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6.0

Jun 30, 2018
06/18

by
A. L. Saraiva; A. Baena; M. J. Calderón; Belita Koiller

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We provide here a roadmap for modeling silicon nano-devices with one or two group V donors (D). We discuss systems containing one or two electrons, that is, D^0, D^-, D_2^+ and D_2^0 centers. The impact of different levels of approximation is discussed. The most accurate instances -- for which we provide quantitative results -- are within multivalley effective mass including the central cell correction and a configuration interaction account of the electron-electron correlations. We also derive...

Topics: Mesoscale and Nanoscale Physics, Condensed Matter

Source: http://arxiv.org/abs/1407.8224

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5.0

Jun 30, 2018
06/18

by
A. Zazunov; A. Brunetti; A. Levy Yeyati; R. Egger

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We present a comprehensive theoretical framework for the Andreev bound state population dynamics in superconducting weak links. Contrary to previous works, our approach takes into account the generated nonequilibrium distribution of the continuum quasiparticle states in a self-consistent way. As application of our theory, we show that the coupling of the superconducting contact to environmental phase fluctuations induces a charge imbalance of the continuum quasiparticle population. This...

Topics: Superconductivity, Mesoscale and Nanoscale Physics, Condensed Matter

Source: http://arxiv.org/abs/1407.7991

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71

Jun 30, 2018
06/18

by
A. de Paz; B. Naylor; J. Huckans A. Carrance; O. Gorceix; E. Marechal; P. Pedri; B. Laburthe-Tolra; L. Vernac

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We experimentally study the spin dynamics of mesoscopic ensembles of ultracold magnetic spin-3 atoms located in two separated wells of an optical dipole trap. We use a radio-frequency sweep to selectively flip the spin of the atoms in one of the wells, which produces two separated spin domains of opposite polarization. We observe that these engineered spin domains are metastable with respect to the long-range magnetic dipolar interactions between the two ensembles. The absence of inter-cloud...

Topics: Physics, Quantum Gases, Atomic Physics, Quantum Physics, Condensed Matter

Source: http://arxiv.org/abs/1407.8130

3
3.0

Jun 30, 2018
06/18

by
Amadeo Jimenez-Alba; Karl Landsteiner; Luis Melgar

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We study the magneto response with non-conserved currents in Holography. Non-conserved currents are dual to massive vector fields in AdS. We introduce the mass in a gauge invariant way via the St\"uckelberg mechanism. In particular we find generalizations of the Chiral Magnetic Effect, the Chiral Separation Effect and the Chiral Magnetic Wave. Since the associated charge is not conserved we need to source it explicitly by a coupling, the generalization of the chemical potential. In this...

Topics: High Energy Physics - Theory, High Energy Physics - Phenomenology, Strongly Correlated Electrons,...

Source: http://arxiv.org/abs/1407.8162

4
4.0

Jun 30, 2018
06/18

by
Anna M. Barry; F. Hajir; P. G. Kevrekidis

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In this work, we construct suitable generating functions for vortices of alternating signs in the realm of Bose-Einstein condensates. In addition to the vortex-vortex interaction included in earlier fluid dynamics constructions of such functions, the vortices here precess around the center of the trap. This results in the generating functions of the vortices of positive charge and of negative charge satisfying a modified, so-called, Tkachenko differential equation. From that equation, we...

Topics: Nonlinear Sciences, Quantum Gases, Mathematics, Pattern Formation and Solitons, Mathematical...

Source: http://arxiv.org/abs/1407.7965

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6.0

Jun 30, 2018
06/18

by
Brian Swingle; John McGreevy

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We give a detailed physical argument for the area law for entanglement entropy in gapped phases of matter arising from local Hamiltonians. Our approach is based on renormalization group (RG) ideas and takes a resource oriented perspective. We report four main results. First, we argue for the "weak area law": any gapped phase with a unique ground state on every closed manifold obeys the area law. Second, we introduce an RG based classification scheme and give a detailed argument that...

Topics: Quantum Physics, High Energy Physics - Theory, Strongly Correlated Electrons, Condensed Matter

Source: http://arxiv.org/abs/1407.8203

3
3.0

Jun 30, 2018
06/18

by
Bruno Rousseau; François Lapointe; Minh Nguyen; Maxime Biron; Etienne Gaufrès; Saman Choubak; Zheng Han; Vincent Bouchiat; Patrick Desjardins; Michel Côté; Richard Martel

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Herein, intervalley scattering is exploited to account for anomalous antiresonances in the infrared spectra of doped and disordered single layer graphene. We present infrared spectroscopy measurements of graphene grafted with iodophenyl moieties in both reflection microscopy and transmission configurations. Asymmetric transparency windows at energies corresponding to phonon modes near the {\Gamma} and K points are observed, in contrast to the featureless spectrum of pristine graphene. These...

