Two unrelated problems can be reduced to a model of a Bose gas interacting with a gauge field: (i) the effect of thermal fluctuations on a system of vortices in bulk superconductors in fields ${\mathit{H}}_{\mathit{c}1}$ \ensuremath{\ll}H\ensuremath{\ll} ${\mathit{H}}_{\mathit{c}2}$ , and (ii) charged, spinless excitations in two-dimensional (2D) strongly correlated electron systems. Both problems are important for the theory of high-temperature superconductors. We study this model in three regimes: at finite temperatures, assuming that the gauge field is purely transverse; at T=0, for the purely static (2D Coulomb) interaction; and at T=0, for a weak Coulomb interaction and a strong transverse one. Transverse interactions suppress the temperature of the superfluid transition significantly. A sufficiently strong transvese interaction is shown to produce a phase separation as the temperature decreases (in the absence of Coulomb repulsion). If there is Coulomb repulsion, the ground state does not have off-diagonal long-range order but the superfluid density is not zero unless the Coulomb constant exceeds a critical value. Sufficiently strong coupling to the transverse field destroys superfluidity as well. In the normal state formed at large couplings, the translational invariance is intact. We propose a bosonic ground state that is not superfluid at T=0. We discuss the implications of these results both for vortex liquids and strongly correlated electron systems.Two unrelated problems can be reduced to a model of a Bose gas interacting with a gauge field: (i) the effect of thermal fluctuations on a system of vortices in bulk superconductors in fields ${\mathit{H}}_{\mathit{c}1}$\ensuremath{\ll}H\ensuremath{\ll}${\mathit{H}}_{\mathit{c}2}$, and (ii) charged, spinless excitations in two-dimensional (2D) strongly correlated electron systems. Both problems are important for the theory of high-temperature superconductors. We study this model in three regimes: at finite temperatures, assuming that the gauge field is purely transverse; at T=0, for the purely static (2D Coulomb) interaction; and at T=0, for a weak Coulomb interaction and a strong transverse one. Transverse interactions suppress the temperature of the superfluid transition significantly. A sufficiently strong transvese interaction is shown to produce a phase separation as the temperature decreases (in the absence of Coulomb repulsion). If there is Coulomb repulsion, the ground state does not have off-diagonal long-range order but the superfluid density is not zero unless the Coulomb constant exceeds a critical value. Sufficiently strong coupling to the transverse field destroys superfluidity as well. In the normal state formed at large couplings, the translational invariance is intact. We propose a bosonic ground state that is not superfluid at T=0. We discuss the implications of these results both for vortex liquids and strongly correlated electron systems.

Physical review. B, Condensed matterDec 1, 199382 citations

Superfluid behavior of a 2D Bose gas

J. Beugnon

Bulletin of the American Physical SocietyJun 5, 20130 citations

Quasicondensate and superfluid fraction in the two-dimensional charged boson gas at finite temperature

Ezio Strepparola, Anna Minguzzi, M. P. Tosi

The Bogoliubov--de Gennes equations are solved for the Coulomb Bose gas describing a fluid of charged bosons at finite temperature. The approach is applicable in the weak-coupling regime and the extent of its quantitative usefulness is tested in the three-dimensional fluid, for which diffusion Monte Carlo data are available on the condensate fraction at zero temperature. The one-body density matrix is then evaluated by the same approach for the two-dimensional fluid with ${e}^{2}/r$ interactions, to demonstrate the presence of a quasicondensate from its power-law decay with increasing distance and to evaluate the superfluid fraction as a function of temperature at weak coupling.The Bogoliubov--de Gennes equations are solved for the Coulomb Bose gas describing a fluid of charged bosons at finite temperature. The approach is applicable in the weak-coupling regime and the extent of its quantitative usefulness is tested in the three-dimensional fluid, for which diffusion Monte Carlo data are available on the condensate fraction at zero temperature. The one-body density matrix is then evaluated by the same approach for the two-dimensional fluid with ${e}^{2}/r$ interactions, to demonstrate the presence of a quasicondensate from its power-law decay with increasing distance and to evaluate the superfluid fraction as a function of temperature at weak coupling.

arXiv:cond-mat/0012171Physical review. B, Condensed matterFeb 14, 20018 citations

Drag effect for a bilayer charged-Bose-gas system

B. Tanatar, A. K. Das

The Coulomb-drag effect, which has previously been considered theoretically and experimentally for a system of two electron gas layers, is studied for a system of two charged-Bose-gas (CBG) layers within an analytically solvable model. We consider a bilayer CBG in the presence of counterflow which, in superfluid mixtures and in spatially separated superconductors, leads to a drag effect. We investigate the effects of counterflow on the collective excitations, interaction energy, screened interactions, induced charge densities, and plasmon density of states in the bilayer CBG. These quantities, many of which have not been considered in connection with Coulomb drag in a bilayer electron gas, show how the many-body properties are affected, and thus provide additional insights into the drag effect. \textcopyright{} 1996 The American Physical Society.The Coulomb-drag effect, which has previously been considered theoretically and experimentally for a system of two electron gas layers, is studied for a system of two charged-Bose-gas (CBG) layers within an analytically solvable model. We consider a bilayer CBG in the presence of counterflow which, in superfluid mixtures and in spatially separated superconductors, leads to a drag effect. We investigate the effects of counterflow on the collective excitations, interaction energy, screened interactions, induced charge densities, and plasmon density of states in the bilayer CBG. These quantities, many of which have not been considered in connection with Coulomb drag in a bilayer electron gas, show how the many-body properties are affected, and thus provide additional insights into the drag effect. \textcopyright{} 1996 The American Physical Society.

Physical review. B, Condensed matterNov 15, 199622 citations

Two unrelated problems can be reduced to a model of a Bose gas interacting with a gauge field: (i) the effect of thermal fluctuations on a system of vortices in bulk superconductors in fields

{\mathit{H}}_{\mathit{c}1}

\ensuremath{\ll}H\ensuremath{\ll}

{\mathit{H}}_{\mathit{c}2}

, and (ii) charged, spinless excitations in two-dimensional (2D) strongly correlated electron systems. Both problems are important for the theory of high-temperature superconductors. We study this model in three regimes: at finite temperatures, assuming that the gauge field is purely transverse; at T=0, for the purely static (2D Coulomb) interaction; and at T=0, for a weak Coulomb interaction and a strong transverse one. Transverse interactions suppress the temperature of the superfluid transition significantly. A sufficiently strong transvese interaction is shown to produce a phase separation as the temperature decreases (in the absence of Coulomb repulsion). If there is Coulomb repulsion, the ground state does not have off-diagonal long-range order but the superfluid density is not zero unless the Coulomb constant exceeds a critical value. Sufficiently strong coupling to the transverse field destroys superfluidity as well. In the normal state formed at large couplings, the translational invariance is intact. We propose a bosonic ground state that is not superfluid at T=0. We discuss the implications of these results both for vortex liquids and strongly correlated electron systems.

{e}^{2}/r

interactions, to demonstrate the presence of a quasicondensate from its power-law decay with increasing distance and to evaluate the superfluid fraction as a function of temperature at weak coupling.