n INFN, Padova, Italy"
],
[
"Matarrese",
"S.",
"",
"Physics Dept. and INFN, Padova, Italy"
],
[
"Riotto",
"A.",
"",
"Dep. de Physique Theorique, Geneva, Switzerland and INFN Padova,\n Italy"
]
] |
0707.2895 | Sara Seager | S. Seager (MIT), M. Kuchner (GSFC), C. Hier-Majumder (DTM/Ciw), B.
Militzer (GL/Ciw) | Mass-Radius Relationships for Solid Exoplanets | ApJ, in press, 33 pages including 16 figures | null | 10.1086/521346 | null | astro-ph | null | We use new interior models of cold planets to investigate the mass-radius
relationships of solid exoplanets, considering planets made primarily of iron,
silicates, water, and carbon compounds. We find that the mass-radius
relationships for cold terrestrial-mass planets of all compositions we
considered follow a generic functional form that is not a simple power law:
$\log_{10} R_s = k_1 + 1/3 \log_{10}(M_s) - k_2 M_s^{k_3}$ for up to $M_p
\approx 20 M_{\oplus}$, where $M_s$ and $R_s$ are scaled mass and radius
values. This functional form arises because the common building blocks of solid
planets all have equations of state that are well approximated by a modified
polytrope of the form $\rho = \rho_0 + c P^n$.
We find that highly detailed planet interior models, including temperature
structure and phase changes, are not necessary to derive solid exoplanet bulk
composition from mass and radius measurements. For solid exoplanets with no
substantial atmosphere we have also found that: with 5% fractional uncertainty
in planet mass and radius it is possible to distinguish among planets composed
predominantly of iron or silicates or water ice but not more detailed
compositions; with $\sim$~5% uncertainty water ice planets with $\gtrsim 25%$
water by mass may be identified; the minimum plausible planet size for a given
mass is that of a pure iron planet; and carbon planet mass-radius relationships
overlap with those of silicate and water planets due to similar zero-pressure
densities and equations of state. We propose a definition of "super Earths''
based on the clear distinction in radii between planets with significant gas
envelopes and those without.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 13:14:57 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Seager",
"S.",
"",
"MIT"
],
[
"Kuchner",
"M.",
"",
"GSFC"
],
[
"Hier-Majumder",
"C.",
"",
"DTM/Ciw"
],
[
"Militzer",
"B.",
"",
"GL/Ciw"
]
] |
0707.2896 | Roberto Rampazzo | R. Rampazzo, A. Marino, R. Tantalo, D. Bettoni, L.M. Buson, C. Chiosi,
G. Galletta, R. Grueztbauch, R.M. Rich | The GALEX UV emission in shell galaxies: tracing galaxy "rejuvenation"
episodes | Accepted for publication in MNRAS Main Journal, 21 pages, 15 figures | null | 10.1111/j.1365-2966.2007.12246.x | null | astro-ph | null | We present the GALEX far FUV and near NUV ultraviolet imaging of three nearby
shell galaxies, namely NGC 2865, NGC 5018 and NGC 7135. The system of shells
and fine structures visible in the optical is detected in the NUV image of NGC
2865 and in both NUV and FUV images of NGC 7135. The NUV image of NGC 5018 does
not present shell structures. We detect absorption features in the nuclear
region of all three galaxies. NGC 2865 has a nearly flat colour profile with
(FUV-NUV)~2 throughout the whole galaxy. NGC 7135 is blue in the center
(FUV-NUV)~0 and as red as (FUV-NUV)~1.5 in the outskirts, including the faint
shell-like feature. We investigate the ability of the nuclear GALEX (FUV-NUV)
colour to provide information about rejuvenation phenomena in the stellar
populations of the shell galaxies. To this aim, we derive from theory the
relationship between the Mg2, Hbeta, HgammaA, HdeltaA Lick line-strength
indices and the (FUV-NUV) colour. We extend the study to a sample of early-type
galaxies with emission lines in their optical spectra (Annibali et al. 2007).
In the index vs.(FUV-NUV) colour diagrams, most of the galaxies are well
explained by passively evolving SSPs. On the average, ages and metallicities of
the galaxies in our sample estimated from optical line-strength indices are
consistent with those inferred from the (FUV-NUV) colour. In general, all the
colours but for (FUV-NUV) and (FUV-V), become nearly age insensitive when 1-2
Gyr have elapsed from the last star forming event. Considering composite
stellar population models with a recent burst of star formation, we suggest
that the position of the NGC 7135 and NGC 2865 nuclei in the (FUV-NUV)-Hbeta
plane could be explained in term of a recent rejuvenation episode. (Abridged)
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 13:22:33 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Rampazzo",
"R.",
""
],
[
"Marino",
"A.",
""
],
[
"Tantalo",
"R.",
""
],
[
"Bettoni",
"D.",
""
],
[
"Buson",
"L. M.",
""
],
[
"Chiosi",
"C.",
""
],
[
"Galletta",
"G.",
""
],
[
"Grueztbauch",
"R.",
""
],
[
"Rich",
"R. M.",
""
]
] |
0707.2897 | Pasquini Barbara | B. Pasquini and S. Boffi (Pavia U. & INFN, Pavia) | Electroweak structure of the nucleon, meson cloud and light-cone
wavefunctions | references updated and typos in figure 2 corrected; to be published
in Phys. Rev. D | Phys.Rev.D76:074011,2007 | 10.1103/PhysRevD.76.074011 | null | hep-ph | null | The meson-cloud model of the nucleon consisting of a system of three valence
quarks surrounded by a meson cloud is applied to study the electroweak
structure of the proton and neutron. Light-cone wavefunctions are derived for
the dressed nucleon as pictured to be part of the time a bare nucleon and part
of the time a baryon-meson system. Configurations are considered where the
baryon can be a nucleon or a \Delta and the meson can be a pion as well as a
vector meson such as the \rho or the \omega. An overall good description of the
electroweak form factors is obtained. The contribution of the meson cloud is
small and only significant at low Q^2. Mixed-symmetry S'-wave components in the
wavefunction are most important to reproduce the neutron electric form factor.
