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Sep 21, 2013
09/13

by
F. -J. Jiang

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Motivated by the indication of a new critical theory for the spin-1/2 Heisenberg model with a spatially staggered anisotropy on the square lattice as suggested in \cite{Wenzel08}, we re-investigate the phase transition of this model induced by dimerization using first principle Monte Carlo simulations. We focus on studying the finite-size scaling of $\rho_{s1} 2L$ and $\rho_{s2} 2L$, where $L$ stands for the spatial box size used in the simulations and $\rho_{si}$ with $i \in \{1,2\}$ is the...

Source: http://arxiv.org/abs/1108.0715v1

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Sep 19, 2013
09/13

by
F. -J. Jiang

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Motivated by the so-called cubical regime in magnon chiral perturbation theory, we propose a new method to calculate the low-energy constant, namely the spin-wave velocity $c$ of spin-1/2 antiferromagnets with $O(N)$ symmetry in a Monte Carlo simulation. Specifically we suggest that $c$ can be determined by $c = L/\beta$ when the squares of the spatial and temporal winding numbers are tuned to be the same in the Monte Carlo calculations. Here $\beta$ and $L$ are the inverse temperature and the...

Source: http://arxiv.org/abs/1009.6122v1

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Sep 19, 2013
09/13

by
F. -J. Jiang

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Puzzled by the indication of a new critical theory for the spin-1/2 Heisenberg model with a spatially staggered anisotropy on the square lattice as suggested in \cite{Wenzel08}, we re-investigate the phase transition of this model induced by dimerization using first principle Monte Carlo simulations. We focus on studying the finite-size scaling of $\rho_{s1} L$ and $\rho_{s2} L$, where $L$ stands for the spatial box size used in the simulations and $\rho_{si}$ with $i \in \{1,2\}$ is the...

Source: http://arxiv.org/abs/1010.6267v1

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Sep 22, 2013
09/13

by
T. Han; J. Jiang

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We study the general Higgs-weak boson coupling with CP-violation via the process e+e- -> f \bar f h. We categorize the signal channels by sub-processes Zh production and ZZ fusion and construct four CP asymmetries by exploiting polarized e+e- beams. We find complementarity among the sub-processes and the asymmetries to probe the real and imaginary parts of the CP-violating form factor. Certain asymmetries with unpolarized beams can retain significant sensitivity to the coupling. We conclude...

Source: http://arxiv.org/abs/hep-ph/0011271v1

SCADA (Supervisory Control And Data Acquisition) systems have always been susceptible to cyber-attacks. Different types of cyber-attacks could occur depending on the architecture and configurations used in the SCADA system. To protect cyber infrastructure from above attacks a growing collaborative effort between cyber security professionals and researchers from private and academia has involved in designing variety of intelligent intrusion detection systems. This paper introduces a new European...

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Sep 22, 2013
09/13

by
F. -J. Jiang; U. Gerber

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Puzzled by the indication of a new critical theory for the spin-1/2 Heisenberg model with a spatially staggered anisotropy on the square lattice as suggested in \cite{Wenzel08}, we study a similar anisotropic spin-1/2 Heisenberg model on the honeycomb lattice. The critical point where the phase transition occurs due to the dimerization as well as the critical exponent $\nu$ are analyzed in great detail. Remarkly, using most of the available data points in conjunction with the expected...

Source: http://arxiv.org/abs/0906.2539v3

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Sep 22, 2013
09/13

by
F. -J. Jiang; U. Gerber

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We study the quantum phase transition from a super solid phase to a solid phase of rho = 1/2 for the extended Bose-Hubbard model on the honeycomb lattice using first principles Monte Carlo calculations. The motivation of our study is to quantitatively understand the impact of theoretical input, in particular the dynamical critical exponent z, in calculating the critical exponent nu. Hence we have carried out four sets of simulations with beta = 2N^{1/2}, beta = 8N^{1/2}, beta = N/2, and beta =...

Source: http://arxiv.org/abs/1101.3073v1

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Sep 22, 2013
09/13

by
J. Jiang; J. X. Wang

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Increasing observations are becoming available about a relatively weak, but persistent, non-axisymmetric magnetic field co-existing with the dominant axisymmetric field on the Sun. It indicates that the non-axisymmetric magnetic field plays an important role in the origin of solar activity. A linear non-axisymmetric alpha2-Omega dynamo model is set up to discuss the characteristics of the axisymmetric m=0 and the first non-axisymmetric m=1 modes and to provide further the theoretical bases to...

