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0705.1198
Shengqi Zhou
Sheng-Qi Zhou, Chao Sun and Ke-Qing Xia
Measured oscillations of the velocity and temperature fields in turbulent Rayleigh-B\'{e}nard convection in a rectangular cell
6 pages, 6 figures. submitted to PRE
null
10.1103/PhysRevE.76.036301
null
physics.flu-dyn
null
Temperature and velocity oscillations have been found in a rectangular Rayleigh-B\'{e}nard convection cell, in which one large scale convection roll exists. At $Ra=8.9 \times 10^{11}$ and $Pr=4$, temperature oscillation can be observed in most part of the system and the oscillation period remains almost constant, $t_T = 74 \pm 2$ seconds. Velocity oscillation can only be found in its horizontal component, $v_y$ (perpendicular to large scale circulation plane), near the cell sidewall, its oscillation period is also constant, $t_T = 65 \pm 2$ seconds, at these positions. Temperature and velocity oscillations have different Ra dependence, which are respectively indicated by Peclect number $Pe_T = 0.55Ra^{0.47}$ and $Pe_v = 0.28Ra^{0.50}$ . In comparison to the case of cylindrical cell, we find that the velocity oscillation is affected by the system geometry.
[ { "version": "v1", "created": "Wed, 9 May 2007 01:48:23 GMT" } ]
2009-11-13T00:00:00
[ [ "Zhou", "Sheng-Qi", "" ], [ "Sun", "Chao", "" ], [ "Xia", "Ke-Qing", "" ] ]
0705.1199
Osamu Fujino
Osamu Fujino
A transcendental approach to Koll\'ar's injectivity theorem II
30 pages, v2: added many corollaries, v3: minor modifications, v4: minor revision following referee's comments
null
null
null
math.AG math.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We treat a relative version of the main theorem in my previous paper: A transcendental approach to Koll\'ar's injectivity theorem. More explicitly, we give a curvature condition that implies Koll\'ar type cohomology injectivity theorems in the relative setting. To carry out this generalization, we use the Ohsawa-Takegoshi twisted version of Nakano's identity.
[ { "version": "v1", "created": "Wed, 9 May 2007 02:23:57 GMT" }, { "version": "v2", "created": "Sun, 23 Jan 2011 04:19:52 GMT" }, { "version": "v3", "created": "Fri, 28 Jan 2011 01:49:45 GMT" }, { "version": "v4", "created": "Mon, 5 Mar 2012 01:30:59 GMT" } ]
2012-03-06T00:00:00
[ [ "Fujino", "Osamu", "" ] ]
0705.1200
Toru Kanzaki
Toru Kanzaki, Masahiro Kawasaki, Kazunori Kohri, Takeo Moroi
Cosmological Constraints on Neutrino Injection
33 pages, 23 figures
Phys.Rev.D76:105017,2007
10.1103/PhysRevD.76.105017
null
hep-ph astro-ph
null
We derive general constraints on the relic abundances of a long-lived particle which mainly decays into a neutrino (and something else) at cosmological time scales. Such an exotic particle may show up in various particle-physics models based on physics beyond the standard model. The constraints are obtained from big-bang nucleosynthesis, cosmic microwave background and diffuse neutrino and photon fluxes, depending on the lifetime and the electromagnetic and hadronic branching ratios.
[ { "version": "v1", "created": "Wed, 9 May 2007 02:49:21 GMT" } ]
2008-11-26T00:00:00
[ [ "Kanzaki", "Toru", "" ], [ "Kawasaki", "Masahiro", "" ], [ "Kohri", "Kazunori", "" ], [ "Moroi", "Takeo", "" ] ]
0705.1201
Mucio A. Continentino
Mucio A. Continentino, Igor T. Padilha
Asymmetric superconductivity in metallic systems
new enlarged version, new title, 7 pages, 7 figures
null
10.1088/0953-8984/20/9/095216
null
cond-mat.supr-con astro-ph cond-mat.stat-mech cond-mat.str-el hep-th
null
Different types of superfluid ground states have been investigated in systems of two species of fermions with Fermi surfaces that do not match. This study is relevant for cold atomic systems, condensed matter physics and quark matter. In this paper we consider this problem in the case the fermionic quasi-particles can transmute into one another and only their total number is conserved. We use a BCS approximation to study superconductivity in two-band metallic systems with inter and intra-band interactions. Tuning the hybridization between the bands varies the mismatch of the Fermi surfaces and produces different instabilities. For inter-band attractive interactions we find a first order normal-superconductor and a homogeneous metastable phase with gapless excitations. In the case of intra-band interactions, the transition from the superconductor to the normal state as hybridization increases is continuous and associated with a quantum critical point. The case when both interactions are present is also considered.
[ { "version": "v1", "created": "Wed, 9 May 2007 02:40:59 GMT" }, { "version": "v2", "created": "Wed, 22 Aug 2007 18:37:43 GMT" } ]
2016-09-21T00:00:00
[ [ "Continentino", "Mucio A.", "" ], [ "Padilha", "Igor T.", "" ] ]
0705.1202
Mark Breese Professor
M B H Breese
Deflection of High-Energy Cosmic Radiation Ions using a Bent Crystal Shield
4 figures submitted to Journal of Advances in Space Research
null
null
null
astro-ph physics.space-ph
null
A bent crystal shield which is capable of deflecting cosmic radiation ions of all atomic numbers away from spacecraft using the ion channeling effect is described. Its effect on the transmitted angular distribution of heavy, high-energy ions is characterized using Monte Carlo channeling simulations. Ions up to an energy limit set by the bent crystal curvature radius are deflected by the full curvature angle. A bent crystal shield with a 1 x 1 cm2 surface area capable of deflecting such ions with energies up to 100 GeV/nucleon is fabricated in which the lattice planes across the entrance surface are uniformly aligned.
[ { "version": "v1", "created": "Wed, 9 May 2007 02:54:58 GMT" } ]
2007-05-23T00:00:00
[ [ "Breese", "M B H", "" ] ]
0705.1203
Benjamin Wilson
Benjamin J. Wilson (University of Sydney / Universidade de Sao Paulo)
Highest-Weight Theory for Truncated Current Lie Algebras
42 pages. An extract from the author's PhD thesis. See also: http://www.maths.usyd.edu.au/u/benw/
null
null
null
math.RT math-ph math.MP
null
Let g denote a Lie algebra over a field of characteristic zero, and let T(g) denote the tensor product of g with a ring of truncated polynomials. The Lie algebra T(g) is called a truncated current Lie algebra, or in the special case when g is finite-dimensional and semisimple, a generalized Takiff algebra. In this paper a highest-weight theory for T(g) is developed when the underlying Lie algebra g possesses a triangular decomposition. The principal result is the reducibility criterion for the Verma modules of T(g) for a wide class of Lie algebras g, including the symmetrizable Kac-Moody Lie algebras, the Heisenberg algebra, and the Virasoro algebra. This is achieved through a study of the Shapovalov form.
[ { "version": "v1", "created": "Wed, 9 May 2007 03:46:31 GMT" } ]
2007-05-23T00:00:00
[ [ "Wilson", "Benjamin J.", "", "University of Sydney / Universidade de Sao Paulo" ] ]
0705.1204
Farhan Rana
Farhan Rana
Electron-Hole Generation and Recombination Rates for Coulomb Scattering in Graphene
13 pages, 7 figures
null
10.1103/PhysRevB.76.155431
null
cond-mat.mes-hall cond-mat.mtrl-sci
null
We calculate electron-hole generation and recombination rates for Coulomb scattering (Auger recombination and impact ionization) in Graphene. The conduction and valence band dispersion relation in Graphene together with energy and momentum conservation requirements restrict the phase space for Coulomb scattering so that electron-hole recombination times can be much longer than 1 ps for electron-hole densities smaller than $10^{12}$ cm$^{-2}$.
[ { "version": "v1", "created": "Wed, 9 May 2007 04:14:20 GMT" }, { "version": "v2", "created": "Mon, 14 May 2007 05:05:40 GMT" } ]
2009-11-13T00:00:00
[ [ "Rana", "Farhan", "" ] ]
0705.1205
Michael Scheibner
M. Scheibner, I. V. Ponomarev, E. A. Stinaff, M. F. Doty, A. S. Bracker, C. S. Hellberg, T. L. Reinecke, and D. Gammon
Photoluminescence Spectroscopy of the Molecular Biexciton in Vertically Stacked Quantum Dot Pairs
4 pages, 5 figures, (v2, revision based on reviewers comments, published)
Phys. Rev. Lett. 99, 197402 (2007)
10.1103/PhysRevLett.99.197402
null
cond-mat.other
null
We present photoluminescence studies of the molecular neutral biexciton-exciton spectra of individual vertically stacked InAs/GaAs quantum dot pairs. We tune either the hole or the electron levels of the two dots into tunneling resonances. The spectra are described well within a few-level, few-particle molecular model. Their properties can be modified broadly by an electric field and by structural design, which makes them highly attractive for controlling nonlinear optical properties.
[ { "version": "v1", "created": "Wed, 9 May 2007 04:18:59 GMT" }, { "version": "v2", "created": "Thu, 8 Nov 2007 20:51:20 GMT" } ]
2007-11-08T00:00:00
[ [ "Scheibner", "M.", "" ], [ "Ponomarev", "I. V.", "" ], [ "Stinaff", "E. A.", "" ], [ "Doty", "M. F.", "" ], [ "Bracker", "A. S.", "" ], [ "Hellberg", "C. S.", "" ], [ "Reinecke", "T. L.", "" ], [ "Gammon", "D.", "" ] ]
0705.1206
Jan-Uwe Ness
J.-U. Ness, S. Starrfield, A.P. Beardmore, M.F. Bode, J.J. Drake, A. Evans, R.D. Gehrz, M.R. Goad, R. Gonzalez-Riestra, P. Hauschildt, J. Krautter, T.J. O'Brien, J.P. Osborne, K.L. Page, R.A. Schoenrich, C.E. Woodward
The SSS phase of RS Ophiuchi observed with Chandra and XMM-Newton I.: Data and preliminary Modeling
16 pages, 10 figures, 4 tables. Accepted by ApJ; v2: Co-author Woodward added
Astrophys.J.665:1334-1348,2007
10.1086/519676
null
astro-ph
null
The phase of Super-Soft-Source (SSS) emission of the sixth recorded outburst of the recurrent nova RS Oph was observed twice with Chandra and once with XMM-Newton. The observations were taken on days 39.7, 54.0, and 66.9 after outburst. We confirm a 35-sec period on day 54.0 and found that it originates from the SSS emission and not from the shock. We discus the bound-free absorption by neutral elements in the line of sight, resonance absorption lines plus self-absorbed emission line components, collisionally excited emission lines from the shock, He-like intersystem lines, and spectral changes during an episode of high-amplitude variability. We find a decrease of the oxygen K-shell absorption edge that can be explained by photoionization of oxygen. The absorption component has average velocities of -1286+-267 km/s on day 39.7 and of -771+-65 km/s on day 66.9. The wavelengths of the emission line components are consistent with their rest wavelengths as confirmed by measurements of non-self absorbed He-like intersystem lines. We have evidence that these lines originate from the shock rather than the outer layers of the outflow and may be photoexcited in addition to collisional excitations. We found collisionally excited emission lines that are fading at wavelengths shorter than 15A that originate from the radiatively cooling shock. On day 39.5 we find a systematic blue shift of -526+-114 km/s from these lines. We found anomalous He-like f/i ratios which indicates either high densities or significant UV radiation near the plasma where the emission lines are formed. During the phase of strong variability the spectral hardness light curve overlies the total light curve when shifted by 1000sec. This can be explained by photoionization of neutral oxygen in the line of sight if the densities of order 10^{10}-10^{11} cm^{-3}.
[ { "version": "v1", "created": "Wed, 9 May 2007 05:03:52 GMT" }, { "version": "v2", "created": "Fri, 18 May 2007 03:25:22 GMT" } ]
2009-06-23T00:00:00
[ [ "Ness", "J. -U.", "" ], [ "Starrfield", "S.", "" ], [ "Beardmore", "A. P.", "" ], [ "Bode", "M. F.", "" ], [ "Drake", "J. J.", "" ], [ "Evans", "A.", "" ], [ "Gehrz", "R. D.", "" ], [ "Goad", "M. R.", "" ], [ "Gonzalez-Riestra", "R.", "" ], [ "Hauschildt", "P.", "" ], [ "Krautter", "J.", "" ], [ "O'Brien", "T. J.", "" ], [ "Osborne", "J. P.", "" ], [ "Page", "K. L.", "" ], [ "Schoenrich", "R. A.", "" ], [ "Woodward", "C. E.", "" ] ]
0705.1207
Arunava Bhadra Dr.
A. Bhadra and S. C. Das
Comment on "On Mach's critique of Newton and Copernicus"
Six pages, to appear in AJP
Am.J.Phys.75:850-854,2007
10.1119/1.2716032
null
gr-qc
null
Hartman and Nissim-Sabat have argued that Mach's idea of the relativity of rotational motion suffers from internal inconsistencies and leads to a contradiction that there cannot be a stationary bucket in a rotating universe. They also claimed that non-inertial electromagnetic and stellar aberration observations can distinguish between a rotating and a stationary universe, whereas according to Mach there cannot be any observable way to distinguish these two cases. We contest these objections.
[ { "version": "v1", "created": "Wed, 9 May 2007 05:43:44 GMT" } ]
2008-11-26T00:00:00
[ [ "Bhadra", "A.", "" ], [ "Das", "S. C.", "" ] ]
0705.1208
Holger Then
B. Thid\'e, H. Then, J. Sj\"oholm, K. Palmer, J. Bergman, T. D. Carozzi, Ya. N. Istomin, N. H. Ibragimov, and R. Khamitova
Utilization of photon orbital angular momentum in the low-frequency radio domain
4 pages, 5 figures. Changed title, identical to the paper published in PRL
Phys.Rev.Lett.99:087701,2007
10.1103/PhysRevLett.99.087701
null
astro-ph physics.class-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We show numerically that vector antenna arrays can generate radio beams which exhibit spin and orbital angular momentum characteristics similar to those of helical Laguerre-Gauss laser beams in paraxial optics. For low frequencies (< 1 GHz), digital techniques can be used to coherently measure the instantaneous, local field vectors and to manipulate them in software. This opens up for new types of experiments that go beyond those currently possible to perform in optics, for information-rich radio physics applications such as radio astronomy, and for novel wireless communication concepts.
[ { "version": "v1", "created": "Wed, 9 May 2007 05:46:12 GMT" }, { "version": "v2", "created": "Thu, 24 May 2007 08:15:05 GMT" }, { "version": "v3", "created": "Sat, 2 May 2009 02:30:41 GMT" } ]
2017-04-27T00:00:00
[ [ "Thidé", "B.", "" ], [ "Then", "H.", "" ], [ "Sjöholm", "J.", "" ], [ "Palmer", "K.", "" ], [ "Bergman", "J.", "" ], [ "Carozzi", "T. D.", "" ], [ "Istomin", "Ya. N.", "" ], [ "Ibragimov", "N. H.", "" ], [ "Khamitova", "R.", "" ] ]
0705.1209
Tshilidzi Marwala
E. Habtemariam, T. Marwala and M. Lagazio
Artificial Intelligence for Conflict Management
20 pages
null
null
null
cs.AI
null
Militarised conflict is one of the risks that have a significant impact on society. Militarised Interstate Dispute (MID) is defined as an outcome of interstate interactions, which result on either peace or conflict. Effective prediction of the possibility of conflict between states is an important decision support tool for policy makers. In a previous research, neural networks (NNs) have been implemented to predict the MID. Support Vector Machines (SVMs) have proven to be very good prediction techniques and are introduced for the prediction of MIDs in this study and compared to neural networks. The results show that SVMs predict MID better than NNs while NNs give more consistent and easy to interpret sensitivity analysis than SVMs.
