Finite-temperature dynamics of a bosonic Josephson junction

Abstract

In the framework of the stochastic projected Gross-Pitaevskii equation we investigate finite-temperature dynamics of a bosonic Josephson junction (BJJ) formed by a Bose-Einstein condensate of atoms in a two-well trapping potential. We extract the characteristic properties of the BJJ from the stationary finite-temperature solutions and compare the dynamics of the system with the resistively shunted Josephson model. Analyzing the decay dynamics of the relative population imbalance we estimate the effective normal conductance of the junction induced by thermal atoms. The calculated normal conductance at various temperatures is then compared with predictions of the noise-less model and the model of ballistic transport of thermal atoms.

Critical Transport and Vortex Dynamics in a Thin Atomic Josephson Junction

“…This is characterized by high-frequency coherent oscillations of the population imbalance around a non-zero value, driven by a monotonically increasing relative phase [10,13,[15][16][17][18]. Even without thermally induced decay of the population imbalance [12,17,21], the stability of MQST depends on whether vortices nucleated inside the barrier annihilate therein [22,23], or penetrate into the superfluid reservoirs. Re-cent experiments with inhomogeneous three-dimensional Fermi superfluids [24,25] revealed the intimate connection between phase slippage and dissipation arising from vortices created within the barrier and shed into the superfluid.…”

“…We stress that the standard twomode model [10,13] that captures both Josephson and MQST dynamics of previous experiments [16,18] is out of its validity range due to the considered values of the ratio V 0 /µ and to the thinness of the junctions [38]. Although dissipative effects can be phenomenologically modeled by damped two-mode [21,35,36] and RSJ-circuital models [7], such approaches provide limited insight into the microscopic dissipative processes.…”

Projected Gross–Pitaevskii Equation for Ring-Shaped Bose–Einstein Condensates

“…We conclude that this is the optimal cut-off energy for such system and use only this value for the rest of this section. It is worth noting that, in realistic finite-temperature calculations, the choice of the cut-off energy is a nontrivial problem, and its definition is related to the temperature of the sys- tem [10,11,19]. For the purposes of the present feasibility study, which does not address any real finitetemperature processes, the cut-off value is considered only as a measure of the basis size and, consequently, the quality of a spectral representation of the condensate wave function.…”

“…The latter will be the main focus of the present work. A wide range of physical problems addressed with PGPE and its modifications includes, in particular, the Bosecondensation and quasicondensation [6][7][8], dynamical generation [9] and decay [10] of quantum vortices, and dissipative bosonic Josephson effect [11].…”

dc to ac Josephson transition in a dc atom superconducting quantum interference device

“…( 14) a term proportional to the RCSJ normal current −G∆µ, along with a phenomenological value of the conductance G [20]. More elaborate procedures that quantitatively take into account the effect of damping at a finite temperature could be carried out by resorting to a stochastic projected GP equation [42].…”