Related papers: Quantum orientational melting of mesoscopic cluste…
In a recent paper ["Cluster Model of Decagonal Tilings" (to be published in Phys. Rev. B)], we have introduced a cluster model for decagonal tilings in two dimensions. This model is now extended to three dimensions. Two-dimensional tilings…
Monodisperse ensembles of particles that have cluster crystalline phases at low temperatures can model a number of physical systems, such as vortices in type-1.5 superconductors, colloidal suspensions and cold atoms. In this work we study a…
The superfluidity and Bose-Einstein condensation of indirect excitons in two-dimensional quantum dot are studied by path-integral Monte Carlo simulations. The temperature dependence of superfluid and bose-condensed fraction are calculated…
Macroscopically ordered arrays of vortices in quantum liquids, such as superconductors, He-II, and atom Bose-Einstein Condensates (BEC), demonstrate macroscopic coherence in flowing superfluids [1-4]. Despite of the rich variety of systems…
We study the quantum melting of stripe phases in models with competing short range and long range interactions decaying with distance as $1/r^{\sigma}$ in two space dimensions. At zero temperature we find a two step disordering of the…
Particle fluctuations in mesoscopic Bose systems of arbitrary spatial dimensionality are considered. Both ideal Bose gases and interacting Bose systems are studied in the regions above the Bose-Einstein condensation temperature $T_c$ as…
Inspired by recent experiments on Bose-Einstein condensates in ring traps, we investigate the topological properties of the phase of a one-dimensional Bose field in the presence of both thermal and quantum fluctuations -- the latter ones…
A mesoscopic system of indirect dipolar bosons trapped by a harmonic potential is considered. The system has a number of physical realizations including dipole excitons, atoms with large dipolar moment, polar molecules, Rydberg atoms in…
We exploit the Quantum Cluster Variational Method (QCVM) to study the $J_1$-$J_2$ model for quantum Ising spins. We first describe the QCVM and discuss how it is related to other Mean Field approximations. The phase diagram of the model is…
We study the two-dimensional spatially separated electron-hole system with density imbalance at absolute zero temperature. By means of the mean-field theory, we find that the Fulde-Ferrell state is fairly stabilized by the order parameter…
We study the thermodynamics of ultrasmall metallic grains with the mean level spacing comparable or larger than the pairing correlation energy in the whole range of temperatures. A complete picture of the thermodynamics in such systems is…
We investigate the number fluctuations in small cells of quantum gases pointing out important deviations from the thermodynamic limit fixed by the isothermal compressibility. Both quantum and thermal fluctuations in weakly as well as highly…
We study the fluctuation properties of a one-dimensional many-body quantum system composed of interacting bosons, and investigate the regimes where quantum noise or, respectively, thermal excitations are dominant. For the latter we develop…
Wigner crystallization of electrons in a 2D quantum dots is reported. It proceeds in two stages: I) via radial ordering of electrons on shells and II) freezing of the inter-shell rotation. The phase boundary of the crystal is computed in…
The tunneling between the two ground states of an Ising ferromagnet is a typical example of many-body tunneling processes between two local minima, as they occur during quantum annealing. Performing quantum Monte Carlo (QMC) simulations we…
The point at absolute zero where matter becomes unstable to new forms of order is called a quantum critical point (QCP). The quantum fluctuations between order and disorder that develop at this point induce profound transformations in the…
The dynamics of an exciton-polariton superfluid resonantly pumped in a semiconductor microcavity are investigated by mean-field theory. Modulational instability develops into crystalline order and then ordered and disordered states…
A dimer of bound atoms cannot melt, only dissociate. Bulk metals show a well defined first order transition between their solid and liquid phases. The appearance of the melting transition is explored for increasing clusters sizes via the…
The theory describing quantum-smectics in 2+1 dimensions, based on topological quantum melting is presented. This is governed by a dislocation condensate characterized by an ordering of Burger's vector and this `dual shear superconductor'…
Fractional quantum Hall liquids can accomodate various degrees of spatial ordering. The most likely scenarios are a Hall hexatic, Hall smectic, and Hall crystal, in which respectively orientational, one--dimensional translational, and…