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6.0

Jun 30, 2018
06/18

by
Akitoshi Kawamura; Yusuke Kobayashi

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Suppose we want to patrol a fence (line segment) using k mobile agents with given speeds v_1, ..., v_k so that every point on the fence is visited by an agent at least once in every unit time period. Czyzowicz et al. conjectured that the maximum length of the fence that can be patrolled is (v_1 + ... + v_k)/2, which is achieved by the simple strategy where each agent i moves back and forth in a segment of length v_i/2. We disprove this conjecture by a counterexample involving k = 6 agents. We...

Topics: Multiagent Systems, Computing Research Repository, Computational Geometry, Robotics

Source: http://arxiv.org/abs/1407.8194

7
7.0

Jun 30, 2018
06/18

by
Alejandro Edera; Yanela Strappa; Facundo Bromberg

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Markov networks are models for compactly representing complex probability distributions. They are composed by a structure and a set of numerical weights. The structure qualitatively describes independences in the distribution, which can be exploited to factorize the distribution into a set of compact functions. A key application for learning structures from data is to automatically discover knowledge. In practice, structure learning algorithms focused on "knowledge discovery" present...

Topics: Computing Research Repository, Data Structures and Algorithms, Learning

Source: http://arxiv.org/abs/1407.8088

5
5.0

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

5
5.0

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

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9.0

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

8
8.0

Jun 30, 2018
06/18

by
Richard Baraniuk; Simon Foucart; Deanna Needell; Yaniv Plan; Mary Wootters

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Binary measurements arise naturally in a variety of statistical and engineering applications. They may be inherent to the problem---e.g., in determining the relationship between genetics and the presence or absence of a disease---or they may be a result of extreme quantization. In one-bit compressed sensing it has recently been shown that the number of one-bit measurements required for signal estimation mirrors that of unquantized compressed sensing. Indeed, $s$-sparse signals in $\mathbb{R}^n$...

Topics: Mathematics, Computing Research Repository, Information Theory, Statistics Theory, Statistics

Source: http://arxiv.org/abs/1407.8246

5
5.0

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

7
7.0

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

6
6.0

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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Jun 30, 2018
06/18

by
Yixuan Xie; Jinhong Yuan; Qifu; Sun

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We propose two types, namely Type-I and Type-II, quantum stabilizer codes using quadratic residue sets of prime modulus given by the form $p=4n\pm1$. The proposed Type-I stabilizer codes are of cyclic structure and code length $N=p$. They are constructed based on multi-weight circulant matrix generated from idempotent polynomial, which is obtained from a quadratic residue set. The proposed Type-II stabilizer codes are of quasi-cyclic (QC) structure and code length $N=pk$, where $k$ is the size...

Topics: Mathematics, Computing Research Repository, Information Theory

Source: http://arxiv.org/abs/1407.8249

6
6.0

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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8.0

Jun 30, 2018
06/18

by
Yuan Zhu; Siyun Tang

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In this paper, a new algebraic soft-decision decoding algorithm for Reed-Solomon code is presented. It is based on rational interpolation and the interpolation points are constructed by Berlekamp-Messay algorithm. Unlike the traditional K{\"o}tter-Vardy algorithm, new algorithm needs interpolation for two smaller multiplicity matrixes, due to the corresponding factorization algorithm for re-constructing codewords.

Topics: Mathematics, Computing Research Repository, Information Theory

Source: http://arxiv.org/abs/1407.8069

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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

5
5.0

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