Topics: Mesoscale and Nanoscale Physics, Materials Science, Condensed Matter

Source: http://arxiv.org/abs/1407.8141

4
4.0

Jun 30, 2018
06/18

by
D. J. Hepburn; E. MacLeod; G. J. Ackland

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We present a comprehensive set of first principles electronic structure calculations to study transition metal solutes and their interactions with point defects in austenite. Clear trends were observed across the series. Solute-defect interactions were strongly correlated to the solute size factors, consistent with local strain field effects. Strong correlations with results in ferrite show insensitivity to the underlying crystal structure in Fe. Oversized solutes act as strong traps for...

Topics: Materials Science, Condensed Matter

Source: http://arxiv.org/abs/1407.7996

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4.0

Jun 30, 2018
06/18

by
Daniel E. Sheehy

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The ground-state phase diagram of attractively-interacting Fermi gases in two dimensions with a population imbalance is investigated. We find the regime of stability for the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase, in which pairing occurs at finite wave vector, and determine the magnitude of the pairing amplitude $\Delta$ and FFLO wavevector $q$ in the ordered phase, finding that $\Delta$ can be of the order of the two-body binding energy. Our results rely on a careful analysis of the...

Topics: Quantum Gases, Condensed Matter

Source: http://arxiv.org/abs/1407.8021

3
3.0

Jun 30, 2018
06/18

by
Diego Rainis; Daniel Loss

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We consider electronic transport through semiconducting nanowires (W) with spin-orbit interaction (SOI), in a hybrid N-W-N setup where the wire is contacted by normal-metal leads (N). We investigate the conductance behavior of the system as a function of gate and bias voltage, magnetic field, wire length, temperature, and disorder. The transport calculations are performed numerically and are based on standard recursive Green's function techniques. In particular, we are interested in...

Topics: Mesoscale and Nanoscale Physics, Condensed Matter

Source: http://arxiv.org/abs/1407.8239

3
3.0

Jun 30, 2018
06/18

by
E. Nicklas; W. Muessel; H. Strobel; P. G. Kevrekidis; M. K. Oberthaler

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The dynamical evolution of spatial patterns in a complex system can reveal the underlying structure and stability of stationary states. As a model system we employ a two-component rubidium Bose-Einstein condensate at the transition from miscible to immiscible with the additional control of linear interconversion. Excellent agreement is found between the detailed experimental time evolution and the corresponding numerical mean-field computations. Analyzing the dynamics of the system, we find...

Topics: Quantum Gases, Nonlinear Sciences, Pattern Formation and Solitons, Condensed Matter

Source: http://arxiv.org/abs/1407.8049

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5.0

Jun 30, 2018
06/18

by
Ezequiel E. Ferrero; Kirsten Martens; Jean-Louis Barrat

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We study consequences of long-range elasticity in thermally assisted dynamics of yield stress materials. Within a two-dimensinal mesoscopic model we calculate the mean-square displacement and the dynamical structure factor for tracer particle trajectories. The ballistic regime at short time scales is associated with a compressed exponential decay in the dynamical structure factor, followed by a subdiffusive crossover prior to the onset of diffusion. We relate this crossover to spatiotemporal...

Topics: Statistical Mechanics, Soft Condensed Matter, Disordered Systems and Neural Networks, Condensed...

Source: http://arxiv.org/abs/1407.8014

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5.0

Jun 30, 2018
06/18

by
Huy Nguyen; Hao Shi; Jie Xu; Shiwei Zhang

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We describe CPMC-Lab, a Matlab program for the constrained-path and phaseless auxiliary-field Monte Carlo methods. These methods have allowed applications ranging from the study of strongly correlated models, such as the Hubbard model, to ab initio calculations in molecules and solids. The present package implements the full ground-state constrained-path Monte Carlo (CPMC) method in Matlab with a graphical interface, using the Hubbard model as an example. The package can perform calculations in...

