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0705.1898
Francesco de Martini
Tiziano De Angelis, Francesco De Martini, Eleonora Nagali, and Fabio Sciarrino
Experimental test of the no signaling theorem
4 pages, 4 figures
Phys. Rev. Lett. 99, 193601 (2007)
10.1103/PhysRevLett.99.193601
null
quant-ph
null
In 1981 N. Herbert proposed a gedanken experiment in order to achieve by the ''First Laser Amplified Superluminal Hookup'' (FLASH) a faster than light communication (FTL) by quantum nonlocality. The present work reports the first experimental realization of that proposal by the optical parametric amplification of a single photon belonging to an entangled EPR pair into an output field involving 5 x 10^3 photons. A thorough theoretical and experimental analysis explains in general and conclusive terms the precise reasons for the failure of the FLASH program as well as of any similar FTL proposals.
[ { "version": "v1", "created": "Mon, 14 May 2007 09:55:10 GMT" }, { "version": "v2", "created": "Thu, 17 May 2007 08:20:11 GMT" } ]
2009-11-13T00:00:00
[ [ "De Angelis", "Tiziano", "" ], [ "De Martini", "Francesco", "" ], [ "Nagali", "Eleonora", "" ], [ "Sciarrino", "Fabio", "" ] ]
0705.1899
Tim Dokchitser
Tim Dokchitser, Vladimir Dokchitser
Self-duality of Selmer groups
12 pages; to appear in Proc. Cam. Phil. Soc
Proc. Cam. Phil. Soc. 146 (2009), 257-267
10.1017/S0305004108001989
null
math.NT
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The first part of the paper gives a new proof of self-duality for Selmer groups: if A is an abelian variety over a number field K, and F/K is a Galois extension with Galois group G, then the Q_pG-representation naturally associated to the p-infinity Selmer group of A/F is self-dual. The second part describes a method for obtaining information about parities of Selmer ranks from the local Tamagawa numbers of A in intermediate extensions of F/K.
[ { "version": "v1", "created": "Mon, 14 May 2007 09:46:35 GMT" }, { "version": "v2", "created": "Thu, 12 Jun 2008 17:38:33 GMT" } ]
2013-09-23T00:00:00
[ [ "Dokchitser", "Tim", "" ], [ "Dokchitser", "Vladimir", "" ] ]
0705.1900
Julia Sedova Viktorovna
A.P. Kuznetsov, I.R. Sataev, J.V. Sedova
Dynamics of coupled non-identical systems with period-doubling cascade
13 pages, 7 figures
null
10.1134/S1560354708010024
null
nlin.CD
null
Structure of bifurcation diagram in the plane of parameters controlling period-doublings for the system of coupled logistic maps is discussed. The analysis is carried out by computing the charts of dynamical regimes and charts of Lyapunov exponents giving showy and effective illustrations. The critical point of codimension two at the border of chaos is found. It is a terminal point for the Feigenbaum critical line. The bifurcation analysis in the vicinity of this point is presented.
[ { "version": "v1", "created": "Mon, 14 May 2007 09:54:37 GMT" } ]
2014-02-24T00:00:00
[ [ "Kuznetsov", "A. P.", "" ], [ "Sataev", "I. R.", "" ], [ "Sedova", "J. V.", "" ] ]
0705.1901
Andreas Reisenegger
Andreas Reisenegger, Rafael Benguria, Joaquin P. Prieto, Pablo A. Araya, Dong Lai
Hall drift of axisymmetric magnetic fields in solid neutron-star matter
8 pages, 5 figure panels; new version with very small correction; accepted by Astronomy & Astrophysics
null
10.1051/0004-6361:20077874
null
astro-ph math-ph math.MP nlin.SI physics.plasm-ph
null
Hall drift, i. e., transport of magnetic flux by the moving electrons giving rise to the electrical current, may be the dominant effect causing the evolution of the magnetic field in the solid crust of neutron stars. It is a nonlinear process that, despite a number of efforts, is still not fully understood. We use the Hall induction equation in axial symmetry to obtain some general properties of nonevolving fields, as well as analyzing the evolution of purely toroidal fields, their poloidal perturbations, and current-free, purely poloidal fields. We also analyze energy conservation in Hall instabilities and write down a variational principle for Hall equilibria. We show that the evolution of any toroidal magnetic field can be described by Burgers' equation, as previously found in plane-parallel geometry. It leads to sharp current sheets that dissipate on the Hall time scale, yielding a stationary field configuration that depends on a single, suitably defined coordinate. This field, however, is unstable to poloidal perturbations, which grow as their field lines are stretched by the background electron flow, as in instabilities earlier found numerically. On the other hand, current-free poloidal configurations are stable and could represent a long-lived crustal field supported by currents in the fluid stellar core.
[ { "version": "v1", "created": "Mon, 14 May 2007 10:02:57 GMT" }, { "version": "v2", "created": "Fri, 29 Jun 2007 20:53:03 GMT" } ]
2009-11-13T00:00:00
[ [ "Reisenegger", "Andreas", "" ], [ "Benguria", "Rafael", "" ], [ "Prieto", "Joaquin P.", "" ], [ "Araya", "Pablo A.", "" ], [ "Lai", "Dong", "" ] ]
0705.1902
C. A. Dominguez
Cesareo A. Dominguez, Juan I. Jottar, Marcelo Loewe, Bernard Willers
Pion form factor in the Kroll-Lee-Zumino model
Revised version corrects a misprint in Eq.(1)
Phys.Rev.D76:095002,2007
10.1103/PhysRevD.76.095002
UCT-TP-267/07
hep-ph nucl-th
null
The renormalizable Abelian quantum field theory model of Kroll, Lee, and Zumino is used to compute the one-loop vertex corrections to the tree-level, Vector Meson Dominance (VMD) pion form factor. These corrections, together with the known one-loop vacuum polarization contribution, lead to a substantial improvement over VMD. The resulting pion form factor in the space-like region is in excellent agreement with data in the whole range of accessible momentum transfers. The time-like form factor, known to reproduce the Gounaris-Sakurai formula at and near the rho-meson peak, is unaffected by the vertex correction at order $\cal{O}$$(g_\rpp^2)$.
[ { "version": "v1", "created": "Mon, 14 May 2007 10:16:10 GMT" }, { "version": "v2", "created": "Mon, 13 Aug 2007 09:20:40 GMT" }, { "version": "v3", "created": "Tue, 14 Aug 2007 17:22:35 GMT" } ]
2008-11-26T00:00:00
[ [ "Dominguez", "Cesareo A.", "" ], [ "Jottar", "Juan I.", "" ], [ "Loewe", "Marcelo", "" ], [ "Willers", "Bernard", "" ] ]
0705.1903
Jarmo Hietarinta
Jarmo Hietarinta and Claude Viallet
Searching for integrable lattice maps using factorization
To appear in Journal of Physics A. Some changes in references
J. Phys. A: Math. Theor. 40 (2007) 12629
10.1088/1751-8113/40/42/S09
null
nlin.SI
null
We analyze the factorization process for lattice maps, searching for integrable cases. The maps were assumed to be at most quadratic in the dependent variables, and we required minimal factorization (one linear factor) after 2 steps of iteration. The results were then classified using algebraic entropy. Some new models with polynomial growth (strongly associated with integrability) were found. One of them is a nonsymmetric generalization of the homogeneous quadratic maps associated with KdV (modified and Schwarzian), for this new model we have also verified the "consistency around a cube".
[ { "version": "v1", "created": "Mon, 14 May 2007 11:15:04 GMT" }, { "version": "v2", "created": "Fri, 8 Jun 2007 09:42:41 GMT" } ]
2011-05-27T00:00:00
[ [ "Hietarinta", "Jarmo", "" ], [ "Viallet", "Claude", "" ] ]
0705.1904
Michael Varnava
Michael Varnava, Daniel Browne and Terry Rudolph
Loss Tolerant Linear Optical Quantum Memory By Measurement Based Quantum Computing
20 pages, 10 figures. to appear in New Journal of Physics Focus Issue on "Measurement-based quantum information processing"
New J. Phys. 9 203 (2007)
10.1088/1367-2630/9/6/203
null
quant-ph
null
We give a scheme for loss tolerantly building a linear optical quantum memory which itself is tolerant to qubit loss. We use the encoding recently introduced in [Phys. Rev. Lett. 97, 120501, (2006)] and give a method for efficiently achieving this. The entire approach resides within the "One-way" model for quantum computing. Our results suggest that it is possible to build a loss tolerant quantum memory, such that if the requirement is to keep the data stored over arbitrarily long times then this is possible with only polynomially increasing resources and logarithmically increasing individual photon life times.
[ { "version": "v1", "created": "Mon, 14 May 2007 10:43:22 GMT" } ]
2007-09-12T00:00:00
[ [ "Varnava", "Michael", "" ], [ "Browne", "Daniel", "" ], [ "Rudolph", "Terry", "" ] ]
0705.1905
Koji Nagata
Koji Nagata
Multipartite omnidirectional generalized Bell inequality
4 pages
J. Phys. A: Math. Theor. 40 (2007) 13101-13106.
10.1088/1751-8113/40/43/017
null
quant-ph
null
We derive a multipartite generalized Bell inequality which involves the entire range of settings for each of the local observers. Especially, it is applied to show non-local behavior of a six-qubit mixture of Greenberger-Horne-Zeilinger correlations stronger than previous Bell inequalities. For certain noise admixture to the correlations an explicit local realistic model exists in the case of a standard Bell experiment. Bell experiments with many local settings reveal the non-locality of the state. It turns out that the new inequality is more stringent than many other Bell inequalities in the specific quantum state.
[ { "version": "v1", "created": "Mon, 14 May 2007 10:48:43 GMT" }, { "version": "v2", "created": "Mon, 10 Sep 2007 06:02:15 GMT" } ]
2009-11-13T00:00:00
[ [ "Nagata", "Koji", "" ] ]
0705.1906
Spyros Basilakos
Ioannis Contopoulos and Spyros Basilakos (Academy of Athens)
The tension of cosmological magnetic fields as a contribution to dark energy
6 pages, 2 figures, A&A in press
Astron.Astrophys.471:59,2007
10.1051/0004-6361:20077384
null
astro-ph
null
We propose that cosmological magnetic fields generated in regions of finite spatial dimensions may manifest themselves in the global dynamics of the Universe as `dark energy'. We test our model in the context of spatially flat cosmological models by assuming that the Universe contains non-relativistic matter $\rho_m\propto \alpha^{-3}$, dark energy $\rho_{Q}\propto \alpha^{-3(1+w)}$, and an extra fluid with $\rho_{B} \propto \alpha^{n-3}$ that corresponds to the magnetic field. We place constraints on the main cosmological parameters of our model by combining the recent supernovae type Ia data and the differential ages of passively evolving galaxies. In particular, we find that the model which best reproduces the observational data when $\Omega_m=0.26$ is one with $\Omega_{B}\simeq 0.03$, $n\simeq 7.68$, $\Omega_{Q}\simeq 0.71$ and $w\simeq -0.8$.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:14:37 GMT" } ]
2019-08-19T00:00:00
[ [ "Contopoulos", "Ioannis", "", "Academy of Athens" ], [ "Basilakos", "Spyros", "", "Academy of Athens" ] ]
0705.1907
Dean Robinson
M. Yu. Kuchiev and D. J. Robinson
Electron-positron pair creation by Coulomb and laser fields in the tunneling regime
15 pages, 4 figures
null
10.1103/PhysRevA.76.012107
null
physics.atom-ph
null
Electron-positron pair creation due to combined nuclear Coulomb and strong laser fields is investigated for the tunneling regime. The energy spectra and angular distributions of the pair are found analytically for the first time. The energy spectrum for each lepton exhibits a sharp maximum located well above the threshold for any polarization of the laser field. The angular distributions of leptons depend on the polarization: for the linear polarization both leptons move predominantly along the laser beam direction; for the circular polarization leptons are emitted in a thin-walled cone centered on the laser beam. The spectral and angular distributions found are governed by the intensity and frequency of the field, and the frequency independent total pair creation rates comply with the previously known results. A new method of calculation - the vicinal approximation - which uses the fact that the pair production takes place in the close vicinity of the nucleus, is suggested.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:29:00 GMT" } ]
2009-11-13T00:00:00
[ [ "Kuchiev", "M. Yu.", "" ], [ "Robinson", "D. J.", "" ] ]
0705.1908
Henryk Arodz
H. Arod\'z, P. Klimas, T. Tyranowski
Self-similarity for V-shaped field potentials - further examples
17 pages, 4 figures
ActaPhys.Polon.B38:2537-2552,2007
null
TPJU-4/2007
hep-th math-ph math.MP nlin.SI
null
Three new models with V-shaped field potentials $U$ are considered: a complex scalar field $X$ in 1+1 dimensions with $U(X)= |X|$, a real scalar field $\Phi$ in 2+1 dimensions with $U(\Phi) = |\Phi|$, and a real scalar field $\phi$ in 1+1 dimensions with $U{\phi) = \phi \Theta(\phi)$ where $\Theta$ is the step function. Several explicit, self-similar solutions are found. They describe interesting dynamical processes, for example, `freezing' a string in a static configuration.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:13:51 GMT" } ]
2008-11-26T00:00:00
[ [ "Arodź", "H.", "" ], [ "Klimas", "P.", "" ], [ "Tyranowski", "T.", "" ] ]
0705.1909
Reginald Little Sr
Reginald B. Little
On the Enhanced Reverse Beta Processes in Graphene-Iron Composite Nanostructures at High Temperatures in Strong Magnetic Field
null
null
null
null
cond-mat.mtrl-sci
null
Strong dense many-spin interactions have been proposed to organize novel orbital dynamics (the Little Effect) for novel chemical and catalytic phenomena. The recent determinations of the relativistic and quantum Hall effects of carriers in graphene under strong magnetic confinement have substantiated the Little Effect. Moreover such nonclassical phenomena under the stronger magnetic confinement of ferro-nanocatalysts are here shown to organize reverse beta processes and possibly pycnonuclear reactions under high temperature and high-pressure conditions. Such processes have implications for reverse beta reactions and nuclear reactions within the interior of the earth and new technologies for carbon nanotube-ferrometal and nanographene-ferrometal composites.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:18:36 GMT" } ]
2007-05-23T00:00:00
[ [ "Little", "Reginald B.", "" ] ]
0705.1910
Ernest Epshtein
G M Shmelev, I I Maglevanny, E M Epshtein
Conductivity of a superlattice with parabolic miniband
10 pages, 5 figures
null
null
null
cond-mat.mes-hall cond-mat.mtrl-sci
null
The static and high-frequency differential conductivity of a one-dimensional superlattice with parabolic miniband, in which the dispersion law is assumed to be parabolic up to the Brillouin zone edge, are investigated theoretically. Unlike the earlier published works, devoted to this problem, the novel formula for the static current density contains temperature dependence, which leads to the current maximum shift to the low field side with increasing temperature. The high-frequency differential conductivity response properties including the temperature dependence is examined and opportunities of creating a terahertz oscillator on Bloch electron oscillations in such superlattices are discussed. Analysis shows that superlattices with parabolic miniband dispersion law may be used for generation and amplification of terahertz fields only at very low temperatures.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:18:59 GMT" } ]
2007-05-23T00:00:00
[ [ "Shmelev", "G M", "" ], [ "Maglevanny", "I I", "" ], [ "Epshtein", "E M", "" ] ]
0705.1911
Goetz Pfander
Goetz E. Pfander
On the invertibility of "rectangular" bi-infinite matrices and applications in time--frequency analysis
null
null
null
null
math.CA math.FA
null
Finite dimensional matrices having more columns than rows have no left inverses while those having more rows than columns have no right inverses. We give generalizations of these simple facts to bi--infinite matrices and use those to obtain density results for $p$--frames of time--frequency molecules in modulation spaces and identifiability results for operators with bandlimited Kohn--Nirenberg symbols.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:26:11 GMT" } ]
2007-05-23T00:00:00
[ [ "Pfander", "Goetz E.", "" ] ]
0705.1912
Dagmar Timmreck
Dagmar Timmreck
Necessary Conditions for Geometric Realizability of Simplicial Complexes
19 pages, 2 figures version 2: updated bibliography
null
null
null
math.MG math.CO
null
We associate with any simplicial complex $\K$ and any integer $m$ a system of linear equations and inequalities. If $\K$ has a simplicial embedding in $\R^m$ then the system has an integer solution. This result extends the work of I. Novik (2000).