Charge and magnetization densities are deduced as a function of both the radial
distance from the nucleon center and the transverse distance with respect to
the direction of the three-momentum transfer. In the latter case a central
negative charge is found for the neutron. The up and down quark distributions
associated with the Fourier transform of the axial form factor have opposite
sign, with the consequence that the probability to find an up (down) quark with
positive helicity is maximal when it is (anti)aligned with the proton helicity.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 15:02:47 GMT"
},
{
"version": "v2",
"created": "Mon, 8 Oct 2007 16:16:28 GMT"
}
] | 2008-11-26T00:00:00 | [
[
"Pasquini",
"B.",
"",
"Pavia U. & INFN, Pavia"
],
[
"Boffi",
"S.",
"",
"Pavia U. & INFN, Pavia"
]
] |
0707.2898 | Alexandre Eremenko | A. Eremenko, L. W. Liao and T. W. Ng | Meromorphic solutions of higher order Briot-Bouquet differential
equations | null | Math. Proc. Cambridge Philos. Soc., v. 146, no. 1 (2009) 197-206 | 10.1017/S030500410800176X | null | math.CA math.CV | null | For differential equations $P(y^{(k)},y)=0,$ where $P$ is a polynomial, we
prove that all meromorphic solutions having at least one pole are elliptic
functions, possibly degenerate.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 13:35:00 GMT"
},
{
"version": "v2",
"created": "Mon, 3 Mar 2008 15:10:12 GMT"
}
] | 2012-02-07T00:00:00 | [
[
"Eremenko",
"A.",
""
],
[
"Liao",
"L. W.",
""
],
[
"Ng",
"T. W.",
""
]
] |
0707.2899 | Marina Poltavskaya I | T. N. Antsygina, M. I. Poltavskaya, I. I. Poltavsky, and K. A. Chishko | Thermodynamics of low dimensional spin-1/2 Heisenberg ferromagnets in an
external magnetic field within Green function formalism | 11 pages, 14 figures | null | 10.1103/PhysRevB.77.024407 | null | cond-mat.str-el cond-mat.dis-nn | null | The thermodynamics of low dimensional spin-1/2 Heisenberg ferromagnets (HFM)
in an external magnetic field is investigated within a second-order two-time
Green function formalism in the wide temperature and field range. A crucial
point of the proposed scheme is a proper account of the analytical properties
for the approximate transverse commutator Green function obtained as a result
of the decoupling procedure. A good quantitative description of the correlation
functions, magnetization, susceptibility, and heat capacity of the HFM on a
chain, square and triangular lattices is found for both infinite and
finite-sized systems. The dependences of the thermodynamic functions of 2D HFM
on the cluster size are studied. The obtained results agree well with the
corresponding data found by Bethe ansatz, exact diagonalization, high
temperature series expansions, and quantum Monte Carlo simulations.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 13:35:28 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Antsygina",
"T. N.",
""
],
[
"Poltavskaya",
"M. I.",
""
],
[
"Poltavsky",
"I. I.",
""
],
[
"Chishko",
"K. A.",
""
]
] |
0707.2900 | Karen Hatsagortsyan | Michael Klaiber, Karen Z. Hatsagortsyan, Christoph H. Keitel | Zeptosecond $\gamma$-ray pulses | null | null | null | null | physics.atom-ph physics.optics | null | High-order harmonic generation (HHG) in the relativistic regime is employed
to obtain zeptosecond pulses of $\gamma$-rays. The harmonics are generated from
atomic systems in counterpropagating strong attosecond laser pulse trains of
linear polarization. In this setup recollisions of the ionized electrons can be
achieved in the highly relativistic regime via a reversal of the commonly
deteriorating drift and without instability of the electron dynamics such as in
a standing laser wave. As a result, coherent attosecond $\gamma$-rays in the 10
MeV energy range as well as coherent zeptosecond $\gamma$-ray pulses of MeV
photon energy for time-resolved nuclear spectroscopy become feasible.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 13:58:27 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Klaiber",
"Michael",
""
],
[
"Hatsagortsyan",
"Karen Z.",
""
],
[
"Keitel",
"Christoph H.",
""
]
] |
0707.2901 | Kiyokazu Myojin | Kiyokazu Myojin, Ryusuke Ikeda | Effect of in-plane line defects on field-tuned superconductor-insulator
transition behavior in homogeneous thin film | 16 pages, 14 figures | null | 10.1143/JPSJ.76.094710 | null | cond-mat.supr-con | null | Field-tuned superconductor-insulator transition (FSIT) behavior in 2D
isotropic and homogeneous thin films is usually accompanied by a nonvanishing
critical resistance at low $T$. It is shown that, in a 2D film including line
defects paralle to each other but with random positions perpendicular to them,
the (apparent) critical resistance in low $T$ limit vanishes, as in the 1D
quantum superconducting (SC) transition, under a current parallel to the line
defects. This 1D-like critical resistive behavior is more clearly seen in
systems with weaker point disorder and may be useful in clarifying whether the
true origin of FSIT behavior in the parent superconductor is the glass
fluctuation or the quantum SC fluctuation. As a by-product of the present
calculation, it is also pointed out that, in 2D films with line-like defects
with a long but {\it finite} correlation length parallel to the lines, a
quantum metallic behavior intervening the insulating and SC ones appears in the
resistivity curves.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 15:42:48 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Myojin",
"Kiyokazu",
""
],
[
"Ikeda",
"Ryusuke",
""
]
] |
0707.2902 | Brian Rodriguez | B.J. Rodriguez, S. Jesse, K. Seal, A.P. Baddorf, S.V. Kalinin, and P.