Topics: Strongly Correlated Electrons, Condensed Matter

Source: http://arxiv.org/abs/1407.7967

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4.0

Jun 30, 2018
06/18

by
Jige Chen; Yi Gao; Chunlei Wang; Renliang Zhang; Hong Zhao; Haiping Fang

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Thermally driven nanotube nanomotors provide linear mass transportation controlled by a temperature gradient. However, the underlying mechanism is still unclear where the mass transportation velocity in experiment is much lower than that resulting from simulations. Considering that defects are common in fabricated nanotubes, we use molecular dynamics simulations to show that the mass transportation would be considerably impeded by the potential barriers or wells induced by the defects, which...

Topics: Mesoscale and Nanoscale Physics, Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1407.8263

3
3.0

Jun 30, 2018
06/18

by
Jing Tang; Shuo Cao; Yunan Gao; Yue Sun; Weidong Geng; David A. Williams; Kuijuan Jin; Xiulai Xu

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We report a photoluminescence (PL) spectroscopy study of charge state control in single self-assembled InAs/GaAs quantum dots by applying electric and/or magnetic fields at 4.2 K. Neutral and charged exciton complexes were observed under applied bias voltages from -0.5 V to 0.5 V by controlling the carrier tunneling. The highly negatively charged exciton emission becomes stronger with increasing pumping power, arising from the fact that electrons have a smaller effective mass than holes and are...

Topics: Mesoscale and Nanoscale Physics, Condensed Matter

Source: http://arxiv.org/abs/1407.7980

5
5.0

Jun 30, 2018
06/18

by
Krzysztof Jachymski; Michał Krych; Paul S. Julienne; Zbigniew Idziaszek

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We consider a general problem of inelastic collision of particles interacting with power-law potentials. Using quantum defect theory we derive an analytical formula for the energy-dependent complex scattering length, valid for arbitrary collision energy, and use it to analyze the elastic and reactive collision rates. Our theory is applicable for both universal and non-universal collisions. The former corresponds to the unit reaction probability at short range, while in the latter case the...

Topics: Physics, Quantum Gases, Atomic Physics, Quantum Physics, Condensed Matter

Source: http://arxiv.org/abs/1407.8030

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3.0

Jun 30, 2018
06/18

by
Kyle B. Hollingshead; Thomas M. Truskett

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We use molecular dynamics simulations to test integral equation theory predictions for the structure of fluids of spherical particles with eight different piecewise-constant pair interaction forms comprising a hard core and a combination of two shoulders and/or wells. Since model pair potentials like these are of interest for discretized or coarse-grained representations of effective interactions in complex fluids (e.g., for computationally intensive inverse optimization problems), we focus...

Topics: Soft Condensed Matter, Condensed Matter

Source: http://arxiv.org/abs/1407.8060

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4.0

Jun 30, 2018
06/18

by
L. P. Pitaevskii

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This paper is devoted to the calculation of the momentum of localized excitations, such as solitons and vortex rings, moving in a superfluid. The direct calculation of the momentum by integration of the mass flux density results in a badly-converging integral. I suggest a method for the renormalization of the integral with the explicit separation of a term related to the vortex line. This term can be calculated explicitly and gives the main contribution for the rings whose size is large...

Topics: Quantum Gases, Condensed Matter

Source: http://arxiv.org/abs/1407.8081

4
4.0

Jun 30, 2018
06/18

by
M. Salehi; S. A. Jafari

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Bismuth and its alloys provide a paradigm to realize three dimensional materials whose low-energy effective theory is given by Dirac equation in 3+1 dimensions. We study the quantum transport properties of three dimensional Dirac materials within the framework of Landauer-B\"uttiker formalism. Charge carriers in normal metal satisfying the Schr\"odinger equation, can be split into four-component with appropriate matching conditions at the boundary with the three dimensional Dirac...

Topics: Mesoscale and Nanoscale Physics, Strongly Correlated Electrons, Condensed Matter

Source: http://arxiv.org/abs/1407.8048

4
4.0

Jun 30, 2018
06/18

by
M. Zuppardo; J. P. Santos; G. De Chiara; M. Paternostro; F. L. Semiao; G. M. Palma

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We describe an apparatus designed to make non-demolition measurements on a Bose-Einstein condensate (BEC) trapped in a double-well optical cavity. This apparatus contains, as well as the bosonic gas and the trap, an optical cavity. We show how the interaction between the light and the atoms, under appropriate conditions, can allow for a weakly disturbing yet highly precise measurement of the population imbalance between the two wells and its variance. We show that the setting is well suited for...

