Spatial distribution of superfluidity and superfluid distillation of Bose liquids

BEC-BCS crossover and the mobility edge: superfluid-insulator transitions and reentrant superfluidity in disordered Fermi gases

A superfluid-insulator transition is known to occur in strongly disordered Fermi gases, in both the BCS and BEC regimes; here, we address the properties of this transition across the BEC-BCS crossover. We argue that the critical disorder strength at which superfluidity is lost changes non-monotonically with detuning from Feshbach resonance, and that a reentrant superfluid phase arises for detunings near the fermionic mobility edge. Our analysis of the intermediate regime is quantitatively valid for narrow resonances and near four dimensions, and provides a simple physical picture of this regim…

Superfluidity and Stabilities of a Bose-Einstein condensate with periodically modulated interatomic interaction

We study theoretically the superfluidity and stability of a Bose-Einstein condensate (BEC) whose interatomic scattering length is periodically modulated with optical Feshbach resonance. Our numerical study finds that the properties of this periodic BEC are strongly influenced by the modulation strength. When the modulation strength is small, only the Bloch waves close to the Brillouin zone edge suffer both Landau and dynamical instabilities. When the modulation strength is strong enough, all Bloch waves become dynamically unstable. In other words, the periodic BEC loses its superfluidity compl…

Probing superfluidity of periodically trapped ultracold atoms in a cavity by transmission spectroscopy

We study a system of periodic Bose condensed atoms coupled to cavity photons using the input-output formalism. We show that the cavity will either act as a through pass Lorentzian filter when the superfluid fraction of the condensate is minimum or completely reflect the input field when the superfluid fraction is maximum. We show that by monitoring the ratio between the transmitted field and the reflected field, one can estimate the superfluid fraction.

Condensate-free superfluidity induced by frustrated proximity effect

Since the discovery of superfluidity in He4 and Landau's phenomenological theory, the relationship between Bose condensation and superfluidity has been intensely debated. He4 is known by now to be both superfluid and condensed at low temperature, and more generally, in dimension D\geq2, all superfluid bosonic models realized in experiments are condensed in their ground-state, the most recent example being provided by ultracold bosonic atoms trapped in an optical lattice. In this paper, it is shown that a 2D gas of bosons which is not condensed at T=0 can be achieved by populating a layer throu…

玻色-爱因斯坦凝聚、超流性与超导性的现代理论导论

Introduction to the Modern Theory of Bose-Einstein Condensation, Superfluidity, and Superconductivity

本文综述玻色-爱因斯坦凝聚、超流性与超导性的现代理论，给出相关热力学原理与运动方程，通过⁴He模拟获λ相变等结果，介绍高温超导统计力学理论并与传统方法批判性对比。

Twenty years of magnon Bose condensation and spin current superfluidity in 3He-B

20 years ago a new quantum state of matter was discovered and identified. The observed dynamic quantum state of spin precession in superfluid 3He-B bears the properties of spin current superfluidity, Bose condensation of spin waves -- magnons, off-diagonal long-range order and related phenomena of quantum coherence