Source: http://arxiv.org/abs/astro-ph/0702508v1

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4.0

Jun 27, 2018
06/18

by
D. -R. Tan; F. -J. Jiang

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The thermal and ground state properties of a class of three-dimensional (3D) random-exchange spin-1/2 antiferromagnets are studied using first principles quantum Monte Carlo method. Our motivation is to examine whether the newly discovered universal properties, which connect the N\'eel temperature and the staggered magnetization density, for the clean 3D quantum dimerized Heisenberg models remain valid for the random-exchange models considered here. Remarkably, similar to the clean systems, our...

Topics: Condensed Matter, Strongly Correlated Electrons, Disordered Systems and Neural Networks, High...

Source: http://arxiv.org/abs/1504.05563

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Sep 21, 2013
09/13

by
F. J. Jiang; F. Kämpfer; M. Nyfeler

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Motivated by the possible mechanism for the pinning of the electronic liquid crystal direction in YBCO as proposed in \cite{Pardini08}, we use the first principles Monte Carlo method to study the spin 1/2 Heisenberg model with antiferromagnetic couplings $J_{1}$ and $J_{2}$ on the square lattice. The corresponding low-energy constants, namely the spin stiffness $\rho_s$, the staggered magnetization density ${\cal M}_s$, the spin wave velocity $c$, as well as the ground state energy density...

Source: http://arxiv.org/abs/0902.4861v3

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Sep 23, 2013
09/13

by
Z. -K. Su; S. -J. Jiang

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The non-Markovian master equations are derived to study quantum discord dynamics of two qubits coupled to a common reservoir and two independent reservoirs, respectively. We compare the dynamics under different parameters, such as reservoir spectra and resonant parameters, at high temperature and at zero temperature. The results indicate that the dynamics at these two extreme temperatures share similar characters, as well as differences.

Source: http://arxiv.org/abs/1105.4911v1

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Sep 19, 2013
09/13

by
Jay J. Jiang; David W. Conrath

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This paper presents a new approach for measuring semantic similarity/distance between words and concepts. It combines a lexical taxonomy structure with corpus statistical information so that the semantic distance between nodes in the semantic space constructed by the taxonomy can be better quantified with the computational evidence derived from a distributional analysis of corpus data. Specifically, the proposed measure is a combined approach that inherits the edge-based approach of the edge...

Source: http://arxiv.org/abs/cmp-lg/9709008v1

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0.0

Jun 30, 2018
06/18

by
L. Zhao; J. Jiang; Y. Liu

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We present a design of a spin-flip Zeeman slower controlled by a fast feedback circuit for a sodium Bose-Einstein condensate apparatus. We also demonstrate how the efficiency of the slower strongly depends on its intrinsic parameters, and compare these observations with a few theoretical models. Our findings lead to a simple three-step procedure of designing an optimal Zeeman slower for neutral atoms, especially for those atomic species with high initial velocities, such as sodium and lithium...

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

Source: http://arxiv.org/abs/1401.7181

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0.0

Jun 30, 2018
06/18

by
J. Jiang; W. Li; X. Cai

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Two stochastic models are proposed to generate a system composed of two interdependent scale-free (SF) or Erd\H{o}s-R\'{e}nyi (ER) networks where interdependent nodes are connected with exponential or power-law relation, as well as different dependence strength, respectively. Each subnetwork grows through the addition of new nodes with constant accelerating random attachment in the first model but with preferential attachment in the second model. Two subnetworks interact with multi-support and...

Topics: Physics, Physics and Society, Computing Research Repository, Social and Information Networks

Source: http://arxiv.org/abs/1402.6555

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Sep 23, 2013
09/13

by
F. -J. Jiang; B. C. Tiburzi

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Using flavor twisted boundary conditions, we study nucleon matrix elements of the vector current. We twist only the active quarks that couple to the current. Finite volume corrections due to twisted boundary conditions are determined using partially twisted, partially quenched, heavy baryon chiral perturbation theory, which we develop for the graded group SU(7|5). Asymptotically these corrections are exponentially small in the volume, but can become pronounced for small twist angles. Utilizing...