Topics: Quantum Physics, Quantum Gases, Condensed Matter

Source: http://arxiv.org/abs/1407.8077

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9.0

Jun 30, 2018
06/18

by
Manpreet Singh; Tapan Mishra; Ramesh V. Pai; B. P. Das

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We obtain the complete quantum phase diagram of bosons on a two-leg ladder in the presence of attractive onsite and repulsive interchain nearest-neighbor interactions by imposing the onsite three-body constraint. We find three distinct phases; namely, the atomic superfluid (ASF), dimer superfluid (DSF), and the dimer rung insulator (DRI). In the absence of the interchain nearest-neighbor repulsion, the system exhibits a transition from the ASF to the DSF phase with increasing onsite attraction....

Topics: Quantum Gases, Condensed Matter

Source: http://arxiv.org/abs/1407.7950

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4.0

Jun 30, 2018
06/18

by
Mark D. Lee; Janne Ruostekoski

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We formulate computationally efficient classical stochastic measurement trajectories for a multimode quantum system under continuous observation. Specifically, we consider the nonlinear dynamics of an atomic Bose-Einstein condensate contained within an optical cavity subject to continuous monitoring of the light leaking out of the cavity. The classical trajectories encode within a classical phase-space representation a continuous quantum measurement process conditioned on a given detection...

Topics: Quantum Physics, Quantum Gases, Condensed Matter

Source: http://arxiv.org/abs/1407.8090

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8.0

Jun 30, 2018
06/18

by
O. Hen; L. B. Weinstein; E. Piasetzky; G. A. Miller; M. M. Sargsian; Y. Sagi

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Background: The high momentum distribution of atoms in two spin-state ultra-cold atomic gases with strong short-range interactions between atoms with different spins, which can be described using Tan's contact, are dominated by short range pairs of different fermions and decreases as $k^{-4}$. In atomic nuclei the momentum distribution of nucleons above the Fermi momentum ($k>k_F \approx 250$ Mev/c) is also dominated by short rangecorrelated different-fermion (neutron-proton) pairs. Purpose:...

Topics: Quantum Gases, Nuclear Experiment, Nuclear Theory, Condensed Matter

Source: http://arxiv.org/abs/1407.8175

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5.0

Jun 30, 2018
06/18

by
P. L. S. Lopes; V. Shivamoggi; A. O. Caldeira

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Thermodynamic measurements of magnetic fluxes and I-V characteristics in SQUIDs offer promising paths to the characterization of topological superconducting phases. We consider the problem of macroscopic quantum tunneling in an rf-SQUID in a topological superconducting phase. We show that the topological order shifts the tunneling rates and quantum levels, both in the parity conserving and fluctuating cases. The latter case is argued to actually enhance the signatures in the slowly fluctuating...

Topics: Mesoscale and Nanoscale Physics, Condensed Matter

Source: http://arxiv.org/abs/1407.8182

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4.0

Jun 30, 2018
06/18

by
P. Papakonstantinou

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It has been revealed through numerical calculations that the Second Random Phase Approximation (SRPA) with the Hartree-Fock solution as its reference state results in 1) spurious states at genuinely finite energy, contrary to common expectation, and 2) unstable solutions, which within the first-order Random Phase Approximation correspond to real low-energy collective vibrations. In the present work, these shortcomings of SRPA are shown to not contradict Thouless' theorem about the...

Topics: Other Condensed Matter, Strongly Correlated Electrons, Nuclear Theory, Condensed Matter

Source: http://arxiv.org/abs/1407.7943

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7.0

Jun 30, 2018
06/18

by
Rachele Nerattini; Andrea Trombettoni; Lapo Casetti

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A relation between O$(n)$ models and Ising models has been recently conjectured [L. Casetti, C. Nardini, and R. Nerattini, Phys. Rev. Lett. 106, 057208 (2011)]. Such a relation, inspired by an energy landscape analysis, implies that the microcanonical density of states of an O$(n)$ spin model on a lattice can be effectively approximated in terms of the density of states of an Ising model defined on the same lattice and with the same interactions. Were this relation exact, it would imply that...

Topics: Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1407.7966

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10.0

Jun 30, 2018
06/18

by
S. A. Mikhailov

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A quantum theory of the third-harmonic generation in graphene is presented. An analytical formula for the nonlinear conductivity tensor $\sigma^{(3)}_{\alpha\beta\gamma\delta}(\omega,\omega,\omega)$ is derived. Resonant maxima of the third harmonic are shown to exist at low frequencies $\omega\ll E_F/\hbar$, as well as around the frequency $\omega=2E_F/\hbar$, where $E_F$ is the Fermi energy in graphene. At the input power of a CO$_2$ laser ($\lambda\approx 10$ $\mu$m) of about 1 MW/cm$^2$ the...