Rack | Fabrication, Dynamics, and Electrical Properties of Insulated SPM Probes
for Electrical and Electromechanical Imaging in Liquids | 3 figs | Appl. Phys. Lett. 91, 093130 (2007) | 10.1063/1.2778762 | null | cond-mat.mtrl-sci | null | Insulated cantilever probes with a high aspect ratio conducting apex have
been fabricated and their dynamic and electrical properties analyzed. The
cantilevers were coated with silicon dioxide and a via was fabricated through
the oxide at the tip apex and backfilled with tungsten to create an insulated
probe with a conducting tip. The stiffness and Q-factor of the cantilevers
increased after the modifications and their resonances shifted to higher
frequencies. The coupling strength between the cantilever and the coating are
determined. The applications to conductive and electromechanical imaging of
ferroelectric domains are illustrated, and a probe apex repair process is
demonstrated.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:05:19 GMT"
}
] | 2008-03-13T00:00:00 | [
[
"Rodriguez",
"B. J.",
""
],
[
"Jesse",
"S.",
""
],
[
"Seal",
"K.",
""
],
[
"Baddorf",
"A. P.",
""
],
[
"Kalinin",
"S. V.",
""
],
[
"Rack",
"P.",
""
]
] |
0707.2903 | Denis Rastegaev Mr. | D.A. Rastegaev, Yu.Yu. Balega, E.V. Malogolovets (Special
Astrophysical Observatory, Russia) | Speckle Interferometry of Metal-Poor Stars in the Solar Neighborhood. I | 8 pages, 4 figures, accepted to Astrophysical Bulletin | null | 10.1134/S1990341307030042 | null | astro-ph | null | We report the results of speckle-interferometric observations of 109 high
proper-motion metal-poor stars made with the 6-m telescope of the Special
Astrophysical Observatory of the Russian Academy of Sciences. We resolve eight
objects -- G102-20, G191-55, BD+19$^\circ$~1185A, G89-14, G87-45, G87-47,
G111-38, and G114-25 -- into individual components and we are the first to
astrometrically resolve seven of these stars. New resolved systems included two
triple (G111-38, G87-47) and one quadruple (G89-14) star. The ratio of
single-to-binary-to-triple-to-quadruple systems among the stars of our sample
is equal to 71:28:6:1.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:05:08 GMT"
},
{
"version": "v2",
"created": "Fri, 20 Jul 2007 08:56:04 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Rastegaev",
"D. A.",
"",
"Special\n Astrophysical Observatory, Russia"
],
[
"Balega",
"Yu. Yu.",
"",
"Special\n Astrophysical Observatory, Russia"
],
[
"Malogolovets",
"E. V.",
"",
"Special\n Astrophysical Observatory, Russia"
]
] |
0707.2904 | Henrik Beuther | H. Beuther, Q. Zhang, T.R. Hunter, T.K. Sridharan, E.A. Bergin | The 10^5Lsun High-Mass Protostellar Object IRAS23151+5912 | 9 pages, 7 figures, accepted for Astronomy and Astrophysics | null | 10.1051/0004-6361:20077992 | null | astro-ph | null | While most sources above 10^5Lsun have already formed an Ultracompact HII
region (UCHII), this is not necessarily the case for sources of lower
luminosity. Characterizing sources in the transition phase, i.e., very luminous
objects without any detectable free-free emission, is important for a general
understanding of massive star formation. Therefore, we observed the luminous
High-Mass Protostellar Object IRAS23151+5912 with the Submillimeter Array at
875mum in the submm continuum and spectral line emission at sub-arcsecond
resolution. The 875mum submm continuum emission has been resolved into at least
two condensations. The previously believed driving source of one of the
outflows, the infrared source IRS1, is ~0.9'' offset from the main submm peak.
Over the entire 4GHz bandwidth we detect an intermediate dense spectral line
forest with 27 lines from 8 different species, isotopologues or
vibrationally-torsionally excited states. Temperature estimates based on the
CH3OH line series result in values of T(Peak1)~150+-50K and T(Peak2)~80~30K for
the two submm peak positions, respectively. The SiO(8-7) red- and blue-shifted
line maps indicate the presence of two molecular outflows. In contrast, the
vibrationally-torsionally excited CH3OH line exhibits a velocity gradient
approximately perpendicular to one of the outflows. With a size of
approximately 5000AU and no Keplerian rotation signature, this structure does
not resemble a genuine accretion disk but rather a larger-scale rotating toroid
that may harbor a more common accretion disk at its so far unresolved center.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:08:22 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Beuther",
"H.",
""
],
[
"Zhang",
"Q.",
""
],
[
"Hunter",
"T. R.",
""
],
[
"Sridharan",
"T. K.",
""
],
[
"Bergin",
"E. A.",
""
]
] |
0707.2905 | Dmitry Semenov | Ya. Pavlyuchenkov (1), D. Semenov (1), Th. Henning (1), St. Guilloteau
(2), V. Pietu (3), R. Launhardt (1), A. Dutrey (2) ((1) Max Planck Institute
for Astronomy in Heidelberg, (2) Laboratoire d'Astrophysique de Bordeaux, (3)
IRAM Grenoble) | Molecular line radiative transfer in protoplanetary disks: Monte Carlo
simulations versus approximate methods | 47 pages, 12 figures, accepted for publication in ApJ | null | 10.1086/521872 | null | astro-ph | null | We analyze the line radiative transfer in protoplanetary disks using several
approximate methods and a well-tested Accelerated Monte Carlo code. A low-mass
flaring disk model with uniform as well as stratified molecular abundances is
adopted. Radiative transfer in low and high rotational lines of CO, C18O, HCO+,
DCO+, HCN, CS, and H2CO is simulated. The corresponding excitation
temperatures, synthetic spectra, and channel maps are derived and compared to
the results of the Monte Carlo calculations. A simple scheme that describes the
conditions of the line excitation for a chosen molecular transition is
elaborated. We find that the simple LTE approach can safely be applied for the
low molecular transitions only, while it significantly overestimates the
intensities of the upper lines. In contrast, the Full Escape Probability (FEP)
approximation can safely be used for the upper transitions ($J_{\rm up} \ga 3$)
but it is not appropriate for the lowest transitions because of the maser
effect. In general, the molecular lines in protoplanetary disks are partly
subthermally excited and require more sophisticated approximate line radiative
transfer methods. We analyze a number of approximate methods, namely, LVG, VEP
(Vertical Escape Probability) and VOR (Vertical One Ray) and discuss their
algorithms in detail. In addition, two modifications to the canonical Monte
Carlo algorithm that allow a significant speed up of the line radiative
transfer modeling in rotating configurations by a factor of 10--50 are
described.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:08:58 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pavlyuchenkov",
"Ya.",
""
],
[
"Semenov",
"D.",
""
],
[
"Henning",
"Th.",
""
],
[
"Guilloteau",
"St.",
""
],
[
"Pietu",
"V.",
""
],
[
"Launhardt",
"R.",
""
],
[
"Dutrey",
"A.",
""
]
] |
0707.2906 | H. Panagopoulos | A. Skouroupathis and H. Panagopoulos | Two-loop renormalization of scalar and pseudoscalar fermion bilinears on
the lattice | 30 pages, 15 figures. Correction of a minor mistake in the 2-loop
result for $Z_S$ and $Z_P$. The mistake affects (very slightly) Eqs.(51-54);
the change in numerical values is too small to alter the ensuing plots. All
conclusions remain unchanged | Phys.Rev.D76:094514,2007; Erratum-ibid.D78:119901,2008 | 10.1103/PhysRevD.76.094514 10.1103/PhysRevD.78.119901 | null | hep-lat | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We compute the two-loop renormalization functions, in the RI $^\prime$
scheme, of local bilinear quark operators $\bar{\psi}\Gamma\psi$, where
$\Gamma$ denotes the Scalar and Pseudoscalar Dirac matrices, in the lattice
formulation of QCD. We consider both the flavor non-singlet and singlet
operators; the latter, in the scalar case, leads directly to the two-loop
fermion mass renormalization, $Z_m$.