[ { "version": "v1", "created": "Wed, 9 May 2007 05:53:30 GMT" } ]
2007-05-23T00:00:00
[ [ "Habtemariam", "E.", "" ], [ "Marwala", "T.", "" ], [ "Lagazio", "M.", "" ] ]
0705.1210
Manuel Blickle
Manuel Blickle, Mircea Musta\c{t}\v{a}, Karen Smith
F-thresholds of hypersurfaces
19 pages; v.2: a slight modification of the argument allowed us to extend our results to the case of an arbitrary regular F-finite ring; v.3: final version, to appear in Transactions of the AMS
Trans. Amer. Math. Soc. 361 (2009), no. 12, 6549-6565
null
null
math.AG math.AC
null
We continue our study of F-thresholds begun in math/0607660 by an in depth analysis of the hypersurface case. We use the D--module theoretic description of generalized test ideals which allows us to show that in any F--finite regular ring the F-thresholds of hypersurfaces are discrete and rational (in math/0607660 the finite type over a field case was shown for arbitrary ideals). Furthermore we show that any limit of F-pure thresholds of principal ideals in bouneded dimension is again an F-pure-threshold, hence in particular the limit is rational. The study of the set of F-pure-thresholds leads to natural analogs of conjectures of Shokurov and Koll\'{a}r (for log canonical thresholds) in the case of F-pure-thresholds.
[ { "version": "v1", "created": "Wed, 9 May 2007 06:32:58 GMT" }, { "version": "v2", "created": "Wed, 18 Jul 2007 14:53:16 GMT" }, { "version": "v3", "created": "Thu, 10 Jan 2008 16:42:44 GMT" } ]
2011-02-18T00:00:00
[ [ "Blickle", "Manuel", "" ], [ "Mustaţǎ", "Mircea", "" ], [ "Smith", "Karen", "" ] ]
0705.1211
Mohammad Sami
E. Elizalde, S. Jhingan, S. Nojiri, S. D. Odintsov, M. Sami and I. Thongkool
Dark energy generated from a (super)string effective action with higher order curvature corrections and a dynamical dilaton
15 pages, 7 eps figures, minor corrections, published version
Eur.Phys.J.C53:447-457,2008
10.1140/epjc/s10052-007-0463-8
null
hep-th astro-ph gr-qc hep-ph
null
We investigate the possibility of a dark energy universe emerging from an action with higher-order string loop corrections to Einstein gravity in the presence of a massless dilaton. These curvature corrections (up to $R^4$ order) are different depending upon the type of (super)string model which is considered. We find in fact that Type II, heterotic, and bosonic strings respond differently to dark energy. A dark energy solution is shown to exist in the case of the bosonic string, while the other two theories do not lead to realistic dark energy universes. Detailed analysis of the dynamical stability of the de-Sitter solution is presented for the case of a bosonic string. A general prescription for the construction of a de-Sitter solution for the low-energy (super)string effective action is also indicated. Beyond the low-energy (super)string effective action, when the higher-curvature correction coefficients depend on the dilaton, the reconstruction of the theory from the universe expansion history is done with a corresponding prescription for the scalar potentials.
[ { "version": "v1", "created": "Wed, 9 May 2007 06:34:22 GMT" }, { "version": "v2", "created": "Thu, 25 Oct 2007 14:30:14 GMT" } ]
2008-11-26T00:00:00
[ [ "Elizalde", "E.", "" ], [ "Jhingan", "S.", "" ], [ "Nojiri", "S.", "" ], [ "Odintsov", "S. D.", "" ], [ "Sami", "M.", "" ], [ "Thongkool", "I.", "" ] ]
0705.1212
Veer Awana Dr
Rahul Tripathi, V.P.S. Awana (NPL-India) S. Balamurugan (NIMS-Japan), R.K. Kotnala, RamKishore, H. Kishan (NPL-India) and E. Takayama-Muromachi (NIMS-Japan)
Inter comparison of the magneto transport of La2/3Ca1/3MnO3: Ag/In polycrystalline composites
13 pages of TEXT+Figs
IEEE Transcations on Magnetics Vol. 43, No. 6, June (2007)
10.1109/TMAG.2007.893114
null
cond-mat.str-el cond-mat.mtrl-sci
null
In this article, we report the synthesis, magneto transport features, and magnetization of polycrystalline La2/3Ca1/3MnO3:Agx/Inx composites with x = 0, 0.1, 0.2, 0.3 and 0.4. In case of Ag the temperature coefficient of resistance (TCR) near ferromagnetic (FM) transition enhances significantly with addition of Ag. The FM transition temperature (TFM) is also increased slightly with Ag doping. Magneto-transport measurements revealed that magneto-resistance (MR) is found to be maximum near TFM. Very sharp TCR is seen near TFM with highest value of up to 15 % for Ag (0.4) sample, which is an order of magnitude higher than as for pristine sample and is the best value yet reported for any polycrystalline LCMO compound. Increased TCR, TFM and significant above room temperature MR of La2/3Ca1/3MnO3:Agx composites is explained on the basis of improved grains size. Interestingly the La2/3Ca1/3MnO3:Inx composites behaved exactly in opposite way resulting in decreased TFM, and TCR compared to pristine LCMO compound. In fact the grains morphology of LCMO:Inx composites is seen inferior to pristine LCMO which is opposite to the LCMO:Agx case.
[ { "version": "v1", "created": "Wed, 9 May 2007 06:43:34 GMT" } ]
2009-11-13T00:00:00
[ [ "Tripathi", "Rahul", "", "NPL-India" ], [ "Awana", "V. P. S.", "", "NPL-India" ], [ "Balamurugan", "S.", "", "NIMS-Japan" ], [ "Kotnala", "R. K.", "", "NPL-India" ], [ "RamKishore", "", "", "NPL-India" ], [ "Kishan", "H.", "", "NPL-India" ], [ "Takayama-Muromachi", "E.", "", "NIMS-Japan" ] ]
0705.1213
Xavier Caruso
Xavier Caruso (IRMAR)
Sch\'emas en groupes et poids de Diamond-Serre
18 pages
null
null
null
math.NT math.RT
null
This note is a correction of (statement and proof of) proposition 3.3.1 of Toby Gee's preprint intitled *On the weights of mod p Hilbert modular forms*. The aim is to compare Galois representations arising from extensions of some group schemes (over the ring of integers of a p-adic field) endowed with a descent data, and extensions of some crystalline representations with given Hodge-Tate weights. The main tool of the proof is the theory of Breuil.
[ { "version": "v1", "created": "Wed, 9 May 2007 07:08:15 GMT" } ]
2007-05-23T00:00:00
[ [ "Caruso", "Xavier", "", "IRMAR" ] ]
0705.1214
Tshilidzi Marwala
Tshilidzi Marwala
Control of Complex Systems Using Bayesian Networks and Genetic Algorithm
6 pages
null
null
null
cs.CE cs.NE
null
A method based on Bayesian neural networks and genetic algorithm is proposed to control the fermentation process. The relationship between input and output variables is modelled using Bayesian neural network that is trained using hybrid Monte Carlo method. A feedback loop based on genetic algorithm is used to change input variables so that the output variables are as close to the desired target as possible without the loss of confidence level on the prediction that the neural network gives. The proposed procedure is found to reduce the distance between the desired target and measured outputs significantly.
[ { "version": "v1", "created": "Wed, 9 May 2007 07:08:58 GMT" } ]
2007-05-23T00:00:00
[ [ "Marwala", "Tshilidzi", "" ] ]
0705.1215
Damien Chablat
Anatoly Pashkevich (Robotic Laboratory), Damien Chablat (IRCCyN), Philippe Wenger (IRCCyN)
Kinematic Calibration of the Orthoglide-Type Mechanisms
null
Symposium on Information Control Problems in Manufacturing (2006) 1-6
null
null
cs.RO
null
The paper proposes a novel calibration approach for the Orthoglide-type mechanisms based on observations of the manipulator leg parallelism during motions between the prespecified test postures. It employs a low-cost measuring system composed of standard comparator indicators attached to the universal magnetic stands. They are sequentially used for measuring the deviation of the relevant leg location while the manipulator moves the TCP along the Cartesian axes. Using the measured differences, the developed algorithm estimates the joint offsets that are treated as the most essential parameters to be adjusted. The sensitivity of the measurement methods and the calibration accuracy are also studied. Experimental results are presented that demonstrate validity of the proposed calibration technique.
[ { "version": "v1", "created": "Wed, 9 May 2007 07:21:35 GMT" } ]
2007-05-23T00:00:00
[ [ "Pashkevich", "Anatoly", "", "Robotic Laboratory" ], [ "Chablat", "Damien", "", "IRCCyN" ], [ "Wenger", "Philippe", "", "IRCCyN" ] ]
0705.1216
Pei Wang
Pei Wang
Variations of Gauss-Codazzi-Ricci Equations in Kaluza-Klein Reduction (String Theory) and Cauchy Problem (General Relativity)
null
null
null
null
hep-th
null
We find a kind of variations of Gauss-Codazzi-Ricci equations suitable for Kaluza-Klein reduction and Cauchy problem. Especially the counterpart of extrinsic curvature tensor has antisymmetric part as well as symmetric one. If the dependence of metric tensor on reduced dimensions is negligible it becomes a pure antisymmetric tensor.
[ { "version": "v1", "created": "Wed, 9 May 2007 07:23:17 GMT" } ]
2007-05-23T00:00:00
[ [ "Wang", "Pei", "" ] ]
0705.1217
Damien Chablat
J\'erome Renotte (IRCCyN), Damien Chablat (IRCCyN), Jorge Angeles (CIM)
The Design of a Novel Prismatic Drive for a Three-DOF Parallel-Kinematics Machine
null
ASME Design Engineering Technical Conferences (2004) 1-10
null
null
cs.RO
null
The design of a novel prismatic drive is reported in this paper. This transmission is based on Slide-O-Cam, a cam mechanism with multiple rollers mounted on a common translating follower. The design of Slide-O-Cam was reported elsewhere. This drive thus provides pure-rolling motion, thereby reducing the friction of rack-and-pinions and linear drives. Such properties can be used to design new transmissions for parallel-kinematics machines. In this paper, this transmission is optimized to replace ball-screws in Orthoglide, a three-DOF parallel robot optimized for machining applications.
[ { "version": "v1", "created": "Wed, 9 May 2007 07:27:45 GMT" } ]
2007-05-23T00:00:00
[ [ "Renotte", "Jérome", "", "IRCCyN" ], [ "Chablat", "Damien", "", "IRCCyN" ], [ "Angeles", "Jorge", "", "CIM" ] ]
0705.1218
Damien Chablat
Anatoly Pashkevich (ROBOTIC Laboratory), Roman Gomolitsky (ROBOTIC Laboratory), Philippe Wenger (IRCCyN), Damien Chablat (IRCCyN)
Calibration of quasi-isotropic parallel kinematic Machines: Orthoglide
null
Fourth International Conference on Informatics in Control, Automation and Robotics (09/05/2007) 1-8
null
null
cs.RO
null
The paper proposes a novel approach for the geometrical model calibration of quasi-isotropic parallel kinematic mechanisms of the Orthoglide family. It is based on the observations of the manipulator leg parallelism during motions between the specific test postures and employs a low-cost measuring system composed of standard comparator indicators attached to the universal magnetic stands. They are sequentially used for measuring the deviation of the relevant leg location while the manipulator moves the TCP along the Cartesian axes. Using the measured differences, the developed algorithm estimates the joint offsets and the leg lengths that are treated as the most essential parameters. Validity of the proposed calibration technique is confirmed by the experimental results.
[ { "version": "v1", "created": "Wed, 9 May 2007 07:30:48 GMT" } ]
2007-05-23T00:00:00
[ [ "Pashkevich", "Anatoly", "", "ROBOTIC Laboratory" ], [ "Gomolitsky", "Roman", "", "ROBOTIC\n Laboratory" ], [ "Wenger", "Philippe", "", "IRCCyN" ], [ "Chablat", "Damien", "", "IRCCyN" ] ]
0705.1219
Ahmad Ajdarzadeh Oskouei
Ali Akbar Wahedy Zarch, Hassan Kaatuzian, Ahmad Ajdarzadeh Oskouei, Ahmad Amjadi
Analysis and Design of an Organic High Speed Digital Electro-Optic Switch
null
null
null
null
quant-ph
null
We have analyzed and designed an organic high speed digital optical switch (DOS) based on transverse electro-optic effect. In analysis section, we proposed a quantum photonic model (QPM) to explain linear electro-optic (EO) effect. This model interpret this effect by photon-electron interaction in attosecond regime. We simulate applied electric field on molecule and crystal by Monte-Carlo method in time domain. We show how a waveguide response to an optical signal with different wavelengths when a transverse electric field applied to the waveguide. In design section, we configure conceptually a 2 * 2 EO switch with full adiabatic coupler. In this DOS, we use a rib waveguides that its core has been constructed from NPP crystal. This switch is smaller at least to one-half of similar DOS in dimensions.
[ { "version": "v1", "created": "Wed, 9 May 2007 07:37:09 GMT" } ]
2007-05-23T00:00:00
[ [ "Zarch", "Ali Akbar Wahedy", "" ], [ "Kaatuzian", "Hassan", "" ], [ "Oskouei", "Ahmad Ajdarzadeh", "" ], [ "Amjadi", "Ahmad", "" ] ]
0705.1220
Deryk Osthus
Deryk Osthus and Rachel Watkinson
A simple solution to Ulam's liar game with one lie
null
null
null
null
math.CO
null
Ulam asked for the maximum number of questions required to determine an integer between one and one million by asking questions whose answer is `Yes' or `No' and where one untruthful answer is allowed. Pelc showed that the number of questions required is 25. Here we give a simple proof of this result.
[ { "version": "v1", "created": "Wed, 9 May 2007 07:42:47 GMT" } ]
2007-05-23T00:00:00
[ [ "Osthus", "Deryk", "" ], [ "Watkinson", "Rachel", "" ] ]
0705.1221
Michael Bonitz
C. Henning, P. Ludwig, A. Filinov, A. Piel, M. Bonitz
Ground state of a confined Yukawa plasma including correlation effects
revtex file plus 7 eps figures
Physical Review E 76, 036404 (2007)
10.1103/PhysRevE.76.036404
null
physics.plasm-ph
null
The ground state of an externally confined one-component Yukawa plasma is derived analytically using the local density approximation (LDA). In particular, the radial density profile is computed. The results are compared with the recently obtained mean-field (MF) density profile \cite{henning.pre06}. While the MF results are more accurate for weak screening, LDA with correlations included yields the proper description for large screening. By comparison with first-principle simulations for three-dimensional spherical Yukawa crystals we demonstrate that both approximations complement each other. Together they accurately describe the density profile in the full range of screening parameters.
[ { "version": "v1", "created": "Wed, 9 May 2007 07:47:02 GMT" } ]
2009-11-13T00:00:00
[ [ "Henning", "C.", "" ], [ "Ludwig", "P.", "" ], [ "Filinov", "A.", "" ], [ "Piel", "A.", "" ], [ "Bonitz", "M.", "" ] ]
0705.1222
David Kleinhans
David Kleinhans, Rudolf Friedrich, Matthias Waechter, Joachim Peinke
Markov properties in presence of measurement noise
7 pages, 4 figures
null
10.1103/PhysRevE.76.041109
null
physics.data-an
null
Recently, several powerful tools for the reconstruction of stochastic differential equations from measured data sets have been proposed [e.g. Siegert et al., Physics Letters A 243, 275 (1998); Hurn et al., Journal of Time Series Analysis 24, 45 (2003)]. Efficient application of the methods, however, generally requires Markov properties to be fulfilled. This constraint typically seems to be violated on small scales, which frequently is attributed to physical effects. On the other hand, measurement noise such as uncorrelated measurement and discretization errors has large impacts on the statistics of measurements on small scales. We demonstrate, that the presence of measurement noise, likewise, spoils Markov properties of an underlying Markov processes. This fact is promising for the further development of techniques for the reconstruction of stochastic processes from measured data, since limitations at small scales might stem from artificial noise sources rather than from intrinsic properties of the dynamics of the underlying process. Measurement noise, however, can be controlled much better than the intrinsic dynamics of the underlying process.
