cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Conclusions from CDF Results on CP Violation in D^0 \to π^+π^-, K^+K^- and Future Tasks
Creators: name: Bigi, Ikaros I.
name: Paul, Ayan
name: Recksiegel, Stefan
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Within the Standard Model (SM) one predicts both direct and indirect CP violation in D^0 \to π^+π^-, K^+K^- transitions, although the effects are tiny: Indirect CP asymmetry cannot exceed O(10^{-4}), probably even O(10^{-5}); direct effects are estimated at not larger than 10^{-4}. At B factories direct and indirect asymmetries have been studied with /τ_{D^0} ~ 1; no CP asymmetry was found with an upper bound of about 1%. CDF has shown intriguing data on CP violation in D^0 \to π^+π^- [K^+K^-] with /τ_{D^0} ~ 2.4 [2.65]. Also, CDF has not seen any CP violation. For direct CP asymmetry, CDF has a sensitivity similar to the combination of the B factories, yet for indirect CP violation it yields a significantly smaller sensitivity of a_{cp}^{ind}=(-0.01 +- 0.06_{stat} +- 0.05_{syst})% due to it being based on longer decay times. New Physics models (NP) like Little Higgs Models with T-Parity (LHT) can produce an indirect CP asymmetry up to 1%; CDF's findings thus cover the upper range of realistic NP predictions ~ 0.1 - 1%. One hopes that LHCb and a Super-Flavour Factory will probe the lower range down to ~0.01%. Such non-ad-hoc NP like LHT cannot enhance direct CP violation significantly over the SM level in D^0 \to π^+π^-, K^+K^- and D^{\pm} \to π^{\pm}K^+K^- transitions, but others might well do so.
description: 11 pages, 1 figure. V2 has minor corrections and corresponds to the published version
Un cas simple de correspondance de Jacquet-Langlands modulo l
Creators: name: Dat, Jean-Francois
name: Vigneras, with an appendix by Marie-France
Publisher: name: arXiv
Year: 2010
Subjects: subject: Representation Theory (math.RT)
subject: Number Theory (math.NT)
subject: FOS: Mathematics

description: Let G be a general linear group over a p-adic field and let D^* be an anisotropic inner form of G. The Jacquet-Langlands correspondence between irreducible complex representations of D^* and discrete series of G does not behave well with respect to reduction modulo l\neq p. However we show that the Langlands-Jacquet transfer, from the Grothendieck group of admissible l-adic representations of G to that of D^* is compatible with congruences and reduces modulo l to a similar transfer for l-modular representations, which moreover can be characterized by some Brauer characters identities. Studying more carefully this transfer, we deduce a bijection between irreducible l-modular representations of D^* and "super-Speh" l-modular representations of G. Via reduction mod l, this latter bijection is compatible with the classical Jacquet-Langlands correspondence composed with the Zelevinsky involution. Our arguments rely on Vigneras' classification of representations of G. Finally we discuss the question whether our Langlands-Jacquet transfer sends irreducibles to effective virtual representations up to a sign. This presumably boils down to some unknown properties of parabolic affine Kazhdan-Lusztig polynomials.
description: Fixed an incorrect argument in the proof of Proposition 2.3.2
Using Superconducting Qubit Circuits to Engineer Exotic Lattice Systems
Creators: name: Tsomokos, Dimitris I.
name: Ashhab, Sahel
name: Nori, Franco
Publisher: name: arXiv
Year: 2010
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We propose an architecture based on superconducting qubits and resonators for the implementation of a variety of exotic lattice systems, such as spin and Hubbard models in higher or fractal dimensions and higher-genus topologies. Spin systems are realized naturally using qubits, while superconducting resonators can be used for the realization of Bose-Hubbard models. Fundamental requirements for these designs, such as controllable interactions between arbitrary qubit pairs, have recently been implemented in the laboratory, rendering our proposals feasible with current technology.
description: 7 pages (two-column), 3 figures
Memorandum from Robertson D. Ward to Charles Dollard, March 15, 1940
Creators: name: Ward, Robertson Dwight 1905-
Publisher: name: Columbia University
Year: 2019
Subjects: Race relations
African Americans--Social conditions
Endowments

description: Carnegie Corporation Treasurer Robertson D. Ward writes to Charles Dollard to confirm his approval of the latest statement of expenditures from the Carnegie-Myrdal Study, and provides an itemized list of appropriations for the study thus far.