[ { "version": "v1", "created": "Mon, 14 May 2007 11:27:21 GMT" }, { "version": "v2", "created": "Thu, 21 Jun 2007 13:44:18 GMT" } ]
2007-06-21T00:00:00
[ [ "Timmreck", "Dagmar", "" ] ]
0705.1913
Lucas Lacasa
A. Ferrera, B. Luque, L. Lacasa, E. Valero
Self-overlap as a method of analysis in Ising models
Accepted in Physical Review E
null
10.1103/PhysRevE.75.061103
null
cond-mat.stat-mech
null
The damage spreading method (DS) provided a useful tool to obtain analytical results of the thermodynamics and stability of the 2D Ising model --amongst many others--, but it suffered both from ambiguities in its results and from large computational costs. In this paper we propose an alternative method, the so called self-overlap method, based on the study of correlation functions measured at subsequent time steps as the system evolves towards its equilibrium. Applying markovian and mean field approximations to a 2D Ising system we obtain both analytical and numerical results on the thermodynamics that agree with the expected behavior. We also provide some analytical results on the stability of the system. Since only a single replica of the system needs to be studied, this method would seem to be free from the ambiguities that afflicted DS. It also seems to be numerically more efficient and analytically simpler.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:29:53 GMT" } ]
2009-11-13T00:00:00
[ [ "Ferrera", "A.", "" ], [ "Luque", "B.", "" ], [ "Lacasa", "L.", "" ], [ "Valero", "E.", "" ] ]
0705.1914
Goetz Pfander
Goetz E. Pfander
Measurement of time--varying Multiple--Input Multiple--Output Channels
null
null
null
null
math.FA math.CA
null
We derive a criterion on the measurability / identifiability of Multiple--Input Multiple--Output (MIMO) channels based on the size of the so-called spreading support of its subchannels. Novel MIMO transmission techniques provide high-capacity communication channels in time-varying environments and exact knowledge of the transmission channel operator is of key importance when trying to transmit information at a rate close to channel capacity.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:38:49 GMT" } ]
2007-05-23T00:00:00
[ [ "Pfander", "Goetz E.", "" ] ]
0705.1915
John Kouvakis
John Kouvakis, Fotis Georgatos
A Technical Report On Grid Benchmarking using ATLAS V.O
29 pages, 35 figures, including charts and results of benchmarking over the grid, ATLAS V.O
null
null
null
cs.PF
null
Grids include heterogeneous resources, which are based on different hardware and software architectures or components. In correspondence with this diversity of the infrastructure, the execution time of any single job, as well as the total grid performance can both be affected substantially, which can be demonstrated by measurements. Running a simple benchmarking suite can show this heterogeneity and give us results about the differences over the grid sites.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:39:52 GMT" }, { "version": "v2", "created": "Fri, 25 May 2007 07:56:22 GMT" }, { "version": "v3", "created": "Sun, 3 Jun 2007 06:57:27 GMT" } ]
2007-06-13T00:00:00
[ [ "Kouvakis", "John", "" ], [ "Georgatos", "Fotis", "" ] ]
0705.1916
Niko Jokela
Niko Jokela, Matti Jarvinen, Esko Keski-Vakkuri, Jaydeep Majumder
Disk Partition Function and Oscillatory Rolling Tachyons
17 pages, 2 figures. v4: discussion clarified, appendix added, conclusions unchanged; version to appear in J.Phys.A
J.Phys.A41:015402,2008
10.1088/1751-8113/41/1/015402
HIP-2007-11/TH
hep-th
null
An exact cubic open string field theory rolling tachyon solution was recently found by Kiermaier et. al. and Schnabl. This oscillatory solution has been argued to be related by a field redefinition to the simple exponential rolling tachyon deformation of boundary conformal theory. In the latter approach, the disk partition function takes a simple form. Out of curiosity, we compute the disk partition function for an oscillatory tachyon profile, and find that the result is nevertheless almost the same.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:55:52 GMT" }, { "version": "v2", "created": "Thu, 7 Jun 2007 13:40:35 GMT" }, { "version": "v3", "created": "Fri, 3 Aug 2007 13:54:59 GMT" }, { "version": "v4", "created": "Fri, 30 Nov 2007 14:28:18 GMT" } ]
2008-11-26T00:00:00
[ [ "Jokela", "Niko", "" ], [ "Jarvinen", "Matti", "" ], [ "Keski-Vakkuri", "Esko", "" ], [ "Majumder", "Jaydeep", "" ] ]
0705.1917
Biswajit Pradhan
B. Pradhan, Pankaj Agrawal and A. K. Pati
Teleportation and Superdense coding with Genuine quadripartite entangled states
40 pages, no figures
null
null
null
quant-ph
null
We investigate the usefulness of different classes of genuine quadripartite entangled states as quantum resources for teleportation and superdense coding. We examine the possibility of teleporting unknown one, two and three qubit states. We show that one can use the teleportation protocol to send any general one and two qubit states. A restricted class of three qubit states can also be faithfully teleported. We also explore superdense coding protocol in single-receiver and multi-receiver scenarios. We show that there exist genuine quadripartite entangled states that can be used to transmit four cbits by sending two qubits. We also discuss some interesting features of multi-receiver scenario under LOCC paradigm.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:51:27 GMT" } ]
2007-05-23T00:00:00
[ [ "Pradhan", "B.", "" ], [ "Agrawal", "Pankaj", "" ], [ "Pati", "A. K.", "" ] ]
0705.1918
J\"urgen Falb
J. Falb, A. Muramatsu
Massive CP$^1$ theory from a microscopic model for doped antiferromagnets
24 pages, no figures
Nuclear Physics B Vol 795/3 pp 519-548 2008
10.1016/j.nuclphysb.2007.10.025
null
cond-mat.str-el
null
A path-integral for the t-J model in two dimensions is constructed based on Dirac quantization, with an action found originally by Wiegmann (Phys. Rev. Lett. {\bf 60}, 821 (1988); Nucl. Phys. B323, 311 (1989)). Concentrating on the low doping limit, we assume short range antiferromagnetic order of the spin degrees of freedom. Going over to a local spin quantization axis of the dopant fermions, that follows the spin degree of freedom, staggered CP$^1$ fields result and the constraint against double occupancy can be resolved. The staggered CP$^1$ fields are split into slow and fast modes, such that after a gradient expansion, and after integrating out the fast modes and the dopant fermions, a CP$^1$ field-theory with a massive gauge field is obtained that describes generically incommensurate coplanar magnetic structures, as discussed previously in the context of frustrated quantum antiferromagnets. Hence, the possibility of deconfined spinons is opened by doping a colinear antiferromagnet.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:52:50 GMT" } ]
2008-03-04T00:00:00
[ [ "Falb", "J.", "" ], [ "Muramatsu", "A.", "" ] ]
0705.1919
Erez Sabbag
Neri Merhav and Erez Sabbag
Optimal Watermark Embedding and Detection Strategies Under Limited Detection Resources
36 pages, 5 figures. Revised version. Submitted to IEEE Transactions on Information Theory
null
10.1109/ISIT.2006.261759
null
cs.IT cs.CR math.IT
null
An information-theoretic approach is proposed to watermark embedding and detection under limited detector resources. First, we consider the attack-free scenario under which asymptotically optimal decision regions in the Neyman-Pearson sense are proposed, along with the optimal embedding rule. Later, we explore the case of zero-mean i.i.d. Gaussian covertext distribution with unknown variance under the attack-free scenario. For this case, we propose a lower bound on the exponential decay rate of the false-negative probability and prove that the optimal embedding and detecting strategy is superior to the customary linear, additive embedding strategy in the exponential sense. Finally, these results are extended to the case of memoryless attacks and general worst case attacks. Optimal decision regions and embedding rules are offered, and the worst attack channel is identified.
[ { "version": "v1", "created": "Mon, 14 May 2007 12:00:29 GMT" } ]
2016-11-15T00:00:00
[ [ "Merhav", "Neri", "" ], [ "Sabbag", "Erez", "" ] ]
0705.1920
Peihong Gu
Pei-Hong Gu, Utpal Sarkar
Leptogenesis, Dark Matter and Higgs Phenomenology at TeV
7 pages, 3 figures. References added. Accepted by NPB
Nucl.Phys.B789:245-257,2008
10.1016/j.nuclphysb.2007.08.004
null
hep-ph
null
We propose an interesting model of neutrino masses to realize leptogenesis and dark matter at the TeV scale. A real scalar is introduced to naturally realize the Majorana masses of the right-handed neutrinos. We also include a new Higgs doublet that contributes to the dark matter of the universe. The neutrino masses come from the vacuum expectation value of the triplet Higgs scalar. The right-handed neutrinos are not constrained by the neutrino masses and hence they could generate leptogenesis at the TeV scale without subscribing to resonant leptogenesis. In our model, all new particles could be observable at the forthcoming Large Hardon Collider or the proposed future International Linear Collider.
[ { "version": "v1", "created": "Mon, 14 May 2007 12:03:44 GMT" }, { "version": "v2", "created": "Mon, 21 May 2007 09:18:49 GMT" }, { "version": "v3", "created": "Wed, 15 Aug 2007 08:13:45 GMT" } ]
2008-11-26T00:00:00
[ [ "Gu", "Pei-Hong", "" ], [ "Sarkar", "Utpal", "" ] ]
0705.1921
Luca Tornatore
L. Tornatore, S. Borgani, K. Dolag, F. Matteucci
Chemical enrichment of galaxy clusters from hydrodynamical simulations
to appear on MNRAS
null
10.1111/j.1365-2966.2007.12070.x
null
astro-ph
null
We present cosmological hydrodynamical simulations of galaxy clusters aimed at studying the process of metal enrichment of the intra--cluster medium (ICM). These simulations have been performed by implementing a detailed model of chemical evolution in the Tree-SPH \gd code. This model allows us to follow the metal release from SNII, SNIa and AGB stars, by properly accounting for the lifetimes of stars of different mass, as well as to change the stellar initial mass function (IMF), the lifetime function and the stellar yields. As such, our implementation of chemical evolution represents a powerful instrument to follow the cosmic history of metal production. The simulations presented here have been performed with the twofold aim of checking numerical effects, as well as the impact of changing the model of chemical evolution and the efficiency of stellar feedback.
[ { "version": "v1", "created": "Sat, 12 May 2007 11:22:34 GMT" } ]
2009-11-13T00:00:00
[ [ "Tornatore", "L.", "" ], [ "Borgani", "S.", "" ], [ "Dolag", "K.", "" ], [ "Matteucci", "F.", "" ] ]
0705.1922
Veniamin Morgenshtern
Veniamin I. Morgenshtern and Helmut Boelcskei
Crystallization in large wireless networks
30 pages, 6 figures, submitted to journal IEEE Transactions on Information Theory
Information Theory, IEEE Transactions on , vol.53, no.10, pp.3319-3349, Oct. 2007
10.1109/TIT.2007.904789
null
cs.IT math.IT
null
We analyze fading interference relay networks where M single-antenna source-destination terminal pairs communicate concurrently and in the same frequency band through a set of K single-antenna relays using half-duplex two-hop relaying. Assuming that the relays have channel state information (CSI), it is shown that in the large-M limit, provided K grows fast enough as a function of M, the network "decouples" in the sense that the individual source-destination terminal pair capacities are strictly positive. The corresponding required rate of growth of K as a function of M is found to be sufficient to also make the individual source-destination fading links converge to nonfading links. We say that the network "crystallizes" as it breaks up into a set of effectively isolated "wires in the air". A large-deviations analysis is performed to characterize the "crystallization" rate, i.e., the rate (as a function of M,K) at which the decoupled links converge to nonfading links. In the course of this analysis, we develop a new technique for characterizing the large-deviations behavior of certain sums of dependent random variables. For the case of no CSI at the relay level, assuming amplify-and-forward relaying, we compute the per source-destination terminal pair capacity for M,K converging to infinity, with K/M staying fixed, using tools from large random matrix theory.