Topics: Mesoscale and Nanoscale Physics, Condensed Matter

Source: http://arxiv.org/abs/1407.8169

4
4.0

Jun 30, 2018
06/18

by
S. B. Yuste; E. Abad; K. Lindenberg

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Anomalous diffusion, in particular subdiffusion, is frequently invoked as a mechanism of motion in dense biological media, and may have a significant impact on the kinetics of binding/unbinding events at the cellular level. In this work we incorporate anomalous diffusion in a previously developed model for FRAP experiments. Our particular implementation of subdiffusive transport is based on a continuous time random walk (CTRW) description of the motion of fluorescent particles, as CTRWs lend...

Topics: Subcellular Processes, Quantitative Biology, Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1407.8226

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3.0

Jun 30, 2018
06/18

by
Salvatore Mandrà; Gian Giacomo Guerreschi; Alán Aspuru-Guzik

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Adiabatic quantum optimization is a procedure to solve a vast class of optimization problems by slowly changing the Hamiltonian of a quantum system. The evolution time necessary for the algorithm to be successful scales inversely with the minimum energy gap encountered during the dynamics. Unfortunately, the direct calculation of the gap is strongly limited by the exponential growth in the dimensionality of the Hilbert space associated to the quantum system. Although many special-purpose...

Topics: Quantum Physics, Physics, Computational Physics, Disordered Systems and Neural Networks, Condensed...

Source: http://arxiv.org/abs/1407.8183

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7.0

Jun 30, 2018
06/18

by
Seymur Cahangirov; V. Ongun Ozcelik; Angel Rubio; Salim Ciraci

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Based on first-principles calculation we predict two new thermodynamically stable layered-phases of silicon, named as silicites, which exhibit strong directionality in the electronic and structural properties. As compared to silicon crystal, they have wider indirect band gaps but also increased absorption in the visible range making them more interesting for photovoltaic applications. These stable phases consist of intriguing stacking of dumbbell patterned silicene layers having trigonal...

Topics: Mesoscale and Nanoscale Physics, Materials Science, Condensed Matter

Source: http://arxiv.org/abs/1407.7981

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5.0

Jun 30, 2018
06/18

by
Steven M. Flores; Robert M. Ziff; Jacob J. H. Simmons

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In a recent article, one of the authors used $c=0$ logarithmic conformal field theory to predict crossing-probability formulas for percolation clusters inside a hexagon with free boundary conditions. In this article, we verify these predictions with high-precision computer simulations. Our simulations generate percolation-cluster perimeters with hull walks on a triangular lattice inside a hexagon. Each sample comprises two hull walks, and the order in which these walks strike the bottom and...

Topics: Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1407.8163

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3.0

Jun 30, 2018
06/18

by
T. Konno; T. Adachi; M. Imaizumi; T. Noji; T. Kawamata; Y. Koike

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In order to investigate details of the superconducting (SC) gap in the iron-chalcogenide superconductors, the specific heat, C, of FeSe_1-x_Te_x_ with x=0.6-1 has been measured in magnetic fields. Using the two-gap model, it has been found that the smaller SC gap is significantly depressed by the application of magnetic field, resulting in the increase of the slope of the C/T vs T^2^ plot at low temperatures. From the specific-heat measurements at very low temperatures down to 0.4 K, it has...

Topics: Superconductivity, Condensed Matter

Source: http://arxiv.org/abs/1407.8266

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4.0

Jun 30, 2018
06/18

by
Taras Verkholyak; Jozef Strecka; Frederic Mila; Kai P. Schmidt

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Exact ground states of a spin-1/2 Ising-Heisenberg model on the Shastry-Sutherland lattice with Heisenberg intra-dimer and Ising inter-dimer couplings are found by two independent rigorous procedures. The first method uses a unitary transformation to establish a mapping correspondence with an effective classical spin model, while the second method relies on the derivation of an effective hard-core boson model by continuous unitary transformations. Both methods lead to equivalent effective...