[ { "version": "v1", "created": "Wed, 9 May 2007 07:51:59 GMT" }, { "version": "v2", "created": "Sat, 11 Aug 2007 06:51:14 GMT" } ]
2009-11-13T00:00:00
[ [ "Kleinhans", "David", "" ], [ "Friedrich", "Rudolf", "" ], [ "Waechter", "Matthias", "" ], [ "Peinke", "Joachim", "" ] ]
0705.1223
Mikhail Zobov
M. Zobov, A. Battisti, A. Clozza, V. Lollo, C. Milardi, B. Spataro, A. Stella, C. Vaccarezza (LNF INFN)
Impact of Ion Clearing Electrodes on Beam Dynamics in DAFNE
Invited Talk at the mini-Workshop on Electron Cloud Clearing (ECL2), CERN, 1-2 March 2007. 7 pages, 14 figures, 1 table
JINST 2:P08002,2007
10.1088/1748-0221/2/08/P08002
null
physics.acc-ph
null
Presently clearing electrodes are being considered as a possible cure of e-cloud driven problems in existing and future colliders. 'Invisible' electrodes, made of a thin highly resistive layer pasted on a dielectric plate, have been proposed as one of design solutions for the e-cloud clearing. For the first time such electrodes were successfully used in the electron-positron accumulator (EPA) of LEP. Similar electrodes had been using for a long time for ion clearing purposes in the DAFNE electron ring. Theoretical considerations and experimental measurements at DAFNE have revealed a substantial contribution of the ion clearing electrodes (ICE) to the machine broad-band impedance giving rise to several harmful effects degrading the collider performance. In this paper we discuss the impact of the electrodes on DAFNE beam dynamics, show the results of ICE wake field and impedance calculations and compare them with available experimental data. We also describe the procedure of ICE removal from the wiggler sections of the electron ring that has resulted in remarkable improvements in terms of beam dynamics and geometric luminosity.
[ { "version": "v1", "created": "Wed, 9 May 2007 07:52:16 GMT" } ]
2011-04-11T00:00:00
[ [ "Zobov", "M.", "", "LNF INFN" ], [ "Battisti", "A.", "", "LNF INFN" ], [ "Clozza", "A.", "", "LNF INFN" ], [ "Lollo", "V.", "", "LNF INFN" ], [ "Milardi", "C.", "", "LNF INFN" ], [ "Spataro", "B.", "", "LNF INFN" ], [ "Stella", "A.", "", "LNF INFN" ], [ "Vaccarezza", "C.", "", "LNF INFN" ] ]
0705.1224
Sourav Chatterjee
Sourav Chatterjee
Fluctuations of eigenvalues and second order Poincar\'e inequalities
37 pages. To appear in PTRF
null
null
null
math.PR math.OA
null
Linear statistics of eigenvalues in many familiar classes of random matrices are known to obey gaussian central limit theorems. The proofs of such results are usually rather difficult, involving hard computations specific to the model in question. In this article we attempt to formulate a unified technique for deriving such results via relatively soft arguments. In the process, we introduce a notion of `second order Poincar\'e inequalities': just as ordinary Poincar\'e inequalities give variance bounds, second order Poincar\'e inequalities give central limit theorems. The proof of the main result employs Stein's method of normal approximation. A number of examples are worked out, some of which are new. One of the new results is a CLT for the spectrum of gaussian Toeplitz matrices.
[ { "version": "v1", "created": "Wed, 9 May 2007 07:58:31 GMT" }, { "version": "v2", "created": "Wed, 22 Aug 2007 09:09:37 GMT" }, { "version": "v3", "created": "Sun, 25 Nov 2007 08:14:17 GMT" } ]
2007-11-25T00:00:00
[ [ "Chatterjee", "Sourav", "" ] ]
0705.1225
S. Q. Wu
Jun-Jin Peng, Shuang-Qing Wu
Hawking radiation from the Schwarzschild black hole with a global monopole via gravitational anomaly
4 pages, no figure, 3nd revsion with one reference added
Chin.Phys.B17:825-828,2008
10.1088/1674-1056/17/3/016
null
hep-th gr-qc
null
Hawking flux from the Schwarzschild black hole with a global monopole is obtained by using Robinson and Wilczek's method. Adopting a dimension reduction technique, the effective quantum field in the (3+1)--dimensional global monopole background can be described by an infinite collection of the (1+1)--dimensional massless fields if neglecting the ingoing modes near the horizon, where the gravitational anomaly can be cancelled by the (1+1)--dimensional black body radiation at the Hawking temperature.
[ { "version": "v1", "created": "Wed, 9 May 2007 08:24:08 GMT" }, { "version": "v2", "created": "Thu, 7 Jun 2007 11:11:27 GMT" }, { "version": "v3", "created": "Wed, 11 Jul 2007 12:03:54 GMT" } ]
2008-11-26T00:00:00
[ [ "Peng", "Jun-Jin", "" ], [ "Wu", "Shuang-Qing", "" ] ]
0705.1226
Yvan Castin
Luca Giorgetti (CNR-BEC-INFM), Iacopo Carusotto (CNR-BEC-INFM), Yvan Castin (LKB - Lhomond)
A semi-classical field method for the equilibrium Bose gas and application to thermal vortices in two dimensions
19 pages
Physical Review A 76 (16/07/2007) 013613
10.1103/PhysRevA.76.013613
null
cond-mat.other
null
We develop a semi-classical field method for the study of the weakly interacting Bose gas at finite temperature, which, contrarily to the usual classical field model, does not suffer from an ultraviolet cut-off dependence. We apply the method to the study of thermal vortices in spatially homogeneous, two-dimensional systems. We present numerical results for the vortex density and the vortex pair distribution function. Insight in the physics of the system is obtained by comparing the numerical results with the predictions of simple analytical models. In particular, we calculate the activation energy required to form a vortex pair at low temperature.
[ { "version": "v1", "created": "Wed, 9 May 2007 08:33:22 GMT" } ]
2009-11-13T00:00:00
[ [ "Giorgetti", "Luca", "", "CNR-BEC-INFM" ], [ "Carusotto", "Iacopo", "", "CNR-BEC-INFM" ], [ "Castin", "Yvan", "", "LKB - Lhomond" ] ]
0705.1227
Petar Popovski
Petar Popovski, Hiroyuki Yomo, Kentaro Nishimori, and Rocco Di Taranto
Rate Adaptation for Cognitive Radio under Interference from Primary Spectrum User
submitted to IEEE Journal on Selected Areas in Communications "Cognitive Radio: Theory and Applications", March 2007
null
null
null
cs.IT cs.NI math.IT
null
A cognitive radio can operate as a secondary system in a given spectrum. This operation should use limited power in order not to disturb the communication by primary spectrum user. Under such conditions, in this paper we investigate how to maximize the spectral efficiency in the secondary system. A secondary receiver observes a multiple access channel of two users, the secondary and the primary transmitter, respectively. We show that, for spectrally-efficient operation, the secondary system should apply Opportunistic Interference Cancellation (OIC). With OIC, the secondary system decodes the primary signal when such an opportunity is created by the primary rate and the power received from the primary system. For such an operation, we derive the achievable data rate in the secondary system. When the primary signal is decodable, we devise a method, based on superposition coding, by which the secondary system can achieve the maximal possible rate. Finally, we investigate the power allocation in the secondary system when multiple channels are used. We show that the optimal power allocation with OIC can be achieved through intercepted water-filling instead of the conventional water-filling. The results show a significant gain for the rate achieved through an opportunistic interference cancellation.
[ { "version": "v1", "created": "Wed, 9 May 2007 08:50:53 GMT" } ]
2007-07-13T00:00:00
[ [ "Popovski", "Petar", "" ], [ "Yomo", "Hiroyuki", "" ], [ "Nishimori", "Kentaro", "" ], [ "Di Taranto", "Rocco", "" ] ]
0705.1228
Boris Kosyakov
B. P. Kosyakov
Massless interacting particles
LaTeX; 20 pages; V4: discussion is slightly modified to clarify some important points, relevant references are added
J.Phys.A41:465401,2008
10.1088/1751-8113/41/46/465401
null
hep-th
null
We show that classical electrodynamics of massless charged particles and the Yang--Mills theory of massless quarks do not experience rearranging their initial degrees of freedom into dressed particles and radiation. Massless particles do not radiate. We consider a version of the direct interparticle action theory for these systems following the general strategy of Wheeler and Feynman.
[ { "version": "v1", "created": "Wed, 9 May 2007 08:52:27 GMT" }, { "version": "v2", "created": "Fri, 24 Aug 2007 04:55:48 GMT" }, { "version": "v3", "created": "Tue, 25 Sep 2007 22:30:50 GMT" }, { "version": "v4", "created": "Mon, 7 Apr 2008 03:25:22 GMT" } ]
2008-11-26T00:00:00
[ [ "Kosyakov", "B. P.", "" ] ]
0705.1229
Luis Brey
L. Brey, H. A. Fertig and S. Das Sarma
Diluted Graphene Antiferromagnet
5 pages, two figures included
Physical Review Letters 99, 116802 (2007)
10.1103/PhysRevLett.99.116802
null
cond-mat.mes-hall cond-mat.mtrl-sci
null
We study RKKY interactions between local magnetic moments for both doped and undoped graphene. We find in both cases that the interactions are primarily ferromagnetic for moments on the same sublattice, and antiferromagnetic for moments on opposite sublattices. This suggests that at sufficiently low temperatures dilute magnetic moments embedded in graphene can order into a state analogous to that of a dilute antiferromagnet. We find that in the undoped case one expects no net magnetic moment, and demonstrate numerically that this effect generalizes to ribbons where the magnetic response is strongest at the edge, suggesting the possibility of an unusual spin-transfer device. For doped graphene we find that moments at definite lattice sites interact over longer distances than those placed in interstitial sites of the lattice ($1/R^2$ vs. $1/R^3$) because the former support a Kohn anomaly that is suppressed in the latter due to the absence of backscattering.
[ { "version": "v1", "created": "Wed, 9 May 2007 08:55:11 GMT" } ]
2009-11-13T00:00:00
[ [ "Brey", "L.", "" ], [ "Fertig", "H. A.", "" ], [ "Sarma", "S. Das", "" ] ]
0705.1230
Pawel Bryk
Luis G. MacDowell, Pawel Bryk
Direct calculation of interfacial tensions from computer simulation: Results for freely jointed tangent hard sphere chains
20 pages, 6 figures, Phys. Rev. E in press,
null
10.1103/PhysRevE.75.061609
null
cond-mat.soft cond-mat.stat-mech
null
We develop a methodology for the calculation of surface free energies based on the probability distribution of a wandering interface. Using a simple extension of the NpT sampling, we allow the interface area to randomly probe the available space and evaluate the surface free energy from histogram analysis and the corresponding average. The method is suitable for studying systems with either continuous or discontinuous potentials, as it does not require explicit evaluation of the virial. The proposed algorithm is compared with known results for the surface tension of Lennard--Jones and Square Well fluid, as well as for the interface tension of a bead--spring polymer model and good agreement is found. We also calculate interfacial tensions of freely jointed tangent hard sphere chains on athermal walls for a wide range of chain lengths and densities. The results are compared with three different theoretical approaches, Scaled Particle Theory, the Yu and Wu density functional theory and an analytical approximation based on the latter approach. Whereas SPT only yields qualitative results, the last two approaches are found to yield very good agreement with simulations.
[ { "version": "v1", "created": "Wed, 9 May 2007 08:57:57 GMT" } ]
2009-11-13T00:00:00
[ [ "MacDowell", "Luis G.", "" ], [ "Bryk", "Pawel", "" ] ]
0705.1231
\'Agnes K\'osp\'al
\'A. K\'osp\'al, P. \'Abrah\'am, T. Prusti, J. Acosta-Pulido, S. Hony, A. Mo\'or, R. Siebenmorgen
The outburst of the eruptive young star OO Serpentis between 1995 and 2006
12 pages, 7 figures, accepted for publication in A&A
null
10.1051/0004-6361:20066108
null
astro-ph
null
OO Serpentis is a deeply embedded pre-main sequence star that went into outburst in 1995 and gradually faded afterwards. Its eruption resembled the well-known FU Orionis-type or EX Lupi-type outbursts. Since very few such events have ever been documented at infrared wavelengths, our aim is to study the temporal evolution of OO Ser in the infrared. OO Ser was monitored with the Infrared Space Observatory starting 4 months after peak brightness and covering 20 months. In 2004-2006 we again observed OO Ser from the ground and complemented this dataset with archival Spitzer obsevations also from 2004. We analysed these data with special attention to source confusion and constructed light curves at 10 different wavelengths as well as spectral energy distributions. The outburst caused brightening in the whole infrared regime. According to the infrared light curves, OO Ser started a wavelength-independent fading after peak brightness. Later the flux decay became slower but stayed wavelength-independent. The fading is still ongoing, and current fading rates indicate that OO Ser will not return to quiescent state before 2011. The outburst timescale of OO Ser seems to be shorter than that of FUors, but longer than that of EXors. The outburst timescale and the moderate luminosity suggest that OO Ser is different from both FUors and EXors, and shows similarities to the recently erupted young star V1647 Ori. Based on its spectral energy distribution and bolometric temperature, OO Ser seems to be an early class I object, with an age of < 10^5 yr. The object is probably surrounded by an accretion disc and a dense envelope. Due to the shorter outburst timescales, the viscosity in the circumstellar disc of OO Ser is probably an order of magnitude higher than usual for FUors.
[ { "version": "v1", "created": "Wed, 9 May 2007 08:58:38 GMT" } ]
2009-11-13T00:00:00
[ [ "Kóspál", "Á.", "" ], [ "Ábrahám", "P.", "" ], [ "Prusti", "T.", "" ], [ "Acosta-Pulido", "J.", "" ], [ "Hony", "S.", "" ], [ "Moór", "A.", "" ], [ "Siebenmorgen", "R.", "" ] ]
0705.1232
Jens Eisert
H.M. Wiseman and J. Eisert
Nontrivial quantum effects in biology: A skeptical physicists' view
15 pages, minor typographical errors corrected
null
10.1142/9781848162556_0017
null
physics.gen-ph q-bio.OT quant-ph
null
Invited contribution to "Quantum Aspects of Life", D. Abbott Ed. (World Scientific, Singapore, 2007).
[ { "version": "v1", "created": "Wed, 9 May 2007 09:00:41 GMT" }, { "version": "v2", "created": "Sun, 27 May 2007 12:13:13 GMT" } ]
2016-12-21T00:00:00
[ [ "Wiseman", "H. M.", "" ], [ "Eisert", "J.", "" ] ]
0705.1233
Peter Hess O
Peter O. Hess and Walter Greiner
Pseudo-Complex Field Theory
21 pages, 1 figure
Int.J.Mod.Phys.E16:1643-1679,2007
10.1142/S0218301307006964
null
hep-th
null
A new formulation of field theory is presented, based on a pseudo-complex description. An extended group structure is introduced, implying a minimal scalar length, rendering the theory regularized a la Pauli-Villars. Cross sections are calculated for the scattering of an electron at an external Coulomb field and the Compton scattering. Deviations due to a smallest scalar length are determined. The theory also permits a modification of the minimal coupling scheme, resulting in a generalized dispersion relation. A shift of the Greisen-Zatsepin-Kuzmin-limit (GZK) of the cosmic ray spectrum is the consequence.