Higgs transitions of spin ice
Creators: name: Powell, Stephen
Publisher: name: arXiv
Year: 2011
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Frustrated magnets such as spin ice exhibit Coulomb phases, where correlations have power-law forms at long distances. Applied perturbations can cause ordering transitions which cannot be described by the usual Landau paradigm, and are instead naturally viewed as Higgs transitions of an emergent gauge theory. Starting from a classical statistical model of spin ice, it is shown that a variety of possible phases and transitions can be described by this approach. Certain cases are identified where continuous transitions are argued to be likely; the predicted critical behavior may be tested in experiments or numerical simulations.
description: 23 pages, 10 figures; v2: published version with minor changes; ancillary file "Figures3D.nb" is a Mathematica (v7) notebook containing figures as rotatable 3D graphics (see http://www.wolfram.com/cdf-player/ for a free viewer)
Use of activity theory as basis for a novel needs-finding technique for medical device development in low-resource environments
Creators: name: Rismani, Shalaleh
Publisher: name: University of British Columbia
Year: 2017

description: According to the World Health Organization, appropriate medical devices are not sufficiently available in low-resource environments within low and middle income countries. Lack of systematic structures, challenges with entering existing markets and incomplete understanding of design needs within these contexts are the key reasons for this problem. It is challenging to understand the needs for medical device development in low and middle income countries because the problem space has complex socioeconomic, political, technical and clinical constraints to navigate. Existing needs-finding techniques for engineering design do not provide an explicit means of identifying and synthesizing these complex factors. The main contribution of this thesis is development of a novel needs-finding technique for medical device development, specifically for low-resource environments. The proposed novel technique is empirically compared to the needs-finding technique of the well-established Stanford Biodesign Process. In a series of studies, the Activity Theory-based Needs-finding Technique (ATNF), based on Activity Theory, was integrated into the engineering design process. The cultural historical Activity Theory, rooted in Russian psychology, provides a framework for analyzing human activity and social structures. The ATNF proposes a modified activity system that explicitly situates technology within an activity. Mapping activities and identifying tension points within them allow for a fuller understanding of design needs. The ATNF method was initially investigated through its detailed application on a case study in the field of health technology development in low-resource environments. Thereafter, an ethnographic comparative study was completed to investigate the ATNF technique and the Biodesign technique by examining the differences between the needs statements and the process of developing them. The results indicate that the novel ATNF method is more effective in identifying an appropriate scope and desired change. However, the design artefacts from the ATNF and the Biodesign techniques equally cover socioeconomic, clinical and technical issues. This suggests that the strength of the ATNF technique is in creating connections between issues to develop an appropriate scope and in identifying desired change. The research supports that the ATNF technique is a viable needs-finding method and that it has particular strengths that could be leveraged for medical device development in low-resource environments.
Giant Tunneling Electroresistance Effect Driven by an Electrically Controlled Spin Valve at a Complex Oxide Interface
Creators: name: Burton, J. D.
name: Tsymbal, E. Y.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: A giant tunneling electroresistance effect may be achieved in a ferroelectric tunnel junction by exploiting the magnetoelectric effect at the interface between a ferroelectric barrier and magnetic La1-xSrxMnO3 electrode. Using first-principles density functional theory we demonstrate that a few magnetic monolayers of La1-xSrxMnO3 near the interface act, in response to ferroelectric polarization reversal, as an atomic scale spin-valve by filtering spin-dependent current. This effect produces more than an order of magnitude change in conductance, and thus constitutes a giant resistive switching effect.
description: 4 pages, 4 figures
Letter from Gunnar Myrdal to T. Arnold Hill, April 6, 1940
Creators: name: Myrdal, Gunnar, 1898-1987
Publisher: name: Columbia University
Year: 2019
Subjects: Race relations
African Americans--Social conditions
Endowments

description: Gunnar Myrdal writes to T. Arnold Hill to confirm details of Hill's work for the Carnegie-Myrdal Study following Hill's departure from the National Urban League.
Fluctuations as probe of the QCD phase transition and freeze-out in heavy ion collisions at LHC and RHIC
Creators: name: Friman, B.
name: Karsch, F.
name: Redlich, K.
name: Skokov, V.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We discuss the relevance of higher order moments of net baryon number fluctuations for the analysis of freeze-out and critical conditions in heavy ion collisions at LHC and RHIC. Using properties of O(4) scaling functions, we discuss the generic structure of these higher moments at vanishing baryon chemical potential and apply chiral model calculations to explore their properties at non-zero baryon chemical potential. We show that the ratios of the sixth to second and eighth to second order moments of the net baryon number fluctuations change rapidly in the transition region of the QCD phase diagram. Already at vanishing baryon chemical potential they deviate considerably from the predictions of the hadron resonance gas model which reproduce the second to fourth order moments of the net proton number fluctuations at RHIC. We point out that the sixth order moments of baryon number and electric charge fluctuations remain negative at the chiral transition temperature. Thus, they offer the possibility to probe the proximity of the thermal freeze-out to the crossover line.
description: 24 pages, 12 EPS files, revised version, to appear in EPJC
Letter from Rowena S. Hadsell to Frederick P. Keppel, March 12, 1940
Creators: name: Hadsell, Rowena Saeger
Publisher: name: Columbia University
Year: 2019
Subjects: Race relations
African Americans--Social conditions
Endowments

description: Letter attached to June 1, 1939-February 29, 1940 statement from the Carnegie-Myrdal Study.