Source: http://arxiv.org/abs/0810.1495v1

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Sep 21, 2013
09/13

by
F. -J. Jiang; U. -J. Wiese

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The 2-d spin 1/2 Heisenberg antiferromagnet with exchange coupling $J$ is investigated on a periodic square lattice of spacing $a$ at very small temperatures using the loop-cluster algorithm. Monte Carlo data for the staggered and uniform susceptibilities are compared with analytic results obtained in the systematic low-energy effective field theory for the staggered magnetization order parameter. The low-energy parameters of the effective theory, i.e.\ the staggered magnetization density...

Source: http://arxiv.org/abs/1011.6205v1

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Sep 19, 2013
09/13

by
F. -J. Jiang; B. C. Tiburzi

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We investigate the utility of partially twisted boundary conditions in lattice calculations of meson observables. For dynamical simulations, we show that the pion dispersion relation is modified by volume effects. In the isospin limit, we demonstrate that the pion electromagnetic form factor can be computed on the lattice at continuous values of the momentum transfer. Furthermore, the finite volume effects are under theoretical control for extraction of the pion charge radius.

Source: http://arxiv.org/abs/hep-lat/0610103v2

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Sep 18, 2013
09/13

by
V. Barger; T. Han; J. Jiang

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We study the production at future $e^+e^-$ linear colliders of the heavy neutral Higgs bosons $H$ and $A$ of the minimal supersymmetric standard model in association with top and bottom quarks. The cross sections have a strong dependence on the parameter $\tan\beta$, and thus provide a good way to determine it. At a linear collider with $\sqrt s = 0.5-1$ TeV and expected integrated luminosities, we find significant sensitivities for determining $\tan\beta$. In the Supergravity scenario, the...

Source: http://arxiv.org/abs/hep-ph/0006223v1

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Sep 18, 2013
09/13

by
N. G. Deshpande; G. Eilam; J. Jiang

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We consider the existence of the state X^0 (214 MeV) in Sigma^+ -> p mu^+ mu^- decay found by the HyperCP collaboration. We assume that a fundamental spin zero boson X^0 coupled to quarks leads to flavor changing s -> d X^0 process. We estimate the scalar and pseudoscalar coupling constants by considering Sigma^+ -> p X^0 and K^+ -> pi^+ X^0 processes, and find that pseudoscalar coupling dominates. We then evaluate the branching ratios for K_L -> pi^0 pi^0 X^0, pi^+ pi^- X^0 and...

Source: http://arxiv.org/abs/hep-ph/0509081v2

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0.0

Jun 30, 2018
06/18

by
J. Jiang; R. H. Cameron; M. Schuessler

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The tilt angles of sunspot groups represent the poloidal field source in Babcock-Leighton-type models of the solar dynamo and are crucial for the build-up and reversals of the polar fields in Surface Flux Transport (SFT) simulations. The evolution of the polar field is a consequence of Hale's polarity rules, together with the tilt angle distribution which has a systematic component (Joy's law) and a random component (tilt-angle scatter). We determine the scatter using the observed tilt angle...

Topics: Astrophysics, Solar and Stellar Astrophysics

Source: http://arxiv.org/abs/1406.5564

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Jun 29, 2018
06/18

by
D. -R. Tan; F. -J. Jiang

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The N\'eel temperature, staggered magnetization density, as well as the spinwave velocity of a three-dimensional (3D) quantum Heisenberg model with antiferromagnetic disorder (randomness) are calculated using first principles non-perturbative quantum Monte Carlo simulations. In particular, we examine the validity of universal scaling relations that are related to these three studied physical quantities. These relations are relevant to experimental data and are firmly established for clean...

Topics: Disordered Systems and Neural Networks, Condensed Matter, Strongly Correlated Electrons

Source: http://arxiv.org/abs/1608.03835

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0.0

Jun 30, 2018
06/18

by
L. Zhao; J. Jiang; T. Tang; M. Webb; Y. Liu

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We experimentally demonstrate that spin dynamics and the phase diagram of spinor condensates can be conveniently tuned by a two-dimensional optical lattice. Spin population oscillations and a lattice-tuned separatrix in phase space are observed in every lattice where a substantial superfluid fraction exists. In a sufficiently deep lattice, we observe a phase transition from a longitudinal polar phase to a broken-axisymmetry phase in steady states of lattice-confined spinor condensates. The...