As a prerequisite for the above, we also compute the quark field
renormalization, $Z_{\psi}$, up to two loops.
We use the clover action for fermions and the Wilson action for gluons. Our
results are given as a polynomial in $c_{SW}$, in terms of both the
renormalized and bare coupling constant, in the renormalized Feynman gauge. We
also confirm the 1-loop renormalization functions, for generic gauge.
Finally, we present our results in the $\bar{MS}$ scheme, for easier
comparison with calculations in the continuum.
The corresponding results, for fermions in an arbitrary representation, are
included in an Appendix.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:10:44 GMT"
},
{
"version": "v2",
"created": "Mon, 22 Oct 2007 06:53:41 GMT"
},
{
"version": "v3",
"created": "Mon, 24 Nov 2008 09:34:38 GMT"
}
] | 2014-11-18T00:00:00 | [
[
"Skouroupathis",
"A.",
""
],
[
"Panagopoulos",
"H.",
""
]
] |
0707.2907 | Euihun Joung | E. Joung, J. Mourad, R. Parentani | Group theoretical approach to quantum fields in de Sitter space II. The
complementary and discrete series | 39 pages, 1 figure | JHEP 0709:030,2007 | 10.1088/1126-6708/2007/09/030 | null | hep-th | null | We use an algebraic approach based on representations of de Sitter group to
construct covariant quantum fields in arbitrary dimensions. We study the
complementary and the discrete series which correspond to light and massless
fields and which lead new feature with respect to the massive principal series
we previously studied (hep-th/0606119). When considering the complementary
series, we make use of a non-trivial scalar product in order to get local
expressions in the position representation. Based on these, we construct a
family of covariant canonical fields parametrized by SU(1,1)/U(1). Each of
these correspond to the dS invariant alpha-vacua. The behavior of the modes at
asymptotic times brings another difficulty as it is incompatible with the usual
definition of the in and out vacua. We propose a generalized notion of these
vacua which reduces to the usual conformal vacuum in the conformally massless
limit. When considering the massless discrete series we find that no covariant
field obeys the canonical commutation relations. To further analyze this
singular case, we consider the massless limit of the complementary scalar
fields we previously found. We obtain canonical fields with a deformed
representation by zero modes. The zero modes have a dS invariant vacuum with
singular norm. We propose a regularization by a compactification of the scalar
field and a dS invariant definition of the vertex operators. The resulting
two-point functions are dS invariant and have a universal logarithmic infrared
divergence.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:20:50 GMT"
}
] | 2009-11-18T00:00:00 | [
[
"Joung",
"E.",
""
],
[
"Mourad",
"J.",
""
],
[
"Parentani",
"R.",
""
]
] |
0707.2908 | S\'{e}bastien Chambeu | S\'ebastien Chambeu, Aline Kurtzmann | Some particular self-interacting diffusions: Ergodic behaviour and
almost sure convergence | Published in at http://dx.doi.org/10.3150/10-BEJ310 the Bernoulli
(http://isi.cbs.nl/bernoulli/) by the International Statistical
Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm) | Bernoulli 2011, Vol. 17, No. 4, 1248-1267 | 10.3150/10-BEJ310 | IMS-BEJ-BEJ310 | math.PR math.ST stat.TH | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | This paper deals with some self-interacting diffusions $(X_t,t\geq 0)$ living
on $\mathbb{R}^d$. These diffusions are solutions to stochastic differential
equations: \[\mathrm{d}X_t=\mathrm{d}B_t-g(t)\nabla
V(X_t-\bar{\mu}_t)\,\mathrm{d}t,\] where $\bar{\mu}_t$ is the empirical mean of
the process $X$, $V$ is an asymptotically strictly convex potential and $g$ is
a given function. We study the ergodic behaviour of $X$ and prove that it is
strongly related to $g$. Actually, we show that $X$ is ergodic (in the limit
quotient sense) if and only if $\bar{\mu}_t$ converges a.s. We also give some
conditions (on $g$ and $V$) for the almost sure convergence of $X$.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:12:01 GMT"
},
{
"version": "v2",
"created": "Thu, 4 Dec 2008 14:26:48 GMT"
},
{
"version": "v3",
"created": "Wed, 4 Jan 2012 12:33:35 GMT"
}
] | 2012-01-05T00:00:00 | [
[
"Chambeu",
"Sébastien",
""
],
[
"Kurtzmann",
"Aline",
""
]
] |
0707.2909 | Juan Guillermo Diaz Ochoa Dr. | Juan G. Diaz Ochoa | Evolutionary dynamics and diversity in populations | 11 Pages, 9 Figures | null | null | null | physics.bio-ph physics.soc-ph | null | The dynamics of populations is rich, taking into account that both, the
individual's actions and the population's fitness are coupled. The way in which
an individual chooses a strategy depends off course on the interaction with
other individuals and the relation between selection and mutation within the
population. The present model considers individuals with {\it memory}. This
memory is represented by a device where information of past actions is stored
as bits in a 1D Ising chain. The selection of a new individual action depends
on the individual's memory. If the selection of a strategy does not improve the
individual's fitness, a new individual with different memory size replaces it.