[ { "version": "v1", "created": "Wed, 9 May 2007 09:00:43 GMT" } ]
2008-11-26T00:00:00
[ [ "Hess", "Peter O.", "" ], [ "Greiner", "Walter", "" ] ]
0705.1234
Yuri V. Kovchegov
Yuri V. Kovchegov, Anastasios Taliotis
Early Time Dynamics in Heavy Ion Collisions from AdS/CFT Correspondence
24 pages, 2 figures; v2: some references added, minor typos corrected
Phys.Rev.C76:014905,2007
10.1103/PhysRevC.76.014905
null
hep-ph hep-th nucl-th
null
We study the matter produced in heavy ion collisions assuming that this matter is strongly interacting and employing AdS/CFT correspondence to investigate its dynamics. At late proper times we show that Bjorken hydrodynamics solution, obtained recently by Janik and Peschanski using gauge-gravity duality [hep-th/0512162], can be singled out by simply requiring that the metric tensor is a real and single-valued function of the coordinates everywhere in the bulk, without imposing any constraints on the curvature invariant. At early proper times we use similar strategy to show that the energy density approaches a constant as proper time goes to zero. We therefore demonstrate that the strong coupling dynamics incorporates the isotropization transition in heavy ion collisions. By matching our early-time regime with the late-time one of Janik and Peschanski we estimate the isotropization time at RHIC to be approximately 0.3 fm/c, in good agreement with results of hydrodynamic simulations.
[ { "version": "v1", "created": "Wed, 9 May 2007 19:44:30 GMT" }, { "version": "v2", "created": "Tue, 10 Jul 2007 15:38:35 GMT" } ]
2008-11-26T00:00:00
[ [ "Kovchegov", "Yuri V.", "" ], [ "Taliotis", "Anastasios", "" ] ]
0705.1235
Thanh Mai Pham Ngoc
Thanh Mai Pham Ngoc (PMA)
Statistical minimax approach of the Hausdorff moment problem
21 pages
Inverse Problems (2008) 24 045018
10.1088/0266-5611/24/4/045018
null
math.ST stat.TH
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The purpose of this paper is to study the problem of estimating a compactly supported density of probability from noisy observations of its moments. In fact, we provide a statistical approach to the famous Hausdorff classical moment problem. We prove an upper bound and a lower bound on the rate of convergence of the mean squared error showing that the considered estimator attains minimax rate over the corresponding smoothness classes.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:07:54 GMT" }, { "version": "v2", "created": "Thu, 10 May 2007 15:18:13 GMT" }, { "version": "v3", "created": "Thu, 23 Apr 2009 06:10:22 GMT" } ]
2013-10-09T00:00:00
[ [ "Ngoc", "Thanh Mai Pham", "", "PMA" ] ]
0705.1236
Eduardo Nunes-Pereira
A.R. Alves-Pereira, E.J. Nunes-Pereira, J.M.G.Martinho and M.N. Berberan-Santos
Radiation trapping in 1D using the Markov chain formalism: A computational physics project
null
null
10.1088/0143-0807/28/6/008
null
physics.ed-ph physics.comp-ph
null
A computational model study for complete frequency redistribution linear incoherent two-level atomic radiation trapping in optically dense media using the multiple scattering representation is presented. This model study discuss at length the influence of the spectral distributions, overall opacity and emission quantum yield to trapping distorted ensemble quantities stressing physical insight and with a non-specialist audience in mind. Macroscopic reemission yield, lifetime, steady state spectra and spatial distributions are calculated as a function of intrinsic emission yield, opacity and external excitation mode for Doppler, Lorentz and Voigt lineshapes. The work could constitute the basis for a final undergraduate or beginning graduate project in computational physics instruction and implements the analytical developments of the previous instalment of this contribution.
[ { "version": "v1", "created": "Wed, 9 May 2007 09:07:26 GMT" } ]
2009-11-13T00:00:00
[ [ "Alves-Pereira", "A. R.", "" ], [ "Nunes-Pereira", "E. J.", "" ], [ "Martinho", "J. M. G.", "" ], [ "Berberan-Santos", "M. N.", "" ] ]
0705.1237
Bruno Machet
Quentin Duret (LPTHE), Bruno Machet (LPTHE)
The neighborhood of the Standard Model: mixing angles and quark-lepton complementarity for three generations of non-degenerate coupled fermions
null
null
null
null
hep-ph
null
We investigate the potential (small) deviations from the unitarity of the mixing matrix that are expected to occur, because of mass splittings, in the Quantum Field Theory of non-degenerate coupled systems. We extend our previous analysis concerning mixing angles, which led to a precise determination of the Cabibbo angle, to the case of three generations of fermions. We show that the same condition for neutral currents of mass eigenstates, i.e. that universality of diagonal currents is violated with the same strength as the absence of non-diagonal ones, is satisfied: on one hand, by the three CKM mixing angles with a precision higher than the experimental uncertainty; on the other hand, by a neutrino-like mixing pattern in which theta_{23} is maximal, and tan (2 theta_{12})=2. This last pattern turns out to satisfy exactly the "quark-lepton complementarity condition" theta_c + theta_{12}= pi/4. Moreover, among all solutions, two values for the third neutrino mixing angle arise which satisfy the bound sin^2(theta_{13}) < 0.1: theta_{13} = +/- 5.7 10^{-3} and theta_{13} = +/- 0.2717. The so-called "Neighborhood of the Standard Model" is thus confirmed to exhibit special patterns which presumably originate in physics "Beyond the Standard Model".
[ { "version": "v1", "created": "Wed, 9 May 2007 09:08:33 GMT" } ]
2007-05-23T00:00:00
[ [ "Duret", "Quentin", "", "LPTHE" ], [ "Machet", "Bruno", "", "LPTHE" ] ]
0705.1238
Simon F. Ross
Eric G. Gimon, Thomas S. Levi and Simon F. Ross
Geometry of non-supersymmetric three-charge bound states
23 pages, no figures
JHEP 0708:055,2007
10.1088/1126-6708/2007/08/055
DCPT-07/19
hep-th
null
We study the smooth non-supersymmetric three-charge microstates of Jejjala, Madden, Ross and Titchener [hep-th/0504181] using Kaluza-Klein reductions of the solutions to five and four dimensions. Our aim is to improve our understanding of the relation between these non-supersymmetric solutions and the well-studied supersymmetric cases. We find some surprising qualitative differences. In the five-dimensional description, the solution has orbifold fixed points which break supersymmetry locally, so the geometries cannot be thought of as made up of separate half-BPS centers. In the four-dimensional description, the two singularities in the geometry are connected by a conical singularity, which makes it impossible to treat them independently and assign unambiguous brane charges to these centers.
[ { "version": "v1", "created": "Wed, 9 May 2007 09:09:03 GMT" }, { "version": "v2", "created": "Tue, 12 Jun 2007 12:46:05 GMT" } ]
2009-04-22T00:00:00
[ [ "Gimon", "Eric G.", "" ], [ "Levi", "Thomas S.", "" ], [ "Ross", "Simon F.", "" ] ]
0705.1239
Dimosthenis Stamopoulos
D. Stamopoulos, E. Manios, M. Pissas
Stray-fields-based magnetoresistance mechanism in Ni80Fe20-Nb-Ni80Fe20 trilayers
9 pages, 7 figures
Phys. Rev. B 75, 184504 (2007)
10.1103/PhysRevB.75.184504
null
cond-mat.supr-con cond-mat.mtrl-sci
null
We report on the transport and magnetic properties of hybrid trilayers and bilayers that consist of low spin-polarized Ni80Fe20 exhibiting in-plane but no uniaxial anisotropy and low-Tc Nb. We reveal a magnetoresistance effect that is pronounced. In our trilayers the magnetoresistance exhibits an increase of two orders of magnitude when the superconducting state is reached: from the conventional normal-state values 0.6 % it goes up to 1000 % for temperatures below Tc. In contrast, in the bilayers the effect is only minor since from 3% in the normal state increases only to 70 % for temperatures below Tc. Magnetization data of both the longitudinal and transverse magnetic components are presented. Most importantly, we present data not only for the normal state of Nb but also in its superconducting state. Strikingly, these data show that below its Tc SC the Nb interlayer under the influence of the outer Ni80Fe20 layers attains a magnetization component transverse to the external field. By comparing the transport and magnetization data we propose a candidate mechanism that could motivate the pronounced magnetoresistance effect observed in the trilayers. Adequate magnetostatic coupling of the outer Ni80Fe20 layers is motivated by stray fields that emerge naturally in their whole surface due to the multidomain magnetic structure that they attain near coercivity. Atomic force microscopy is employed in order to examine the possibility that such magnetostatic coupling could be promoted by interface roughness. Referring to the bilayers, although out-of-plane rotation of the magnetization of the single Ni80Fe20 layer is still observed, in these structures magnetostatic coupling does not occur due to the absence of a second Ni80Fe20 one so that the observed magnetoresistance peaks are only modest.
[ { "version": "v1", "created": "Wed, 9 May 2007 17:22:07 GMT" } ]
2007-05-23T00:00:00
[ [ "Stamopoulos", "D.", "" ], [ "Manios", "E.", "" ], [ "Pissas", "M.", "" ] ]
0705.1240
Rachid Ouyed
Rachid Ouyed, Denis Leahy, Jan Staff, and Brian Niebergal (University of Calgary, Alberta, Canada)
Quark-nova explosion inside a collapsar: application to Gamma Ray Bursts
10 journal pages and 5 figures (updated references and extended discussions; accepted for publication in Advances in Astronomy)
null
10.1155/2009/463521
null
astro-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
If a quark-nova occurs inside a collapsar, the interaction between the quark-nova ejecta (relativistic iron-rich chunks) and the collapsar envelope, leads to features indicative of those observed in Gamma Ray Bursts. The quark-nova ejecta collides with the stellar envelope creating an outward moving cap (Gamma ~ 1-10) above the polar funnel. Prompt gamma-ray burst emission from internal shocks in relativistic jets (following accretion onto the quark star) become visible after the cap becomes optically thin. Model features include: (i) precursor activity (optical, X-ray, gamma-ray), (ii) prompt gamma-ray emission, and (iii) afterglow emission. We discuss SN-less long duration GRBs, short hard GRBs (including association and non-association with star forming regions), dark GRBs, the energetic X-ray flares detected in Swift GRBs, and the near-simultaneous optical and gamma-ray prompt emission observed in GRBs in the context of our model.
[ { "version": "v1", "created": "Wed, 9 May 2007 09:29:03 GMT" }, { "version": "v2", "created": "Sun, 15 Jun 2008 16:50:41 GMT" }, { "version": "v3", "created": "Wed, 11 Mar 2009 04:34:34 GMT" } ]
2017-02-15T00:00:00
[ [ "Ouyed", "Rachid", "", "University\n of Calgary, Alberta, Canada" ], [ "Leahy", "Denis", "", "University\n of Calgary, Alberta, Canada" ], [ "Staff", "Jan", "", "University\n of Calgary, Alberta, Canada" ], [ "Niebergal", "Brian", "", "University\n of Calgary, Alberta, Canada" ] ]
0705.1241
Dieter W. Heermann
Dieter W. Heermann and Manfred Bohn
Percolation in a Class of Band Structured Random Matrices
null
null
null
null
cond-mat.stat-mech cond-mat.other
null
We define a class of random matrix ensembles that pertain to random looped polymers. Such random looped polymers are a possible model for bio-polymers such as chromatin in the cell nucleus. It is shown that the distribution of the largest eigenvalue $\lambda_{max}$ depends on a percolation transition in the entries of the random matrices. Below the percolation threshold the distribution is multi-peaked and changes above the threshold to the Tracy-Widom distribution. We also show that the distribution of the eigenvalues is neither of the Wigner form nor gaussian.
[ { "version": "v1", "created": "Wed, 9 May 2007 09:42:54 GMT" } ]
2009-04-16T00:00:00
[ [ "Heermann", "Dieter W.", "" ], [ "Bohn", "Manfred", "" ] ]
0705.1242
Thorsten Tepper-Garc\'ia
Thorsten Tepper-Garcia, Uta Fritze
Stochastic Absorption of the Light of Background Sources due to Intergalactic Neutral Hydrogen I. Testing different line-number evolution models via the cosmic flux decrement
Accepted by MNRAS. Matches accepted version after changes following referee's report
null
10.1111/j.1365-2966.2007.12691.x
null
astro-ph
null
[Abridged] We test the accuracy of different models of the attenuation of light due to resonant scattering by intergalactic neutral hydrogen by comparing their predictions of the evolution of the mean cosmic flux decrement, D_A, to measurements of this quantity based on observations. To this end, we use data available in the literature and our own measurements of the cosmic flux decrement for 25 quasars in the redshift range 2.71 < z < 5.41 taken from the SDSS Data Release 5. In order to perform the measurements of D_A, we fit a power-law to the continuum redward of the Lya emission line, and extrapolate this fit to region blueward of it, where the flux is severely affected by absorption due to intervening HI absorbers. We compute, using numerical simulations, the redshift evolution of D_A accounting for the presence of Lya Forest absorbers and Lyman limit systems randomly distributed along the line-of-sight, and compute its intrinsic scatter at the 1-, 2-, and 3-sigma level due to fluctuations in the absorber properties (column density, Doppler parameter, redshift) along different lines-of-sight. The numerical simulations consist of Monte Carlo realizations of distributions of the absorber properties constrained from observations. The results from the models considered here confirm our theoretical expectation that the distribution of D_A at any given redshift be well described by a lognormal distribution function. This implies that the effective optical depth, usually defined as the negative logarithm of the average flux, 1 - D_A, is very accurately Gaussian distributed, in contrast to previous studies. This result is independent to the form of the input distribution functions, and rather insensitive to the presence of high-column density absorbers, such as the Lyman limit systems.
[ { "version": "v1", "created": "Wed, 9 May 2007 14:29:21 GMT" }, { "version": "v2", "created": "Fri, 9 Nov 2007 16:31:39 GMT" } ]
2015-05-13T00:00:00
[ [ "Tepper-Garcia", "Thorsten", "" ], [ "Fritze", "Uta", "" ] ]
0705.1243
Bernhard Kroetz
Bernhard Kroetz
Crown theory for the upper halfplane
Minor stylistic changes
Contemp. Math. 488 (2009), 147--182
null
null
math.RT
null
I exemplify part of my recent work on the upper halfplane.
[ { "version": "v1", "created": "Wed, 9 May 2007 09:46:04 GMT" }, { "version": "v2", "created": "Mon, 2 Jul 2007 12:24:00 GMT" } ]
2009-10-21T00:00:00
[ [ "Kroetz", "Bernhard", "" ] ]
0705.1244
Marc Schoenauer
Nicolas Godzik (INRIA Futurs, INRIA Rocquencourt), Marc Schoenauer (INRIA Futurs, INRIA Rocquencourt), Mich\`ele Sebag (INRIA Futurs, LRI)
Evolving Symbolic Controllers
null
Dans 4th European Workshop on Evolutionary Robotics, 2611 (2003) 638-650
null
null
cs.AI
null
The idea of symbolic controllers tries to bridge the gap between the top-down manual design of the controller architecture, as advocated in Brooks' subsumption architecture, and the bottom-up designer-free approach that is now standard within the Evolutionary Robotics community. The designer provides a set of elementary behavior, and evolution is given the goal of assembling them to solve complex tasks. Two experiments are presented, demonstrating the efficiency and showing the recursiveness of this approach. In particular, the sensitivity with respect to the proposed elementary behaviors, and the robustness w.r.t. generalization of the resulting controllers are studied in detail.
[ { "version": "v1", "created": "Wed, 9 May 2007 09:53:31 GMT" } ]
2007-05-23T00:00:00
[ [ "Godzik", "Nicolas", "", "INRIA Futurs, INRIA Rocquencourt" ], [ "Schoenauer", "Marc", "", "INRIA Futurs, INRIA Rocquencourt" ], [ "Sebag", "Michèle", "", "INRIA Futurs, LRI" ] ]
0705.1245
Raphael Rouquier
Masaki Kashiwara and Raphael Rouquier
Microlocalization of rational Cherednik algebras
36 pages, minor corrections, to appear in Duke Math. Journal
null
null
null
math.RT math.AG math.QA
null
We construct a microlocalization of the rational Cherednik algebras $H$ of type $S_n$. This is achieved by a quantization of the Hilbert scheme $\Hilb^n\C^2$ of $n$ points in $\C^2$. We then prove the equivalence of the category of $H$-modules and the one of modules over its microlocalization under certain conditions on the parameter.