[ { "version": "v1", "created": "Mon, 14 May 2007 12:23:39 GMT" } ]
2011-07-15T00:00:00
[ [ "Morgenshtern", "Veniamin I.", "" ], [ "Boelcskei", "Helmut", "" ] ]
0705.1923
Orfeu Bertolami
Orfeu Bertolami and Carla Carvalho
Spontaneous Symmetry Breaking in the Bulk as a Localization Mechanism of Fields on the Brane
Revtex 4, 23 pages
Phys.Rev.D76:104048,2007
10.1103/PhysRevD.76.104048
DF/IST-1.2007
hep-th
null
We consider real and complex scalar fields non-minimally coupled to gravity in the bulk spacetime and study their impact on the brane upon acquiring a non-vanishing vacuum expectation value. When examining the case of the complex scalar field, a minimally coupled U(1) gauge field is also considered so that spontaneous symmetry breaking can take place. Particular attention is paid to the terms arising from the junction conditions, which act towards reinforcing the mechanism of spontaneous symmetry breaking. We find that the embedding of a braneworld universe in a bulk spacetime endowed with matter fields can induce this mechanism at very high energies, which implies the localization on the brane of the bulk fields.
[ { "version": "v1", "created": "Mon, 14 May 2007 12:14:35 GMT" } ]
2008-11-26T00:00:00
[ [ "Bertolami", "Orfeu", "" ], [ "Carvalho", "Carla", "" ] ]
0705.1924
Francis Bursa
Francis Bursa
Matching of Wilson loop eigenvalue densities in 1+1, 2+1 and 3+1 dimensions
23 pages, 10 figures
Phys.Rev.D76:034503,2007
10.1103/PhysRevD.76.034503
null
hep-th hep-lat
null
We investigate the matching of eigenvalue densities of Wilson loops in SU(N) lattice gauge theory: the eigenvalue densities in 1+1, 2+1 and 3+1 dimensions are nearly identical when the traces of the loops are equal. We show that the matching is present to at least second order in the strong-coupling expansion, and also to second order in perturbation theory. We find that in the continuum limit there is matching at all values of the trace for bare Wilson loops. We confirm numerically that there is matching in these limits and find there are small violations away from them. We discuss the implications for the bulk transitions and for non-analytic gap formation at N = infinity in 2+1 and 3+1 dimensions.
[ { "version": "v1", "created": "Mon, 14 May 2007 12:20:20 GMT" } ]
2008-11-26T00:00:00
[ [ "Bursa", "Francis", "" ] ]
0705.1925
Jidong Zhong
Jidong Zhong and Shangteng Huang
Double Sided Watermark Embedding and Detection with Perceptual Analysis
This paper is a supplement to a paper to be published in IEEE Transactions on Information Forensics and Security
null
null
null
cs.MM cs.CR
null
In our previous work, we introduced a double-sided technique that utilizes but not reject the host interference. Due to its nice property of utilizing but not rejecting the host interference, it has a big advantage over the host interference schemes in that the perceptual analysis can be easily implemented for our scheme to achieve the locally bounded maximum embedding strength. Thus, in this work, we detail how to implement the perceptual analysis in our double-sided schemes since the perceptual analysis is very important for improving the fidelity of watermarked contents. Through the extensive performance comparisons, we can further validate the performance advantage of our double-sided schemes.
[ { "version": "v1", "created": "Mon, 14 May 2007 12:23:43 GMT" } ]
2007-05-23T00:00:00
[ [ "Zhong", "Jidong", "" ], [ "Huang", "Shangteng", "" ] ]
0705.1926
Tobias Kaiser
Tobias Kaiser
The Dirichlet problem in the plane with semianalytic raw data, quasianalyticity and o-minimal structures
37 pages
null
null
null
math.LO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate the Dirichlet solution for a semianalytic continuous function on the boundary of a semianalytic bounded domain in the plane. We show that the germ of the Dirichlet solution at a boundary point with angle greater than 0 lies in a certain quasianalytic class used by Ilyashenko in his work on Hilbert's 16th problem. With this result we can prove that the Dirichlet solution is definable in an o-minimal structure if the angle at a singular boundary point of the domain is an irrational multiple of $\pi$.
[ { "version": "v1", "created": "Mon, 14 May 2007 12:25:39 GMT" }, { "version": "v2", "created": "Mon, 21 Jul 2008 11:21:21 GMT" } ]
2008-07-21T00:00:00
[ [ "Kaiser", "Tobias", "" ] ]
0705.1927
Fanny Godet
Fanny Godet (LMJL)
Linear Prediction of Long-Memory Processes: Asymptotic Results on Mean-squared Errors
null
null
null
null
math.ST stat.TH
null
We present two approaches for linear prediction of long-memory time series. The first approach consists in truncating the Wiener-Kolmogorov predictor by restricting the observations to the last $k$ terms, which are the only available values in practice. We derive the asymptotic behaviour of the mean-squared error as $k$ tends to $ + \infty$. By contrast, the second approach is non-parametric. An AR($k$) model is fitted to the long-memory time series and we study the error that arises in this misspecified model.
[ { "version": "v1", "created": "Mon, 14 May 2007 12:28:03 GMT" } ]
2007-05-23T00:00:00
[ [ "Godet", "Fanny", "", "LMJL" ] ]
0705.1928
Morten Hjorth-Jensen
E. Ovrum and M. Hjorth-Jensen
Quantum computation algorithm for many-body studies
16 pages, 10 figures, revtex style
null
null
null
quant-ph math-ph math.MP nucl-th physics.comp-ph
null
We show in detail how the Jordan-Wigner transformation can be used to simulate any fermionic many-body Hamiltonian on a quantum computer. We develop an algorithm based on appropriate qubit gates that takes a general fermionic Hamiltonian, written as products of a given number of creation and annihilation operators, as input. To demonstrate the applicability of the algorithm, we calculate eigenvalues and eigenvectors of two model Hamiltonians, the well-known Hubbard model and a generalized pairing Hamiltonian. Extensions to other systems are discussed.
[ { "version": "v1", "created": "Mon, 14 May 2007 12:33:29 GMT" } ]
2007-05-23T00:00:00
[ [ "Ovrum", "E.", "" ], [ "Hjorth-Jensen", "M.", "" ] ]
0705.1929
Gregory Gabadadze
Gregory Gabadadze
Cargese Lectures on Brane Induced Gravity
17 pages; based on Carg\`ese lectures of 2006; to appear in proceedings
Nucl.Phys.Proc.Suppl.171:88-98,2007
10.1016/j.nuclphysbps.2007.06.005
NYU-TH-07/03/16
hep-th astro-ph
null
A brief introduction is given to the subject of brane induced gravity. The 5D example is discussed in detail. The 4D laws of gravity are obtained on a brane embedded in an infinite volume extra space, where the problem of stabilization of the volume modulus is absent. The theory has two classically disjoint branches of solutions -- the conventional and self-accelerated one. The conventional branch gives a perturbatively stable model of a metastable graviton, with potentially testable predictions within the Solar system. The self-accelerated branch, on the other hand, provides an existence proof for an idea that the accelerated expansion of the Universe could be due to modified gravity. The issue of perturbative stability of the self-accelerated branch is obscured by a breakdown of the conventional perturbative expansion. However, a certain exact non-perturbative solution found in hep-th/0612016 exhibits a net negative gravitational mass, while this mass is positive on the conventional branch. This suggest that the self-accelerated solution must be non-perturbatively unstable. A proposal to overcome this problem in an extension of the original model, that also allows for the quantum gravity scale to be unrestricted, is briefly discussed.
[ { "version": "v1", "created": "Mon, 14 May 2007 12:38:22 GMT" } ]
2008-11-26T00:00:00
[ [ "Gabadadze", "Gregory", "" ] ]
0705.1930
Peter M. Jacobs
P. Jacobs, D. Kharzeev, B. Mueller, J. Nagle, K. Rajagopal and S. Vigdor
Phases of QCD: Summary of the Rutgers Long Range Plan Town Meeting
null
null
null
null
nucl-ex nucl-th
null
This White Paper summarizes the outcome of the Town Meeting on Phases of QCD that took place January 12-14, 2007 at Rutgers University, as part of the NSAC 2007 Long Range Planning process.
[ { "version": "v1", "created": "Mon, 14 May 2007 05:40:53 GMT" } ]
2007-05-23T00:00:00
[ [ "Jacobs", "P.", "" ], [ "Kharzeev", "D.", "" ], [ "Mueller", "B.", "" ], [ "Nagle", "J.", "" ], [ "Rajagopal", "K.", "" ], [ "Vigdor", "S.", "" ] ]
0705.1931
Thomas Danielson
ZEUS Collaboration: S. Chekanov, et al
Multijet production at low $x_{\rm Bj}$ in deep inelastic scattering at HERA
27 pages, 12 figures, 5 tables, submitted to Nucl. Phys. B
Nucl.Phys.B786:152-180,2007
10.1016/j.nuclphysb.2007.05.027
DESY-07-062
hep-ex
null
Inclusive dijet and trijet production in deep inelastic $ep$ scattering has been measured for $10<Q^2<100$ GeV$^2$ and low Bjorken $x$, $10^{-4}<x_{\rm Bj}<10^{-2}$. The data were taken at the HERA $ep$ collider with centre-of-mass energy $\sqrt{s} = 318 \gev$ using the ZEUS detector and correspond to an integrated luminosity of $82 {\rm pb}^{-1}$. Jets were identified in the hadronic centre-of-mass (HCM) frame using the $k_{T}$ cluster algorithm in the longitudinally invariant inclusive mode. Measurements of dijet and trijet differential cross sections are presented as functions of $Q^2$, $x_{\rm Bj}$, jet transverse energy, and jet pseudorapidity. As a further examination of low-$x_{\rm Bj}$ dynamics, multi-differential cross sections as functions of the jet correlations in transverse momenta, azimuthal angles, and pseudorapidity are also presented. Calculations at $\mathcal{O}(\alpha_{s}^3)$ generally describe the trijet data well and improve the description of the dijet data compared to the calculation at $\mathcal{O}(\alpha_{s}^2)$.
[ { "version": "v1", "created": "Mon, 14 May 2007 12:40:33 GMT" } ]
2012-08-03T00:00:00
[ [ "ZEUS Collaboration", "", "" ], [ "Chekanov", "S.", "" ] ]
0705.1932
Lev Ananikyan
Lev Ananikyan
Spin Effects in Quantum Chromodynamics and Recurrence Lattices with Multi-Site Exchanges
PhD Thesis, 93 pages, 35 figures
null
null
null
cond-mat.stat-mech hep-ph
null
In this thesis, we consider some spin effects in QCD and recurrence lattices with multi-site exchanges. Main topic of our manuscript are critical phenomena in spin systems defined on the recurrence lattices. Main tool of our approach is the method of recursive (hierarchical) lattices. We apply the method of dynamical mapping (or recursive lattices) for investigation of magnetic properties of the fluid and solid $^3$He, phase transitions in crystals and macromolecules. First, we analyze the helix-coil phase transition for polypeptides and proteins, and describe an quasi unfolding transition (like the cold denaturation process) for the degree of helicity (the order parameter for macromolecules). Next we consider the recurrent models of $^3$He defined on the square, Husimi and hexagon lattices. Using the method of dynamical mapping, the magnetization curves with plateaus, bifurcation point and one period doubling are obtained. Then we investigate the model with cubic symmetry defined on the Bethe lattice and containing both linear and quadratic spin-spin interactions. The magnetization of the system is calculated, and a complex structure of the phase transitions between the disordered, partially ordered and completely ordered states is observed. In the framework of QCD, we consider the azimuthal asymmetries in heavy flavor production in the lepton-nucleon deep inelastic scattering (DIS). We calculate the azimuthal (or $\phi$-) dependence of the next-to-leading order heavy-quark-initiated contributions to DIS. It is shown that, contrary to the basic gluon-initiated component, the photon-quark scattering mechanism is practically $\cos2\phi$-independent. We investigate the possibility of measuring both nonperturbative (intrinsic) and perturbative (CTEQ, MRST) charm distributions using the $\cos2\phi$ asymmetry.
[ { "version": "v1", "created": "Mon, 14 May 2007 11:36:14 GMT" } ]
2009-09-29T00:00:00
[ [ "Ananikyan", "Lev", "" ] ]
0705.1933
Peter Kleban
Jacob J. H. Simmons, Peter Kleban, and Robert M. Ziff
Percolation Crossing Formulas and Conformal Field Theory
12 pages, 5 figures. Numerics improved; minor corrections
J.Phys.A40:F771,2007
10.1088/1751-8113/40/31/F03
null
cond-mat.stat-mech cond-mat.dis-nn hep-th math-ph math.MP math.PR
null
Using conformal field theory, we derive several new crossing formulas at the two-dimensional percolation point. High-precision simulation confirms these results. Integrating them gives a unified derivation of Cardy's formula for the horizontal crossing probability $\Pi_h(r)$, Watts' formula for the horizontal-vertical crossing probability $\Pi_{hv}(r)$, and Cardy's formula for the expected number of clusters crossing horizontally $\mathcal{N}_h(r)$. The main step in our approach implies the identification of the derivative of one primary operator with another. We present operator identities that support this idea and suggest the presence of additional symmetry in $c=0$ conformal field theories.
[ { "version": "v1", "created": "Mon, 14 May 2007 02:16:27 GMT" }, { "version": "v2", "created": "Sun, 3 Jun 2007 20:34:27 GMT" } ]
2008-11-26T00:00:00
[ [ "Simmons", "Jacob J. H.", "" ], [ "Kleban", "Peter", "" ], [ "Ziff", "Robert M.", "" ] ]
0705.1934
Balazs Dora
Bal\'azs D\'ora, Peter Thalmeier
Reentrant Kondo effect in Landau quantized graphene
8 pages, 6 figures
Phys. Rev. B 76, 115435 (2007)
10.1103/PhysRevB.76.115435
null
cond-mat.str-el cond-mat.mes-hall
null
We have studied the interplay of an Anderson impurity in Landau quantized graphene, with special emphasis on the influence of the chemical potential. Within the slave-boson mean-field theory, we found reentrant Kondo behaviour by varying the chemical potential or gate voltage. Between Landau levels, the density of states is suppressed, and by changing the graphene's Fermi energy, we cross from metallic to semiconducting regions. Hence, the corresponding Kondo behaviour is also influenced. The f-level spectral function reveals both the presence of Landau levels in the conduction band and the Kondo resonance.
