Rotational bosonic current in a quasi-condensate confined in an optical toroidal trap

Abstract

We investigate the possibility of inducing a bosonic current which is rotational ( − → ∇× − → v = − → 0 ) in a pseudo 1D quasi-condensate confined in an optical toroidal trap. The stability of such a current is also analyzed using hydrodynamics approach. We find that such a current is uniform when the circular symmetry is preserved and energetically stable when the modes of elementary excitations are restricted to one dimension. This scheme allows to distinguish between a quasi and a true condensate by measuring the rotational spectra of the sample.

Scale-invariant thermodynamics of a toroidally trapped Bose gas

“…In the scale invariant regime given by Eq. ( 23) G(α) can be approximated by the quadratic expansion of the potential about the minimum (28). The integral (9), given by…”

“…Theoretical efforts have focussed on BECs far below T c . Many features of toroidal geometry have been studied, including topological phases [15], the stability of macroscopic persistent currents [16,17,18,19,20,21] , excitation spectra [22], atomic phase interference devices [23], vortex-vortex interactions [24], generation of excitations via stirring [25], dynamics of sonic horizons [26], parametric amplification of phonons [27], rotational current generation [28], the interplay of interactions and rotation [29], giant vortices [30], and vortex signatures [31]. Ideal gas theory has recently been used [32] to study the rapidly rotating Bose gas in a quartically stabilized harmonic trap realized at ENS [33].…”

Geometric scale invariance as a route to macroscopic degeneracy: Loading a toroidal trap with a Bose or Fermi gas

“…2(a) it is clear that the quantum depletion is not significantly enhanced in the toroid. We can gain some approximate quantitative understanding of this as follows: Using n(x) = (mU 0 n c (x)) 3/2 /3π 2 3 for the depletion at T = 0 from [33], to lowest order U 0 n c (x) ≈ µ ht (N ) − V (x), using the chemical potential from (17), and the harmonic-toroid density of states from the first term of (A9), we get in the harmonic toroid limit Fig. 2(a).…”

“…Many features of toroidal geometry have been studied, including topological phases [9], the stability of macroscopic persistent currents [10] , excitation spectra [11], atomic phase interference devices [12], vortex-vortex interactions [13], generation of excitations via stirring [14], dynamics of sonic horizons [15], parametric amplification of phonons [16], rotational current generation [17], the interplay of interactions and rotation [18], giant vortices [19], and vortex signatures [20]. Ideal gas theory has recently been used [21] to study the rapidly rotating Bose gas in a quartically stabilized harmonic trap realized at ENS [22].…”

Quantum simulation of non-trivial topology

“…In effect, by managing the internal interactions between the internal states, we will show how to turn an open 1D optical lattice into a system with periodic boundary conditions (PBC), a cylinder, a torus or a Möbius strip. Our proposal can be engineered also using other platforms and/or may be combined with other techniques.Such as the ones allowing for well-established toroidal compactifications [68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83], or the speckle potentials allowing to simulate in a controlled way disorder [84,85].The paper is organized as follows. Section 2 presents the general strategy to simulate non-trivial topology on a quantum system, while the experimental aspects are discussed in section 3.…”