Now showing items 1-20 of 78

• #### 4He adsorbed outside a single carbon nanotube ﻿

(2012-10-08)
Article
Open Access
The phase diagrams of 4He adsorbed on the external surfaces of single armchair carbon nanotubes with radii in the range 3.42–10.85 Å are calculated using the diffusion Monte Carlo method. For nanotubes narrower than a ...
• #### Atomic monolayer deposition on the surface of nanotube mechanical resonators ﻿

(2014-05-14)
Article
Open Access
We study monolayers of noble gas atoms (Xe, Kr, Ar, and Ne) deposited on individual ultraclean suspended nanotubes. For this, we record the resonance frequency of the mechanical motion of the nanotube, since it provides a ...
• #### Berezinskii-Kosterlitz-Thouless transition in two-dimensional dipolar stripes ﻿

(American Physical Society (APS), 2019-12-05)
Article
Open Access
A two-dimensional quantum system of dipoles, with a polarization angle not perpendicular to the plane, shows a transition from a gas to a stripe phase. We have studied the thermal properties of these two phases using the ...
• #### Composite boson description of a low-density gas of excitons ﻿

(2017-10-13)
Article
Open Access
Ground-state properties of a fermionic Coulomb gas are calculated using the fixed-node diffusion Monte Carlo method. The validity of the composite boson description is tested for different densities. We extract the ...
• #### Diffusion Monte Carlo methods for spin-orbit-coupled ultracold Bose gases ﻿

(American Physical Society (APS), 2018-11-27)
Article
Open Access
We present two diffusion Monte Carlo (DMC) algorithms for systems of ultracold quantum gases featuring synthetic spin-orbit interactions. The first one is a spin-integrated DMC method which provides fixed-phase energy ...
• #### Dilute dipolar quantum droplets beyond the extended Gross-Pitaevskii equation ﻿

(American Physical Society, 2019-11-08)
Article
Open Access
Dipolar quantum droplets are exotic quantum objects that are self-bound due to the subtle balance of attraction, repulsion, and quantum correlations. Here we present a systematic study of the critical atom number of these ...
• #### Dipolar Bose Supersolid Stripes ﻿

(2017-12-20)
Article
Open Access
We study the superfluid properties of a system of fully polarized dipolar bosons moving in the XY plane. We focus on the general case where the polarization field forms an arbitrary angle a with respect to the Z axis, ...
• #### Dislocation structure and mobility in hcp rare-gas solids: quantum versus classical ﻿

(Multidisciplinary Digital Publishing Institute (MDPI), 2018-02-01)
Article
Open Access
We study the structural and mobility properties of edge dislocations in rare-gas crystals with the hexagonal close-packed (hcp) structure by using classical simulation techniques. Our results are discussed in the light of ...
• #### Distinguishability, degeneracy, and correlations in three harmonically trapped bosons in one dimension ﻿

(2014-12-01)
Article
Open Access
We study a system of two bosons of one species and a third atom of a second species in a one-dimensional parabolic trap at zero temperature. We assume contact repulsive inter- and intraspecies interactions. By means of an ...
• #### Droplets of trapped quantum dipolar bosons ﻿

(2016-11-10)
Article
Open Access
Strongly interacting systems of dipolar bosons in three dimensions confined by harmonic traps are analyzed using the exact path integral ground-state Monte Carlo method. By adding a repulsive two-body potential, we find a ...
• #### Dynamic structure factor of liquid He 4 across the normal-superfluid transition ﻿

(2016-03-08)
Article
Open Access
We have carried out a microscopic study of the dynamic structure factor of liquid He4 across the normal-superfluid transition temperature using the path integral Monte Carlo method. The ill-posed problem of the inverse ...
• #### Dynamic structure function of a cold Fermi gas at unitarity ﻿

(Institute of Physics (IOP), 2014-08-14)
Article
Open Access
We present a theoretical study of the dynamic structure function of a resonantly interacting two-component Fermi gas at zero temperature. Our approach is based on dynamic many-body theory able to describe excitations in ...
• #### Elastic constants of incommensurate solid 4He from diffusion Monte Carlo simulations ﻿

(2013-06-28)
Article
Open Access
We study the elastic properties of incommensurate solid 4He in the limit of zero temperature. Specifically, we calculate the pressure dependence of the five elastic constants (C11, C12, C13, C33, and C44), longitudinal and ...
• #### Elusive structure of helium trimers ﻿

(2016-08-23)
Article
Open Access
Over the years many He–He interaction potentials have been developed, some very sophisticated, including various corrections beyond the Born–Oppenheimer approximation. Most of them were used to predict properties of helium ...
• #### Ferromagnetic transition of a two-component Fermi gas of hard spheres ﻿

(2012-03-12)
Article
Open Access
We use microscopic many-body theory to analyze the problem of itinerant ferromagnetism in a repulsive atomic Fermi gas of hard spheres. Using simple arguments we show that the available theoretical predictions for the onset ...
• #### Few trapped quantum dipoles: quantum versus classical structures ﻿

(2018-01-31)
Article
Open Access
We analyze the ground state of a two-dimensional quantum system of a few strongly confined dipolar bosons. Dipoles arrange in different stable structures that depend on the tilting polarization angle and the anisotropy of ...
• #### Few-body bound states of two-dimensional bosons ﻿

(American Physical Society (APS), 2020-04-07)
Article
Open Access
We study clusters of the type $A_NB_M$ with N=M=3 in a two-dimensional mixture of A and B bosons, with attractive AB and equally repulsive AA and BB interactions. In order to check universal aspects of the problem, we ...
• #### Finite-range effects in ultradilute quantum drops ﻿

(2020-05-27)
Article
Open Access
In the first experimental realization of dilute Bose–Bose liquid drops using two hyperfine states of 39K some discrepancies between theory and experiment were observed. The standard analysis of the data using the Lee–Huang–Yang ...
• #### First-principles modeling of quantum nuclear effects and atomic interactions in solid He-4 at high pressure ﻿

(2015-01-07)
Article
Open Access
We present a first-principles computational study of solid He-4 at T = 0 K and pressures up to similar to 160 GPa. Our computational strategy consists in using van der Waals density functional theory (DFT-vdW) to describe ...
• #### First-principles modeling of three-body interactions in highly compressed solid helium ﻿

(2015-12-31)
Article
Open Access
We present a set of three-body interaction models based on the Slater-Kirkwood (SK) potential that are suitable for the study of the energy, structural, and elastic properties of solid He4 at high pressure. Our effective ...