Both, actions and memory are observables that characterize the population. They
can change in time, and both depend on the fitness of the population. This
model allows the implementation of {\it learning} parameters as well as an {\it
external information source}, acting as an {\it external field} which drives
individuals to select one preferred action. In particular we show that the {\it
diversity} of the population, measured as a {\it Shannon's diversity index}
(equivalent to a neg-entropy), is not only related to the {\it energy
consumption and size} of the system, but is also related to the way in which
the individuals are influenced by the {\it external field}.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:17:52 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Ochoa",
"Juan G. Diaz",
""
]
] |
0707.2910 | Aline Kurtzmann | Sebastien Chambeu, Aline Kurtzmann | Convergence in distribution of some particular self-interacting
diffusions: the simulated annealing method | companion paper to 0707.2908 | null | null | null | math.PR | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | The present paper is concerned with some self-interacting diffusions
$(X_t,t\geq 0)$ living on $\mathbb{R}^d$. These diffusions are solutions to
stochastic differential equations: $$\mathrm{d}X_t = \mathrm{d}B_t - g(t)\nabla
V(X_t - \bar{\mu}_t) \mathrm{d}t$$ where $\bar{\mu}_t$ is the empirical mean of
the process $X$, $V$ is an asymptotically strictly convex potential and $g$ is
a given function. The authors have still studied the ergodic behavior of $X$
and proved that it is strongly related to $g$. We go further and give necessary
and sufficient conditions (for small $g$'s) in order that $X$ converges in
probability to $X_\infty$ (which is related to the global minima of $V$).
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:18:04 GMT"
},
{
"version": "v2",
"created": "Thu, 4 Dec 2008 14:27:58 GMT"
}
] | 2008-12-04T00:00:00 | [
[
"Chambeu",
"Sebastien",
""
],
[
"Kurtzmann",
"Aline",
""
]
] |
0707.2911 | Matteo Cavalleri | Matteo Cavalleri, Michael Odelius, Dennis Nordlund, Anders Nilsson and
Lars G.M. Pettersson | Half or full core-hole in density functional theory X-ray absorption
spectrum calculations of water? | 4 pages, 3 figures | Phys. Chem. Chem. Phys., 15, 2854 (2005) | 10.1039/B505723J | null | cond-mat.soft cond-mat.mtrl-sci | null | We analyze the performance of two different core-hole potentials in the
theoretical modeling of XAS of ice, liquid and gas phase water; the use of a
full core-hole (FCH) in the calculations, as suggested by Hetenyi et al. [J.
Chem. Phys. 120 (18), 8632 (2004)], gives poor agreement with experiment in
terms of intensity distribution as well as transition energies, while the half
core hole (HCH) potential, in the case of water, provides a better compromise
between initial and final state effects, leading to good agreement with the
experimental data.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:39:11 GMT"
}
] | 2017-09-13T00:00:00 | [
[
"Cavalleri",
"Matteo",
""
],
[
"Odelius",
"Michael",
""
],
[
"Nordlund",
"Dennis",
""
],
[
"Nilsson",
"Anders",
""
],
[
"Pettersson",
"Lars G. M.",
""
]
] |
0707.2912 | Bruno Bellomo | Bruno Bellomo, Stephen M. Barnett and John Jeffers | Frictional quantum decoherence | 18 pages, 7 figures | J. Phys. A: Math. Theor. 40 (2007) 9437-9453 | 10.1088/1751-8113/40/31/019 | null | quant-ph | null | The dynamics associated with a measurement-based master equation for quantum
Brownian motion are investigated. A scheme for obtaining time evolution from
general initial conditions is derived. This is applied to analyze dissipation
and decoherence in the evolution of both a Gaussian and a Schr\"{o}dinger cat
initial state. Dependence on the diffusive terms present in the master equation
is discussed with reference to both the coordinate and momentum
representations.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:30:03 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Bellomo",
"Bruno",
""
],
[
"Barnett",
"Stephen M.",
""
],
[
"Jeffers",
"John",
""
]
] |
0707.2913 | R. Hlubina | R. Hlubina | Possible vortex splitting in the cuprate superconductors | minor changes, added reference | null | null | null | cond-mat.supr-con | null | We propose that the observed splitting of the vortices in the cuprates into
fractional vortices (partons) may be of static rather than of dynamic origin.
This interpretation is backed by a study of a model with a dominant d-wave and
subdominant s-wave pairing interaction. We find that the vortex may split into
two partons, both of which carry one half of the magnetic flux quantum. The
partons are hold together by a confining string along which the phase jumps
approximately by pi and their equilibrium distance increases with lowering the
energy difference epsilon between the pairing states. The partons become
deconfined at the critical point where epsilon vanishes.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:31:50 GMT"
},
{
"version": "v2",
"created": "Tue, 4 Sep 2007 13:04:49 GMT"
}
] | 2007-09-04T00:00:00 | [
[
"Hlubina",
"R.",
""
]
] |
0707.2914 | Xinxian Zheng | Ali Soleyman Jahan, Xinxian Zheng | Pretty clean monomial ideals and linear quotients | null | null | null | null | math.AC | null | We study basic properties of monomial ideals with linear quotients. It is
shown that if the monomial ideal $I$ has linear quotients, then the squarefree
part of $I$ and each component of $I$ as well as $\mm I$ have linear quotients,
where $\mm$ is the graded maximal ideal of the polynomial ring. As an analogy
to the Rearrangement Lemma of Bj\"orner and Wachs we also show that for a
monomial ideal with linear quotients the admissible order of the generators can
be chosen degree increasingly.
As a generalization of the facet ideal of a forest, we define monomial ideals
of forest type and show that they are pretty clean. This result recovers a
recent result of Tuly and Villarreal about the shellability of a clutter with
the free vertex property. As another consequence of this result we show that if
$I$ is a monomial ideal of forest type, then Stanley's conjecture on Stanley
decomposition holds for $S/I$. We also show that a clutter is totally balanced
if and only if it has the free vertex property.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:38:20 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Jahan",
"Ali Soleyman",
""
],
[
"Zheng",
"Xinxian",
""
]
] |
0707.2915 | Tanja M. Kneiske | Tanja M. Kneiske | Gamma-ray background: a review | 10 pages, 2 figures, proc. of FRASCATI workshop 2007, Vulcano, Italy,
to be pub. in Chinese Journal of Astronomy & Astrophysics, final version | null | null | null | astro-ph | null | The gamma-ray background is still a subject under great debate.
All phenomena in the universe emitting gamma-rays can contribute directly as
diffuse emission or as an isotropic component from unresolved point sources.