[ { "version": "v1", "created": "Mon, 14 May 2007 13:02:36 GMT" } ]
2012-09-04T00:00:00
[ [ "Dóra", "Balázs", "" ], [ "Thalmeier", "Peter", "" ] ]
0705.1935
Eric Meloche
E. Meloche and M. L. Plumer
Field induced tricritical behavior in the S=1/2 quasi one-dimensional frustrated Ising antiferromagnet
4 pages, 3 figures
null
null
null
cond-mat.str-el
null
The results of extensive histogram cluster heat-bath Monte Carlo simulations on the critical behavior of the quasi-one dimensional Ising antiferromagnet on a stacked triangular lattice are presented. A small applied field is shown to induce a crossover from XY universality to mean-field tricritical behavior. Experimental estimates of critical exponents suggest that these two types of phase transitions are observed in S=1 CsNiCl$_3$ and $S=1/2$ CsCoBr$_3$, respectively. The present results demonstrate that this difference can be explained by an unusual staggered magnetic field arising from quantum exchange mixing previously proposed to account for spin excitations in $S=1/2$ quasi-one-dimensional Ising antiferromagnets.
[ { "version": "v1", "created": "Mon, 14 May 2007 13:07:13 GMT" } ]
2007-05-23T00:00:00
[ [ "Meloche", "E.", "" ], [ "Plumer", "M. L.", "" ] ]
0705.1936
Thomas K\"uhn
T. K\"uhn, D. V. Anghel, Y. M. Galperin and M. Manninen
Interaction of Lamb modes with two-level systems in amorphous nanoscopic membranes
9 pages, 2 figures
Phys. Rev. B 76, 165425 (2007)
10.1103/PhysRevB.76.165425
null
cond-mat.mes-hall cond-mat.dis-nn
null
Using a generalized model of interaction between a two-level system (TLS) and an arbitrary deformation of the material, we calculate the interaction of Lamb modes with TLSs in amorphous nanoscopic membranes. We compare the mean free paths of the Lamb modes with different symmetries and calculate the heat conductivity $\kappa$. In the limit of an infinitely wide membrane, the heat conductivity is divergent. Nevertheless, the finite size of the membrane imposes a lower cut-off for the phonons frequencies, which leads to the temperature dependence $\kappa\propto T(a+b\ln T)$. This temperature dependence is a hallmark of the TLS-limited heat conductance at low temperature.
[ { "version": "v1", "created": "Mon, 14 May 2007 13:09:08 GMT" } ]
2007-10-31T00:00:00
[ [ "Kühn", "T.", "" ], [ "Anghel", "D. V.", "" ], [ "Galperin", "Y. M.", "" ], [ "Manninen", "M.", "" ] ]
0705.1937
Giulia Zanderighi
Giulia Zanderighi
Accurate predictions for heavy quark jets
4 pages, 4 figures, talk given at 42nd Rencontres de Moriond on QCD and High-Energy Hadronic Interactions, La Thuile, March 2007 and at the 15th International Workshop on Deep-Inelastic Scattering and related subjects, Munich, April 2007
null
null
CERN-PH-TH-2007-081
hep-ph
null
Heavy-flavour jets enter many of today's collider studies, yet NLO predictions for these quantities are subject to large uncertainties, larger than the corresponding experimental errors. We propose a new, infrared safe definition of heavy-quark jets which allows one to reduce theoretical uncertainties by a factor of three.
[ { "version": "v1", "created": "Mon, 14 May 2007 13:11:33 GMT" } ]
2007-05-23T00:00:00
[ [ "Zanderighi", "Giulia", "" ] ]
0705.1938
Gloria Koenigsberger
Gloria Koenigsberger and Edmundo Moreno
The extraordinary LBV/WR system HD 5980
Presented in : `` Massive stars: fundamental parameters and circumstellar interactions", conference in honour of Virpi Niemela's 70th birthday; 5 pages, 3 figures
null
null
null
astro-ph
null
The LBV/WR system HD 5980 contains a short-period, eccentric binary system with interacting stellar winds. In this paper we summarize results from model calculations of the tidal flows on the LBV component showing that energy dissipation rates, E-dot, associated with turbulent viscosity are orbital-phase dependent as well as variable over the stellar surface. We speculate that if E-dot contributes towards driving mass-loss, the strongest wind-wind interaction effects may occur after periastron passage. In addition, the model suggests the presence of stronger outflows localized at polar angles theta~30 --50 degrees during part of the orbital cycle. Thus, the analysis of wind-wind interactions in this system requires that models be revised to incorporate non-stationary and asymmetric wind structures.
[ { "version": "v1", "created": "Mon, 14 May 2007 13:11:40 GMT" } ]
2007-05-23T00:00:00
[ [ "Koenigsberger", "Gloria", "" ], [ "Moreno", "Edmundo", "" ] ]
0705.1939
Hamed Haddadi MSc MIEE
Richard G. Clegg, Hamed Haddadi, Raul Landa, Miguel Rio
Towards Informative Statistical Flow Inversion
null
null
null
null
cs.NI cs.PF
null
A problem which has recently attracted research attention is that of estimating the distribution of flow sizes in internet traffic. On high traffic links it is sometimes impossible to record every packet. Researchers have approached the problem of estimating flow lengths from sampled packet data in two separate ways. Firstly, different sampling methodologies can be tried to more accurately measure the desired system parameters. One such method is the sample-and-hold method where, if a packet is sampled, all subsequent packets in that flow are sampled. Secondly, statistical methods can be used to ``invert'' the sampled data and produce an estimate of flow lengths from a sample. In this paper we propose, implement and test two variants on the sample-and-hold method. In addition we show how the sample-and-hold method can be inverted to get an estimation of the genuine distribution of flow sizes. Experiments are carried out on real network traces to compare standard packet sampling with three variants of sample-and-hold. The methods are compared for their ability to reconstruct the genuine distribution of flow sizes in the traffic.
[ { "version": "v1", "created": "Mon, 14 May 2007 13:14:33 GMT" } ]
2007-05-23T00:00:00
[ [ "Clegg", "Richard G.", "" ], [ "Haddadi", "Hamed", "" ], [ "Landa", "Raul", "" ], [ "Rio", "Miguel", "" ] ]
0705.1940
Martin Dressel
Martin Dressel
Charge-Ordering Phenomena in One-Dimensional Solids
review, 60 year Drittes Physikalisches Institut, Universitat Gottingen, 22 page, 19 figures
null
null
null
cond-mat.str-el
null
As the dimensionality is reduced, the world becomes more and more interesting; novel and fascinating phenomena show up which call for understanding. Physics in one dimension is a fascinating topic for theory and experiment: for the former often a simplification, for the latter always a challenge. Various ways will be demonstrated how one-dimensional structures can be achieved in reality. In particular organic conductors could establish themselves as model systems for the investigation of the physics in reduced dimensions. In the metallic state of a one-dimensional solid, Fermi-liquid theory breaks down and spin and charge degrees of freedom become separated. But the metallic phase is not stable in one dimension: as the temperature is reduced, the electronic charge and spin tend to arrange themselves in an ordered fashion due to strong correlations. The competition of the different interactions is responsible for which broken-symmetry ground state is eventually realized in a specific compound and which drives the system towards an insulating state. Here we review the various ordering phenomena and how they can be identified by dielectric and optic measurements.
[ { "version": "v1", "created": "Sun, 13 May 2007 20:10:33 GMT" } ]
2007-05-23T00:00:00
[ [ "Dressel", "Martin", "" ] ]
0705.1941
Gary Sinclair
Gary F. Sinclair and Natalia Korolkova
Cross-Kerr interaction in a four-level atomic system
5 pages, resubmitted to Physical Review A with clarified style and correction to Fig 1
null
10.1103/PhysRevA.76.033803
null
quant-ph
null
We derive the form of the cross-Kerr interaction in a four-level atomic system in the N-configuration. We use time-independent perturbation theory to calculate the eigenenergies and eigenstates of the Schrodinger equation for the system. The system is considered as a perturbation of a Raman resonant three-level lambda scheme for which exact solutions are known. We show that within the strong control field limit the cross-Kerr interaction can arise between two weak probe fields. The strength of this nonlinear coupling is several orders of magnitude larger than that achievable using optical fibres.
[ { "version": "v1", "created": "Mon, 14 May 2007 13:36:18 GMT" }, { "version": "v2", "created": "Thu, 12 Jul 2007 14:44:13 GMT" } ]
2009-11-13T00:00:00
[ [ "Sinclair", "Gary F.", "" ], [ "Korolkova", "Natalia", "" ] ]
0705.1942
Alessandra Bernardi
Alessandra Bernardi
Ideals of varieties parameterized by certain symmetric tensors
19 pages
Journ. of P. and A. Algebra, 212, (2008), 6, pp. 1542-1559
10.1016/j.jpaa.2007.10.022
null
math.AG math.AC
null
The ideal of a Segre variety is generated by the 2-minors of a generic hypermatrix of indeterminates. We extend this result to the case of Segre-Veronese varieties. The main tool is the concept of weak generic hypermatrix which allows us to treat also the case of projection of Veronese surfaces from a set of generic points and of Veronese varieties from a Cohen-Macaulay subvariety of codimension 2.
[ { "version": "v1", "created": "Mon, 14 May 2007 13:36:46 GMT" }, { "version": "v2", "created": "Wed, 10 Oct 2007 10:37:07 GMT" }, { "version": "v3", "created": "Wed, 17 Oct 2007 10:31:08 GMT" } ]
2011-05-19T00:00:00
[ [ "Bernardi", "Alessandra", "" ] ]
0705.1943
Alexander Bolonkin
A. Bolonkin
Electrostatic Climber for Space Elevator and Launcher
12 pages, 2 figures, 1 table
null
null
null
physics.gen-ph physics.space-ph
null
Author details research on the new, very prospective, electrostatic Space Elevator climber based on a new electrostatic linear engine previously offered at the 42nd Joint Propulsion Conference (AIAA-2006-5229) and published in AEAT, Vol.78, No.6, 2006, pp. 502-508. The electrostatic climber discussed can have any speed (and braking), the energy for climber movement is delivered by a lightweight high-voltage line into a Space Elevator-holding cable from Earth electric generator. This electric line also can be used for delivery electric energy to a Geosynchronous Space Station. At present, the best solution of the climber problem (announced by NASA as one important awarding problem of Space Elevator) is problematic. Author also shows the linear electrostatic engine may be used as realistic power space launcher at the present time. Two projects illustrate these new devices. Key words: Space elevator, Electrostatic climber for space elevator, Electrostatic space launcher, Electrostatic accelerator. This work is presented as paper AIAA-2007-5838 for 43 Joint Propulsion Conference, Cincinnati, Ohio, USA, 9-11 July, 2007,
[ { "version": "v1", "created": "Mon, 14 May 2007 13:37:13 GMT" } ]
2007-05-23T00:00:00
[ [ "Bolonkin", "A.", "" ] ]
0705.1944
Sergio Ciuchi
E. Cappelluti, S. Ciuchi, S. Fratini
Polaronic features in the optical properties of the Holstein-t-J model
improved version, as submitted to Phys. Rev. B
Phys. Rev. B, 76, 125111 (2007)
10.1103/PhysRevB.76.125111
null
cond-mat.str-el
null
We derive the exact solution for the optical conductivity $\sigma(\omega)$ of one hole in the Holstein-t-J model in the framework of dynamical mean-field theory (DMFT). We investigate the magnetic and phonon features associated with polaron formation as a function of the exchange coupling $J$, of the electron-phonon interaction $\lambda$ and of the temperature. Our solution directly relates the features of the optical conductivity to the excitations in the single-particle spectral function, revealing two distinct mechanisms of closing and filling of the optical pseudogap that take place upon varying the microscopic parameters. We show that the optical absorption at the polaron crossover is characterized by a coexistence of a magnon peak at low frequency and a broad polaronic band at higher frequency. An analytical expression for $\sigma(\omega)$ valid in the polaronic regime is presented.
[ { "version": "v1", "created": "Mon, 14 May 2007 13:37:19 GMT" }, { "version": "v2", "created": "Tue, 12 Jun 2007 15:22:07 GMT" } ]
2008-02-07T00:00:00
[ [ "Cappelluti", "E.", "" ], [ "Ciuchi", "S.", "" ], [ "Fratini", "S.", "" ] ]
0705.1945
Ivan Santamaria-Holek
I. Santamaria-Holek, A. Perez-Madrid
The non-equilibrium work relation. Thermodynamic analysis and microscopic foundations
16 pages 1 figure
null
10.1016/j.physa.2007.10.071
null
cond-mat.stat-mech
null
We discuss the conditions for which the non-equilibrium work relation is valid by means of thermodynamic and microscopic arguments.
[ { "version": "v1", "created": "Mon, 14 May 2007 13:58:03 GMT" }, { "version": "v2", "created": "Fri, 22 Jun 2007 17:34:27 GMT" }, { "version": "v3", "created": "Fri, 7 Sep 2007 13:48:39 GMT" } ]
2009-11-13T00:00:00
[ [ "Santamaria-Holek", "I.", "" ], [ "Perez-Madrid", "A.", "" ] ]
0705.1946
Brian M. Andersen
Brian M. Andersen, Yu. S. Barash, S. Graser, P. J. Hirschfeld
Novel Josephson Effects in d-wave Superconductor Junctions with Antiferromagnetic Interlayers
6 pages, 4 figures
Phys. Rev. B 77, 054501 (2008)
10.1103/PhysRevB.77.054501
null
cond-mat.supr-con cond-mat.mes-hall
null
We calculate the dc supercurrent through a Josephson tunnel junction consisting of an antiferromagnetic (AF) interlayer sandwiched between two d-wave superconductors (d). Such d/AF/d junctions exhibit a rich dependence of the Josephson current on the interlayer parameters, including the possibility of 0-pi transitions with varying temperature or interlayer thickness. Furthermore, we study d/I/d junctions when the dSC leads include subdominant magnetic correlations. In this case induced magnetism near the interface can strongly diminish the critical current for 110 oriented junctions whereas no suppression is obtained for the 100 orientation. This may help resolve a long-standing puzzle of the critical current versus grain boundary angle in high-T_c superconductors.
[ { "version": "v1", "created": "Mon, 14 May 2007 14:08:12 GMT" }, { "version": "v2", "created": "Thu, 11 Oct 2007 08:18:01 GMT" } ]
2009-11-13T00:00:00
[ [ "Andersen", "Brian M.", "" ], [ "Barash", "Yu. S.", "" ], [ "Graser", "S.", "" ], [ "Hirschfeld", "P. J.", "" ] ]
0705.1947
Quanhua Xu
Turdebek N. Bekjan and Quanhua Xu
Riesz and Szeg\"o type factorizations for noncommutative Hardy spaces
To appear in J. Operator Theory
null
null
null
math.OA math.FA
null
Let $\A$ be a finite subdiagonal algebra in Arveson's sense. Let $H^p(\A)$ be the associated noncommutative Hardy spaces, $0<p\le\8$. We extend to the case of all positive indices most recent results about these spaces, which include notably the Riesz, Szeg\"o and inner-outer type factorizations. One new tool of the paper is the contractivity of the underlying conditional expectation on $H^p(\A)$ for $p<1$.