Topics: Quantum Gases, Condensed Matter

Source: http://arxiv.org/abs/1412.8702

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Sep 22, 2013
09/13

by
K. S. Cheng; L. Zhang; P. Leung; Z. J. Jiang

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We study the $\gamma$-ray emission properties of pulsars by using a new self-consistent outer gap model. The outer gap can exist in pulsars with age over million years old if the effect of magnetic inclination angle as well as the average properties of the outer gap are considered. The mature $\gamma$-ray pulsars, whose ages are between 0.3 to 3 million years old, are able to move up to high galactic latitude. Moreover, their $\gamma$-ray luminosity are weaker and their spectra are softer than...

Source: http://arxiv.org/abs/astro-ph/0403203v1

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Jul 20, 2013
07/13

by
Kingman Cheung; Cheng-Wei Chiang; N. G. Deshpande; J. Jiang

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Certain string-inspired Z' models have non-universal interactions to three families of fermions and induced tree-level flavor-changing couplings. We use recent results on B_s-anti-B_s mixing to constrain the size of the flavor-changing couplings in the b-s sector. In some highly predictive Z' models, such a constraint on b-s coupling can be translated into the flavor-diagonal couplings. Based on the Z' production limits at the Tevatron, we obtain the limit on the leptonic couplings of Z' and...

Source: http://arxiv.org/abs/hep-ph/0604223v1

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Sep 23, 2013
09/13

by
R. H. Cameron; J. Jiang; D. Schmitt; M. Schüssler

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We model the surface magnetic field and open flux of the Sun from 1913 to 1986 using a surface flux transport model, which includes the observed cycle-to-cycle variation of sunspot group tilts. The model reproduces the empirically derived time evolution of the solar open magnetic flux, and the reversal times of the polar fields. We find that both the polar field and the axial dipole moment resulting from this model around cycle minimum correlate with the strength of the following cycle.

Source: http://arxiv.org/abs/1006.3061v1

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Sep 18, 2013
09/13

by
Cheng-Wei Chiang; N. G. Deshpande; J. Jiang

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Flavor-changing and CP-violating interactions of Z' to fermions are generally present in models with extra U(1) gauge symmetry that are string-inspired or related to broken gauged family symmetry. We study the consequences of such couplings in fermion electric dipole moments, muon g-2, and K and B meson mixings. From experimental limits or measured values, we constrain the off-diagonal Z' couplings to fermions. Some of these constraints are comparable or stronger than the existing constraints...

Source: http://arxiv.org/abs/hep-ph/0606122v1

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0.0

Jun 30, 2018
06/18

by
J. Jiang; L. Zhao; M. Webb; Y. Liu

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We experimentally study two quantum phase transitions in a sodium spinor condensate immersed in a microwave dressing field. We also demonstrate that many previously unexplored regions in the phase diagram of spinor condensates can be investigated by adiabatically tuning the microwave field across one of the two quantum phase transitions. This method overcomes two major experimental challenges associated with some widely used methods, and is applicable to other atomic species. Agreements between...

Topics: Quantum Gases, Condensed Matter

Source: http://arxiv.org/abs/1404.7102

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Sep 21, 2013
09/13

by
F. -J. Jiang; B. C. Tiburzi; A. Walker-Loud

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Two-flavor chiral expansions provide a useful perturbative framework to study hadron properties. Such expansions should exhibit marked improvement over the conventional three-flavor chiral expansion. Although in principle one can formulate two-flavor theories for the various hyperon multiplets, the nearness of kaon thresholds can seriously undermine the effectiveness of such two-flavor theories in practice. We investigate the importance of virtual kaon thresholds on hyperon properties,...

Source: http://arxiv.org/abs/1011.1302v1

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Sep 23, 2013
09/13

by
M. -T. Kao; D. -J. Tan; F. -J. Jiang

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Motivated by the unexpected Monte Carlo results as well as the theoretical proposal of a large correction to scaling for the critical theory of the 2-d staggered-dimer spin-1/2 Heisenberg model on the square lattice, we study the phase transitions induced by dimerization of several dimerized quantum Heisenberg models with spatial anisotropy using first principles Monte Carlo method. Remarkably, while our Monte Carlo data for all the models considered here, including the herringbone- and...