The question of the origin of the extragalactic component cannot be answered
without determining the galactic emission. To discuss in detail all models
resulting in gamma-ray background contributions is far beyond the scope of this
paper. Therefore the focus will be on recent publications on the extragalactic
high energy (>100 MeV) part of the gamma-ray background.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:52:14 GMT"
},
{
"version": "v2",
"created": "Thu, 29 Nov 2007 11:29:30 GMT"
}
] | 2007-11-29T00:00:00 | [
[
"Kneiske",
"Tanja M.",
""
]
] |
0707.2916 | Christophe Texier | Christophe Texier | Effect of connecting wires on the decoherence due to electron-electron
interaction in a metallic ring | LaTeX, 4 pages, 4 eps figures | Phys. Rev. B 76, 153312 (2007) | 10.1103/PhysRevB.76.153312 | null | cond-mat.dis-nn cond-mat.mes-hall | null | We consider the weak localization in a ring connected to reservoirs through
leads of finite length and submitted to a magnetic field. The effect of
decoherence due to electron-electron interaction on the harmonics of AAS
oscillations is studied, and more specifically the effect of the leads. Two
results are obtained for short and long leads regimes. The scale at which the
crossover occurs is discussed. The long leads regime is shown to be more
realistic experimentally.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:53:45 GMT"
}
] | 2008-04-10T00:00:00 | [
[
"Texier",
"Christophe",
""
]
] |
0707.2917 | Pierluigi Falco | P. Falco, V. Mastropietro | Renormalization Group and Asymptotic Spin--Charge separation for Chiral
Luttinger liquids | 45 pages, 11 figures | null | 10.1007/s10955-007-9474-y | null | cond-mat.str-el math-ph math.MP | null | The phenomenon of Spin-Charge separation in non-Fermi liquids is well
understood only in certain solvable d=1 fermionic systems. In this paper we
furnish the first example of asymptotic Spin-Charge separation in a d=1 non
solvable model. This goal is achieved using Renormalization Group approach
combined with Ward-Identities and Schwinger-Dyson equations, corrected by the
presence of a bandwidth cut-offs. Such methods, contrary to bosonization, could
be in principle applied also to lattice or higher dimensional systems.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 17:07:30 GMT"
}
] | 2010-01-29T00:00:00 | [
[
"Falco",
"P.",
""
],
[
"Mastropietro",
"V.",
""
]
] |
0707.2918 | Pierre Lugan | Pierre Lugan (LCFIO), David Cl\'ement (LCFIO), Philippe Bouyer
(LCFIO), Alain Aspect (LCFIO), Laurent Sanchez-Palencia (LCFIO) | Anderson Localization of Bogolyubov Quasiparticles in Interacting
Bose-Einstein Condensates | published version (no significant changes compared to last version) | Physical Review Letters 99, 18 (2007) 180402 | 10.1103/PhysRevLett.99.180402 | null | cond-mat.other | null | We study the Anderson localization of Bogolyubov quasiparticles in an
interacting Bose-Einstein condensate (with healing length \xi) subjected to a
random potential (with finite correlation length \sigma_R). We derive
analytically the Lyapunov exponent as a function of the quasiparticle momentum
k and we study the localization maximum k_{max}. For 1D speckle potentials, we
find that k_{max} is proportional to 1/\xi when \xi is much larger than
\sigma_R while k_{max} is proportional to 1/\sigma_R when \xi is much smaller
than \sigma_R, and that the localization is strongest when \xi is of the order
of \sigma_R. Numerical calculations support our analysis and our estimates
indicate that the localization of the Bogolyubov quasiparticles is accessible
in current experiments with ultracold atoms.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:58:57 GMT"
},
{
"version": "v2",
"created": "Wed, 7 Nov 2007 21:38:14 GMT"
}
] | 2007-11-07T00:00:00 | [
[
"Lugan",
"Pierre",
"",
"LCFIO"
],
[
"Clément",
"David",
"",
"LCFIO"
],
[
"Bouyer",
"Philippe",
"",
"LCFIO"
],
[
"Aspect",
"Alain",
"",
"LCFIO"
],
[
"Sanchez-Palencia",
"Laurent",
"",
"LCFIO"
]
] |
0707.2919 | Wagner L. F. Marcolino | C. B. Pereira (1), W. L. F. Marcolino (1,2), M. Machado (3) and F. X.
de Araujo (1) ((1) Observatorio Nacional/MCT, (2) LAM (3) Departamento de
Fisica/UERJ) | Spectroscopic analysis of two peculiar emission line stars: RJHA 49 and
SS73 21 | 8 pages, 3 figures. Accepted for publication in Astronomy &
Astrophysics | null | 10.1051/0004-6361:20077669 | null | astro-ph | null | Aims: To investigate the spectra and the evolutionary stages of two peculiar
emission-line stars: RJHA 49 and SS73 21. Methods: We used low and high
resolution optical data. Line identifications and measurements were performed
for several features in their spectra. Results: For each object, we have
derived the extinction and the excitation temperature from a set of [Fe II]
lines, and the electron density from [N II] lines. For RJHA 49, no detailed
spectroscopic study was done so far. Regarding SS73 21, our low resolution
spectrum have confirmed the main characteristics found in previous works. On
the other side, from our high resolution data, we have found that the Halpha
line presents a double-peak, in contrast with the suggestion in the literature
that it should reveal a P-Cygni profile. Surprisingly, we found a few He I
transitions resembling P-Cygni profiles (e.g. He I 5876), directly suggesting
that mass loss is active in SS73 21. We also discussed the nature of these two
objects based on the data obtained. Although the evolutionary status of SS73 21
seems well established from previous studies (a proto-planetary nebula), the
situation for RJHA 49 is not so clear mainly due to its unknown distance.