[ { "version": "v1", "created": "Wed, 9 May 2007 09:54:43 GMT" }, { "version": "v2", "created": "Mon, 8 Oct 2007 13:48:36 GMT" } ]
2007-10-08T00:00:00
[ [ "Kashiwara", "Masaki", "" ], [ "Rouquier", "Raphael", "" ] ]
0705.1246
Aleksandra Andi\'c
Aleksandra Andi\'c
The Position of High Frequency Waves with Respect to the Granulation Pattern
Article has 12 pages and 7 images. It is accepted in Solar Physics Journal
null
10.1007/s11207-007-0289-4
null
astro-ph
null
High frequency velocity oscillations were observed in the spectral lines Fe I 543.45nm and 543.29nm, using 2D spectroscopy with a Fabry- Perot and speckle reconstruction, at the VTT in Tenerife. We investigate the radial component of waves with frequencies in the range 8 - 22mHz in the internetwork, network and a pore. We find that the occurrence of waves do not show any preference on location and are equally distributed over down-flows and up-flows, regardless of the activity of the observed area in the line of Fe I 543.45nm. The waves observed in the lower formed line of Fe I 543.29nm seem to appear preferentially over down-flows.
[ { "version": "v1", "created": "Wed, 9 May 2007 09:55:31 GMT" } ]
2016-08-14T00:00:00
[ [ "Andić", "Aleksandra", "" ] ]
0705.1247
Davide Gabrielli
L. Bertini, A. De Sole, D. Gabrielli, G. Jona--Lasinio, C. Landim
Stochastic interacting particle systems out of equilibrium
36 pages
J. Stat. Mech. Theory Exp., (2007) P07014
10.1088/1742-5468/2007/07/P07014
Roma01.Math
cond-mat.stat-mech
null
This paper provides an introduction to some stochastic models of lattice gases out of equilibrium and a discussion of results of various kinds obtained in recent years. Although these models are different in their microscopic features, a unified picture is emerging at the macroscopic level, applicable, in our view, to real phenomena where diffusion is the dominating physical mechanism. We rely mainly on an approach developed by the authors based on the study of dynamical large fluctuations in stationary states of open systems. The outcome of this approach is a theory connecting the non equilibrium thermodynamics to the transport coefficients via a variational principle. This leads ultimately to a functional derivative equation of Hamilton-Jacobi type for the non equilibrium free energy in which local thermodynamic variables are the independent arguments. In the first part of the paper we give a detailed introduction to the microscopic dynamics considered, while the second part, devoted to the macroscopic properties, illustrates many consequences of the Hamilton-Jacobi equation. In both parts several novelties are included.
[ { "version": "v1", "created": "Wed, 9 May 2007 10:03:56 GMT" } ]
2015-12-18T00:00:00
[ [ "Bertini", "L.", "" ], [ "De Sole", "A.", "" ], [ "Gabrielli", "D.", "" ], [ "Jona--Lasinio", "G.", "" ], [ "Landim", "C.", "" ] ]
0705.1248
Mustapha Jazar
Moukaddem Nazih
L'Univers en expansion et probl\`emes d'\'energie
arXiv admin note: substantial text overlap with arXiv:0708.3743
null
null
null
physics.gen-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we first construct a mathematical model for the Universe expansion that started up with the original Big Bang. Next, we discuss the problematic of the mechanical and physical laws invariance regarding the spatial frame exchanges. We then prove the (theoretical) existence of a variable metric $g_t$, depending on time and satisfying to a simplified Einstein equation, so that all free ordinary trajectories are geodesics. This is done by considering the classical Galileo-Newtonian space and time relation, by using generalized Newtonian principles and adding the approved physical new ones (as covariance principle, Mach principle, the Einstein equivalence principle ...) in order to establish a new cosmological model of the dynamical Universe as being $(U(t))_{t\geq 0}=(B_e(O,t),g_t)_{t\geq 0}$, where $B_e(O,t)$ is the Euclidean ball of radius $t$ in $\mathbb R^3$. The cosmological metric $g_t$ is totally determined, at time $t$, by the mass energy distribution $E_t(X)$ on $B_e(O,t)$. We study also the black holes phenomenon and we prove that the total and global cosmological energy distribution $E_t(X)$ satisfies to the wave equation whose solutions are characterized by pseudo-frequencies depending on time and related to the spectrum of the Dirichlet problem on the unit ball $B_e(O,1)$ for the Laplace-Beltrami operator -$\Delta$. Our model is consistent in the sense that all Newtonian and classical physical laws are valid as particular cases in classical situations. Then, we show that all basic results of Modern Physics are still valid without using the second postulate of special relativity nor the uncertainty principle.
[ { "version": "v1", "created": "Wed, 9 May 2007 10:04:10 GMT" }, { "version": "v10", "created": "Thu, 17 Jun 2010 08:19:41 GMT" }, { "version": "v11", "created": "Sat, 18 Dec 2010 11:45:38 GMT" }, { "version": "v12", "created": "Wed, 23 Nov 2011 08:33:47 GMT" }, { "version": "v13", "created": "Tue, 9 Oct 2012 07:37:38 GMT" }, { "version": "v2", "created": "Tue, 3 Jul 2007 08:38:39 GMT" }, { "version": "v3", "created": "Wed, 19 Mar 2008 11:35:27 GMT" }, { "version": "v4", "created": "Tue, 21 Oct 2008 08:02:47 GMT" }, { "version": "v5", "created": "Mon, 20 Jul 2009 08:23:08 GMT" }, { "version": "v6", "created": "Tue, 25 Aug 2009 11:10:22 GMT" }, { "version": "v7", "created": "Thu, 5 Nov 2009 10:02:00 GMT" }, { "version": "v8", "created": "Mon, 1 Feb 2010 12:18:48 GMT" }, { "version": "v9", "created": "Wed, 17 Mar 2010 20:12:49 GMT" } ]
2012-10-10T00:00:00
[ [ "Nazih", "Moukaddem", "" ] ]
0705.1249
Jerome Chenevez
J. Chenevez, M. Falanga, E. Kuulkers, R. Walter, L. Bildsten, S. Brandt, N. Lund, T. Oosterbroek, and J. Zurita Heras
IGR J17254-3257, a new bursting neutron star
4 pages, 4 figures, 1 table; accepted for publication in A&A Letters. 1 reference (Cooper & Narayan, 2007) corrected
null
10.1051/0004-6361:20077494
null
astro-ph
null
The study of the observational properties of uncommonly long bursts from low luminosity sources with extended decay times up to several tens of minutes is important when investigating the transition from a hydrogen-rich bursting regime to a pure helium regime and from helium burning to carbon burning as predicted by current burst theories. IGR J17254-3257 is a recently discovered X-ray burster of which only two bursts have been recorded: an ordinary short type I X-ray burst, and a 15 min long burst. An upper limit to its distance is estimated to about 14.5 kpc. The broad-band spectrum of the persistent emission in the 0.3-100 keV energy band obtained using contemporaneous INTEGRAL and XMM-Newton data indicates a bolometric flux of 1.1x10^-10 erg/cm2/s corresponding, at the canonical distance of 8 kpc, to a luminosity about 8.4x10^35 erg/s between 0.1-100 keV, which translates to a mean accretion rate of about 7x10^-11 solar masses per year. The low X-ray persistent luminosity of IGR J17254-3257 seems to indicate the source may be in a state of low accretion rate usually associated with a hard spectrum in the X-ray range. The nuclear burning regime may be intermediate between pure He and mixed H/He burning. The long burst is the result of the accumulation of a thick He layer, while the short one is a prematurate H-triggered He burning burst at a slightly lower accretion rate.
[ { "version": "v1", "created": "Wed, 9 May 2007 10:08:13 GMT" }, { "version": "v2", "created": "Thu, 10 May 2007 10:22:18 GMT" } ]
2009-11-13T00:00:00
[ [ "Chenevez", "J.", "" ], [ "Falanga", "M.", "" ], [ "Kuulkers", "E.", "" ], [ "Walter", "R.", "" ], [ "Bildsten", "L.", "" ], [ "Brandt", "S.", "" ], [ "Lund", "N.", "" ], [ "Oosterbroek", "T.", "" ], [ "Heras", "J. Zurita", "" ] ]
0705.1250
Dibyendu Das
Somnath Bhattacharya, Dibyendu Das, Satya N. Majumdar
Persistence of a Rouse polymer chain under transverse shear flow
6 pages
Phys. Rev. E, 75, 061122 (2007).
10.1103/PhysRevE.75.061122
null
cond-mat.stat-mech
null
We consider a single Rouse polymer chain in two dimensions in presence of a transverse shear flow along the $x$ direction and calculate the persistence probability $P_0(t)$ that the $x$ coordinate of a bead in the bulk of the chain does not return to its initial position up to time $t$. We show that the persistence decays at late times as a power law, $P_0(t)\sim t^{-\theta}$ with a nontrivial exponent $\theta$. The analytical estimate of $\theta=0.359...$ obtained using an independent interval approximation is in excellent agreement with the numerical value $\theta\approx 0.360\pm 0.001$.
[ { "version": "v1", "created": "Wed, 9 May 2007 10:13:54 GMT" } ]
2009-11-13T00:00:00
[ [ "Bhattacharya", "Somnath", "" ], [ "Das", "Dibyendu", "" ], [ "Majumdar", "Satya N.", "" ] ]
0705.1251
Esben Halvorsen
Esben Bistrup Halvorsen
Diagonalizing the Frobenius
Revised (simplified) version. 12 pages
null
null
null
math.AC
null
Over a Noetherian, local ring R of prime characteristic p, the Frobenius functor F induces a diagonalizable map on certain quotients of rational Grothendieck groups. This leads to an explicit formula for the Dutta multiplicity, and it is shown that a weaker version of Serre's vanishing conjecture holds if only chi(F(X)) = p^{dim R}chi(X) for all bounded complexes X of finitely generated, projective modules with finite length homology.
[ { "version": "v1", "created": "Wed, 9 May 2007 10:27:03 GMT" }, { "version": "v2", "created": "Sun, 30 Sep 2007 09:50:48 GMT" } ]
2007-09-30T00:00:00
[ [ "Halvorsen", "Esben Bistrup", "" ] ]
0705.1252
Peter Talkner
Peter Talkner, Peter Hanggi
The Tasaki-Crooks quantum fluctuation theorem
null
J. Phys. A 40, F569-F571 (2007)
null
null
cond-mat.stat-mech
null
Starting out from the recently established quantum correlation function expression of the characteristic function for the work performed by a force protocol on the system [cond-mat/0703213] the quantum version of the Crooks fluctuation theorem is shown to emerge almost immediately by the mere application of an inverse Fourier transformation.
[ { "version": "v1", "created": "Wed, 9 May 2007 10:30:51 GMT" } ]
2007-06-21T00:00:00
[ [ "Talkner", "Peter", "" ], [ "Hanggi", "Peter", "" ] ]
0705.1253
Esben Halvorsen
Anders J. Frankild and Esben Bistrup Halvorsen
Dualities and intersection multiplicities
null
null
null
null
math.AC
null
Let R be a commutative, noetherian, local ring. Topological Q-vector spaces modelled on full subcategories of the derived category of R are constructed in order to study intersection multiplicities.
[ { "version": "v1", "created": "Wed, 9 May 2007 10:32:13 GMT" } ]
2007-05-23T00:00:00
[ [ "Frankild", "Anders J.", "" ], [ "Halvorsen", "Esben Bistrup", "" ] ]
0705.1254
Hujeirat
A. Hujeirat
An implicit numerical algorithm general relativistic hydrodynamics
23 pages, 11 figures. This article has been replaced by arXiv:0801.1017
null
null
null
gr-qc
null
An implicit numerical algorithm general relativistic hydrodynamics This article has been replaced by arXiv:0801.1017
[ { "version": "v1", "created": "Wed, 9 May 2007 10:43:34 GMT" }, { "version": "v2", "created": "Wed, 9 Jan 2008 13:35:12 GMT" } ]
2016-09-08T00:00:00
[ [ "Hujeirat", "A.", "" ] ]
0705.1255
Fausto Borgonovi
G.P. Berman. A.R. Bishop, F. Borgonovi, V.I. Tsifrinovich
Controllable Adiabatic Manipulation of the Qubit State
3 pages 2 figures
International Journal of Quantum Information (IJQI) 5, No 5 667-672 (2007)
null
null
quant-ph
null
We propose a scheme which implements a controllable change of the state of the target spin qubit in such a way that both the control and the target spin qubits remain in their ground states. The interaction between the two spins is mediated by an auxiliary spin, which can transfer to its excited state. Our scheme suggests a possible relationship between the gate and adiabatic quantum computation.
[ { "version": "v1", "created": "Wed, 9 May 2007 10:49:30 GMT" } ]
2013-07-08T00:00:00
[ [ "Bishop", "G. P. Berman. A. R.", "" ], [ "Borgonovi", "F.", "" ], [ "Tsifrinovich", "V. I.", "" ] ]
0705.1256
Yu-Ao Chen
Yu-Ao Chen, Shuai Chen, Zhen-Sheng Yuan, Bo Zhao, Chih-Sung Chuu, Joerg Schmiedmayer and Jian-Wei Pan
Memory-built-in quantum teleportation with photonic and atomic qubits
19 pages 3 figures 1 table
Nature Physics 4, 103-107 (2008)
10.1038/nphys832
null
quant-ph
null
The combination of quantum teleportation and quantum memory of photonic qubits is essential for future implementations of large-scale quantum communication and measurement-based quantum computation. Both steps have been achieved separately in many proof-of-principle experiments, but the demonstration of memory-built-in teleportation of photonic qubits remains an experimental challenge. Here, we demonstrate teleportation between photonic (flying) and atomic (stationary) qubits. In our experiment, an unknown polarization state of a single photon is teleported over 7 m onto a remote atomic qubit that also serves as a quantum memory. The teleported state can be stored and successfully read out for up to 8 micro-second. Besides being of fundamental interest, teleportation between photonic and atomic qubits with the direct inclusion of a readable quantum memory represents a step towards an efficient and scalable quantum network.
[ { "version": "v1", "created": "Wed, 9 May 2007 10:52:47 GMT" }, { "version": "v2", "created": "Mon, 21 Jan 2008 16:36:39 GMT" } ]
2008-02-20T00:00:00
[ [ "Chen", "Yu-Ao", "" ], [ "Chen", "Shuai", "" ], [ "Yuan", "Zhen-Sheng", "" ], [ "Zhao", "Bo", "" ], [ "Chuu", "Chih-Sung", "" ], [ "Schmiedmayer", "Joerg", "" ], [ "Pan", "Jian-Wei", "" ] ]
0705.1257
Alberto Hern\'andez-M\'inguez
A. Hern\'andez-M\'inguez, F. Maci\`a, J. M. Hernandez, G. Abril, A. Garc\'ia-Santiago, J. Tejada and F. Parisi
Spatial motion of the magnetic avalanches associated to the CO-AFM to CD-FM transition in La$_{0.225}$Pr$\_{0.40}$Ca$\_{0.375}$MnO$\_{3}$ manganite
4 pages, 6 figures
null
null
null
cond-mat.other
null
Very fast magnetic avalanches in (La, Pr)-based manganites are the signature of a phase transition from an insulating blocked charge-ordered (CO-AFM) state to a charge delocalized ferromagnetic (CD-FM) state. We report here the experimental observation that this transition does not occur neither simultaneously nor randomly in the whole sample but there is instead a spatial propagation with a velocity of the order of tens of m/s. Our results show that avalanches are originated in the inside of the sample, move to the outside and occur at values of the applied magnetic field that depend on the CD-FM fraction in the sample. Moreover, a change in the gradient of the magnetic field along the sample shifts the point where the avalanches are ignited.