[ { "version": "v1", "created": "Mon, 14 May 2007 14:01:31 GMT" } ]
2007-05-23T00:00:00
[ [ "Bekjan", "Turdebek N.", "" ], [ "Xu", "Quanhua", "" ] ]
0705.1948
Quanhua Xu
Caiheng Ouyang and Quanhua Xu
BMO functions and Carleson measures with values in uniformly convex spaces
To appear in Canadian J. Math
null
null
null
math.OA math.FA
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper studies the relationship between vector-valued BMO functions and the Carleson measures defined by their gradients. Let $dA$ and $dm$ denote Lebesgue measures on the unit disc $D$ and the unit circle $\mathbb T$, respectively. For $1< q<\infty$ and a Banach space $B$ we prove that there exists a positive constant $c$ such that $$\sup_{z_0\in D}\int_{D}(1-|z|)^{q-1}\|\nabla f(z)\|^q P_{z_0}(z) dA(z) \le c^q\sup_{z_0\in D}\int_{\T}\|f(z)-f(z_0)\|^qP_{z_0}(z) dm(z)$$ holds for all trigonometric polynomials $f$ with coefficients in $B$ iff $B$ admits an equivalent norm which is $q$-uniformly convex, where $$P_{z_0}(z)=\frac{1-|z_0|^2}{|1-\bar{z_0}z|^2} .$$ The validity of the converse inequality is equivalent to the existence of an equivalent $q$-uniformly smooth norm.
[ { "version": "v1", "created": "Mon, 14 May 2007 14:14:32 GMT" }, { "version": "v2", "created": "Thu, 5 Jun 2008 12:17:39 GMT" } ]
2008-06-05T00:00:00
[ [ "Ouyang", "Caiheng", "" ], [ "Xu", "Quanhua", "" ] ]
0705.1949
Chiu Fan Lee
Siu Lung Law, Chiu Fan Lee, Sam Howison and Jeff N. Dewynne
Correlated multi-asset portfolio optimisation with transaction cost
Manuscript completely rewritten
null
null
null
q-fin.PM physics.data-an physics.soc-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We employ perturbation analysis technique to study multi-asset portfolio optimisation with transaction cost. We allow for correlations in risky assets and obtain optimal trading methods for general utility functions. Our analytical results are supported by numerical simulations in the context of the Long Term Growth Model.
[ { "version": "v1", "created": "Mon, 14 May 2007 14:34:40 GMT" }, { "version": "v2", "created": "Sat, 23 Jun 2007 15:48:25 GMT" }, { "version": "v3", "created": "Tue, 5 May 2009 21:29:09 GMT" } ]
2009-05-06T00:00:00
[ [ "Law", "Siu Lung", "" ], [ "Lee", "Chiu Fan", "" ], [ "Howison", "Sam", "" ], [ "Dewynne", "Jeff N.", "" ] ]
0705.1950
Paolo Lisca
Paolo Lisca
Sums of lens spaces bounding rational balls
20 pages, 4 figures
Algebr. Geom. Topol. 7 (2007) 2141-2164
10.2140/agt.2007.7.2141
null
math.GT
null
We classify connected sums of three-dimensional lens spaces which smoothly bound rational homology balls. We use this result to determine the order of each lens space in the group of rational homology 3-spheres up to rational homology cobordisms, and to determine the concordance order of each 2-bridge knot.
[ { "version": "v1", "created": "Mon, 14 May 2007 14:37:34 GMT" } ]
2014-10-01T00:00:00
[ [ "Lisca", "Paolo", "" ] ]
0705.1951
Bertrand Duplantier
Bertrand Duplantier
Brownian Motion, "Diverse and Undulating"
107 pages, 21 figures, expanded and updated version of the article originally published in Einstein, 1905-2005, Poincar\'e Seminar 2005 (Birkh\"auser Verlag, 2006). Original version also available at http://www.birkhauser.ch/3-7643-7435-7
Brownian Motion, "Diverse and Undulating'', in "Einstein, 1905-2005". Poincar\'e Seminar 2005, Th. Damour, O. Darrigol, B. Duplantier and V. Rivasseau, Editors, pp. 201-293 (Birkh\"auser Verlag, Basel, 2006)
null
null
cond-mat.stat-mech cond-mat.soft math-ph math.HO math.MP math.PR physics.chem-ph physics.hist-ph
null
We describe in detail the history of Brownian motion, as well as the contributions of Einstein, Sutherland, Smoluchowski, Bachelier, Perrin and Langevin to its theory. The always topical importance in physics of the theory of Brownian motion is illustrated by recent biophysical experiments, where it serves, for instance, for the measurement of the pulling force on a single DNA molecule. In a second part, we stress the mathematical importance of the theory of Brownian motion, illustrated by two chosen examples. The by-now classic representation of the Newtonian potential by Brownian motion is explained in an elementary way. We conclude with the description of recent progress seen in the geometry of the planar Brownian curve. At its heart lie the concepts of conformal invariance and multifractality, associated with the potential theory of the Brownian curve itself.
[ { "version": "v1", "created": "Mon, 14 May 2007 14:37:47 GMT" } ]
2016-09-08T00:00:00
[ [ "Duplantier", "Bertrand", "" ] ]
0705.1952
Quanhua Xu
Marius Junge and Quanhua Xu
Noncommutative Burkholder/Rosenthal inequalities II: applications
To appear in Isreal J; Math
null
null
null
math.OA math.FA math.PR
null
We show norm estimates for the sum of independent random variables in noncommutative $L_p$-spaces for $1<p<\infty$ following our previous work. These estimates generalize the classical Rosenthal inequality in the commutative case. Among applications, we derive an equivalence for the $p$-norm of the singular values of a random matrix with independent entries, and characterize those symmetric subspaces and unitary ideals which can be realized as subspaces of a noncommutative $L_p$ for $2<p<\infty$.
[ { "version": "v1", "created": "Mon, 14 May 2007 14:38:39 GMT" } ]
2007-05-23T00:00:00
[ [ "Junge", "Marius", "" ], [ "Xu", "Quanhua", "" ] ]
0705.1953
Jordan Skittrall
Ben C. Allanach, Jordan P. Skittrall, K. Sridhar
Z boson decay to photon plus Kaluza-Klein graviton in large extra dimensions
47 pages, uses feynmp for diagrams. v2: typographical corrections for letter-sized paper and to correct feynmf parsing error. v3: minor error in polarisation averaging and reference corrected. v4: reflects changes for published version; arithmetic error corrected and reference updated; section on transversality conditions not present in published version retained
JHEP 0711:089,2007
10.1088/1126-6708/2007/11/089
DAMTP-2007-42, TIFR/TH/07-08
hep-ph
null
In the large extra dimensional ADD scenario, Z bosons undergo a one-loop decay into a photon and Kaluza-Klein towers of gravitons/gravi-scalars. We calculate such a decay width, extending previous arguments about the general form of the four-dimensional on-shell amplitude. The amplitudes calculated are relevant to processes in other extra dimensional models where the Standard Model fields are confined to a 4-brane.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:49:17 GMT" }, { "version": "v2", "created": "Tue, 22 May 2007 23:35:15 GMT" }, { "version": "v3", "created": "Mon, 23 Jul 2007 15:46:15 GMT" }, { "version": "v4", "created": "Fri, 18 Jan 2008 11:56:18 GMT" } ]
2009-01-06T00:00:00
[ [ "Allanach", "Ben C.", "" ], [ "Skittrall", "Jordan P.", "" ], [ "Sridhar", "K.", "" ] ]
0705.1954
Thomas Tucker J
Dragos Ghioca, Thomas J. Tucker, Michael E. Zieve
Intersections of polynomial orbits, and a dynamical Mordell-Lang conjecture
19 pages; to appear in Inventiones Mathematicae; in this version we modified the exposition in view of the referee's comments
Inventiones Math. 171 (2008), 463--483
10.1007/s00222-007-0087-5
null
math.NT math.AG math.DS
null
We prove that if nonlinear complex polynomials of the same degree have orbits with infinite intersection, then the polynomials have a common iterate. We also prove a special case of a conjectured dynamical analogue of the Mordell-Lang conjecture.
[ { "version": "v1", "created": "Mon, 14 May 2007 18:04:01 GMT" }, { "version": "v2", "created": "Mon, 8 Oct 2007 16:38:34 GMT" } ]
2009-11-13T00:00:00
[ [ "Ghioca", "Dragos", "" ], [ "Tucker", "Thomas J.", "" ], [ "Zieve", "Michael E.", "" ] ]
0705.1955
Sirichai Chongchitnan
Sirichai Chongchitnan, George Efstathiou
Can we ever distinguish between quintessence and a cosmological constant?
10 pages, 6 figures. Version published in Phys. Rev. D
Phys.Rev.D76:043508,2007
10.1103/PhysRevD.76.043508
null
astro-ph hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Many ambitious experiments have been proposed to constrain dark energy and detect its evolution. At present, observational constraints are consistent with a cosmological constant and there is no firm evidence for any evolution in the dark energy equation of state w. In this paper, we pose the following question: suppose that future dark energy surveys constrain w at low redshift to be consistent with -1 to a percent level accuracy, what are the implications for models of dynamical dark energy? We investigate this problem in a model-independent way by following quintessence field trajectories in `energy' phase-space. Attractor dynamics in this phase-space leads to two classes of acceptable models: 1) models with flat potentials, i.e. an effective cosmological constant, and 2) models with potentials that suddenly flatten with a characteristic kink. The prospect of further constraining the second class of models from distance measurements and fluctuation growth rates at low redshift (z<3) seems poor. However, in some models of this second class, the dark energy makes a significant contribution to the total energy density at high redshift. Such models can be further constrained from observation of the cosmic microwave background anisotropies and from primordial nucleosynthesis. It is possible, therefore, to construct models in which the dark energy at high redshift causes observable effects, even if future dark energy surveys constrain w at low redshift to be consistent with -1 to high precision.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:28:45 GMT" }, { "version": "v2", "created": "Sun, 22 Jul 2007 19:33:53 GMT" }, { "version": "v3", "created": "Wed, 8 Aug 2007 15:05:39 GMT" }, { "version": "v4", "created": "Thu, 26 Feb 2009 17:36:42 GMT" } ]
2009-02-26T00:00:00
[ [ "Chongchitnan", "Sirichai", "" ], [ "Efstathiou", "George", "" ] ]
0705.1956
Dan Chen
Dan Chen
A Branch and Cut Algorithm for the Halfspace Depth Problem
110 pages, 25 figures
null
null
null
cs.CG
null
The concept of data depth in non-parametric multivariate descriptive statistics is the generalization of the univariate rank method to multivariate data. Halfspace depth is a measure of data depth. Given a set S of points and a point p, the halfspace depth (or rank) k of p is defined as the minimum number of points of S contained in any closed halfspace with p on its boundary. Computing halfspace depth is NP-hard, and it is equivalent to the Maximum Feasible Subsystem problem. In this thesis a mixed integer program is formulated with the big-M method for the halfspace depth problem. We suggest a branch and cut algorithm. In this algorithm, Chinneck's heuristic algorithm is used to find an upper bound and a related technique based on sensitivity analysis is used for branching. Irreducible Infeasible Subsystem (IIS) hitting set cuts are applied. We also suggest a binary search algorithm which may be more stable numerically. The algorithms are implemented with the BCP framework from the COIN-OR project.
[ { "version": "v1", "created": "Mon, 14 May 2007 15:31:22 GMT" } ]
2007-05-23T00:00:00
[ [ "Chen", "Dan", "" ] ]
0705.1957
Yuriy Kosevich
Yuriy A. Kosevich, Leonid I. Manevitch, and Alexander V. Savin
Wandering breathers and self-trapping in weakly coupled nonlinear chains: classical counterpart of macroscopic tunneling quantum dynamics
33 pages, 16 figures
null
10.1103/PhysRevE.77.046603
null
nlin.PS
null
We present analytical and numerical studies of phase-coherent dynamics of intrinsically localized excitations (breathers) in a system of two weakly coupled nonlinear oscillator chains. We show that there are two qualitatively different dynamical regimes of the coupled breathers, either immovable or slowly-moving: the periodic transverse translation (wandering) of low-amplitude breather between the chains, and the one-chain-localization of high-amplitude breather. These two modes of coupled nonlinear excitations, which involve large number of anharmonic oscillators, can be mapped onto two solutions of a single pendulum equation, detached by a separatrix mode. We also study two-chain breathers, which can be considered as bound states of discrete breathers with different symmetry and center locations in the coupled chains, and bifurcation of the anti-phase two-chain breather into the one-chain one. Delocalizing transition of 1D breather in 2D system of a large number of parallel coupled nonlinear chains is described, in which the breather, initially excited in a given chain, abruptly spreads its vibration energy in the whole 2D system upon decreasing breather frequency or amplitude below the threshold one. The threshold breather frequency is above the cut off phonon frequency in 2D system, and the threshold breather amplitude scales as square root of the inter-chain coupling constant. Delocalizing transition of discrete vibrational breather in 2D and 3D systems of coupled nonlinear chains has an analogy with delocalizing transition for Bose-Einstein condensates in 2D and 3D optical lattices.
[ { "version": "v1", "created": "Mon, 14 May 2007 15:12:09 GMT" }, { "version": "v2", "created": "Tue, 15 Jan 2008 05:28:51 GMT" } ]
2009-11-13T00:00:00
[ [ "Kosevich", "Yuriy A.", "" ], [ "Manevitch", "Leonid I.", "" ], [ "Savin", "Alexander V.", "" ] ]
0705.1958
Mishkatul Bhattacharya
M. Bhattacharya
How to detect level crossings without looking at the spectrum
Accepted for publication in the American Journal of Physics
null
10.1119/1.2757622
null
physics.atom-ph
null
We remind the reader that it is possible to tell if two or more eigenvalues of a matrix are equal, without calculating the eigenvalues. We then use this property to detect (avoided) crossings in the spectra of quantum Hamiltonians representable by matrices. This approach provides a pedagogical introduction to (avoided) crossings, is capable of handling realistic Hamiltonians analytically, and offers a way to visualize crossings which is sometimes superior to that provided by the spectrum. We illustrate the method using the Breit-Rabi Hamiltonian to describe the hyperfine-Zeeman structure of the ground state hydrogen atom in a uniform magnetic field.
