We study the fully frustrated $\mathrm{XY}$ model on a square lattice with use of Monte Carlo simulations. find phase transition at finite temperature ${T}_{I}$ specific-heat data being consistent logarithmic divergence. The helicity modulus $\ensuremath{\Upsilon}$ jumps to zero value $\frac{\ensuremath{\Upsilon}}{{k}_{B}T}\ensuremath{\gtrsim}\frac{2}{\ensuremath{\pi}}$ $T\ensuremath{\lesssim}{T}_{I}$. application models behavior coupled Josephson junction arrays is discussed.

We carry out numerical simulations to study transport behavior about the jamming transition of a model granular material in two dimensions at zero temperature. Shear viscosity $\ensuremath{\eta}$ is computed as function particle volume density $\ensuremath{\rho}$ and applied shear stress $\ensuremath{\sigma}$, for diffusively moving particles with soft core interaction. find an excellent scaling collapse our data variable...

A class of uniformly frustrated $\mathrm{xy}$ models which describe the behavior a Josephson-junction array in transverse magnetic field is considered. The frustration $f$ fraction flux quantum applied per unit cell lattice. ground-state energy ${E}_{0}$ and critical current are computed for several rational $f$. arbitrary discussed, it concluded that resistive transition temperature $f=\frac{p}{q}$ bounded by...

Molecular dynamics simulations show that gold clusters with about 600–3000 atoms crystallize into a Mackay icosahedron upon cooling from the liquid. A detailed surface analysis shows facets on of icosahedral soften but do not premelt below bulk melting temperature. This softening is found to be due increasing mobility vertex and edge temperature, which leads inter-layer intra-layer diffusion, shrinkage average facet size, so shape cluster nearly spherical at melting.

For a large class of models, the connection between roughening and facet formation is explored in detail. It shown that there universal jump crystal surface curvature at transition. Explicit calculations within one model yield shapes exponent describing near facet. Hyperscaling arguments provide sizes for generalized solid-on-solid models.

We model a two-dimensional periodic array of Josephson junctions in transverse magnetic field by the uniformly frustrated $\mathrm{XY}$ model. report results extensive nonequilibrium simulations within resistively-shunted-junction $I\ensuremath{-}V$ curves are computed for unfrustrated and fully cases, consistency with recent experiments is found. For case, new theoretical ideas presented which show Ising degrees freedom to dominate behavior near ${T}_{c}$.

We perform numerical simulations to determine the shear stress and pressure of steady-state flow in a soft-disk model two dimensions at zero temperature vicinity jamming transition ${\ensuremath{\phi}}_{J}$. use critical point scaling analyses behavior jamming, we find that it is crucial include corrections for reliable analysis. relative size these are much smaller than stress. furthermore superlinear above ${\ensuremath{\phi}}_{J}$, both from analysis direct data extrapolated limit vanishing rate.

The three-dimensional classical XY model on a cubic lattice has been studied using Monte Carlo simulations. finite-size scaling method of the phenomenological renormalization group used to calculate critical exponents \ensuremath{\nu}, v, and \ensuremath{\beta} correlation length, helicity modulus, order parameter. Good agreement with series-expansion results is obtained.

We carry out Monte Carlo simulations of the uniformly frustrated 3d XY model as a for vortex line fluctuations in high Tc superconductor. A density lines f=1/25 is considered. find two sharp phase transitions. The low T an ordered lattice. normal liquid with much entangling, cutting, and loop excitations. An intermediate found which characterized disentangled lines. In this phase, system displays superconducting properties direction parallel to magnetic field, but behavior planes perpendicular field.

We have carried out a Monte Carlo study of anisotropic 3D uniformly frustrated XY models, as model for the type-II high-${\mathit{T}}_{\mathit{c}}$ superconductors. Vortex-line-lattice melting, vortex-line cutting, and entanglement been studied in relation to superconducting phase transition.

We study diffusion in the presence of a hierarchical set barriers. find phase transition dynamics from ordinary to anomalous as parameter controlling relative barrier heights is varied. Similar behavior found suitably defined random systems. Possible connections glassy are discussed.

The jamming of bidisperse soft core disks is considered, using a variety different protocols to produce the jammed state. In agreement with other works, we find that cooling and compression can lead broad range packing fractions ${\ensuremath{\phi}}_{J}$, depending on rate initial configuration; larger degree big particle clustering in configuration, will be value ${\ensuremath{\phi}}_{J}$. contrast, shearing disrupts clustering, leading much narrower ${\ensuremath{\phi}}_{J}$ as shear...