[ { "version": "v1", "created": "Wed, 9 May 2007 10:50:59 GMT" } ]
2007-05-23T00:00:00
[ [ "Hernández-Mínguez", "A.", "" ], [ "Macià", "F.", "" ], [ "Hernandez", "J. M.", "" ], [ "Abril", "G.", "" ], [ "García-Santiago", "A.", "" ], [ "Tejada", "J.", "" ], [ "Parisi", "F.", "" ] ]
0705.1258
Amita B. Deb
A. B. Deb, G. Smirne, R. M. Godun, C. J. Foot
A method of state-selective transfer of atoms between microtraps based on the Franck-Condon Principle
8 pages, 6 figures. Accepted for publication Journal of Physics B (Atomic, molecular and optical physics)
null
10.1088/0953-4075/40/21/001
null
physics.atom-ph
null
We present a method of transferring a cold atom between spatially separated microtraps by means of a Raman transition between the ground motional states of the two traps. The intermediate states for the Raman transition are the vibrational levels of a third microtrap, and we determine the experimental conditions for which the overlap of the wave functions leads to an efficient transfer. There is a close analogy with the Franck-Condon principle in the spectroscopy of molecules. Spin-dependent manipulation of neutral atoms in microtraps has important applications in quantum information processing. We also show that starting with several atoms, precisely one atom can be transferred to the final potential well hence giving deterministic preparation of single atoms.
[ { "version": "v1", "created": "Wed, 9 May 2007 11:11:45 GMT" }, { "version": "v2", "created": "Fri, 28 Sep 2007 19:39:39 GMT" } ]
2009-11-13T00:00:00
[ [ "Deb", "A. B.", "" ], [ "Smirne", "G.", "" ], [ "Godun", "R. M.", "" ], [ "Foot", "C. J.", "" ] ]
0705.1259
Klaus Moenig
Klaus Moenig, Aura Rosca
Towards a measurement of the two-photon decay width of the Higgs boson at a Photon Collider
null
Eur.Phys.J.C57:535-540,2008
10.1140/epjc/s10052-008-0765-5
null
hep-ph
null
A study of the measurement of the two photon decay width times the branching ratio of a Higgs boson with the mass of 120 GeV in photon - photon collisions is presented, assuming a gamma-gamma integrated luminosity of 80 fb^-1 in the high energy part of the spectrum. The analysis is based on the reconstruction of the Higgs events produced in the gamma gamma --> H process, followed by the decay of the Higgs into a bbbar pair. A statistical error of the measurement of the two-photon width times the branching ratio of the Higgs boson decaying into b-quarks is found to be 2.1% for one year of data taking.
[ { "version": "v1", "created": "Wed, 9 May 2007 11:21:05 GMT" } ]
2009-02-16T00:00:00
[ [ "Moenig", "Klaus", "" ], [ "Rosca", "Aura", "" ] ]
0705.1260
Andrei Khrennikov
Andrei Khrennikov
Quantum-like Representation of Extensive Form Games: Wine Testing Game
null
J. Math. Phys., 48, 072107 (2007)
10.1063/1.2752012
null
quant-ph
null
We consider an application of the mathematical formalism of quantum mechanics (QM) outside physics, namely, to game theory. We present a simple game between macroscopic players, say Alice and Bob (or in a more complex form - Alice, Bob and Cecilia), which can be represented in the quantum-like (QL) way -- by using a complex probability amplitude (game's ``wave function'') and noncommutative operators. The crucial point is that games under consideration are so called extensive form games. Here the order of actions of players is important, such a game can be represented by the tree of actions. The QL probabilistic behavior of players is a consequence of incomplete information which is available to e.g. Bob about the previous action of Alice. In general one could not construct a classical probability space underlying a QL-game. This can happen even in a QL-game with two players. In a QL-game with three players Bell's inequality can be violated. The most natural probabilistic description is given by so called contextual probability theory completed by the frequency definition of probability.
[ { "version": "v1", "created": "Wed, 9 May 2007 11:38:12 GMT" } ]
2010-11-30T00:00:00
[ [ "Khrennikov", "Andrei", "" ] ]
0705.1261
Dmitry Vysotsky V
Anatoly P. Napartovich and Dmitry V. Vysotsky
Theory of spatial mode competition in a fiber amplifier
Corrected version, model in section II has been made more optical. Paper is submitted to Phys. Rev. A
null
10.1103/PhysRevA.76.063801
null
physics.optics
null
Theory of monochromatic wave field amplification in a waveguide array based on expansion of the wave field in terms of guided array modes is developed. Equations for the expansion coefficients include cross-modal gain, which completely changes behavior of the amplified wave field. Analysis of two-mode amplification reveals new unusual features in characteristics of two-mode amplifier. Instead of unlimited growth of both modes for incoherent fields, one of the modes grows with no limit and suppresses the lower-power mode. Effects associated with the cross-modal gain are illustrated analytically on a system of two thin parallel planar waveguides. Conditions are found when a mode with lower gain can become the dominant one at the output of amplifier.
[ { "version": "v1", "created": "Wed, 9 May 2007 11:39:00 GMT" }, { "version": "v2", "created": "Mon, 15 Oct 2007 10:08:21 GMT" } ]
2009-11-13T00:00:00
[ [ "Napartovich", "Anatoly P.", "" ], [ "Vysotsky", "Dmitry V.", "" ] ]
0705.1262
Ahmad El Soufi
Ahmad El Soufi (LMPT), Rola Kiwan (LMPT)
Extremal first Dirichlet eigenvalue of doubly connected plane domains and dihedral symmetry
To appear in SIAM Journal on Mathematical Analysis
SIAM Journal on Mathematical Analysis / SIAM Journal of Mathematical Analysis 39, 4 (2007) 1112 --1119
null
null
math.SP math.OC
null
We deal with the following eigenvalue optimization problem: Given a bounded domain $D\subset \R^2$, how to place an obstacle $B$ of fixed shape within $D$ so as to maximize or minimize the fundamental eigenvalue $\lambda_1$ of the Dirichlet Laplacian on $D\setminus B$. This means that we want to extremize the function $\rho\mapsto \lambda_1(D\setminus \rho (B))$, where $\rho$ runs over the set of rigid motions such that $\rho (B)\subset D$. We answer this problem in the case where both $D$ and $B$ are invariant under the action of a dihedral group $\mathbb{D}_n$, $n\ge2$, and where the distance from the origin to the boundary is monotonous as a function of the argument between two axes of symmetry. The extremal configurations correspond to the cases where the axes of symmetry of $B$ coincide with those of $D$.
[ { "version": "v1", "created": "Wed, 9 May 2007 11:41:46 GMT" } ]
2007-12-08T00:00:00
[ [ "Soufi", "Ahmad El", "", "LMPT" ], [ "Kiwan", "Rola", "", "LMPT" ] ]
0705.1263
Ahmad El Soufi
Ahmad El Soufi (LMPT), Sa\"id Ilias (LMPT)
Domain deformations and eigenvalues of the Dirichlet Laplacian in a Riemannian manifold
To appear in Illinois J. Math
Illinois Journal of Mathematics 51 (2007) 645--666
null
null
math.MG math.SP
null
For any bounded regular domain $\Omega$ of a real analytic Riemannian manifold $M$, we denote by $\lambda_{k}(\Omega)$ the $k$-th eigenvalue of the Dirichlet Laplacian of $\Omega$. In this paper, we consider $\lambda_k$ and as a functional upon the set of domains of fixed volume in $M$. We introduce and investigate a natural notion of critical domain for this functional. In particular, we obtain necessary and sufficient conditions for a domain to be critical, locally minimizing or locally maximizing for $\lambda_k$. These results rely on Hadamard type variational formulae that we establish in this general setting.
[ { "version": "v1", "created": "Wed, 9 May 2007 11:42:37 GMT" } ]
2007-09-25T00:00:00
[ [ "Soufi", "Ahmad El", "", "LMPT" ], [ "Ilias", "Saïd", "", "LMPT" ] ]
0705.1264
Jia Zhou
Jia Zhou, Bin Wang, Yungui Gong, Elcio Abdalla
The generalized second law of thermodynamics in the accelerating universe
12 pages, 6 figures, revised version, accepted for publication in Phys. Lett. B
Phys.Lett.B652:86-91,2007
10.1016/j.physletb.2007.06.067
null
gr-qc hep-th
null
We show that in the accelerating universe the generalized second law of thermodynamics holds only in the case where the enveloping surface is the apparent horizon, but not in the case of the event horizon. The present analysis relies on the most recent SNe Ia events, being model independent. Our study might suggest that event horizon is not a physical boundary from the point of view of thermodynamics.
[ { "version": "v1", "created": "Wed, 9 May 2007 11:44:07 GMT" }, { "version": "v2", "created": "Tue, 26 Jun 2007 14:36:50 GMT" } ]
2008-11-26T00:00:00
[ [ "Zhou", "Jia", "" ], [ "Wang", "Bin", "" ], [ "Gong", "Yungui", "" ], [ "Abdalla", "Elcio", "" ] ]
0705.1265
Kurusch Ebrahimi-Fard
Kurusch Ebrahimi-Fard, Dominique Manchon, Frederic Patras
A noncommutative Bohnenblust-Spitzer identity for Rota-Baxter algebras solves Bogoliubov's recursion
improved version, accepted for publication in the Journal of Noncommutative Geometry
Journal of Noncommutative Geometry, Vol. 3, Issue 2 (2009), 181-222
10.4171/JNCG/35
null
math.CO hep-th math-ph math.MP math.RA
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Bogoliubov recursion is a particular procedure appearing in the process of renormalization in perturbative quantum field theory. It provides convergent expressions for otherwise divergent integrals. We develop here a theory of functional identities for noncommutative Rota-Baxter algebras which is shown to encode, among others, this process in the context of Connes-Kreimer's Hopf algebra of renormalization. Our results generalize the seminal Cartier-Rota theory of classical Spitzer-type identities for commutative Rota-Baxter algebras. In the classical, commutative, case, these identities can be understood as deriving from the theory of symmetric functions. Here, we show that an analogous property holds for noncommutative Rota-Baxter algebras. That is, we show that functional identities in the noncommutative setting can be derived from the theory of noncommutative symmetric functions. Lie idempotents, and particularly the Dynkin idempotent play a crucial role in the process. Their action on the pro-unipotent groups such as those of perturbative renormalization is described in detail along the way.
[ { "version": "v1", "created": "Wed, 9 May 2007 11:51:03 GMT" }, { "version": "v2", "created": "Tue, 19 Aug 2008 22:40:43 GMT" } ]
2019-04-09T00:00:00
[ [ "Ebrahimi-Fard", "Kurusch", "" ], [ "Manchon", "Dominique", "" ], [ "Patras", "Frederic", "" ] ]
0705.1266
Sujin Babu
Sujin Babu, Jean Christophe Gimel and Taco Nicolai
Tracer diffusion in colloidal gels
6 pages, 8 figures
J. Phys. Chem. B, 2008, 112 (3), pp 743 - 748
null
null
cond-mat.soft
null
Computer simulations were done of the mean square displacement (MSD) of tracer particles in colloidal gels formed by diffusion or reaction limited aggregation of hard spheres. The diffusion coefficient was found to be determined by the volume fraction accessible to the spherical tracers ($\phi_a$) independent of the gel structure or the tracer size. In all cases, critical slowing down was observed at $\phi_a\approx 0.03$ and was characterized by the same scaling laws reported earlier for tracer diffusion in a Lorentz gas. Strong heterogeneity of the MSD was observed at small $\phi_a$ and was related to the size distribution of pores.
[ { "version": "v1", "created": "Wed, 9 May 2007 11:52:18 GMT" } ]
2009-03-25T00:00:00
[ [ "Babu", "Sujin", "" ], [ "Gimel", "Jean Christophe", "" ], [ "Nicolai", "Taco", "" ] ]
0705.1267
Mirko Krumpe
M. Krumpe (1), G. Lamer (1), A.D. Schwope (1), and B. Husemann (1) ((1) Astrophysikalisches Institut Potsdam, Germany)
RBS1423 - a new QSO with relativistic reflection from an ionised disk
7 pages, 8 figures, accepted for publication in A&A (2 April 2007)
null
10.1051/0004-6361:20067036
null
astro-ph
null
We present the analysis and results of a 20 ks XMM-Newton observation of RBS1423. X-ray spectral analysis is used to establish a significantly broadened relativistic iron K-alpha line from a highly ionised disk. A QSO at z=2.262 was considered to be the optical counterpart of this ROSAT Bright Survey X-ray source. Based on the improved XMM-Newton source position we identified a z=0.208 QSO as optical counterpart to RBS1423. The 0.2-12 keV X-ray luminosity of this radio-quiet QSO is 6x10^{44} erg/s. The XMM-EPIC spectra are well described by a power law with a significantly broadened iron K-alpha line. Disk line models for both Schwarzschild and Kerr black holes require hydrogen-like iron ions to fit the measured line profile. Significant ionisation of the reflection disk is confirmed by model fits with ionised disk models, resulting in an ionisation parameter xi~2000.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:20:09 GMT" } ]
2009-11-13T00:00:00
[ [ "Krumpe", "M.", "", "Astrophysikalisches Institut Potsdam, Germany" ], [ "Lamer", "G.", "", "Astrophysikalisches Institut Potsdam, Germany" ], [ "Schwope", "A. D.", "", "Astrophysikalisches Institut Potsdam, Germany" ], [ "Husemann", "B.", "", "Astrophysikalisches Institut Potsdam, Germany" ] ]
0705.1268
Fabio Gobbi
Fabio Gobbi, Cecilia Mancini
Diffusion covariation and co-jumps in bidimensional asset price processes with stochastic volatility and infinite activity Levy jumps
null
null
10.1117/12.724566
null
math.PR math.ST stat.TH
null
In this paper we consider two processes driven by diffusions and jumps. The jump components are Levy processes and they can both have finite activity and infinite activity. Given discrete observations we estimate the covariation between the two diffusion parts and the co-jumps. The detection of the co-jumps allows to gain insight in the dependence structure of the jump components and has important applications in finance. Our estimators are based on a threshold principle allowing to isolate the jumps. This work follows Gobbi and Mancini (2006) where the asymptotic normality for the estimator of the covariation, with convergence speed given by the squared root of h, was obtained when the jump components have finite activity. Here we show that the speed is the squared root of h only when the activity of the jump components is moderate.
[ { "version": "v1", "created": "Wed, 9 May 2007 12:13:25 GMT" } ]
2009-11-13T00:00:00
[ [ "Gobbi", "Fabio", "" ], [ "Mancini", "Cecilia", "" ] ]
0705.1269
David Andelman
Ariel Abrashkin, David Andelman, Henri Orland
Dipolar Poisson-Boltzmann Equation: Ions and Dipoles Close to Charged Surfaces
4 pages, 2 figures
Phys. Rev. Lett. 99, 077801 (2007)
10.1103/PhysRevLett.99.077801
null
cond-mat.soft cond-mat.stat-mech
null
We present an extension to the Poisson-Boltzmann model where the dipolar features of solvent molecules are taken explicitly into account. The formulation is derived at mean-field level and can be extended to any order in a systematic expansion. It is applied to a two-plate system with oppositely charged surfaces. The ion distribution and profiles in the dipolar order parameter are calculated and can result in a large correction to the inter-plate pressure.
[ { "version": "v1", "created": "Wed, 9 May 2007 12:21:03 GMT" } ]
2012-01-31T00:00:00
[ [ "Abrashkin", "Ariel", "" ], [ "Andelman", "David", "" ], [ "Orland", "Henri", "" ] ]
0705.1270
Romain Neugebauer
Romain Neugebauer, Mark J. van der Laan, Marshall M. Joffe, Ira B. Tager
Causal inference in longitudinal studies with history-restricted marginal structural models
Published at http://dx.doi.org/10.1214/07-EJS050 in the Electronic Journal of Statistics (http://www.i-journals.org/ejs/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Electronic Journal of Statistics 2007, Vol. 1, 119-154
10.1214/07-EJS050
IMS-EJS-EJS_2007_50
math.ST stat.ME stat.TH
null
A new class of Marginal Structural Models (MSMs), History-Restricted MSMs (HRMSMs), was recently introduced for longitudinal data for the purpose of defining causal parameters which may often be better suited for public health research or at least more practicable than MSMs \citejoffe,feldman. HRMSMs allow investigators to analyze the causal effect of a treatment on an outcome based on a fixed, shorter and user-specified history of exposure compared to MSMs. By default, the latter represent the treatment causal effect of interest based on a treatment history defined by the treatments assigned between the study's start and outcome collection. We lay out in this article the formal statistical framework behind HRMSMs. Beyond allowing a more flexible causal analysis, HRMSMs improve computational tractability and mitigate statistical power concerns when designing longitudinal studies. We also develop three consistent estimators of HRMSM parameters under sufficient model assumptions: the Inverse Probability of Treatment Weighted (IPTW), G-computation and Double Robust (DR) estimators. In addition, we show that the assumptions commonly adopted for identification and consistent estimation of MSM parameters (existence of counterfactuals, consistency, time-ordering and sequential randomization assumptions) also lead to identification and consistent estimation of HRMSM parameters.
