相关论文: Vortex excitation in superfluid 4He: A Diffusion M…

We study the superfluid transition of $^4$He in aerogel by Monte Carlo simulations and finite size scaling analysis. Aerogel is a highly porous silica glass, which we model by a diffusion limited cluster aggregation model. The superfluid is…

We report diffusion quantum Monte Carlo calculations of three-dimensional Wigner crystals in the density range r_s=100-150. We have tested different types of orbital for use in the approximate wave functions but none improve upon the simple…

The structure and energetics of superflow around quantized vortices, and the motion inherited by these vortices from this superflow, are explored in the general setting of the superfluidity of helium-four in arbitrary dimensions. The…

An equation previously proposed to describe the evolution of vortex line density in rotating counterflow turbulent tangles in superfluid helium is generalized to incorporate nonvanishing barycentric velocity and velocity gradients. Our…

Recently the Kelvin wave cascade process in superfluid $^4$He at very low temperatures was discussed. In this mechanism, the dynamics of the waves on the vortex lines plays an important role. In order to investigate this mechanism, we study…

We present a comparative study of the rotational characteristics of various molecule-doped 4He clusters using quantum Monte Carlo techniques. The theoretical conclusions obtained from both zero and finite temperature Monte Carlo studies…

We present a numerical study, using the vortex filament model, of vortex tangles in a flow of pure superfluid $^4$He in the $T = 0$ limit through a channel of width $D = 1$ mm for various applied velocities $V$. The flat channel walls are…

We have measured the mass diffusion coefficient D of 3He in superfluid 4He at temperatures lower than were previously possible. The experimental technique utilizes scintillation light produced when neutron react with 3He nuclei, and allows…

Andreev scattering of thermal excitations is a powerful tool for studying quantized vortices and turbulence in superfluid He3-B at very low temperatures. We write Hamilton's equations for a quasiparticle in the presence of a vortex line,…

We have performed quantum Monte Carlo simulations measuring the finite size and temperature superfluid response of helium-4 to the linear and rotational motion of the walls of a nanopore. Within the two-fluid model, the portion of the…

We investigate the interaction potential of superconducting vortices at the full quantum level. We formulate the interaction potential in a constrained path integral and calculate it by the quantum Monte Carlo simulation. The vortex-vortex…

As the magnetic field penetrates the surface of a superconductor, it results in the formation of flux-vortices. It has been predicted that the flux-vortices will have a charged vortex core and create a dipolelike electric field. Such a…

We introduce a new method of statistical analysis to characterise the dynamics of turbulent fluids in two dimensions. We establish that, in equilibrium, the vortex distributions can be uniquely connected to the temperature of the vortex…

Monte Carlo simulations of 2D vortex lattice melting in a thin superconducting film (or alternatively an array of Josephson junctions) are performed in the London limit. Finite size scaling analyses are used to make a detailed test of the…

We report preliminary results of the complementary experimental and numerical studies on spatiotemporal tangle development and streamwise vortex line density (VLD) distribution in counterflowing $^4$He. The experiment is set up in a long…

Monte Carlo simulation is one of the most important tools in the study of diffusion processes. For constant diffusion coefficients, an appropriate Gaussian distribution of particle's steplengths can generate exact results, when compared…

We study lithium systems over a range of number of atoms, e.g., atomic anion, dimer, metallic cluster, and body-centered cubic crystal by the diffusion Monte Carlo method. The calculations include both core and valence electrons in order to…

We present diffusion Monte Carlo (DMC) results on a new metastable, superfluid phase above the crystal ground state in two-dimensional 4He at densities > 0.065 1/A^2. The state is anisotropic with hexatic orbital order. This implies that…

We numerically study the spatial spreading of quantized vortex lines in low temperature liquid helium. The vortex lines, initially concentrated in a small region, diffuse into the surrounding vortex-free helium, a situation which is typical…

Path Integral Monte Carlo calculations of the superfluid density throughout ^4He droplets doped with linear impurities (HCN)_n are presented. After deriving a local estimator for the superfluid density distribution, we find a decreased…