However, from the strength of [N II] 5754 relative to [O I] 6300, the
possibility of RJHA 49 being a LBV object is reduced, and a B[e]-supergiant or
a proto-planetary nebula status is more plausible.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 15:14:02 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Pereira",
"C. B.",
""
],
[
"Marcolino",
"W. L. F.",
""
],
[
"Machado",
"M.",
""
],
[
"de Araujo",
"F. X.",
""
]
] |
0707.2920 | Francois Maucourant | Fran\c{c}ois Maucourant (IRMAR) | A non-homogeneous orbit of a diagonal subgroup | null | null | null | null | math.DS | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Let G=SL(n,R) with n>5. We construct examples of lattices Gamma of G,
subgroup A of the diagonal group and points x in G/Gamma such that the closure
of the orbit Ax is not homogeneous but does not factors through the action of a
one-parameter non-unipotent group. This contradicts a conjecture of Margulis.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:59:30 GMT"
},
{
"version": "v2",
"created": "Thu, 28 Aug 2008 14:05:57 GMT"
}
] | 2008-08-28T00:00:00 | [
[
"Maucourant",
"François",
"",
"IRMAR"
]
] |
0707.2921 | Andrea Pacifici | Alessandro Agnetis, Enrico Grande, Pitu B. Mirchandani, Andrea
Pacifici | Covering a line segment with variable radius discs | 21 pages, 2 figures | null | null | null | cs.DM cs.NA | null | The paper addresses the problem of locating sensors with a circular field of
view so that a given line segment is under full surveillance, which is termed
as the Disc Covering Problem on a Line. The cost of each sensor includes a
fixed component, and a variable component that is proportional to the
field-of-view area. When only one type of sensor or, in general, one type of
disc, is available, then a simple polynomial algorithm solves the problem. When
there are different types of sensors in terms of fixed and variable costs, the
problem becomes NP-hard. A branch-and-bound algorithm as well as an efficient
heuristic are developed. The heuristic very often obtains the optimal solution
as shown in extensive computational testing.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 14:59:47 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Agnetis",
"Alessandro",
""
],
[
"Grande",
"Enrico",
""
],
[
"Mirchandani",
"Pitu B.",
""
],
[
"Pacifici",
"Andrea",
""
]
] |
0707.2922 | Fabrizio Salvatore | The BABAR Collaboration: B. Aubert, et al | Measurement of the tau- --> K- pi0 nu_tau Branching Fraction | 7 pages, 1 figure, submitted to PRD-RC | Phys.Rev.D76:051104,2007 | 10.1103/PhysRevD.76.051104 | null | hep-ex | null | A measurement of the tau- --> K- pi0 nu_tau branching fraction has been made
using 230.2 fb-1 of data recorded by the BABAR detector at the PEP-II e+ e-
collider, located at the Stanford Linear Accelerator Center (SLAC), at a center
of mass energy sqrt{s} close to 10.58 GeV. We measure BF(tau- --> K- pi0
nu_tau) = (0.416 +/- 0.003 (stat) +/- 0.018 (syst)) %.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 15:16:38 GMT"
}
] | 2010-04-12T00:00:00 | [
[
"The BABAR Collaboration",
"",
""
],
[
"Aubert",
"B.",
""
]
] |
0707.2923 | Basarab Nicolescu | Basarab Nicolescu | The Odderon at RHIC and LHC | 7 pages, 2 figures, EDS07 Conference, Hamburg, Germany | null | null | null | hep-ph | null | The Odderon remains an elusive object, 33 years after its invention. The
Odderon is now a fundamental object in QCD and CGC and it has to be found
experimentally if QCD and CGC are right. In the present talk, we show how to
find it at RHIC and LHC. The most spectacular signature of the Odderon is the
predicted difference between the differential cross-sections for proton-proton
and antiproton-proton at high s and moderate t. This experiment can be done by
using the STAR detector at RHIC and by combining these future data with the
already present UA4/2 data. The Odderon could also be found by ATLAS experiment
at LHC by performing a high-precision measurement of the real part of the
hadron elastic scattering amplitude at small t.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 15:14:02 GMT"
}
] | 2007-07-20T00:00:00 | [
[
"Nicolescu",
"Basarab",
""
]
] |
0707.2924 | Markus Mueller | Markus Mueller | On the Quantum Kolmogorov Complexity of Classical Strings | 10 pages, no figures. Published version | Int. J. Quant. Inf. 7, 701-711 (2009) | null | null | quant-ph | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | We show that classical and quantum Kolmogorov complexity of binary strings
agree up to an additive constant. Both complexities are defined as the minimal
length of any (classical resp. quantum) computer program that outputs the
corresponding string.
It follows that quantum complexity is an extension of classical complexity to
the domain of quantum states. This is true even if we allow a small
probabilistic error in the quantum computer's output. We outline a mathematical
proof of this statement, based on an inequality for outputs of quantum
operations and a classical program for the simulation of a universal quantum
computer.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 15:19:19 GMT"
},
{
"version": "v2",
"created": "Tue, 9 Jun 2009 15:31:08 GMT"
}
] | 2009-06-09T00:00:00 | [
[
"Mueller",
"Markus",
""
]
] |
0707.2925 | Davide Donato | R.M. Sambruna (1), F. Tavecchio (2), G. Ghisellini (2), D. Donato (1),
S. T. Holland (1), C. B. Markwardt (1), J. Tueller (1), R. F. Mushotzky (1)
((1) NASA/GSFC; (2) INAF-Osservatorio Astronomico di Brera) | Swift observations of high-redshift radio-loud quasars | Accepted for publication in ApJ; 22 pages, 4 figures | null | 10.1086/521694 | null | astro-ph | null | We report on Swift observations of four z>2 radio-loud quasars (0212+735,
0537-286, 0836+710, and 2149-307), classified as blazars. The sources,
well-known emitters at soft-medium X-rays, were detected at >5sigma with the
BAT experiment in 15-150 keV. No flux variability was detected within the XRT
and BAT exposures, with the exception of 0836+710 which shows an increase of a
factor 4 of the 15-150 keV flux on a timescale of one month. The 0.3-10 keV
spectra are well fitted by power law models, with rather hard continua (photon
indices Gamma_XRT ~1.3-1.5); similarly, the 15-150 keV spectra are described by
power laws with Gamma_BAT ~1.3-1.8. The XRT data exhibit spectral curvature,
which can be modeled either in terms of excess absorption along the line of
sight, or a downward-curved broken power law. In the former case, if the excess
N_H is at the rest-frame of the source, columns of N_H^z=(0.3-6)x10^22 cm^-2
are measured. Modeling of the SEDs of the four quasars shows that the emission
at the higher frequencies, >~ 10^16 Hz, is dominated by the jet, while the
steep optical-to-UV continua, observed with the UVOT, can be attributed to