[ { "version": "v1", "created": "Wed, 9 May 2007 12:22:37 GMT" } ]
2009-09-29T00:00:00
[ [ "Neugebauer", "Romain", "" ], [ "van der Laan", "Mark J.", "" ], [ "Joffe", "Marshall M.", "" ], [ "Tager", "Ira B.", "" ] ]
0705.1271
Damien Chablat
F\'elix Majou (IRCCyN), Philippe Wenger (IRCCyN), Damien Chablat (IRCCyN)
Design of a 3 Axis Parallel Machine Tool for High Speed Machining: The Orthoglide
null
4\`eme Conf\'erence Internationale sur la Conception et la fabrication Int\'egr\'ees en M\'ecanique (2002) 1-10
null
null
cs.RO
null
The Orthoglide project aims at designing a new 3-axis machine tool for High Speed Machining. Basis kinematics is a 3 degree-of-freedom translational parallel mechanism. This basis was submitted to isotropic and manipulability constraints that allowed the optmization of its kinematic architecture and legs architecture. Thus, several leg morphologies are convenient for the chosen mechanism. We explain the process that led us to the choice we made for the Orthoglide. A static study is presented to show how singular configurations of the legs can cause stiffness problems.
[ { "version": "v1", "created": "Wed, 9 May 2007 12:23:53 GMT" } ]
2007-05-23T00:00:00
[ [ "Majou", "Félix", "", "IRCCyN" ], [ "Wenger", "Philippe", "", "IRCCyN" ], [ "Chablat", "Damien", "", "IRCCyN" ] ]
0705.1272
Damien Chablat
Damien Chablat (IRCCyN), St\'ephane Caro (IRCCyN), Philippe Wenger (IRCCyN), Jorge Angeles (CIM)
The Isoconditioning Loci of Planar Three-DOF Parallel Manipulators
null
4\`eme Conf\'erence Internationale sur la Conception et la fabrication Int\'egr\'ees en M\'ecanique (2002) 1-10
null
null
cs.RO
null
The subject of this paper is a special class of parallel manipulators. First, we analyze a family of three-degree-of-freedom manipulators. Two Jacobian matrices appear in the kinematic relations between the joint-rate and the Cartesian-velocity vectors, which are called the "inverse kinematics" and the "direct kinematics" matrices. The singular configurations of these matrices are studied. The isotropic configurations are then studied based on the characteristic length of this manipulator. The isoconditioning loci of all Jacobian matrices are computed to define a global performance index to compare the different working modes.
[ { "version": "v1", "created": "Wed, 9 May 2007 12:27:08 GMT" } ]
2007-05-23T00:00:00
[ [ "Chablat", "Damien", "", "IRCCyN" ], [ "Caro", "Stéphane", "", "IRCCyN" ], [ "Wenger", "Philippe", "", "IRCCyN" ], [ "Angeles", "Jorge", "", "CIM" ] ]
0705.1273
Qingyang Guan
Qingyang Guan
On regularity of SLE_8 curves
This paper has been withdrawn
null
null
null
math.PR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper has been withdrawn by the author due to essential mistakes in some previous versions.
[ { "version": "v1", "created": "Wed, 9 May 2007 17:29:54 GMT" }, { "version": "v2", "created": "Wed, 16 Jan 2008 17:53:20 GMT" }, { "version": "v3", "created": "Wed, 23 Jan 2008 10:08:14 GMT" }, { "version": "v4", "created": "Thu, 14 Aug 2008 16:19:26 GMT" }, { "version": "v5", "created": "Fri, 15 Aug 2008 11:54:41 GMT" }, { "version": "v6", "created": "Sat, 13 Sep 2008 20:36:19 GMT" } ]
2008-09-15T00:00:00
[ [ "Guan", "Qingyang", "" ] ]
0705.1274
Edouard Brainis
E. Brainis, S. Clemmen, and Serge Massar
Generation and amplification of Raman Stokes and anti-Stokes waves
3 pages, 2 figures, submitted to Opt. Lett
null
null
null
physics.optics
null
We present general analytical expressions of Stokes and anti-Stokes spectral photon-flux densities that are spontaneously generated by a single monochromatic pump wave propagating in a single-mode optical fiber. We validate our results by comparing them with experimental data. Limiting cases of the general expressions corresponding to interesting physical situations are discussed.
[ { "version": "v1", "created": "Wed, 9 May 2007 12:46:18 GMT" } ]
2007-05-23T00:00:00
[ [ "Brainis", "E.", "" ], [ "Clemmen", "S.", "" ], [ "Massar", "Serge", "" ] ]
0705.1275
Andrij Rovenchak
Andrij Rovenchak
Weakly-Interacting Bosons in a Trap within Approximate Second Quantization Approach
6 pages, two figures .Presented at the International Symposium on Quantum Fluids and Solids QFS2006 (Kyoto, Japan)
J. Low Temp. Phys. 148(3/4), pp. 411-416 (2007)
10.1007/s10909-007-9406-x
null
math-ph math.MP
null
The theory of Bogoliubov is generalized for the case of a weakly-interacting Bose-gas in harmonic trap. A set of nonlinear matrix equations is obtained to make the diagonalization of Hamiltonian possible. Its perturbative solution is used for the calculation of the energy and the condensate fraction of the model system to show the applicability of the method.
[ { "version": "v1", "created": "Wed, 9 May 2007 12:46:29 GMT" } ]
2011-11-09T00:00:00
[ [ "Rovenchak", "Andrij", "" ] ]
0705.1276
Koenraad M. R. Audenaert
Koenraad M.R. Audenaert
Subadditivity of q-entropies for q>1
2 pages
J. Math. Phys. 48, 083507 (2007)
10.1063/1.2771542
null
math-ph math.MP quant-ph
null
I prove a basic inequality for Schatten q-norms of quantum states on a finite-dimensional bipartite Hilbert space H_1\otimes H_2: 1+||\rho||_q \ge ||\trace_1\rho||_q + ||\trace_2\rho||_q. This leads to a proof--in the finite dimensional case--of Raggio's conjecture (G.A. Raggio, J. Math. Phys.\ \textbf{36}, 4785--4791 (1995)) that the q-entropies S_q(\rho)=(1-\trace[\rho^q])/(q-1) are subadditive for q > 1; that is, for any state \rho, S_q(\rho) is not greater than the sum of the S_q of its reductions, S_q(\rho) \le S_q(\trace_1\rho)+S_q(\trace_2\rho).
[ { "version": "v1", "created": "Wed, 9 May 2007 12:46:30 GMT" } ]
2009-11-13T00:00:00
[ [ "Audenaert", "Koenraad M. R.", "" ] ]
0705.1277
Joseph Kapusta
Joseph I. Kapusta
Strongly Interacting Low Viscosity Matter Created in Heavy Ion Collisions
Plenary talk at Quark Matter 2006 in Shanghai
J.Phys.G34:S295-304,2007
10.1088/0954-3899/34/8/S15
null
nucl-th
null
Substantial collective flow is observed in collisions between large nuclei at high energy, as evidenced by single-particle transverse momentum distributions and by azimuthal correlations among the produced particles. The data are well-reproduced by perfect fluid dynamics. In a separate development, calculation of the dimensionless ratio of shear viscosity eta to entropy density s by Kovtun, Son and Starinets within AdS/CFT yields eta/s = 1/4pi, and they conjectured that this is a lower bound for any physical system. It is shown that the transition from hadrons to quarks and gluons has behavior similar to helium, nitrogen, and water at and near their phase transitions in the ratio eta/s. Therefore it is possible that experimental measurements can pinpoint the location of this transition or rapid crossover in QCD via the viscosity to entropy ratio in addition to and independently of the equation of state.
[ { "version": "v1", "created": "Wed, 9 May 2007 17:53:39 GMT" } ]
2008-11-26T00:00:00
[ [ "Kapusta", "Joseph I.", "" ] ]
0705.1278
Daniel Rosa Gonzalez Dr
Daniel Rosa-Gonzalez, Denis Burgarella, Kirpal Nandra, Daniel Kunth, Elena Terlevich and Roberto Terlevich
Multiwavelength Study of X-ray Selected Star Forming Galaxies within the Chandra Deep Field South
Accepted by MNRAS 2007 May 7
Mon.Not.Roy.Astron.Soc.379:357-369,2007
10.1111/j.1365-2966.2007.11961.x
null
astro-ph
null
We have combined multi-wavelength observations of a selected sample of starforming galaxies with galaxy evolution models in order to compare the results obtained for different SFR tracers and to study the effect that the evolution of the starforming regions has on them. We also aimed at obtaining a better understanding of the corrections due to extinction and nuclear activity on the derivation of the SFR. We selected the sample from Chandra data for the well studied region Chandra Deep Field South (CDFS) and chose the objects that also have UV and IR data from GALEX and GOODS-Spitzer respectively. Our main finding is that there is good agreement between the extinction corrected SFR(UV) and the SFR(X), and we confirm the use of X-ray luminosities as a trustful tracer of recent star formation activity. Nevertheless, at SFR(UV) larger than about 5Msol/year there are several galaxies with an excess of SFR(X) suggesting the presence of an obscured AGN not detected in the optical spectra. We conclude that the IR luminosity is driven by recent star formation even in those galaxies where the SFR(X) is an order of magnitude higher than the SFR(UV) and therefore may harbour an AGN. One object shows SFR(X) much lower than expected based on the SFR(UV); this SFR(X) `deficit' may be due to an early transient phase before most of the massive X-ray binaries were formed. An X-ray deficit could be used to select extremely young bursts in an early phase just after the explosion of the first supernovae associated with massive stars and before the onset of massive X-ray binaries.
[ { "version": "v1", "created": "Wed, 9 May 2007 12:59:57 GMT" } ]
2009-06-23T00:00:00
[ [ "Rosa-Gonzalez", "Daniel", "" ], [ "Burgarella", "Denis", "" ], [ "Nandra", "Kirpal", "" ], [ "Kunth", "Daniel", "" ], [ "Terlevich", "Elena", "" ], [ "Terlevich", "Roberto", "" ] ]
0705.1279
Bernhard Kroetz
Bernhard Kroetz
A novel characterization of the Iwasawa decomposition of a simple Lie group
To appear in an appendix of a physics lecture notes volume
Springer Lecture Notes in Physics 723, 195--201 (2007).
null
null
math.RT
null
It is about the uniqueness of the Iwasawa decomposition.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:07:32 GMT" } ]
2008-07-16T00:00:00
[ [ "Kroetz", "Bernhard", "" ] ]
0705.1280
Damien Chablat
F\'elix Majou (IRCCyN), Philippe Wenger (IRCCyN), Damien Chablat (IRCCyN)
A Novel method for the design of 2-DOF Parallel mechanisms for machining applications
null
8th International Symposium on Advances in Robot Kinematics (2002) 1-11
null
null
cs.RO
null
Parallel Kinematic Mechanisms (PKM) are interesting alternative designs for machine tools. A design method based on velocity amplification factors analysis is presented in this paper. The comparative study of two simple two-degree-of-freedom PKM dedicated to machining applications is led through this method: the common desired properties are the largest square Cartesian workspace for given kinetostatic performances. The orientation and position of the Cartesian workspace are chosen to avoid singularities and to produce the best ratio between Cartesian workspace size and mechanism size. The machine size of each resulting design is used as a comparative criterion.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:18:59 GMT" } ]
2007-05-23T00:00:00
[ [ "Majou", "Félix", "", "IRCCyN" ], [ "Wenger", "Philippe", "", "IRCCyN" ], [ "Chablat", "Damien", "", "IRCCyN" ] ]
0705.1281
Denys Dutykh
Denys Dutykh (1), Frederic Dias (1) ((1) ENS Cachan, CMLA)
Viscous potential free-surface flows in a fluid layer of finite depth
6 pages, published at CRAS. Other author's papers can be downloaded at http://www.cmla.ens-cachan.fr/~dutykh
Comptes Rendus Mathematique (2007), Vol. 345, Issue 2, pp. 113-118
10.1016/j.crma.2007.06.007
null
physics.ao-ph math-ph math.MP nlin.SI physics.class-ph physics.flu-dyn physics.gen-ph
null
It is shown how to model weakly dissipative free-surface flows using the classical potential flow approach. The Helmholtz-Leray decomposition is applied to the linearized 3D Navier-Stokes equations. The governing equations are treated using Fourier--Laplace transforms. We show how to express the vortical component of the velocity only in terms of the potential and free-surface elevation. A new predominant nonlocal viscous term is derived in the bottom kinematic boundary condition. The resulting formulation is simple and does not involve any correction procedure as in previous viscous potential flow theories [Joseph2004]. Corresponding long wave model equations are derived.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:22:31 GMT" }, { "version": "v2", "created": "Sun, 10 Jun 2007 08:36:01 GMT" }, { "version": "v3", "created": "Thu, 2 Aug 2007 07:26:47 GMT" } ]
2020-02-20T00:00:00
[ [ "Dutykh", "Denys", "", "ENS Cachan, CMLA" ], [ "Dias", "Frederic", "", "ENS Cachan, CMLA" ] ]
0705.1282
Damien Chablat
Philippe Wenger (IRCCyN), Damien Chablat (IRCCyN)
Design of a Three-Axis Isotropic Parallel Manipulator for Machining Applications: The Orthoglide
null
Workshop on Fundamental Issues and Future Research Directions for Parallel Mechanisms and Manipulators (2002) 1-9
null
null
cs.RO
null
The orthoglide is a 3-DOF parallel mechanism designed at IRCCyN for machining applications. It features three fixed parallel linear joints which are mounted orthogonally and a mobile platform which moves in the Cartesian x-y-z space with fixed orientation. The orthoglide has been designed as function of a prescribed Cartesian workspace with prescribed kinetostatic performances. The interesting features of the orthoglide are a regular Cartesian workspace shape, uniform performances in all directions and good compactness. A small-scale prototype of the orthoglide under development is presented at the end of this paper.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:23:37 GMT" } ]
2007-05-23T00:00:00
[ [ "Wenger", "Philippe", "", "IRCCyN" ], [ "Chablat", "Damien", "", "IRCCyN" ] ]
0705.1283
Valerio Biancalana
J. Belfi, G. Bevilacqua, V.Biancalana, S. Cartaleva, Y. Dancheva, L. Moi
Cs CPT magnetometer for cardio-signal detection in unshielded environment
6 pages, 5 figures, submitted to JOSA B on 30 March 2007. A problem may exist with fig.2, please download separately as eps
JOSA B 24 (9) (2007), pages 2357-2362
10.1364/JOSAB.24.002357
null
physics.atom-ph physics.ins-det
null
We present first, encouraging results obtained with an experimental apparatus based on Coherent Population Trapping and aimed at detecting biological (cardiac) magnetic field in magnetically compensated, but unshielded volume. The work includes magnetic-field and magnetic-field-gradient compensation and uses differential detection for cancellation of (common mode) magnetic noise. Synchronous data acquisition with a reference (electro-cardiographic or pulse-oximetric) signal allows for improving the S/N in an off-line averaging. The set-up has the relevant advantages of working at room temperature with a small-size head, and of allowing for fast adjustments of the dc bias magnetic field, which results in making the sensor suitable for detecting the bio-magnetic signal at any orientation with respect to the heart axis and in any position around the patient chest, which is not the case with other kinds of magnetometers.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:24:20 GMT" }, { "version": "v2", "created": "Thu, 10 May 2007 16:34:08 GMT" }, { "version": "v3", "created": "Fri, 11 May 2007 12:40:57 GMT" } ]
2013-07-04T00:00:00
[ [ "Belfi", "J.", "" ], [ "Bevilacqua", "G.", "" ], [ "Biancalana", "V.", "" ], [ "Cartaleva", "S.", "" ], [ "Dancheva", "Y.", "" ], [ "Moi", "L.", "" ] ]
0705.1284
Damien Chablat
Damien Chablat (IRCCyN), Philippe Wenger (IRCCyN), Jean-Pierre Merlet (COPRIN)
Workspace Analysis of the Orthoglide using Interval Analysis
null
8th International Symposium on Advances in Robot Kinematics, Kluwer Academic Publishers (2002) 1-10
null
null
cs.RO
null
This paper addresses the workspace analysis of the orthoglide, a 3-DOF parallel mechanism designed for machining applications. This machine features three fixed parallel linear joints which are mounted orthogonally and a mobile platform which moves in the Cartesian x-y-z space with fixed orientation. The workspace analysis is conducted on the bases of prescribed kinetostatic performances. The interesting features of the orthoglide are a regular Cartesian workspace shape, uniform performances in all directions and good compactness. Interval analysis based methods for computing the dextrous workspace and the largest cube enclosed in this workspace are presented.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:24:39 GMT" } ]
2007-05-23T00:00:00
[ [ "Chablat", "Damien", "", "IRCCyN" ], [ "Wenger", "Philippe", "", "IRCCyN" ], [ "Merlet", "Jean-Pierre", "", "COPRIN" ] ]
0705.1285
Damien Chablat
Damien Chablat (IRCCyN), Fouad Bennis (IRCCyN), Bernard Hoessler, Matthieu Guibert
P\'eriph\'eriques haptiques et simulation d'objets, de robots et de mannequins dans un environnement de CAO-Robotique : eM-Virtual Desktop
null
Virtual Concept (2002) 51-56
null
null
cs.RO
null
This paper presents the development of a new software in order to manage objects, robots and mannequins in using the possibilities given by the haptic feedback of the Phantom desktop devices. The haptic device provides 6 positional degree of freedom sensing but three degrees force feedback. This software called eM-Virtual Desktop is integrated in the Tecnomatix's solution called eM-Workplace. The eM-Workplace provides powerful solutions for planning and designing of complex assembly facilities, lines and workplaces. In the digital mockup context, the haptic interfaces can be used to reduce the development cycle of products. Three different loops are used to manage the graphic, the collision detection and the haptic feedback according to theirs own frequencies. The developed software is currently tested in industrial context by a European automotive constructor.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:26:46 GMT" } ]
2007-05-23T00:00:00
[ [ "Chablat", "Damien", "", "IRCCyN" ], [ "Bennis", "Fouad", "", "IRCCyN" ], [ "Hoessler", "Bernard", "" ], [ "Guibert", "Matthieu", "" ] ]
0705.1286
Pramod Sharma Dr.
