Related papers: Exploring the Berezinskii-Kosterlitz-Thouless Tran…
We investigate single-particle excitations and strong-coupling effects in a two-dimensional Fermi gas. Including pairing fluctuations within a Gaussian fluctuation theory, we calculate the density of states $\rho(\omega)$ near the…
One of the most relevant manifestations of the Beresinskii-Kosterlitz-Thouless transition occurs in quasi-two-dimensional superconducting systems. The experimental advances made in the last decade in the investigation of superconducting…
We study the two-dimensional attractive Hubbard model using the mapping onto the half-filled repulsive Hubbard model in a uniform magnetic field coupled to the fermion spins. The low-energy effective action for charge and pairing…
Phase diagrams and electronic transport properties of the helical states in purely two-dimensional (2D) Rashba superconductors coupled with in-plane Zeeman fields are studied. The continuum XY action is derived microscopically by…
In the two-dimensional superfluidity, the proliferation of the vortices and the anti-vortices results in a new class of phase transition, Berezinskii-Kosterlitz-Thouless (BKT) transition. This class of the phase transitions is also…
Recent studies of delocalization-localization transitions in disordered quantum chains have highlighted the role of rare, chain-breaking events that favor localization, in particular for high-energy eigenstates related to many-body…
We investigate the nature of the phase transition occurring in a planar XY-model spin system with dipole-dipole interactions. It is demonstrated that a Berezinskii-Kosterlitz-Thouless (BKT) type of phase transition always takes place at a…
We experimentally investigate the first-order correlation function of a trapped Fermi gas in the two-dimensional BEC-BCS crossover. We observe a transition to a low-temperature superfluid phase with algebraically decaying correlations. We…
We report direct evidence of superfluidity in a quasi two-dimensional Bose gas by observing its dynamical response to a collective excitation. Relying on a novel local correlation analysis, we are able to probe inhomogeneous clouds and…
We study the effect of spin-orbit coupling on both the zero-temperature and non-zero temperature behavior of a two-dimensional (2D) Fermi gas. We include a generic combination of Rashba and Dresselhaus terms into the system Hamiltonian,…
A spin-orbit coupled two-dimensional (2D) Bose gas is shown to simultaneously possess quasi and true long-range order in the total and relative phase sectors, respectively. The total phase undergoes a Berenzinskii- Kosterlitz-Thouless…
We reveal the key role of the $d$-wave symmetry of the superconducting gap in strongly coupled two-dimensional superconductors in determining the properties of the Berezinskii-Kosterlitz-Thouless (BKT) transition, associated with a sizable…
Very recently quasi two-dimensional (2D) systems made of attractive fermionic alkali-metal atoms with a widely tunable interaction due to Fano-Feshbach resonances have been realized. In this way it has been achieved the 2D crossover from…
We report the observation of the Berezinskii-Kosterlitz-Thouless transition for a 2D gas of exciton-polaritons, and through the joint measurement of the first-order coherence both in space and time we bring compelling evidence of a…
We theoretically investigate the superfluid-normal-state Berezinskii-Kosterlitz-Thouless transition in a binary mixture of bosonic atoms with Rabi coupling under balanced densities. We find the nonmonotonic behavior of the transition…
We theoretically investigate first and second sound of a two-dimensional (2D) atomic Bose gas in harmonic traps by solving Landau's two-fluid hydrodynamic equations. For an isotropic trap, we find that first and second sound modes become…
We perform large-scale, numerically exact calculations on the two-dimensional interacting Fermi gas with a contact attraction. Reaching much larger lattice sizes and lower temperatures than previously possible, we determine systematically…
It is known that the loss of phase coherence of Cooper pairs in two-dimensional (2D) superconductivity corresponds to the unbinding of vortex-antivortex pairs with the quasi-long-range order (quasi-LRO) in the order-parameter phase field,…
In a recent article [R. Bombin, F. Mazzanti and J. Boronat, Phys. Rev. A100, 063614 (2019)], it is contended that a two-dimensional system of dipolar bosons, with dipole moments aligned at particular angles with respect to the direction…
We describe a recent experiment performed with rubidium atoms ($^{87}$Rb), aiming at studying the coherence properties of a two-dimensional gas of bosonic particles at low temperature. We have observed in particular a…