Source: http://arxiv.org/abs/1202.1057v2

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Sep 18, 2013
09/13

by
R. Silvotti; S. Dreizler; G. Handler; X. J. Jiang

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We present the results from 135 hours of nearly continuous time series photometry on the ``hybrid'' (H-rich) PG1159 variable star HS2324+3944, obtained in August-September 1997. The power spectrum of the data shows several frequencies (about 20 or more), concentrated in three narrow and very crowded regions near 475, 390 and 950 microHz in decreasing amplitude order. Most (if not all) of the peaks in the latter region are linear combinations of the high-amplitude frequencies between 455 and 500...

Source: http://arxiv.org/abs/astro-ph/9811178v1

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Sep 17, 2013
09/13

by
J. Jiang; R. Cameron; D. Schmitt; M. Schuessler

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By coupling a solar surface flux transport model with an extrapolation of the heliospheric field, we simulate the evolution of the Sun's open magnetic flux and the heliospheric current sheet (HCS) based on observational data of sunspot groups since 1976. The results are consistent with measurements of the interplanetary magnetic field near Earth and with the tilt angle of the HCS as derived from extrapolation of the observed solar surface field. This opens the possibility for an improved...

Source: http://arxiv.org/abs/0912.0108v1

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Sep 19, 2013
09/13

by
K. J. Jiang; L. Deng; M. G. Payne

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Using a single channel active Raman gain medium we show a $(220\pm 20)$ns advance time for an optical pulse of $\tau_{FWHM}=15.4 \mu$s propagating through a 10 cm medium, a lead time that is comparable to what was reported previously. In addition, we have verified experimentally all the features associated with this single channel Raman gain system. Our results show that the reported gain-assisted superluminal propagation should not be attributed to the interference between the two frequencies...

Source: http://arxiv.org/abs/quant-ph/0701164v1

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Sep 18, 2013
09/13

by
M. Nyfeler; F. -J. Jiang; F. Kämpfer; U. -J. Wiese

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Simulations of frustrated quantum antiferromagnets suffer from a severe sign problem. We solve the ergodicity problem of the loop-cluster algorithm in a natural way and apply a powerful strategy to address the sign problem. For the spin 1/2 Heisenberg antiferromagnet on a kagome and on a frustrated square lattice, a nested cluster algorithm eliminates the sign problem for large systems. The method is applicable to general lattice geometries but limited to moderate temperatures.

Source: http://arxiv.org/abs/0803.3538v1

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0.0

Jun 29, 2018
06/18

by
Y. -J Jiang; Y. -K Lau; Emmanuel Royer; J Wu

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We show that the Dirichlet series associated to the Fourier coefficients of a half-integral weight Hecke eigenform at squarefree integers extends analytically to a holomorphic function in the half-plane $\re s\textgreater{}\tfrac{1}{2}$. This exhibits a high fluctuation of the coefficients at squarefree integers.

Topics: Number Theory, Mathematics

Source: http://arxiv.org/abs/1602.08924

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Sep 23, 2013
09/13

by
J. Wang; Yifu Zhu; K. J. Jiang; M. S. Zhan

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In a three-level atomic system coupled by two equal-amplitude laser fields with a frequency separation 2$\delta$, a weak probe field exhibits a multiple-peaked absorption spectrum with a constant peak separation $\delta$. The corresponding probe dispersion exhibits steep normal dispersion near the minimum absorption between the multiple absorption peaks, which leads to simultaneous slow group velocities for probe photons at multiple frequencies separated by $\delta$. We report an experimental...

Source: http://arxiv.org/abs/quant-ph/0312195v1

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Jul 20, 2013
07/13

by
J. Jiang; R. H. Cameron; D. Schmitt; E. Isik

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Context: The Sun's polar fields and open flux around the time of activity minima have been considered to be strongly correlated with the strength of the subsequent maximum of solar activity. Aims: We aim to investigate the behavior of a Babcock-Leighton dynamo with a source poloidal term that is based on the observed sunspot areas and tilts. In particular, we investigate whether the toroidal fields at the base of convection zone from the model are correlated with the observed solar cycle...

Source: http://arxiv.org/abs/1304.5730v1

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Sep 22, 2013
09/13

by
W. Wang; Z. J. Jiang; K. S. Cheng

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The diffuse gamma-rays in the Galactic center region have been studied. We propose that there exists a population of millisecond pulsars (MSPs) in the Galactic Center, which will emit GeV gamma-rays through the synchrotron-curvature radiation as predicted by outer gap models. These GeV gamma-rays from unresolved millisecond pulsars probably contribute to the diffuse gamma-ray spectrum detected by EGRET which displays a break at a few GeV. We have used the Monte Carlo method to obtain the...