thermal emission from the accretion disk. The disk luminosity is between 1% and
10% the jet power, similar to other powerful blazars.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 15:19:32 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Sambruna",
"R. M.",
"",
"NASA/GSFC;"
],
[
"Tavecchio",
"F.",
"",
"INAF-Osservatorio Astronomico di Brera"
],
[
"Ghisellini",
"G.",
"",
"INAF-Osservatorio Astronomico di Brera"
],
[
"Donato",
"D.",
"",
"NASA/GSFC;"
],
[
"Holland",
"S. T.",
"",
"NASA/GSFC;"
],
[
"Markwardt",
"C. B.",
"",
"NASA/GSFC;"
],
[
"Tueller",
"J.",
"",
"NASA/GSFC;"
],
[
"Mushotzky",
"R. F.",
"",
"NASA/GSFC;"
]
] |
0707.2926 | Bernard Levy | Bernard C. Levy | Robust Hypothesis Testing with a Relative Entropy Tolerance | 14 pages, 5 figures, submitted to the IEEE Transactions on
Information Theory, July 2007, revised April 2008 | null | 10.1109/TIT.2008.2008128 | null | cs.IT math.IT | null | This paper considers the design of a minimax test for two hypotheses where
the actual probability densities of the observations are located in
neighborhoods obtained by placing a bound on the relative entropy between
actual and nominal densities. The minimax problem admits a saddle point which
is characterized. The robust test applies a nonlinear transformation which
flattens the nominal likelihood ratio in the vicinity of one. Results are
illustrated by considering the transmission of binary data in the presence of
additive noise.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 15:33:36 GMT"
},
{
"version": "v2",
"created": "Wed, 2 Apr 2008 00:18:43 GMT"
}
] | 2016-11-18T00:00:00 | [
[
"Levy",
"Bernard C.",
""
]
] |
0707.2927 | Jan Draisma | Jan Draisma and Jos in 't panhuis | Constructing simply laced Lie algebras from extremal elements | We made many corrections suggested by a referee, and extended our
results to positive characteristic greater than 2 | Algebra and Number Theory 2(5):551-572, 2008 | null | null | math.RA math.AG | null | For any finite graph Gamma and any field K of characteristic unequal to 2 we
construct an algebraic variety X over K whose K-points parameterise K-Lie
algebras generated by extremal elements, corresponding to the vertices of the
graph, with prescribed commutation relations, corresponding to the non-edges.
After that, we study the case where Gamma is a connected, simply laced Dynkin
diagram of finite or affine type. We prove that X is then an affine space, and
that all points in an open dense subset of X parameterise Lie algebras
isomorphic to a single fixed Lie algebra. If Gamma is of affine type, then this
fixed Lie algebra is the split finite-dimensional simple Lie algebra
corresponding to the associated finite-type Dynkin diagram. This gives a new
construction of these Lie algebras, in which they come together with
interesting degenerations, corresponding to points outside the open dense
subset. Our results may prove useful for recognising these Lie algebras.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 15:41:28 GMT"
},
{
"version": "v2",
"created": "Thu, 27 Mar 2008 09:35:17 GMT"
}
] | 2017-10-10T00:00:00 | [
[
"Draisma",
"Jan",
""
],
[
"panhuis",
"Jos in 't",
""
]
] |
0707.2928 | Yusuke Tsukamoto | Yusuke Tsukamoto and Junichiro Makino | Formation of Protoplanets from Massive Planetesimals in Binary Systems | 26pages, 11 figures. ApJ accepted | null | 10.1086/521593 | null | astro-ph | null | More than half of stars reside in binary or multiple star systems and many
planets have been found in binary systems. From theoretical point of view,
however, whether or not the planetary formation proceeds in a binary system is
a very complex problem, because secular perturbation from the companion star
can easily stir up the eccentricity of the planetesimals and cause
high-velocity, destructive collisions between planetesimals. Early stage of
planetary formation process in binary systems has been studied by restricted
three-body approach with gas drag and it is commonly accepted that accretion of
planetesimals can proceed due to orbital phasing by gas drag. However, the gas
drag becomes less effective as the planetesimals become massive. Therefore it
is still uncertain whether the collision velocity remains small and planetary
accretion can proceed, once the planetesimals become massive. We performed {\it
N}-body simulations of planetary formation in binary systems starting from
massive planetesimals whose size is about 100-500 km. We found that the
eccentricity vectors of planetesimals quickly converge to the forced
eccentricity due to the coupling of the perturbation of the companion and the
mutual interaction of planetesimals if the initial disk model is sufficiently
wide in radial distribution. This convergence decreases the collision velocity
and as a result accretion can proceed much in the same way as in isolated
systems. The basic processes of the planetary formation, such as runaway growth
and oligarchic growth and final configuration of the protoplanets are
essentially the same in binary systems and single star systems, at least in the
late stage where the effect of gas drag is small.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 15:50:46 GMT"
}
] | 2009-11-13T00:00:00 | [
[
"Tsukamoto",
"Yusuke",
""
],
[
"Makino",
"Junichiro",
""
]
] |
0707.2929 | Martin Zirnbauer | P. Littelmann, H.-J. Sommers, M.R. Zirnbauer | Superbosonization of invariant random matrix ensembles | 57 pages, published version | Commun. Math. Phys. 283 (2008) 343 | 10.1007/s00220-008-0535-0 | null | math-ph math.MP | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ | Superbosonization is a new variant of the method of commuting and
anti-commuting variables as used in studying random matrix models of disordered
and chaotic quantum systems. We here give a concise mathematical exposition of
the key formulas of superbosonization. Conceived by analogy with the
bosonization technique for Dirac fermions, the new method differs from the
traditional one in that the superbosonization field is dual to the usual
Hubbard-Stratonovich field. The present paper addresses invariant random matrix
ensembles with symmetry group U(n), O(n), or USp(n), giving precise definitions
and conditions of validity in each case. The method is illustrated at the
example of Wegner's n-orbital model. Superbosonization promises to become a
powerful tool for investigating the universality of spectral correlation
functions for a broad class of random matrix ensembles of non-Gaussian and/or
non-invariant type.
| [
{
"version": "v1",
"created": "Thu, 19 Jul 2007 16:53:23 GMT"
},
{
"version": "v2",
"created": "Sat, 23 Aug 2008 11:19:36 GMT"
}
] | 2008-08-23T00:00:00 | [
[
"Littelmann",
"P.",
""
],
[
"Sommers",
"H. -J.",
""
],
[
"Zirnbauer",
"M. R.",
""
]
] |
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