An infinite-period phase transition versus nucleation in a stochastic model of collective oscillations
Creators: name: Assis, Vladimir R. V.
name: Copelli, Mauro
name: Dickman, Ronald
Publisher: name: arXiv
Year: 2011
Subjects: subject: Biological Physics (physics.bio-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Chaotic Dynamics (nlin.CD)
subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: A lattice model of three-state stochastic phase-coupled oscillators has been shown by Wood et al (2006 Phys. Rev. Lett. 96 145701) to exhibit a phase transition at a critical value of the coupling parameter, leading to stable global oscillations. We show that, in the complete graph version of the model, upon further increase in the coupling, the average frequency of collective oscillations decreases until an infinite-period (IP) phase transition occurs, at which point collective oscillations cease. Above this second critical point, a macroscopic fraction of the oscillators spend most of the time in one of the three states, yielding a prototypical nonequilibrium example (without an equilibrium counterpart) in which discrete rotational (C_3) symmetry is spontaneously broken, in the absence of any absorbing state. Simulation results and nucleation arguments strongly suggest that the IP phase transition does not occur on finite-dimensional lattices with short-range interactions.
description: 15 pages, 8 figures
Global Phase Diagram of the Kondo Lattice: From Heavy Fermion Metals to Kondo Insulators
Creators: name: Yamamoto, Seiji J.
name: Si, Qimiao
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We discuss the general theoretical arguments advanced earlier for the T=0 global phase diagram of antiferromagnetic Kondo lattice systems, distinguishing between the established and the conjectured. In addition to the well-known phase of a paramagnetic metal with a "large" Fermi surface (P_L), there is also an antiferromagnetic phase with a "small" Fermi surface (AF_S). We provide the details of the derivation of a quantum non-linear sigma-model (QNLsM) representation of the Kondo lattice Hamiltonian, which leads to an effective field theory containing both low-energy fermions in the vicinity of a Fermi surface and low-energy bosons near zero momentum. An asymptotically exact analysis of this effective field theory is made possible through the development of a renormalization group procedure for mixed fermion-boson systems. Considerations on how to connect the AF_S and P_L phases lead to a global phase diagram, which not only puts into perspective the theory of local quantum criticality for antiferromagnetic heavy fermion metals, but also provides the basis to understand the surprising recent experiments in chemically-doped as well as pressurized YbRh2Si2. We point out that the AF_S phase still occurs for the case of an equal number of spin-1/2 local moments and conduction electrons. This observation raises the prospect for a global phase diagram of heavy fermion systems in the Kondo-insulator regime. Finally, we discuss the connection between the Kondo breakdown physics discussed here for the Kondo lattice systems and the non-Fermi liquid behavior recently studied from a holographic perspective.
description: (v3) leftover typos corrected. (v2) Published version. 32 pages, 4 figures. Section 7, on the connection between the Kondo lattice systems and the holographic models of non-Fermi liquid, is expanded. (v1) special issue of JLTP on quantum criticality
Chiral and deconfinement transitions in strong coupling lattice QCD with finite coupling and Polyakov loop effects
Creators: name: Nakano, Takashi Z.
name: Miura, Kohtaroh
name: Ohnishi, Akira
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We investigate chiral and deconfinement transitions in the framework of the strong coupling lattice QCD for color SU(3) with one species of unrooted staggered fermion at finite temperature and quark chemical potential. We take account of the leading order Polyakov loop terms as well as the next-to-next-to-leading order (1/g^4) fermionic terms of the strong coupling expansion in the effective action. We investigate the Polyakov loop effects by comparing two approximation schemes, a Haar measure method (no fluctuation from the mean field) and a Weiss mean-field method (with fluctuations). The effective potential is obtained in both cases, and we analytically clarify the Polyakov loop contributions to the effective potential. The Polyakov loop is found to suppress the chiral condensate and to reduce the chiral transition temperature at mu=0, and the chiral transition temperature roughly reproduces the Monte Carlo results at beta=2N_c/g^2 \lesssim 4. The deconfinement transition is found to be the crossover and first order for light (am_0 \lesssim 4 at beta=4) and heavy quark masses, respectively.
description: 13 pages, 15 figures. v2; More dicussions added, figures improved, and typos corrected
Letter from Gunnar Myrdal to Eugene Kinckle Jones, April 5, 1940
Creators: name: Myrdal, Gunnar, 1898-1987
Publisher: name: Columbia University
Year: 2019
Subjects: Race relations
African Americans--Social conditions
Endowments

description: Gunnar Myrdal writes to National Urban League Executive Secretary Eugene Kinckle Jones to follow up on previous correspondence regarding T. Arnold Hill's work for the Carnegie-Myrdal Study in the wake of Hill's resignation from the League.