Source: http://arxiv.org/abs/astro-ph/0501245v1

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Jun 30, 2018
06/18

by
D. Banerjee; F. -J. Jiang; M. Kon; U. -J. Wiese

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We consider a large quantum system with spins $\frac{1}{2}$ whose dynamics is driven entirely by measurements of the total spin of spin pairs. This gives rise to a dissipative coupling to the environment. When one averages over the measurement results, the corresponding real-time path integral does not suffer from a sign problem. Using an efficient cluster algorithm, we study the real-time evolution of a 2-d Heisenberg antiferromagnet, which is driven to a disordered phase, either by sporadic...

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

Source: http://arxiv.org/abs/1405.7882

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Sep 23, 2013
09/13

by
D. Banerjee; F. -J. Jiang; P. Widmer; U. -J. Wiese

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The $(2+1)$-d U(1) quantum link model is a gauge theory, amenable to quantum simulation, with a spontaneously broken SO(2) symmetry emerging at a quantum phase transition. Its low-energy physics is described by a $(2+1)$-d $\RP(1)$ effective field theory, perturbed by a dangerously irrelevant SO(2) breaking operator, which prevents the interpretation of the emergent pseudo-Goldstone boson as a dual photon. At the quantum phase transition, the model mimics some features of deconfined quantum...

Source: http://arxiv.org/abs/1303.6858v1

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Sep 20, 2013
09/13

by
T. B. Bunton; F. -J. Jiang; B. C. Tiburzi

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We use chiral perturbation theory to study the extrapolations necessary to make physical predictions from lattice QCD data for the electromagnetic form factors of pseudoscalar mesons. We focus on the quark mass, momentum, lattice spacing, and volume dependence and apply our results to simulations employing mixed actions of Ginsparg-Wilson valence quarks and staggered sea quarks. To determine charge radii at quark masses on the lattices currently used, we find that all extrapolations except the...

Source: http://arxiv.org/abs/hep-lat/0607001v3

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Jul 22, 2013
07/13

by
F. -J. Jiang; F. Kämpfer; M. Nyfeler; U. -J. Wiese

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Inspired by the lattice structure of the unhydrated variant of the superconducting material Na$_x$CoO$_2 \cdot$yH$_2$O at $ x = {1/3}$, we study the $t$-$J$ model on a honeycomb lattice by using an efficient loop-cluster algorithm. The low-energy physics of the undoped system and of the single hole sector is described by a systematic low-energy effective field theory. The staggered magnetization per spin $\widetilde{{\cal M}}_s = 0.2688(3)$, the spin stiffness $\rho_s = 0.102(2) J$, the spin...

Source: http://arxiv.org/abs/0807.2977v1

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Sep 20, 2013
09/13

by
R. H. Cameron; D. Schmitt; J. Jiang; E. Isik

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The surface flux transport (SFT) model of solar magnetic fields involves empirically well-constrained velocity and magnetic fields. The basic evolution of the Sun's large-scale surface magnetic field is well described by this model. The azimuthally averaged evolution of the SFT model can be compared to the surface evolution of the flux transport dynamo (FTD), and the evolution of the SFT model can be used to constrain several near-surface properties of the FTD model. We compared the results of...

Source: http://arxiv.org/abs/1205.1136v1

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Sep 20, 2013
09/13

by
S. Chandrasekharan; F. -J. Jiang; M. Pepe; U. -J. Wiese

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The order parameter of a finite system with a spontaneously broken continuous global symmetry acts as a quantum mechanical rotor. Both antiferromagnets with a spontaneously broken $SU(2)_s$ spin symmetry and massless QCD with a broken $SU(2)_L \times SU(2)_R$ chiral symmetry have rotor spectra when considered in a finite volume. When an electron or hole is doped into an antiferromagnet or when a nucleon is propagating through the QCD vacuum, a Berry phase arises from a monopole field and the...