[ { "version": "v1", "created": "Mon, 14 May 2007 18:02:44 GMT" } ]
2009-11-13T00:00:00
[ [ "Bhattacharya", "M.", "" ] ]
0705.1959
Luca Ferretti
Luca Ferretti
R-symmetry breaking, runaway directions and global symmetries in O'Raifeartaigh models
16 pages, 1 figure
JHEP 0712:064,2007
10.1088/1126-6708/2007/12/064
SISSA 24/2007/EP
hep-th hep-ph
null
We discuss O'Raifeartaigh models with general R-charge assignments, introduced by Shih to break R-symmetry spontaneously. We argue that most of these models have runaway directions related to the R-symmetry. In addition, we study the simplest model with a U(N) global symmetry and show that in a range of parameters R-symmetry is spontaneously broken in a metastable vacuum.
[ { "version": "v1", "created": "Mon, 14 May 2007 19:51:47 GMT" } ]
2009-04-17T00:00:00
[ [ "Ferretti", "Luca", "" ] ]
0705.1960
Tamiaki Yoneya
Tamiaki Yoneya
Field Theory of Yang-Mills Quantum Mechanics for D Particles
corrected typos, corrected references, 39 pages, 2 figures, version to be published in Prog. Theor. Phys
Prog.Theor.Phys.118:135-167,2007
10.1143/PTP.118.135
UT-Komaba 07-6
hep-th
null
We propose a new field-theoretic framework for formulating the non-relativistic quantum mechanics of D particles in a Fock space of U(N) Yang-Mills theories with all different N in a unified way. D-particle field operators, creating and annihilating a D particle and hence changing N one by one, are defined. The base space of these D-particle fields is a (complex) vector space of infinite dimensions. The gauge invariance of Yang-Mills quantum mechanics is reinterpreted as a quantum-statistical symmetry, which is taken into account by setting up a novel algebraic and projective structure in the formalism. Ordinary physical observables of Yang-Mills theory, obeying the standard algebra, are expressed as bilinear forms of the D-particle fields. Together with the open-closed string duality, our new formulation suggests a trinity of three different but mutually dual viewpoints in string theory.
[ { "version": "v1", "created": "Mon, 14 May 2007 15:26:30 GMT" }, { "version": "v2", "created": "Thu, 17 May 2007 11:42:04 GMT" }, { "version": "v3", "created": "Wed, 11 Jul 2007 04:10:25 GMT" } ]
2009-01-28T00:00:00
[ [ "Yoneya", "Tamiaki", "" ] ]
0705.1961
Athina Mageira
Athina Mageira
$C^*$-alg\`ebres gradu\'ees par un semi-treillis
null
null
null
null
math.OA
null
Graded $C^*$-algebras by a semi lattice were introduced and studied by Anne Boutet de Monvel, Vladimir Georgescu and their collaborators in relation with the quantum N body problem. This thesis is devoted to a systematic study of these algebras and their properties. In particular, we show that they are completely described by their homogenous subalgebras and that they are invariant under several operations such as tensor products, crossed products (by actions of locally compact groups that respect the graduation). We give the $K$-theory of graded $C^*$-algebras and finally, we study some examples of such algebras.
[ { "version": "v1", "created": "Mon, 14 May 2007 15:29:49 GMT" } ]
2007-05-23T00:00:00
[ [ "Mageira", "Athina", "" ] ]
0705.1962
J. Aarts
C. Beekman, I. Komissarov, M. Hesselberth and J. Aarts
Transport properties of microstructured ultrathin films of La0.67Ca0.33MnO3 on SrTiO3
3 pages, 5 figures
null
10.1063/1.2756166
null
cond-mat.mtrl-sci cond-mat.str-el
null
We have investigated the electrical transport properties of 8 nm thick La0.67Ca0.33MnO3 films, sputter-deposited on SrTiO3 (STO), and etched into 5 micrometer-wide bridges by Ar-ion etching. We find that even slight overetching of the film leads to conductance of the STO substrate, and asymmetric and non-linear current-voltage (I-V) characteristics. However, a brief oxygen plasma etch allows full recovery of the insulating character of the substrate. The I-V characteristics of the bridges are then fully linear over a large range of current densities. We find colossal magnetoresistance properties typical for strained LCMO on STO but no signature of non-linear effects (so-called electroresistance) connected to electronic inhomogeneites. In the metallic state below 150 K, the highest current densities lead to heating effects and non-linear I-V characteristics.
[ { "version": "v1", "created": "Mon, 14 May 2007 15:31:02 GMT" } ]
2009-11-13T00:00:00
[ [ "Beekman", "C.", "" ], [ "Komissarov", "I.", "" ], [ "Hesselberth", "M.", "" ], [ "Aarts", "J.", "" ] ]
0705.1963
Dima Yakovlev
P.S. Shternin, D.G. Yakovlev (Ioffe Institute)
Electron-muon heat conduction in neutron star cores via the exchange of transverse plasmons
15 pages, 5 figures, to appear in Phys. Rev. D
Phys.Rev.D75:103004,2007
10.1103/PhysRevD.75.103004
null
astro-ph
null
We calculate the thermal conductivity of electrons and muons kappa_{e-mu} produced owing to electromagnetic interactions of charged particles in neutron star cores and show that these interactions are dominated by the exchange of transverse plasmons (via the Landau damping of these plasmons in nonsuperconducting matter and via a specific plasma screening in the presence of proton superconductivity). For normal protons, the Landau damping strongly reduces kappa_{e-mu} and makes it temperature independent. Proton superconductivity suppresses the reduction and restores the Fermi-liquid behavior kappa_{e-mu} ~ 1/T. Comparing with the thermal conductivity of neutrons kappa_n, we obtain kappa_{e-mu}> kappa_n for T>2 GK in normal matter and for any T in superconducting matter with proton critical temperatures T_c>3e9 K. The results are described by simple analytic formulae.
[ { "version": "v1", "created": "Mon, 14 May 2007 15:31:19 GMT" } ]
2008-12-18T00:00:00
[ [ "Shternin", "P. S.", "", "Ioffe Institute" ], [ "Yakovlev", "D. G.", "", "Ioffe Institute" ] ]
0705.1964
Nan Zhao
Nan Zhao, D.L. Zhou, Jia-Lin Zhu, C.P. Sun
Cooling Torsional Nanomechanical Vibration by Spin-Orbit Interactions
4 pages, 3 figures
null
10.1088/0253-6102/50/6/43
null
cond-mat.mes-hall quant-ph
null
We propose and study a spin-orbit interaction based mechanism to actively cool down the torsional vibration of a nanomechanical resonator made by semiconductor materials. We show that the spin-orbit interactions of electrons can induce a coherent coupling between the electron spins and the torsional modes of nanomechanical vibration. This coherent coupling leads to an active cooling for the torsional modes via the dynamical thermalization of the resonator and the spin ensemble.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:37:35 GMT" } ]
2015-05-13T00:00:00
[ [ "Zhao", "Nan", "" ], [ "Zhou", "D. L.", "" ], [ "Zhu", "Jia-Lin", "" ], [ "Sun", "C. P.", "" ] ]
0705.1965
S. Javad Akhtarshenas
S. J. Akhtarshenas
An Explicit Computation of the Bures Metric Over the Space of $N$-Dimensional Density Matrices
10 pages
J. Phys. A: Math. Theor. 40 (2007) 11333-11341
10.1088/1751-8113/40/37/010
null
quant-ph
null
The aim of this paper is to provide a method for explicit computation of the Bures metric over the space of $N$-level quantum system, based on the coset parametrization of density matrices.
[ { "version": "v1", "created": "Mon, 14 May 2007 15:37:29 GMT" }, { "version": "v2", "created": "Tue, 11 Sep 2007 16:19:07 GMT" } ]
2009-11-13T00:00:00
[ [ "Akhtarshenas", "S. J.", "" ] ]
0705.1966
Patrick Meessen
P. Meessen
All-order consistency of 5d sugra vacua
7 pages LaTeX: fixed a flaw in the argumentation, conclusions unchanged
Phys.Rev.D76:046006,2007
10.1103/PhysRevD.76.046006
IFT-UAM/CSIC07-24
hep-th
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that the maximally supersymmetric vacua of d=5 N=1 sugra remain maximally supersymmetric solutions when taking into account higher order corrections.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:10:05 GMT" }, { "version": "v2", "created": "Mon, 4 Jun 2012 13:25:13 GMT" } ]
2012-06-05T00:00:00
[ [ "Meessen", "P.", "" ] ]
0705.1967
Chris Neugebauer
C. J. Neugebauer and S. N. Taraskin
Supercritical series expansion for the contact process in heterogeneous and disordered environments
15 pages, 12 figures
null
10.1103/PhysRevE.76.011119
null
cond-mat.stat-mech cond-mat.dis-nn
null
The supercritical series expansion of the survival probability for the one-dimensional contact process in heterogeneous and disordered lattices is used for the evaluation of the loci of critical points and critical exponents $\beta$. The heterogeneity and disorder are modeled by considering binary regular and irregular lattices of nodes characterized by different recovery rates and identical transmission rates. Two analytical approaches based on Nested Pad\'e approximants and Partial Differential approximants were used in the case of expansions with respect to two variables (two recovery rates) for the evaluation of the critical values and critical exponents. The critical exponents in heterogeneous systems are very close to those for the homogeneous contact process thus confirming that the contact process in periodic heterogeneous environment belongs to the directed percolation universality class. The disordered systems, in contrast, seem to have continuously varying critical exponents.
[ { "version": "v1", "created": "Mon, 14 May 2007 15:43:56 GMT" } ]
2009-11-13T00:00:00
[ [ "Neugebauer", "C. J.", "" ], [ "Taraskin", "S. N.", "" ] ]
0705.1968
Javier Trujillo Bueno
M. Derouich, J. Trujillo Bueno and R. Manso Sainz
Are collisions with neutral hydrogen important for modelling the Second Solar Spectrum of Ti I and Ca II ?
Accepted for publication in Astronomy and Astrophysics
null
10.1051/0004-6361:20077424
null
astro-ph
null
The physical interpretation of scattering line polarization offers a novel diagnostic window for exploring the thermal and magnetic structure of the quiet regions of the solar atmosphere. Here we evaluate the impact of isotropic collisions with neutral hydrogen atoms on the scattering polarization signals of the 13 lines of multiplet 42 of Ti I and on those of the K line and of the IR triplet of Ca II, with emphasis on the collisional transfer rates between nearby J-levels. To this end, we calculate the linear polarization produced by scattering processes considering realistic multilevel models and solving the statistical equilibrium equations for the multipolar components of the atomic density matrix. We confirm that the lower levels of the 13 lines of multiplet 42 of Ti I are completely depolarized by elastic collisions. We find that upper-level collisional depolarization turns out to have an unnoticeable impact on the emergent linear polarization amplitudes, except for the ${\lambda 4536$ line for which it is possible to notice a rather small depolarization caused by the collisional transfer rates. Concerning the Ca II lines, we show that the collisional rates play no role on the polarization of the upper level of the K line, while they have a rather small depolarizing effect on the atomic polarization of the metastable lower levels of the Ca II IR triplet.