Markov Chain Monte Carlo analysis to constrain Dark Matter properties with directional detection
Creators: name: Billard, J.
name: Mayet, F.
name: Santos, D.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Directional detection is a promising dark matter search strategy. Indeed, weakly interacting massive particle (WIMP)-induced recoils would present a direction dependence toward the Cygnus constellation, while background-induced recoils exhibit an isotropic distribution in the Galactic rest frame. Taking advantage of these characteristic features and even in the presence of a sizeable background, it has recently been shown that data from forthcoming directional detectors could lead either to a competitive exclusion or to a conclusive discovery, depending on the value of the WIMP-nucleon cross section. However, it is possible to further exploit these upcoming data by using the strong dependence of the WIMP signal with : the WIMP mass and the local WIMP velocity distribution. Using a Markov chain Monte Carlo analysis of recoil events, we show for the first time the possibility to constrain the unknown WIMP parameters, both from particle physics (mass and cross section) and Galactic halo (velocity dispersion along the three axis), leading to an identification of non-baryonic dark matter.
description: 15 pages, 12 figures
A Robust Approach to Constraining Dark Matter from Gamma-Ray Data
Creators: name: Baxter, Eric J.
name: Dodelson, Scott
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Photons produced in the annihilations of dark matter particles can be detected by gamma-ray telescopes; this technique of indirect detection serves as a cornerstone of the upcoming assault on the dark matter paradigm. The main obstacle to the extraction of information about dark matter from the annihilation photons is the presence of large and uncertain gamma-ray backgrounds. We present a new technique for using gamma-ray data to constrain the properties of dark matter that makes minimal assumptions about the dark matter and the backgrounds. The technique relies on two properties of the expected signal from annihilations of the smooth dark matter component in our galaxy: 1) it is approximately rotationally symmetric around the axis connecting us to the Galactic Center, and 2) variations from the mean signal are uncorrelated from one pixel to the next. We apply this technique to recent data from the Fermi telescope to generate constraints on the dark matter mass and cross section for a variety of annihilation channels. We quantify the uncertainty introduced into our constraints by uncertainties in the halo profile and by the possibility that the halo is triaxial. The resultant constraint, the flux F \leq 4.5\times10^-6 cm^-2 s^-1 sr^-1 for energies between 1 and 100 GeV at an angle 15 degrees away from the Galactic Center, translates into an upper limit on the velocity weighted annihilation cross section of order 10^-25 cm^3 s^-1 depending on the annihilation mode.
description: 13 pages, 8 figures
Atomic interferometer measurements of Berry's and Aharonov-Anandan's phases for isolated spins S > 1/2 non-linearly coupled to external fields
Creators: name: Bouchiat, Marie-Anne
name: Bouchiat, Claude
Publisher: name: arXiv
Year: 2010
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The aim of the present paper is to propose experiments for observing the significant features of Berry's phases for S>1, generated by spin-Hamiltonians endowed with two couplings, a magnetic dipole and an electric quadrupole one with external B and E fields, as theoretically studied in our previous work. The fields are assumed orthogonal, this mild restriction leading to geometric and algebraic simplifications. Alkali atoms appear as good candidates for interferometric measurements but there are challenges to be overcome. The only practical way to generate a suitable E-field is to use the ac Stark effect which induces an instability of the dressed atom. Besides atom loss, this might invalidate Berry's phase derivation but this latter problem can be solved by an appropriate detuning. The former puts an upper limit to the cycle duration, which is bounded below by the adiabatic condition. By relying upon our previous analysis of the non-adiabatic corrections, we have been able to reach a compromise for the $^{87}$Rb hf level F=2, m=0 state, which is our candidate for an interferometric measurement of the exotic Berry's phase generated by a rotation of the E-field around the fixed B-field. By a numerical simulation we have shown that the non-adiabatic corrections can be kept below the 0.1% level. As an alternative candidate, we discuss the chromium ground state J=S=3, where the instability problem is easily solved. We make a proposal to extend the measurement of Aharonov-Anandan's phase beyond S=1/2 to the $^{87}$Rb hf level F=m=1, by constructing, with the help of light-shifts, a Hamiltonian able to perform a parallel transport along a closed circuit upon the density matrix space, without any adiabatic constraint. In Appendix A, Berry's phase difference for S=3/2 and 1/2, m=1/2 states is used to perform an entanglement of 3 Qbits.