Source: http://arxiv.org/abs/cond-mat/0612252v1

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Sep 18, 2013
09/13

by
K. Sasaki; J. Jiang; R. Saito; S. Onari; Y. Tanaka

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We present a new mechanism of carbon nanotube superconductivity that originates from edge states which are specific to graphene. Using on-site and boundary deformation potentials which do not cause bulk superconductivity, we obtain an appreciable transition temperature for the edge state. As a consequence, a metallic zigzag carbon nanotube having open boundaries can be regarded as a natural superconductor/normal metal/superconductor junction system, in which superconducting states are developed...

Source: http://arxiv.org/abs/cond-mat/0611452v1

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Sep 18, 2013
09/13

by
J. Gunion; T. Han; J. Jiang; A. Sopczak

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The ratio of neutral Higgs field vacuum expectation values, tan(beta), is one of the most important parameters to determine in either the Minimal Supersymmetric Standard Model (MSSM) or a general type-II Two-Higgs Doublet Model (2HDM). Assuming an energy and integrated luminosity of sqrts=500 GeV and L=2000 fb-1 at a future linear collider (LC), we show that a very accurate determination of tan(beta) will be possible for low and high tan(beta) values by measuring the production rates of Higgs...

Source: http://arxiv.org/abs/hep-ph/0212151v1

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Sep 23, 2013
09/13

by
F. -J. Jiang; M. Nyfeler; S. Chandrasekharan; U. -J. Wiese

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Using a loop-cluster algorithm we investigate the spin 1/2 Heisenberg antiferromagnet on a square lattice with exchange coupling $J$ and an additional four-spin interaction of strength $Q$. We confirm the existence of a phase transition separating antiferromagnetism at $J/Q > J_c/Q$ from a valence bond solid (VBS) state at $J/Q < J_c/Q$. Although our Monte Carlo data are consistent with those of previous studies, we do not confirm the existence of a deconfined quantum critical point....

Source: http://arxiv.org/abs/0710.3926v1

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Sep 21, 2013
09/13

by
L. Zhang; K. S. Cheng; Z. J. Jiang; P. Leung

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We re-examine the outer gap size by taking the geometry of the dipole magnetic field into account. Furthermore, we also consider that instead of taking the gap size at half of the light cylinder radius to represent the entire outer gap it is more appropriate to average the entire outer gap size over the distance. When these two factors are considered, the derived outer gap size f is not only the function of period P and magnetic field B of the neutron star, but also the function of the average...

Source: http://arxiv.org/abs/astro-ph/0402089v1

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Jun 30, 2018
06/18

by
D. Banerjee; M. Bögli; C. P. Hofmann; F. -J. Jiang; P. Widmer; U. -J. Wiese

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The quantum dimer model on the square lattice is equivalent to a $U(1)$ gauge theory. Quantum Monte Carlo calculations reveal that, for values of the Rokhsar-Kivelson (RK) coupling $\lambda < 1$, the theory exists in a confining columnar phase. The interfaces separating distinct columnar phases display plaquette order, which, however, is not realized as a bulk phase. Static "electric" charges are confined by flux tubes that consist of multiple strands, each carrying a...

Topics: High Energy Physics - Lattice, Strongly Correlated Electrons, Statistical Mechanics, Condensed...

Source: http://arxiv.org/abs/1406.2077

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1.0

Jun 30, 2018
06/18

by
N. D. Vlasii; C. P. Hofmann; F. -J. Jiang; U. -J. Wiese

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Using the low-energy effective field theory for hole-doped antiferromagnets on the honeycomb lattice, we study the localization of holes on Skyrmions, as a potential mechanism for the preformation of Cooper pairs. In contrast to the square lattice case, for the standard radial profile of the Skyrmion on the honeycomb lattice, only holes residing in one of the two hole pockets can get localized. This differs qualitatively from hole pairs bound by magnon exchange, which is most attractive between...

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

Source: http://arxiv.org/abs/1410.0218

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Sep 23, 2013
09/13

by
T. Wiengarten; J. Kleimann; H. Fichtner; R. Cameron; J. Jiang; R. Kissmann; K. Scherer

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Maps of the radial magnetic field at a heliocentric distance of ten solar radii are used as boundary conditions in the MHD code CRONOS to simulate a 3D inner-heliospheric solar wind emanating from the rotating Sun out to 1 AU. The input data for the magnetic field are the result of solar surface flux transport modelling using observational data of sunspot groups coupled with a current sheet source surface model. Amongst several advancements, this allows for higher angular resolution than that...

Source: http://arxiv.org/abs/1303.4260v1