Pramod K. Sharma
On Power Stable Ideals
10 pages
null
null
null
math.AC
null
We define the notion of a power stable ideal in a polynomial ring $ R[X]$ over an integral domain $ R $. It is proved that a maximal ideal $\chi$ $ M $ in $ R[X]$ is power stable if and only if $ P^t $ is $ P$- primary for all $ t\geq 1 $ for the prime ideal $ P = M \cap R $. Using this we prove that for a Hilbert domain $R$ any radical ideal in $R[X]$ which is a finite intersection G-ideals is power stable. Further, we prove that if $ R $ is a Noetherian integral domain of dimension 1 then any radical ideal in $ R[X] $ is power stable. Finally, it is proved that if every ideal in $ R[X]$ is power stable then $ R $ is a field.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:31:24 GMT" } ]
2019-03-22T00:00:00
[ [ "Sharma", "Pramod K.", "" ] ]
0705.1287
Eric Fusy
Eric Fusy (INRIA Rocquencourt)
Uniform random sampling of planar graphs in linear time
55 pages
null
null
null
math.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This article introduces new algorithms for the uniform random generation of labelled planar graphs. Its principles rely on Boltzmann samplers, as recently developed by Duchon, Flajolet, Louchard, and Schaeffer. It combines the Boltzmann framework, a suitable use of rejection, a new combinatorial bijection found by Fusy, Poulalhon and Schaeffer, as well as a precise analytic description of the generating functions counting planar graphs, which was recently obtained by Gim\'enez and Noy. This gives rise to an extremely efficient algorithm for the random generation of planar graphs. There is a preprocessing step of some fixed small cost. Then, the expected time complexity of generation is quadratic for exact-size uniform sampling and linear for approximate-size sampling. This greatly improves on the best previously known time complexity for exact-size uniform sampling of planar graphs with $n$ vertices, which was a little over $O(n^7)$.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:32:44 GMT" }, { "version": "v2", "created": "Thu, 11 Sep 2008 19:01:03 GMT" }, { "version": "v3", "created": "Thu, 18 Dec 2008 08:05:25 GMT" } ]
2008-12-18T00:00:00
[ [ "Fusy", "Eric", "", "INRIA Rocquencourt" ] ]
0705.1288
Tshilidzi Marwala
E. Marais, T. Marwala
Predicting the Presence of Internet Worms using Novelty Detection
12 pages
null
null
null
cs.CR
null
Internet worms cause billions of dollars in damage yearly, affecting millions of users worldwide. For countermeasures to be deployed timeously, it is necessary to use an automated system to detect the spread of a worm. This paper discusses a method of determining the presence of a worm, based on routing information currently available from Internet routers. An autoencoder, which is a specialized type of neural network, was used to detect anomalies in normal routing behavior. The autoencoder was trained using information from a single router, and was able to detect both global instability caused by worms as well as localized routing instability.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:33:30 GMT" } ]
2007-05-23T00:00:00
[ [ "Marais", "E.", "" ], [ "Marwala", "T.", "" ] ]
0705.1289
Boris Zilbergleyt
B. Zilbergleyt
Discrete Thermodynamics of Lasers
6 pages, 3 figures
null
null
null
physics.optics
null
The paper offers a discrete thermodynamic model of lasers. Laser is an open system; its equilibrium is based on a balance of two thermodynamic forces, one related to the incoming pumping power and another to the emitted light. The basic expression for such equilibrium is a logistic map, graphical solutions to which are pitchfork bifurcation diagrams. As pumping force increases, the relative populations on the ground and lasing branches tend to zero and unity correspondingly. An interesting feature of this model is the line spectrum of the up and down transitions between the branches beyond bifurcation point. Even in a simple case of 2-level laser with only 2 possible transition types (up and down), the spectra look like sets of the line packets, starting well before the population inversion. This effect is an independent confirmation of the Einstein's prohibition on practical realization of 2-level laser. Multilevel lasers may be approached by employing the idea of thermodynamic activity for the emitting atoms. Considering coefficient of thermodynamic activity of the lasing level atoms to be proportional to the ratio of life times on the upper and lasing (the 3d) levels, one can derive a new basic map for the multilevel laser system. For a modest ratio only of 0.01, spontaneous transitions between levels are pushed to the area beyond population inversion, opening a space for the functioning of laser.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:38:49 GMT" } ]
2007-05-23T00:00:00
[ [ "Zilbergleyt", "B.", "" ] ]
0705.1290
Louis J. Clavelli
L. Clavelli
Landscape Implications of Extended Higgs Models
15 pages, 2 figures, extended analysis, some significant changes version 3 to appear in Int. J. Mod. Phys. A
Int.J.Mod.Phys.A23:3509-3523,2008
10.1142/S0217751X08041736
null
hep-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
From several points of view it is strongly suggested that the current universe is unstable and will ultimately decay to one that is exactly supersymmetric (susy). The possibility that atoms and molecules form in this future universe requires that the degenerate electron/selectron mass is non-zero and hence that electroweak symmetry breaking (EWSB) survives the phase transition to exact susy. However, the minimal supersymmetric standard model (MSSM) and several of its extensions have no EWSB in the susy limit. Among the extended higgs models that have been discussed one stands out in this regard. The higgs sector that is revealed at the Large Hadron Collider (LHC) will therefore have implications for the future universe. We also address the question as to whether the transition to the exact susy phase with EWSB is exothermic.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:41:22 GMT" }, { "version": "v2", "created": "Mon, 15 Oct 2007 15:18:24 GMT" }, { "version": "v3", "created": "Tue, 16 Sep 2008 21:20:33 GMT" } ]
2008-11-26T00:00:00
[ [ "Clavelli", "L.", "" ] ]
0705.1291
Alexei Larionov
V.Baran, M. Colonna, M. Di Toro, A.B. Larionov
Spinodal decomposition of low-density asymmetric nuclear matter
10 pages, 10 figures
Nucl.Phys.A632:287-303,1998
10.1016/S0375-9474(98)00006-2
null
nucl-th
null
We investigate the dynamical properties of asymmetric nuclear matter at low density. The occurrence of new instabilities, that lead the system to a dynamical fragment formation, is illustrated, discussing in particular the charge symmetry dependence of the structure of the most important unstable modes. We observe that instabilities are reduced by charge asymmetry, leading to larger size and time scales in the fragmentation process. Configurations with less asymmetric fragments surrounded by a more asymmetric gas are favoured. Interesting variances with respect to a pure thermodynamical prediction are revealed, that can be checked experimentally. All these features are deeply related to the structure of the symmetry term in the nuclear Equation of State (EOS) and could be used to extract information on the low density part of the EOS.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:46:08 GMT" } ]
2008-11-26T00:00:00
[ [ "Baran", "V.", "" ], [ "Colonna", "M.", "" ], [ "Di Toro", "M.", "" ], [ "Larionov", "A. B.", "" ] ]
0705.1292
Andreas P. Nawroth
A. P. Nawroth, J. Peinke, D. Kleinhans, R. Friedrich
Improved estimation of Fokker-Planck equations through optimisation
null
null
10.1103/PhysRevE.76.056102
null
physics.data-an
null
An improved method for the description of hierarchical complex systems by means of a Fokker-Planck equation is presented. In particular the limited-memory Broyden-Fletcher-Goldfarb-Shanno algorithm for constraint problems (L-BFGS-B) is used to minimize the distance between the numerical solutions of the Fokker-Planck equation and the empirical probability density functions and thus to estimate properly the drift and diffusion term of the Fokker-Planck equation. The optimisation routine is applied to a time series of velocity measurements obtained from a turbulent helium gas jet in order to demonstrate the benefits and to quantify the improvements of this new optimisation routine.
[ { "version": "v1", "created": "Wed, 9 May 2007 16:38:50 GMT" } ]
2013-05-29T00:00:00
[ [ "Nawroth", "A. P.", "" ], [ "Peinke", "J.", "" ], [ "Kleinhans", "D.", "" ], [ "Friedrich", "R.", "" ] ]
0705.1293
Pramod Sharma Dr.
Pramod K. Sharma
Some result on K-algebras
8 pages
null
null
null
math.AC
null
We give a new proof of the classical result due to Rodney Y. Sharp and Peter Vamos on the dimension of tensor product of a finite number of field extensions of a given field.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:47:36 GMT" } ]
2007-05-23T00:00:00
[ [ "Sharma", "Pramod K.", "" ] ]
0705.1294
Pierpaolo Vivo
Pierpaolo Vivo, Mario Casartelli, Luca Dall'Asta, Alessandro Vezzani
On a class of rational matrices and interpolating polynomials related to the discrete Laplace operator
18 pag, submitted to "Note di Matematica"
null
null
null
math-ph math.MP
null
Let $\dlap$ be the discrete Laplace operator acting on functions (or rational matrices) $f:\mathbf{Q}_L\to\mathbb{Q}$, where $\mathbf{Q}_L$ is the two dimensional lattice of size $L$ embedded in $\mathbb{Z}_2$. Consider a rational $L\times L$ matrix $\mathcal{H}$, whose inner entries $\mathcal{H}_{ij}$ satisfy $\dlap\mathcal{H}_{ij}=0$. The matrix $\mathcal{H}$ is thus the classical finite difference five-points approximation of the Laplace operator in two variables. We give a constructive proof that $\mathcal{H}$ is the restriction to $\mathbf{Q}_L$ of a discrete harmonic polynomial in two variables for any $L>2$. This result proves a conjecture formulated in the context of deterministic fixed-energy sandpile models in statistical mechanics.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:47:42 GMT" } ]
2007-05-23T00:00:00
[ [ "Vivo", "Pierpaolo", "" ], [ "Casartelli", "Mario", "" ], [ "Dall'Asta", "Luca", "" ], [ "Vezzani", "Alessandro", "" ] ]
0705.1295
Michael Mundt
Michael Mundt, Stephan K\"ummel, Robert van Leeuwen, and Paul-Gerhard Reinhard
Violation of the `Zero-Force Theorem' in the time-dependent Krieger-Li-Iafrate approximation
5 pages, 4 figures
Physical Review A, Vol. 75, 050501(R) (2007)
10.1103/PhysRevA.75.050501
null
cond-mat.mtrl-sci
null
We demonstrate that the time-dependent Krieger-Li-Iafrate approximation in combination with the exchange-only functional violates the `Zero-Force Theorem'. By analyzing the time-dependent dipole moment of Na5 and Na9+, we furthermore show that this can lead to an unphysical self-excitation of the system depending on the system properties and the excitation strength. Analytical aspects, especially the connection between the `Zero-Force Theorem' and the `Generalized-Translation Invariance' of the potential, are discussed.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:48:12 GMT" } ]
2007-05-23T00:00:00
[ [ "Mundt", "Michael", "" ], [ "Kümmel", "Stephan", "" ], [ "van Leeuwen", "Robert", "" ], [ "Reinhard", "Paul-Gerhard", "" ] ]
0705.1296
Zhen-Bin Cao
Yi-Shi Duan, Zhen-Bin Cao
Several new actions of $p$-branes based on bulk scalar fields
12 pages, no figures
null
null
null
hep-th
null
Generally, $p$-branes play central roles in revealing the nonperturbative structures of the string/M-theory. In this paper, through a topological tensor current constructed in terms of a bulk scalar field, we first show some topological properties of $p$-branes, and then mainly discuss the construction of several new actions of $p$-branes. We show that the actions we construct which can be reduced to the Nambu-Goto action or some other simple actions, are all defined naturally in the bulk spacetime, preserving the full spacetime Lorentz invariance and satisfying a self-dual condition.
[ { "version": "v1", "created": "Wed, 9 May 2007 13:48:42 GMT" } ]
2007-05-23T00:00:00
[ [ "Duan", "Yi-Shi", "" ], [ "Cao", "Zhen-Bin", "" ] ]
0705.1297
Virginia Young
Virginia R. Young
Pricing Life Insurance under Stochastic Mortality via the Instantaneous Sharpe Ratio: Theorems and Proofs
null
null
null
null
q-fin.PR math.AP math.OC
null
We develop a pricing rule for life insurance under stochastic mortality in an incomplete market by assuming that the insurance company requires compensation for its risk in the form of a pre-specified instantaneous Sharpe ratio. Our valuation formula satisfies a number of desirable properties, many of which it shares with the standard deviation premium principle. The major result of the paper is that the price per contract solves a linear partial differential equation as the number of contracts approaches infinity. One can interpret the limiting price as an expectation with respect to an equivalent martingale measure. Another important result is that if the hazard rate is stochastic, then the risk-adjusted premium is greater than the net premium, even as the number of contracts approaches infinity. We present a numerical example to illustrate our results, along with the corresponding algorithms.
[ { "version": "v1", "created": "Wed, 9 May 2007 14:11:17 GMT" } ]
2008-12-02T00:00:00
[ [ "Young", "Virginia R.", "" ] ]