description: 23 pages, 6 figures, modifications in the introduction, two paragraphs added
Simulating Urban Land Expansion in the Context of Land Use Planning in the Abuja City-Region, Nigeria
Creators: name: Enoguanbhor, Evidence Chinedu
name: Gollnow, Florian
name: Walker, Blake Byron
name: Nielsen, Jonas Ostergaard
name: Lakes, Tobia
Publisher: name: Humboldt-Universität zu Berlin
Year: 2020
Subjects: subject: Environmental sustainability
subject: Scenarios
subject: Urban expansion
subject: Urban planning
subject: Regional planning
subject: Sub-Saharan Africa
subject: 550 Geowissenschaften

description: In the Global South, including the Sub-Saharan African city-regions, the possible future urban expansion patterns may pose a challenge towards improving environmental sustainability. Land use planning strategies and instruments for regulating urban expansion are faced with challenges, including insufficient data availability to offer insights into the possible future urban expansion. This study integrated empirical data derived from Geographic Information Systems, Remote Sensing, and surveys of experts to offer insights into the possible future urban expansion under spatial planning scenarios to support land use planning and environmental sustainability of city-regions. We analyzed the spatial determinants of urban expansion, calibrated the land cover model using the Multi-Layer Perceptron Neural Network and Markov, and developed three scenarios to simulate land cover from 2017 to 2030 and to 2050. The scenarios include Business As Usual that extrapolates past trends; Regional Land Use Plan that restricts urban expansion to the land designated for urban development, and; Adjusted Urban Land that incorporates the leapfrogged settlements into the land designated for urban development. Additionally, we quantified the potential degradation of environmentally sensitive areas by future urban expansion under the three scenarios. Results indicated a high, little, and no potential degradation of environmentally sensitive areas by the future urban expansion under the Business As Usual, Adjusted Urban Land, and Regional Land Use Plan scenarios respectively. The methods and the baseline information provided, especially from the Adjusted Urban Land scenario showed the possibility of balancing the need for urban expansion and the protection of environmentally sensitive areas. This would be useful to improve the environmental sustainability of the Sub-Saharan African city-regions and across the Global South, where insufficient data availability challenges land use planning.
The Gluonic Field of a Heavy Quark in Conformal Field Theories at Strong Coupling
Creators: name: Chernicoff, Mariano
name: Guijosa, Alberto
name: Pedraza, Juan F.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We determine the gluonic field configuration sourced by a heavy quark undergoing arbitrary motion in N=4 super-Yang-Mills at strong coupling and large number of colors. More specifically, we compute the expectation value of the operator tr[F^2+...] in the presence of such a quark, by means of the AdS/CFT correspondence. Our results for this observable show that signals propagate without temporal broadening, just as was found for the expectation value of the energy density in recent work by Hatta et al. We attempt to shed some additional light on the origin of this feature, and propose a different interpretation for its physical significance. As an application of our general results, we examine when the quark undergoes oscillatory motion, uniform circular motion, and uniform acceleration. Via the AdS/CFT correspondence, all of our results are pertinent to any conformal field theory in 3+1 dimensions with a dual gravity formulation.
description: 1+38 pages, 16 eps figures; v2: completed affiliation; v3: corrected typo, version to appear in JHEP
title: Анализ корреляции уровня когнитивных функций студентов 2 курса с успеваемостью по дисциплине «Нормальная физиология»
Creators: name: Лейфер, Олеся
name: Иванов, Егор
name: Каленова, Ольга
name: Роговцов, Роман
Publisher: name: Новгородский государственный университет имени Ярослава Мудрого (НовГУ)
Year: 2021

description: Когнитивные функции являются основой познания и взаимодействия с окружающим миром человека. В данной статье будет рассматриваться корреляция успеваемости студентов 2 курса Института медицинского образования по дисциплине «Нормальная физиология» от уровня их когнитивных способностей. Данное исследование
проводилось с помощью социологического мониторинга. Проблема сохранения и восстановления когнитивных функций является междисциплинарной, а также одной из глобальных в современной медицине, поэтому она имеет особое значение и считается весьма актуальной в настоящее время.
Simulation of anyons with tensor network algorithms
Creators: name: Pfeifer, Robert N. C.
name: Corboz, Philippe
name: Buerschaper, Oliver
name: Aguado, Miguel
name: Troyer, Matthias
name: Vidal, Guifre
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Interacting systems of anyons pose a unique challenge to condensed matter simulations due to their non-trivial exchange statistics. These systems are of great interest as they have the potential for robust universal quantum computation, but numerical tools for studying them are as yet limited. We show how existing tensor network algorithms may be adapted for use with systems of anyons, and demonstrate this process for the 1-D Multi-scale Entanglement Renormalisation Ansatz (MERA). We apply the MERA to infinite chains of interacting Fibonacci anyons, computing their scaling dimensions and local scaling operators. The scaling dimensions obtained are seen to be in agreement with conformal field theory. The techniques developed are applicable to any tensor network algorithm, and the ability to adapt these ansaetze for use on anyonic systems opens the door for numerical simulation of large systems of free and interacting anyons in one and two dimensions.
description: Fixed typos, matches published version. 16 pages, 21 figures, 4 tables, RevTeX 4-1. For a related work, see arXiv:1006.2478
Magnetic spectrum of the two-dimensional antiferromagnet La2CoO4 studied by inelastic neutron scattering
Creators: name: Babkevich, P.