[ { "version": "v1", "created": "Mon, 14 May 2007 15:46:13 GMT" } ]
2009-11-13T00:00:00
[ [ "Derouich", "M.", "" ], [ "Bueno", "J. Trujillo", "" ], [ "Sainz", "R. Manso", "" ] ]
0705.1969
Dagomir Kaszlikowski
Dagomir Kaszlikowski, Aditi Sen De, Ujjwal Sen, Vlatko Vedral, Andreas Winter
Quantum Correlation Without Classical Correlations
4 pages, no figures; v2: presentation improved, results unchanged, published version
Phys. Rev. Lett. 101, 070502 (2008)
10.1103/PhysRevLett.101.070502
null
quant-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show that genuine multiparty quantum correlations can exist on its own, without a supporting background of genuine multiparty classical correlations, even in macroscopic systems. Such possibilities can have important implications in the physics of quantum information and phase transitions.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:01:11 GMT" }, { "version": "v2", "created": "Thu, 30 Oct 2008 15:39:20 GMT" } ]
2008-10-30T00:00:00
[ [ "Kaszlikowski", "Dagomir", "" ], [ "De", "Aditi Sen", "" ], [ "Sen", "Ujjwal", "" ], [ "Vedral", "Vlatko", "" ], [ "Winter", "Andreas", "" ] ]
0705.1970
Nikolaos Laoutaris
Nikolaos Laoutaris
A Closed-Form Method for LRU Replacement under Generalized Power-Law Demand
null
null
null
null
cs.DS
null
We consider the well known \emph{Least Recently Used} (LRU) replacement algorithm and analyze it under the independent reference model and generalized power-law demand. For this extensive family of demand distributions we derive a closed-form expression for the per object steady-state hit ratio. To the best of our knowledge, this is the first analytic derivation of the per object hit ratio of LRU that can be obtained in constant time without requiring laborious numeric computations or simulation. Since most applications of replacement algorithms include (at least) some scenarios under i.i.d. requests, our method has substantial practical value, especially when having to analyze multiple caches, where existing numeric methods and simulation become too time consuming.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:04:48 GMT" } ]
2007-05-23T00:00:00
[ [ "Laoutaris", "Nikolaos", "" ] ]
0705.1971
Mark W. Johnson
Michael Joachim (Universitaet Muenster), Mark W. Johnson (Penn State Altoona)
Realizing Kasparov's KK-theory groups as the homotopy classes of maps of a Quillen model category
Appeared in Contemporary Math #399: An Alpine Anthology of Homotopy Theory, Dominique Arlettaz and Katherine Hess editors
null
null
null
math.KT math.AT
null
In this article we build a Quillen model category structure on the category of sequentially complete l.m.c.-C*-algebras such that the corresponding homotopy classes of maps Ho(A,B) for separable C*-algebras A and B coincide with the Kasparov groups KK(A,B). This answers an open question posed by Mark Hovey about the possibility of describing KK-theory for C*-algebras using the language of Quillen model categories.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:08:11 GMT" } ]
2007-05-23T00:00:00
[ [ "Joachim", "Michael", "", "Universitaet Muenster" ], [ "Johnson", "Mark W.", "", "Penn State\n Altoona" ] ]
0705.1972
Daniel De Marco
Daniel De Marco, Pasquale Blasi and Todor Stanev
Numerical propagation of high energy cosmic rays in the Galaxy I: technical issues
29 pages, 12 figures, submitted to JCAP
JCAP 0706:027,2007
10.1088/1475-7516/2007/06/027
null
astro-ph
null
We present the results of a numerical simulation of propagation of cosmic rays with energy above $10^{15}$ eV in a complex magnetic field, made in general of a large scale component and a turbulent component. Several configurations are investigated that may represent specific aspects of a realistic magnetic field of the Galaxy, though the main purpose of this investigation is not to achieve a realistic description of the propagation in the Galaxy, but rather to assess the role of several effects that define the complex problem of propagation. Our simulations of Cosmic Rays in the Galaxy will be presented in Paper II. We identified several effects that are difficult to interpret in a purely diffusive approach and that play a crucial role in the propagation of cosmic rays in the complex magnetic field of the Galaxy. We discuss at length the problem of the extrapolation of our results to much lower energies where data are available on the confinement time of cosmic rays in the Galaxy. The confinement time and its dependence on particles' rigidity are crucial ingredients for 1) relating the source spectrum to the observed cosmic ray spectrum; 2) quantifying the production of light elements by spallation; 3) predicting the anisotropy as a function of energy.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:09:19 GMT" } ]
2009-11-13T00:00:00
[ [ "De Marco", "Daniel", "" ], [ "Blasi", "Pasquale", "" ], [ "Stanev", "Todor", "" ] ]
0705.1973
Rim Dib
R. Dib, V. M. Kaspi, F. P. Gavriil
Years of RXTE Monitoring of Anomalous X-ray Pulsar 4U 0142+61: Long-Term Variability
28 pages, 8 figures, accepted by ApJ
null
10.1007/978-1-4020-5998-8_63
null
astro-ph
null
We report on 10 years of monitoring of the 8.7-s Anomalous X-ray Pulsar 4U 0142+61 using the Rossi X-Ray Timing Explorer (RXTE). This pulsar exhibited stable rotation from 2000 March until 2006 February: the RMS phase residual for a spin-down model which includes nu, nudot, and nuddot is 2.3%. We report a possible phase-coherent timing solution valid over a 10-yr span extending back to March 1996. A glitch may have occured between 1998 and 2000, but is not required by the existing timing data. The pulse profile has been evolving since 2000. In particular, the dip of emission between its two peaks got shallower between 2002 and 2006, as if the profile were evolving back to its pre-2000 morphology, following an earlier event, which possibly also included the glitch suggested by the timing data. These profile variations are seen in the 2-4 keV band but not in 6-8 keV. We also detect a slow increase in the pulsed flux between 2002 May and 2004 December, such that it has risen by 36+/-3% over 2.6 years in the 2-10 keV band. The pulsed flux variability and the narrow-band pulse profile changes present interesting challenges to aspects of the magnetar model.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:09:52 GMT" } ]
2020-01-08T00:00:00
[ [ "Dib", "R.", "" ], [ "Kaspi", "V. M.", "" ], [ "Gavriil", "F. P.", "" ] ]
0705.1974
Franco Bagnoli
Franco Bagnoli, Pietro Lio, Luca Sguanci
Risk perception in epidemic modeling
6 pages, 6 figures, completely new version
Phys. Rev. E 76, 061904 (2007)
10.1103/PhysRevE.76.061904
null
q-bio.PE q-bio.OT
null
We investigate the effects of risk perception in a simple model of epidemic spreading. We assume that the perception of the risk of being infected depends on the fraction of neighbors that are ill. The effect of this factor is to decrease the infectivity, that therefore becomes a dynamical component of the model. We study the problem in the mean-field approximation and by numerical simulations for regular, random and scale-free networks. We show that for homogeneous and random networks, there is always a value of perception that stops the epidemics. In the ``worst-case'' scenario of a scale-free network with diverging input connectivity, a linear perception cannot stop the epidemics; however we show that a non-linear increase of the perception risk may lead to the extinction of the disease. This transition is discontinuous, and is not predicted by the mean-field analysis.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:16:34 GMT" }, { "version": "v2", "created": "Fri, 18 May 2007 12:54:36 GMT" }, { "version": "v3", "created": "Thu, 23 Aug 2007 15:56:01 GMT" } ]
2007-12-06T00:00:00
[ [ "Bagnoli", "Franco", "" ], [ "Lio", "Pietro", "" ], [ "Sguanci", "Luca", "" ] ]
0705.1975
Sven-Olaf Moch
M. Czakon, A. Mitov and S. Moch
Heavy-quark production in massless quark scattering at two loops in QCD
17 pages latex, 2 figures
Phys.Lett.B651:147-159,2007
10.1016/j.physletb.2007.06.020
DESY 07-064, SFB/CPP-07-19
hep-ph
null
We present the two-loop virtual QCD corrections to the production of heavy quarks in the quark--anti-quark--annihilation channel in the limit when all kinematical invariants are large compared to the mass of the heavy quark. Our result is exact up to terms suppressed by powers of the heavy-quark mass. The derivation is based on a simple relation between massless and massive scattering amplitudes in gauge theories proposed recently by two of the authors as well as a direct calculation of the massive amplitude at two loops. The results presented here form an important part of the next-to-next-to-leading order QCD contributions to heavy-quark production in hadron-hadron collisions.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:21:14 GMT" } ]
2008-11-26T00:00:00
[ [ "Czakon", "M.", "" ], [ "Mitov", "A.", "" ], [ "Moch", "S.", "" ] ]
0705.1976
Claudio Tessone
V\'ictor M. Egu\'iluz, Claudio J. Tessone
Critical behavior in an evolutionary Ultimatum Game
13 pages, 7 figures
Advances in Complex Systems, Vol. 12, No. 2 (2009) 221-232
10.1142/S0219525909002179
null
nlin.AO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Experimental studies have shown the ubiquity of altruistic behavior in human societies. The social structure is a fundamental ingredient to understand the degree of altruism displayed by the members of a society, in contrast to individual-based features, like for example age or gender, which have been shown not to be relevant to determine the level of altruistic behavior. We explore an evolutionary model aiming to delve how altruistic behavior is affected by social structure. We investigate the dynamics of interacting individuals playing the Ultimatum Game with their neighbors given by a social network of interaction. We show that a population self-organizes in a critical state where the degree of altruism depends on the topology characterizing the social structure. In general, individuals offering large shares but in turn accepting large shares, are removed from the population. In heterogeneous social networks, individuals offering intermediate shares are strongly selected in contrast to random homogeneous networks where a broad range of offers, below a critical one, is similarly present in the population.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:17:19 GMT" }, { "version": "v2", "created": "Wed, 20 May 2009 11:33:34 GMT" } ]
2009-05-27T00:00:00
[ [ "Eguíluz", "Víctor M.", "" ], [ "Tessone", "Claudio J.", "" ] ]
0705.1977
Belghobsi Zouina
Zouina Belghobsi
Correlations with Photons in Heavy-Ion Collisions
4 pages, 6 figures included, talk presented at the 42nd Rencontres de Moriond 2007 "QCD and High Energy Hadronic Interactions" session March, 18-24, La Thuile, Italy. To be appeared in the proceedings Rencontres de Moriond 2007
null
null
null
hep-ph
null
We present a study of two-particle correlation functions involving photons and neutral pions in proton-proton and lead-lead collisions at the LHC energy. The aim is to use these correlation functions to quantify the effects of the medium on the jet decay properties.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:25:58 GMT" } ]
2009-04-16T00:00:00
[ [ "Belghobsi", "Zouina", "" ] ]
0705.1978
Cornelia C. Lang
Cornelia C. Lang (U Iowa), Philip Kaaret (U Iowa), Stephane Corbel (Paris VII/CEA-Saclay) and Allison Mercer (U Iowa)
A Radio Nebula Surrounding the Ultra-luminous X-ray Source in NGC 5408
6 pages, 6 figures, to appear in ApJ, 1 Sept 2007
Astrophys.J.666:79-85,2007
10.1086/519553
null
astro-ph
null
New radio observations of the counterpart of the ultraluminous X-ray source in NGC 5408 show for the first time that the radio emission is resolved with an angular size of 1.5 to 2.0 arcseconds. This corresponds to a physical size of 35-46 pc, and rules out interpretation of the radio emission as beamed emission from a relativistic jet. In addition, the radio spectral index of the counterpart is well determined from three frequencies and found to be alpha=-0.8 pm 0.2. The radio emission is likely to be optically-thin synchrotron emission from a nebula surrounding the X-ray source. The radio luminosity of the counterpart is 3.8 x 10^34 erg/s and the minimum energy required to power the nebula is ~1 x 10^49 erg. These values are two orders of magnitude larger than in any Galactic nebula powered by an accreting compact object.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:29:19 GMT" } ]
2019-08-19T00:00:00
[ [ "Lang", "Cornelia C.", "", "U Iowa" ], [ "Kaaret", "Philip", "", "U Iowa" ], [ "Corbel", "Stephane", "", "Paris VII/CEA-Saclay" ], [ "Mercer", "Allison", "", "U Iowa" ] ]
0705.1979
T. Kiss
T. Kiss, I. Jex, G. Alber and S. Vymetal
Complex chaos in conditional qubit dynamics and purification protocols
null
Acta Phys. Hung. B 26, 229 (2006)
10.1556/APH.26.2006.3-4.1
null
quant-ph
null
Selection of an ensemble of equally prepared quantum systems, based on measurements on it, is a basic step in quantum state purification. For an ensemble of single qubits, iterative application of selective dynamics has been shown to lead to complex chaos, which is a novel form of quantum chaos with true sensitivity to the initial conditions. The Julia set of initial valuse with no convergence shows a complicated structre on the complex plane. The shape of the Julia set varies with the parameter of the dynamics. We present here results for the two qubit case demonstrating how a purification process can be destroyed with chaotic oscillations.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:56:29 GMT" } ]
2007-05-23T00:00:00
[ [ "Kiss", "T.", "" ], [ "Jex", "I.", "" ], [ "Alber", "G.", "" ], [ "Vymetal", "S.", "" ] ]
0705.1980
Pierre-Emmanuel Caprace
Pierre-Emmanuel Caprace (ULB, University of Oxford)
Amenable groups and Hadamard spaces with a totally disconnected isometry group
15 pages
null
10.4171/MCH/168
null
math.GR
null
Let $X$ be a locally compact Hadamard space and $G$ be a totally disconnected group acting continuously, properly and cocompactly on $X$. We show that a closed subgroup of $G$ is amenable if and only if it is (topologically locally finite)-by-(virtually abelian). We are led to consider a set $\bdfine X$ which is a refinement of the visual boundary $\bd X$. For each $x \in \bdfine X$, the stabilizer $G_x$ is amenable.