We carry out a finite size scaling analysis of the jamming transition in frictionless bi-disperse soft core disks two dimensions. consider different protocols: (i) quench from random initial positions, and (ii) quasistatic shearing. By considering fraction jammed states as function packing for systems with numbers particles, we determine spatial correlation length critical exponent $\nu\approx 1$, show that corrections to are crucial analyzing data. earlier numerical results yielding $\nu<1$...

We consider the rheology of soft-core frictionless disks in two dimensions neighborhood athermal jamming transition. From numerical simulations bidisperse, overdamped particles, we argue that divergence viscosity below is characteristic hard-core limit, independent particular interaction. develop a mapping from to particles recovers all critical behavior found earlier scaling analyses. Using this derive relation gives exponent nonlinear Herschel-Bulkley above terms diverging jamming.

Molecular dynamic simulations are used to study the structural stability of gold nanorods upon heating. We show that global rod is governed by free energetics its surface. In particular, an instability surface facets nucleates a bulk leads both and reorganization rod. The reorganizes form new, more stable, {111} facets, while underlying fcc lattice completely reorients align with this new structure. Rods predominantly remain stable until melting.

The linear response of a thermal ensemble vortex pairs to an oscillating applied force is calculated by solving Fokker-Planck equation. result differs quantitatively but not qualitatively from estimate given in the work Ambegaokar, Halperin, Nelson, and Siggia.

We investigate the criticality of jamming transition for overdamped shear-driven frictionless disks in two dimensions different models energy dissipation: (i) Durian's bubble model with dissipation proportional to velocity difference particles contact, and (ii) ``mean-field'' approximation (i), due between particle average uniform shear flow velocity. By considering finite-size behavior pressure, pressure analog viscosity, macroscopic friction $\ensuremath{\sigma}/p$, we argue that these...

We carry out Monte Carlo simulations of the two-dimensional classical neutral Coulomb gas integer charges on a square and triangular lattice, find rich phase diagrams as function temperature chemical potential. At high densities, ground state becomes periodic charge we evidence suggesting that melting transitions these lattices are not always in universality class expected from symmetry analysis. compute inverse dielectric constant...

We carry out an extensive Monte Carlo study of phase transitions in two-dimensional (2D) superconducting networks, applied magnetic field, for square and honeycomb geometries. consider both systems with a dilute vortex density 1/q, dense near full frustration 1/2--1/q. The case gives the continuum limit as q\ensuremath{\rightarrow}\ensuremath{\infty}, serves model uniform film. For this case, we find transition temperature ${\mathit{T}}_{\mathit{c}}$\ensuremath{\sim}1/q, at which lattice...

The thermal conductance of a $^{4}\mathrm{He}$ film has been studied in conjunction with torsional oscillator measurements the superfluid response. A dramatic rise is observed just above Kosterlitz-Thouless transition temperature determined by oscillator. In agreement theoretical predictions Ambegaokar et al., found to diverge as exponential ${(T\ensuremath{-}{T}_{c})}^{\ensuremath{-}\frac{1}{2}}$ for $T\ensuremath{\rightarrow}{{T}_{c}}^{+}$.

Monte Carlo simulations of 2D vortex lattice melting in a thin superconducting film (or alternatively an array Josephson junctions) are performed the London limit. Finite size scaling analyses used to make detailed test dislocation mediated theory KTNHY. We find that transition is weakly first order, with jump shear modulus very close predicted by KTNHY theory. No hexatic liquid phase found.

We carry out Monte Carlo simulations of the uniformly frustrated three-dimensional XY model as a for vortex-line fluctuations in high-temperature superconductors an applied magnetic field. show, comparing systems different size, that there are two distinct phase transitions. At lower ${\mathit{T}}_{\mathit{c}\mathrm{\ensuremath{\perp}}}$, vortex lattice melts, and coherence is lost planes perpendicular to higher ${\mathit{T}}_{\mathit{c}\mathit{z}}$, tangle percolates throughout system,...

The shear-induced fluidization of a carbopol microgel is investigated during long start-up experiments using combined rheology and velocimetry in Couette cells varying gap widths boundary conditions. As already described [Divoux et al., {\it Phys. Rev. Lett.}, 2010, {\bf 104}, 208301], we show that the process this simple yield stress fluid involves transient shear-banding regime whose duration $\tau_f$ decreases as power law applied shear rate $\gp$. Here go one step further by an...

We numerically simulate mechanically stable packings of soft-core, frictionless, bidisperse disks in two dimensions, above the jamming packing fraction ϕ(J). For configurations with a fixed isotropic global stress tensor, we investigate fluctuations local ϕ(r) to test whether such display hyperuniformity that has been claimed exist exactly at our configurations, generated by rapid quench protocol, find persists only out finite length scale and this appears remain as system decreases towards...