name: Prabhakaran, D.
name: Frost, C. D.
name: Boothroyd, A. T.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We report measurements of the magnetic excitation spectrum of the layered antiferromagnet La2CoO4 by time-of-flight neutron inelastic scattering. In the energy range probed in our experiments (0-250 meV) the magnetic spectrum consists of spin-wave modes with strong in-plane dispersion extending up to 60 meV, and a nearly dispersionless peak at 190 meV. The spin-wave modes exhibit a small (~1 meV) dispersion along the magnetic zone boundary. We show that the magnetic spectrum can be described very well by a model of a Heisenberg antiferromagnet that includes the full spin and orbital degrees of freedom of Co2+ in an axially-distorted crystal field. The collective magnetic dynamics are found to be controlled by dominant nearest-neighbour exchange interactions, strong XY-like single-ion anisotropy and a substantial unquenched orbital angular momentum.
description: 8 pages, 7 figures
Zero and low temperature behavior of the two-dimensional $\pm J$ Ising spin glass
Creators: name: Thomas, Creighton K.
name: Huse, David A.
name: Middleton, A. Alan
Publisher: name: arXiv
Year: 2011
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: Scaling arguments and precise simulations are used to study the square lattice $\pm J$ Ising spin glass, a prototypical model for glassy systems. Droplet theory predicts, and our numerical results show, entropically-stabilized long range spin glass order at zero temperature. The low temperature scaling behavior has an important new crossover length scale that produces a power-law dependence of the heat capacity on temperature.
description: 4 pages, 3 figures; v2 for clarifications in presentation (same results)
Disruption of Star Clusters in the Interacting Antennae Galaxies
Creators: name: Karl, Simon J.
name: Fall, S. Michael
name: Naab, Thorsten
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We reexamine the age distribution of star clusters in the Antennae in the context of N-body+hydrodynamical simulations of these interacting galaxies. All of the simulations that account for the observed morphology and other properties of the Antennae have star formation rates that vary relatively slowly with time, by factors of only 1.3 - 2.5 in the past 10^8 yr. In contrast, the observed age distribution of the clusters declines approximately as a power law, dN/dt \propto t^{gamma} with gamma = -1.0, for ages 10^6 yr \la t \la 10^9 yr. These two facts can only be reconciled if the clusters are disrupted progressively for at least 10^8 yr and possibly 10^9 yr. When we combine the simulated formation rates with a power-law model, f_surv \propto t^{delta}, for the fraction of clusters that survive to each age t, we match the observed age distribution with exponents in the range -0.9 \la delta \la -0.6 (with a slightly different delta for each simulation). The similarity between delta and gamma indicates that dN/dt is shaped mainly by the disruption of clusters rather than variations in their formation rate. Thus, the situation in the interacting Antennae resembles that in relatively quiescent galaxies such as the Milky Way and the Magellanic Clouds.
description: 9 pages, 5 figures, 1 table, accepted for publication in the Astrophysical Journal, including revisions after referee report
A high sensitivity ultra-low temperature RF conductance and noise measurement setup
Creators: name: Parmentier, François D.
name: Mahé, Adrien
name: Denis, Anne
name: Berroir, Jean-Marc
name: Glattli, D. Christian
name: Plaçais, Bernard
name: Fève, Gwendal
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: We report on the realization of a high sensitivity RF noise measurement scheme to study small current fluctuations of mesoscopic systems at milliKelvin temperatures. The setup relies on the combination of an interferometric ampli- fication scheme and a quarter-wave impedance transformer, allowing the mea- surement of noise power spectral densities with GHz bandwith up to five orders of magnitude below the amplifier noise floor. We simultaneously measure the high frequency conductance of the sample by derivating a portion of the signal to a microwave homodyne detection. We describe the principle of the setup, as well as its implementation and calibration. Finally, we show that our setup allows to fully characterize a subnanosecond on-demand single electron source. More generally, its sensitivity and bandwith make it suitable for applications manipulating single charges at GHz frequencies.
description: The following article has been submitted to Review of Scientific Instruments
Analytic treatment of the network synchronization problem with time delays
Creators: name: Hod, Shahar
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cellular Automata and Lattice Gases (nlin.CG)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Physics and Society (physics.soc-ph)
subject: FOS: Physical sciences

description: Motivated by novel results in the theory of network synchronization, we analyze the effects of nonzero time delays in stochastic synchronization problems with linear couplings in an arbitrary network. We determine {\it analytically} the fundamental limit of synchronization efficiency in a noisy environment with uniform time delays. We show that the optimal efficiency of the network is achieved for $λτ={π^{3/2}\over{2\sqrtπ+4}}\approx0.738$, where $λ$ is the coupling strength (relaxation coefficient) and $τ$ is the characteristic time delay in the communication between pairs of nodes. Our analysis reveals the underlying mechanism responsible for the trade-off phenomena observed in recent numerical simulations of network synchronization problems.