[ { "version": "v1", "created": "Mon, 14 May 2007 16:59:01 GMT" } ]
2010-02-08T00:00:00
[ [ "Caprace", "Pierre-Emmanuel", "", "ULB, University of Oxford" ] ]
0705.1981
Cheng-Pang Liu
C.-P. Liu and J. Engel
Schiff Screening of Relativistic Nucleon Electric-Dipole Moments by Electrons
4 pages, typeset by REVTeX, submitted to PRC
Phys.Rev.C76:028501,2007
10.1103/PhysRevC.76.028501
LA-UR-07-2423
nucl-th
null
We show, at leading-order in the multipole expansion of the electron-nucleus interaction, that nucleon electric-dipole moments are completely shielded by electrons so that they contribute nothing to atomic electric-dipole moments, even when relativity in the nucleus is taken into account. It is well known that relativistic electron motion, by contrast, leads to dipole moments that are not screened; we discuss the reasons for the difference.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:00:00 GMT" } ]
2008-11-26T00:00:00
[ [ "Liu", "C. -P.", "" ], [ "Engel", "J.", "" ] ]
0705.1982
Diego Blas
D. Blas, C. Deffayet, J. Garriga
Bigravity and Lorentz-violating Massive Gravity
25 pages. v3 Typos corrected, references added. v4 Introduction extended
Phys.Rev.D76:104036,2007
10.1103/PhysRevD.76.104036
null
hep-th gr-qc
null
Bigravity is a natural arena where a non-linear theory of massive gravity can be formulated. If the interaction between the metrics $f$ and $g$ is non-derivative, spherically symmetric exact solutions can be found. At large distances from the origin, these are generically Lorentz-breaking bi-flat solutions (provided that the corresponding vacuum energies are adjusted appropriately). The spectrum of linearized perturbations around such backgrounds contains a massless as well as a massive graviton, with {\em two} physical polarizations each. There are no propagating vectors or scalars, and the theory is ghost free (as happens with certain massive gravities with explicit breaking of Lorentz invariance). At the linearized level, corrections to GR are proportional to the square of the graviton mass, and so there is no vDVZ discontinuity. Surprisingly, the solution of linear theory for a static spherically symmetric source does {\em not} agree with the linearization of any of the known exact solutions. The latter coincide with the standard Schwarzschild-(A)dS solutions of General Relativity, with no corrections at all. Another interesting class of solutions is obtained where $f$ and $g$ are proportional to each other. The case of bi-de Sitter solutions is analyzed in some detail.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:09:16 GMT" }, { "version": "v2", "created": "Mon, 14 May 2007 23:16:54 GMT" }, { "version": "v3", "created": "Mon, 28 May 2007 15:10:09 GMT" }, { "version": "v4", "created": "Wed, 3 Oct 2007 09:03:40 GMT" } ]
2008-11-26T00:00:00
[ [ "Blas", "D.", "" ], [ "Deffayet", "C.", "" ], [ "Garriga", "J.", "" ] ]
0705.1983
Vladimir Belavin
V. A. Belavin
On the N=1 super Liouville four-point functions
23 pages
Nucl.Phys.B798:423-442,2008
10.1016/j.nuclphysb.2008.01.001
null
hep-th
null
We construct the four-point correlation functions containing the top component of the supermultiplet in the Neveu-Schwarz sector of the N=1 SUSY Liouville field theory. The construction is based on the recursive representation for the NS conformal blocks. We test our results in the case where one of the fields is degenerate with a singular vector on the level 3/2. In this case, the correlation function satisfies a third-order ordinary differential equation, which we derive. We numerically verify the crossing symmetry relations for the constructed correlation functions in the nondegenerate case.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:09:19 GMT" } ]
2008-11-26T00:00:00
[ [ "Belavin", "V. A.", "" ] ]
0705.1984
Yuan Xu
Yuan Xu
Reconstruction from Radon projections and orthogonal expansion on a ball
15 pages
null
10.1088/1751-8113/40/26/010
null
math-ph math.MP
null
The relation between Radon transform and orthogonal expansions of a function on the unit ball in $\RR^d$ is exploited. A compact formula for the partial sums of the expansion is given in terms of the Radon transform, which leads to algorithms for image reconstruction from Radon data. The relation between orthogonal expansion and the singular value decomposition of the Radon transform is also exploited.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:10:35 GMT" } ]
2009-11-13T00:00:00
[ [ "Xu", "Yuan", "" ] ]
0705.1985
T. Kiss
M. Stefanak, T. Kiss, I. Jex and B. Mohring
The meeting problem in the quantum random walk
null
J. Phys. A: Math. Gen. 39, 14965 (2006)
10.1088/0305-4470/39/48/009
null
quant-ph
null
We study the motion of two non-interacting quantum particles performing a random walk on a line and analyze the probability that the two particles are detected at a particular position after a certain number of steps (meeting problem). The results are compared to the corresponding classical problem and differences are pointed out. Analytic formulas for the meeting probability and its asymptotic behavior are derived. The decay of the meeting probability for distinguishable particles is faster then in the classical case, but not quadratically faster. Entangled initial states and the bosonic or fermionic nature of the walkers are considered.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:14:16 GMT" } ]
2007-05-23T00:00:00
[ [ "Stefanak", "M.", "" ], [ "Kiss", "T.", "" ], [ "Jex", "I.", "" ], [ "Mohring", "B.", "" ] ]
0705.1986
Andrei Paun
Andrei Paun
On the Hopcroft's minimization algorithm
10 pages, 1 figure
null
null
null
cs.DS
null
We show that the absolute worst case time complexity for Hopcroft's minimization algorithm applied to unary languages is reached only for de Bruijn words. A previous paper by Berstel and Carton gave the example of de Bruijn words as a language that requires O(n log n) steps by carefully choosing the splitting sets and processing these sets in a FIFO mode. We refine the previous result by showing that the Berstel/Carton example is actually the absolute worst case time complexity in the case of unary languages. We also show that a LIFO implementation will not achieve the same worst time complexity for the case of unary languages. Lastly, we show that the same result is valid also for the cover automata and a modification of the Hopcroft's algorithm, modification used in minimization of cover automata.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:15:53 GMT" } ]
2007-05-23T00:00:00
[ [ "Paun", "Andrei", "" ] ]
0705.1987
Umesh Garg
X.wang, R.V.F. Janssens, E.F. Moore, U. Garg, Y. Gu, S. Frauendorf, M.P. Carpenter, S.S. Ghugre, N.J. Hammond, T. Lauritsen, T. Li, G. Mukherjee, N.S. Pattabiraman, D. Seweryniak, S. Zhu
Lifetime measurements of Triaxial Strongly Deformed bands in $^{163}$Tm
8 pages, 5 figures. Submitted to Physical Review C
Phys.Rev.C75:064315,2007
10.1103/PhysRevC.75.064315
null
nucl-ex
null
With the Doppler Shift Attenuation Method, quadrupole transition moments, $Q_t$, were determined for the two recently proposed Triaxial Strongly Deformed (TSD) bands in $^{163}$Tm. The measured $Q_t$ moments indicate that the deformation of these bands is larger than that of the yrast, signature partners. However, the measured values are smaller than those predicted by theory. This observation appears to be valid for TSD bands in several nuclei of the region
[ { "version": "v1", "created": "Mon, 14 May 2007 17:18:42 GMT" } ]
2008-11-26T00:00:00
[ [ "wang", "X.", "" ], [ "Janssens", "R. V. F.", "" ], [ "Moore", "E. F.", "" ], [ "Garg", "U.", "" ], [ "Gu", "Y.", "" ], [ "Frauendorf", "S.", "" ], [ "Carpenter", "M. P.", "" ], [ "Ghugre", "S. S.", "" ], [ "Hammond", "N. J.", "" ], [ "Lauritsen", "T.", "" ], [ "Li", "T.", "" ], [ "Mukherjee", "G.", "" ], [ "Pattabiraman", "N. S.", "" ], [ "Seweryniak", "D.", "" ], [ "Zhu", "S.", "" ] ]
0705.1988
Detlev Buchholz
Detlev Buchholz, Hendrik Grundling
The Resolvent Algebra: A New Approach to Canonical Quantum Systems
52 pages, no figures; v3: as to appear in Journal of Functional Analysis
null
null
null
math.OA math-ph math.MP quant-ph
null
The standard C*-algebraic version of the algebra of canonical commutation relations, the Weyl algebra, frequently causes difficulties in applications since it neither admits the formulation of physically interesting dynamical laws nor does it incorporate pertinent physical observables such as (bounded functions of) the Hamiltonian. Here a novel C*-algebra of the canonical commutation relations is presented which does not suffer from such problems. It is based on the resolvents of the canonical operators and their algebraic relations. The resulting C*-algebra, the resolvent algebra, is shown to have many desirable analytic properties and the regularity structure of its representations is surprisingly simple. Moreover, the resolvent algebra is a convenient framework for applications to interacting and to constrained quantum systems, as we demonstrate by several examples.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:21:23 GMT" }, { "version": "v2", "created": "Wed, 16 May 2007 14:56:24 GMT" }, { "version": "v3", "created": "Thu, 3 Apr 2008 16:10:39 GMT" } ]
2008-04-03T00:00:00
[ [ "Buchholz", "Detlev", "" ], [ "Grundling", "Hendrik", "" ] ]
0705.1989
John Cairns
John A. Cairns
Simulation of Cosmogenic Neutrino Spectra with the GZKFast Event Generator
7 pages, 3 figures
null
null
null
astro-ph
null
GZKFast is a low-cost astrophysical event generator designed to simulate photohadron processes resulting from ultra high energy cosmic ray fluxes. GZKFast is an easy to use event generator which specifically addresses issues relevant to cosmogenic neutrinos and the ultra high energy (UHE) neutrino spectrum. GZKFast injects UHE particles into a simulated cosmic microwave background (CMB) using a Monte Carlo approach. The interaction of each particle is simulated and the resulting detectable events are spooled to log files. Although GZKFast uses a simplified particle physics model and limited accelerator data it generates event distributions which are comparable with more thorough simulations such as the event generator SOPHIA
[ { "version": "v1", "created": "Mon, 14 May 2007 17:25:25 GMT" } ]
2007-05-23T00:00:00
[ [ "Cairns", "John A.", "" ] ]
0705.1990
Keith Gilmore
K. Gilmore (1 and 2), Y. U. Idzerda (2), and M. D. Stiles (1) ((1) National Institute of Standards and Technology, Gaithersburg, MD, (2) Montana State University, Bozeman, MT)
Identification of the dominant precession damping mechanism in Fe, Co, and Ni by first-principles calculations
4 pages, 1 figure
null
10.1103/PhysRevLett.99.027204
null
cond-mat.str-el cond-mat.mtrl-sci
null
The Landau-Lifshitz equation reliably describes magnetization dynamics using a phenomenological treatment of damping. This paper presents first-principles calculations of the damping parameters for Fe, Co, and Ni that quantitatively agree with existing ferromagnetic resonance measurements. This agreement establishes the dominant damping mechanism for these systems and takes a significant step toward predicting and tailoring the damping constants of new materials.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:41:48 GMT" } ]
2009-11-13T00:00:00
[ [ "Gilmore", "K.", "", "1 and 2" ], [ "Idzerda", "Y. U.", "" ], [ "Stiles", "M. D.", "" ] ]
0705.1991
T. Kiss
M. Stefanak, I. Jex, T. Kiss
Recurrence and P\'olya number of quantum walks
null
Phys. Rev. Lett. 100, 020501 (2008)
10.1103/PhysRevLett.100.020501
null
quant-ph
null
We analyze the recurrence probability (P\'olya number) for d-dimensional unbiased quantum walks. A sufficient condition for a quantum walk to be recurrent is derived. As a by-product we find a simple criterion for localisation of quantum walks. In contrast to classical walks, where the P\'olya number is characteristic for the given dimension, the recurrence probability of a quantum walk depends in general on the topology of the walk, choice of the coin and the initial state. This allows to change the character of the quantum walk from recurrent to transient by altering the initial state.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:33:03 GMT" }, { "version": "v2", "created": "Tue, 2 Oct 2007 14:28:25 GMT" } ]
2011-11-09T00:00:00
[ [ "Stefanak", "M.", "" ], [ "Jex", "I.", "" ], [ "Kiss", "T.", "" ] ]
0705.1992
Alexander Konovalov
V.A. Bovdi, A.B. Konovalov
Integral group ring of the Mathieu simple group M24
12 pages
null
null
null
math.RA math.GR
null
We consider the Zassenhaus conjecture for the normalized unit group of the integral group ring of the Mathieu sporadic group $M_{24}$. As a consequence, for this group we confirm Kimmerle's conjecture on prime graphs.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:32:10 GMT" } ]
2007-05-23T00:00:00
[ [ "Bovdi", "V. A.", "" ], [ "Konovalov", "A. B.", "" ] ]
0705.1993
Kapil Krishan
Kapilanjan Krishan
Network structure of chaotic patterns
null
null
null
null
nlin.PS nlin.CD
null
We reduce complex stripped patterns to a basic topological network of edges and vertices to define defects and measure their influence on the pattern. We present statistics on the spatial and temporal distribution of defects within the state of spiral defect chaos state in experiments on Rayleigh Benard convection. These measure the role of boundary influence on the dynamics, and suggest an exponential distribution for the length of edges in the pattern. We also indicate a systematic method to study hierarchies of defect interactions based on the network structure.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:33:14 GMT" } ]
2007-05-23T00:00:00
[ [ "Krishan", "Kapilanjan", "" ] ]
0705.1994
Lucimara Martins
Lucimara Martins and Paula Coelho
Testing the Accuracy of Synthetic Stellar Libraries
18 pages, 16 figures - accepted for publication in MNRAS. Complete paper (which includes online appendix) available at http://www.astro.iag.usp.br/~lucimara/martins_coelho_rev2.ps
null
10.1111/j.1365-2966.2007.11954.x
null
astro-ph
null
In the present work we compare in detail some of the major theoretical libraries with observations, aiming at detecting weaknesses and strengths from the stellar population modelling point of view. We compared model predictions and observations for broad- band colours and for high resolution spectral features. Concerning the broad-band colours, we measured the stellar colour given by three recent sets of model atmospheres and flux distributions(Castelli & Kurucz 2003; Gustafsson et al. 2003; Brott & Hauschildt 2005), and compared them with a recent UBVRIJHK calibration (Worthey & Lee 2007). We found that the models can reproduce with reasonable accuracy the stellar colours for a fair interval in effective temperatures and gravities. The exceptions are: 1) the U-B colour, where the models are typically redder than the observations, and; 2) the very cool stars in general (V-K > ~3).Concerning the high resolution features, we measured 35 spectral indices defined in the literature on three high resolution synthetic libraries (Coelho et al. 2005; Martins et al. 2005; Munari et al. 2005), and compared them with the observed measurements given by three empirical libraries (Valdes et al.2004; Sanchez-Blazquez et al. 2006; Prugniel & Soubiran 2001). We found that the direct comparison between models and observations is not a simple task, given the uncertainties in parameter determinations of empirical libraries. Taking that aside, we found that in general the three libraries present similar behaviours and systematic deviations. For stars with Teff < 7000K, the library by Coelho et al. (2005) is the one with best average performance. We detect that lists of atomic and molecular line opacities still need improvement, specially in the blue region of thespectrum, and for the cool stars (Teff < ~4500K).
[ { "version": "v1", "created": "Mon, 14 May 2007 17:39:20 GMT" } ]
2009-11-13T00:00:00
[ [ "Martins", "Lucimara", "" ], [ "Coelho", "Paula", "" ] ]
0705.1995
James Dent
James B. Dent and Thomas W. Kephart
Minimal Pati-Salam Model from String Theory Unification
8 pages
Phys.Rev.D77:115008,2008
10.1103/PhysRevD.77.115008
null
hep-ph
null
We provide what we believe is the minimal three family ${\cal N} = 1$ SUSY and conformal Pati-Salam Model from type IIB superstring theory. This $Z_3$ orbifolded AdS$\otimes S^5$ model has long lived protons and has potential phenomenological consequences for LHC.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:40:55 GMT" } ]
2008-11-26T00:00:00
[ [ "Dent", "James B.", "" ], [ "Kephart", "Thomas W.", "" ] ]
0705.1996
Michael Nauenberg
Michael Nauenberg
Critique of "Quantum Enigma:Physic encounters Consciousness"
null
null
10.1007/s10701-007-9179-8
null
quant-ph
null
The central claim that understanding quantum mechanics requires a conscious observer, which is made made by B. Rosenblum and F. Kuttner in their book "Quantum Enigma: Physics encounters consciousnes", is shown to be based on various misunderstandings and distortions of the foundations of quantum mechanics.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:44:08 GMT" }, { "version": "v2", "created": "Tue, 15 May 2007 05:23:05 GMT" } ]
2009-11-13T00:00:00
[ [ "Nauenberg", "Michael", "" ] ]
0705.1997
Patrick Huber
Patrick Huber, Klaus Knorr, and Andriy V. Kityk
Capillary Rise of Liquids in Nanopores
4 pages, 1 figure, presented as a talk at the MRS Fall Meeting, Boston (2005) in the session on "Dynamics in Confinement"
Mater. Res. Soc. Symp. Proc. 899E, N7.1 (2006)
null
null
physics.flu-dyn cond-mat.soft physics.bio-ph physics.chem-ph
null
We present measurements on the spontaneous imbibition (capillary rise) of water, a linear hydrocarbon (n-C16H34) and a liquid crystal (8OCB) into the pore space of monolithic, nanoporous Vycor glass (mean pore radius 5 nm). Measurements on the mass uptake of the porous hosts as a function of time, m(t), are in good agreement with the Lucas-Washburn square root of time prediction, typical of imbibition of liquids into porous hosts. The relative capillary rise velocities scale as expected from the bulk fluid parameters.
[ { "version": "v1", "created": "Mon, 14 May 2007 17:44:23 GMT" }, { "version": "v2", "created": "Tue, 15 May 2007 07:35:55 GMT" } ]
2007-05-23T00:00:00
[ [ "Huber", "Patrick", "" ], [ "Knorr", "Klaus", "" ], [ "Kityk", "Andriy V.", "" ] ]