Experimental demonstration of painting arbitrary and dynamic potentials for Bose–Einstein condensates

Abstract

There is a pressing need for robust and straightforward methods to create potentials for trapping Bose-Einstein condensates which are simultaneously dynamic, fully arbitrary, and sufficiently stable to not heat the ultracold gas. We show here how to accomplish these goals, using a rapidly-moving laser beam that "paints" a timeaveraged optical dipole potential in which we create BECs in a variety of geometries, including toroids, ring lattices, and square lattices. Matter wave interference patterns confirm that the trapped gas is a condensate. As a simple illustration of dynamics, we show that the technique can transform a toroidal condensate into a ring lattice and back into a toroid. The technique is general and should work with any sufficiently polarizable low-energy particles.

Shortcuts to adiabaticity: Fast-forward approach

“…V (x, t) in Fig. 2 could be realized with high resolution time-varying optical potentials "painted" by a tightly focused rapidly moving laser beam [37], or by means of spatial light modulators [38]. A simpler approximate approach would involve the combination of three Gaussian beams.…”

One- and two-dimensional solitons supported by singular modulation of quadratic nonlinearity

“…In optical media, spatially nonuniform Kerr nonlinearity can be induced by an accordingly designed inhomogeneous density of nonlinearity-inducing dopants [4], by an inhomogeneous distribution of detuning in a uniform resonant-dopant density [3], or in composite media assembled of different materials [5]. Similar nonlinearity landscapes are relevant in models of Bose-Einstein condensates, where virtually any landscape, controlled by the optical Feshbach resonance [6], can be "painted" in space by a rapidly moving laser beam [7]. In the same context, the nonlinearity can be patterned by means of the magnetic Feshbach resonance, using magnetic lattices [8].…”

Nonadiabatic creation of macroscopic superpositions with strongly correlated one-dimensional bosons in a ring trap

“…Most of the current proposals are based on two-mode Bose-Josephson junctions [3][4][5]. Experimental advances in the realization of ring traps [6][7][8][9][10][11][12] make it realistic to consider other macroscopic superpositions, eg the (collective-mode) superposition of superflow states carrying different values of angular momentum [13][14][15][16], where the coupling between angularmomentum states is provided by a localized barrier which breaks translational invariance; an artificial gauge field (or rotation) [17] gives rise to tunability equivalent to magnetic flux in a SQUID. As a consequence of the ring periodicity, the energy levels of the many-particle system as a function of the flux Φ associated with the artificial gauge field are periodic with period Φ 0 = 2π /m, m * anna.minguzzi@grenoble.cnrs.fr being the atomic mass.…”