description: 4 pages, 1 figure
Directed flow at mid-rapidity in event-by-event hydrodynamics
Creators: name: Gardim, Fernando G.
name: Grassi, Frederique
name: Hama, Yogiro
name: Luzum, Matthew
name: Ollitrault, Jean-Yves
Publisher: name: arXiv
Year: 2011
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Fluctuations in the initial geometry of a nucleus-nucleus collision have been recently shown to result in a new type of directed flow (v_1) that, unlike the usual directed flow, is also present at midrapidity. We compute this new v_1 versus transverse momentum and centrality for Au-Au collisions at RHIC using the hydrodynamic code NeXSPheRIO. We find that the event plane of v_1 is correlated with the angle of the initial dipole of the distribution, as predicted, though with a large dispersion. It is uncorrelated with the reaction plane. Our results are in excellent agreement with results inferred from STAR correlation data.
description: 7 pages, 6 figures; Figure data files included with source; Version accepted for publication (minor changes)
Impurity-doped Kagome Antiferromagnet: A Quantum Dimer Model Approach
Creators: name: Poilblanc, D.
name: Ralko, A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The doping of quantum Heisenberg antiferromagnets on the kagome lattice by non-magnetic impurities is investigated within the framework of a generalized quantum dimer model (QDM) describing a) the valence bond crystal (VBC), b) the dimer liquid and c) the critical region on equal footing. Following the approach by Ralko et al. [Phys. Rev. Lett. 101, 117204 (2008)] for the square and triangular lattices, we introduce the (minimal) extension of the QDM on the Kagome lattice to account for spontaneous creation of mobile S=1/2 spinons at finite magnetic field. Modulations of the dimer density (at zero or finite magnetic field) and of the local field-induced magnetization in the vicinity of impurities are computed using Lanczos Exact Diagonalization techniques on small clusters (48 and 75 sites). The VBC is clearly revealed from its pinning by impurities, while, in the dimer liquid, crystallization around impurities involves only two neighboring dimers. We also find that a next-nearest-neighbor ferromagnetic coupling favors VBC order. Unexpectedly, a small size spinon-impurity bound state appears in some region of the the dimer liquid phase. In contrast, in the VBC phase the spinon delocalizes within a large region around the impurity, revealing the weakness of the VBC confining potential. Lastly, we observe that an impurity concentration as small as 4% enhances dimerization substantially. These results are confronted to the Valence Bond Glass scenario [R.R.P. Singh, Phys. Rev. Lett. 104, 177203 (2010)] and implications to the interpretation of the Nuclear Magnetic Resonance spectra of the Herbertsmithite compound are outlined.
description: Extended version. 9 pages, 11 figures
UV-Protected Inflation
Creators: name: Germani, Cristiano
name: Kehagias, Alex
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In Natural Inflation, the Inflaton is a pseudo-Nambu-Goldstone boson which acquires a mass by explicit breaking of a global shift symmetry at scale f. In this case, for small field values, the potential is flat and stable under radiative corrections. Nevertheless, slow roll conditions enforce f>>M_p making the validity of the whole scenario questionable. In this letter, we show that a coupling of the Inflaton kinetic term to the Einstein tensor allows f<
description: 5 pages; v3: Minkowski limit of the "strong coupling scale" corrected; results unchanged; accepted in Phys. Rev. Lett. 2011
The Most Negative and the Most Positive Value of the Spin Operator for a Many Fermion System
Creators: name: Zamick, Larry
Publisher: name: arXiv
Year: 2011
Subjects: subject: Nuclear Theory (nucl-th)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: We consider the most negative and most positive value of the spin operator for a many nucleon system. In the usual Nilsson model and in the single nucleon model this value has a narrow range.In the Nilsson model with an excited intrinsic state we can get values of the spin operator greater than one.
Additive habit formation: Consumption in incomplete markets with random endowments
Creators: name: Muraviev, Roman
Publisher: name: arXiv
Year: 2011
Subjects: subject: Portfolio Management (q-fin.PM)
subject: Optimization and Control (math.OC)
subject: FOS: Economics and business
subject: FOS: Mathematics
subject: 91B28, 60F15, 91B30

description: We provide a detailed characterization of the optimal consumption stream for the additive habit-forming utility maximization problem, in a framework of general discrete-time incomplete markets and random endowments. This characterization allows us to derive the monotonicity and concavity of the optimal consumption as a function of wealth, for several important classes of incomplete markets and preferences. These results yield a deeper understanding of the fine structure of the optimal consumption and provide a further theoretical support for the classical conjectures of Keynes (1936).