Topics: Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1407.8229

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6.0

Jun 30, 2018
06/18

by
Xue Pan; Mingmei Xu; Yuanfang Wu

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Through the Monte Carlo simulation of the three-dimensional, three-state Potts model, which is a paradigm of finite-temperature pure gauge QCD, we study the fluctuations of generalized susceptibilities near the temperatures of external fields of first-, second-order phase transitions and crossover. Similar peak-like fluctuation appears in the second order susceptibility at three given external fields. Oscillation-like fluctuation appears in the third and fourth order susceptibilities. We find...

Topics: High Energy Physics - Lattice, Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1407.7957

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4.0

Jun 30, 2018
06/18

by
Yawar Mohammadi; Rostam Moradian

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We study the RKKY interaction between two magnetic impurities located on same layer (intralayer case) or on different layers (interlayer case) in undoped bilayer graphene in the four-bands model, by directly calculating the Green functions in the eigenvalues and eigenvectors representation. Our results show that both intra- and interlayer RKKY interactions between two magnetic impurities located on same (opposite) sublattice are always ferromagnetic (antiferromagnetic). Furthermore we find...

Topics: Mesoscale and Nanoscale Physics, Strongly Correlated Electrons, Condensed Matter

Source: http://arxiv.org/abs/1407.7959

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4.0

Jun 30, 2018
06/18

by
Yoshihiro Nishiyama

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The two-magnon-bound-state mass gap m_2 for the two-dimensional quantum Ising model was investigated by means of the numerical diagonalization method; the low-lying spectrum is directly accessible via the numerical diagonalization method. It has been claimed that the ratio m_2/m_1 (m_1: one-magnon mass gap) is a universal constant in the vicinity of the critical point. Aiming to suppress corrections to scaling (lattice artifact), we consider the spin-S=1 Ising model with finely-adjusted...

Topics: Statistical Mechanics, Condensed Matter

Source: http://arxiv.org/abs/1407.8243

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Jun 30, 2018
06/18

by
Yuancheng Fan; Fuli Zhang; Qian Zhao; Zeyong Wei; Hongqiang Li

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Coherent perfect absorber (CPA) was proposed as the time-reversed counterpart to laser: a resonator containing lossy medium instead of gain medium can absorb the coherent optical fields completely. Here, we exploit a monolayer graphene to realize the CPA in a non-resonant manner. It is found that quasi-CPA point exists in the terahertz regime for suspending monolayer graphene, and the CPA can be implemented with the assistant of proper phase modulation among two incident beams at the quasi-CPA...

Topics: Physics, Mesoscale and Nanoscale Physics, Optics, Materials Science, Condensed Matter

Source: http://arxiv.org/abs/1407.7961

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3.0

Jun 30, 2018
06/18

by
Yuchen Peng; Frank Gaitan

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Successful implementation of a fault-tolerant quantum computation on a system of qubits places severe demands on the hardware used to control the many-qubit state. It is known that an accuracy threshold $P_{a}$ exists for any quantum gate that is to be used in such a computation. Specifically, the error probability $P_{e}$ for such a gate must fall below the accuracy threshold: $P_{e} < P_{a}$. Estimates of $P_{a}$ vary widely, though $P_{a}\sim 10^{-4}$ has emerged as a challenging target...

Topics: Quantum Physics, Mesoscale and Nanoscale Physics, Condensed Matter

Source: http://arxiv.org/abs/1407.8074

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6.0

Jun 30, 2018
06/18

by
Z. Gercsi; K. G. Sandeman; A. Fujita

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We present a systematic investigation of the effect of H, B, C, and N interstitials on the electronic, lattice and magnetic properties of La(Fe,Si)$_{13}$ using density functional theory. The parent LaSiFe$_{12}$ alloy has a shallow, double-well free energy function that is the basis of first order itinerant electron metamagnetism. On increasing the dopant concentration, the resulting lattice expansion causes an initial increase in magnetisation for all interstitials that is only maintained at...

Topics: Materials Science, Condensed Matter

Source: http://arxiv.org/abs/1407.7975

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Jun 30, 2018
06/18

by
Zenan Qi; Harold S. Park; David K. Campbell

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Graphene's exceptional mechanical properties, including its highest-known stiffness (1 TPa) and strength (100 GPa) have been exploited for various structural applications. However, graphene is also known to be quite brittle, with experimentally-measured tensile fracture strains that do not exceed a few percent. In this work, we introduce the notion of graphene kirigami, where concepts that have been used almost exclusively for macroscale structures are applied to dramatically enhance the...

Topics: Physics, Computational Physics, Materials Science, Condensed Matter

Source: http://arxiv.org/abs/1407.8113