description: To appear in Mathematics and Financial Economics
Conductivity between Luttinger liquids: coupled chains and bilayer graphene
Creators: name: Mastropietro, Vieri
Publisher: name: arXiv
Year: 2010
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The conductivity properties between Luttinger liquids are analyzed by exact Renormalization Group methods. We prove that in a two chain system or in a model of bilayer graphene, described by two coupled fermionic honeycomb lattices interacting with a gauge field, the transverse optical conductivity at finite temperature is anomalous and decreasing together with the frequency as a power law with Luttinger liquid exponent.
description: Title changed, new section on bilayer graphene added
Weak topological insulator with protected gapless helical states
Creators: name: Imura, Ken-Ichiro
name: Takane, Yositake
name: Tanaka, Akihiro
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: A workable model for describing dislocation lines introduced into a three-dimensional topological insulator is proposed. We show how fragile surface Dirac cones of a weak topological insulator evolve into protected gapless helical modes confined to the vicinity of dislocation line. It is demonstrated that surface Dirac cones of a topological insulator (either strong or weak) acquire a finite-size energy gap, when the surface is deformed into a cylinder penetrating the otherwise surface-less system. We show that when a dislocation with a non-trivial Burgers vector is introduced, the finite-size energy gap play the role of stabilizing the one-dimensional gapless states.
description: 8 pages, 17 figures
The Top Forward Backward Asymmetry with general Z ' couplings
Creators: name: Duraisamy, Murugeswaran
name: Rashed, Ahmed
name: Datta, Alakabha
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The measurement of the top forward-backward asymmetry in $\ttbar$ production measured at the Tevatron shows deviation from the Standard Model prediction. A $ u \to t$ transition via a flavor changing $Z^{\prime}$ can explain the data. We show that left handed $t_Lu_LZ^{\prime}$ couplings can be constrained from $B_{d,s}$ mixing while the constrains on the right handed couplings $t_R u_R Z^{\prime}$ vanish in the limit of $m_u \to 0$. We then consider the most general form of the $t uZ^{\prime}$ interaction which includes vector-axial vector as well as tensor type couplings and study how these couplings affect the top forward-backward asymmetry.
description: 13 pages, 14 figures, minor typos corrected, accepted for publication in Physical Review D
Effects of mechanical rotation on spin currents
Creators: name: Matsuo, Mamoru
name: Ieda, Jun'ichi
name: Saitoh, Eiji
name: Maekawa, Sadamichi
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We study the Pauli--Schrödinger equation in a uniformly rotating frame of reference to describe a coupling of spins and mechanical rotations. The explicit form of the spin-orbit interaction (SOI) with the inertial effects due to the mechanical rotation is presented. We derive equations of motion for a wavepacket of electrons in two-dimensional planes subject to the SOI. The solution is a superposition of two cyclotron motions with different frequencies and a circular spin current is created by the mechanical rotation.
description: 4 pages, 2 figures
Numerical analysis of a reinforcement learning model with the dynamic aspiration level in the iterated Prisoner's Dilemma
Creators: name: Masuda, Naoki
name: Nakamura, Mitsuhiro
Publisher: name: arXiv
Year: 2010
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: FOS: Biological sciences

description: Humans and other animals can adapt their social behavior in response to environmental cues including the feedback obtained through experience. Nevertheless, the effects of the experience-based learning of players in evolution and maintenance of cooperation in social dilemma games remain relatively unclear. Some previous literature showed that mutual cooperation of learning players is difficult or requires a sophisticated learning model. In the context of the iterated Prisoner's Dilemma, we numerically examine the performance of a reinforcement learning model. Our model modifies those of Karandikar et al. (1998), Posch et al. (1999), and Macy and Flache (2002) in which players satisfice if the obtained payoff is larger than a dynamic threshold. We show that players obeying the modified learning mutually cooperate with high probability if the dynamics of threshold is not too fast and the association between the reinforcement signal and the action in the next round is sufficiently strong. The learning players also perform efficiently against the reactive strategy. In evolutionary dynamics, they can invade a population of players adopting simpler but competitive strategies. Our version of the reinforcement learning model does not complicate the previous model and is sufficiently simple yet flexible. It may serve to explore the relationships between learning and evolution in social dilemma situations.
description: 7 figures
Strong Coupling of a Spin Ensemble to a Superconducting Resonator
Creators: name: Kubo, Y.
name: Ong, F. R.
name: Bertet, P.
name: Vion, D.
name: Jacques, V.
name: Zheng, D.
name: Dréau, A.
name: Roch, J. -F.
name: Auffeves, A.
name: Jelezko, F.
name: Wrachtrup, J.
name: Barthe, M. F.
name: Bergonzo, P.
name: Esteve, D.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We report the realization of a quantum circuit in which an ensemble of electronic spins is coupled to a frequency tunable superconducting resonator. The spins are Nitrogen-Vacancy centers in a diamond crystal. The achievement of strong coupling is manifested by the appearance of a vacuum Rabi splitting in the transmission spectrum of the resonator when its frequency is tuned through the NV center electron spin resonance.
description: 4 pages, 3 figures