Transport controlled by Poincaré orbit topology in a driven inhomogeneous lattice gas

Abstract

In periodic quantum systems which are both homogeneously tilted and driven, the interplay between drive and Bloch oscillations controls transport dynamics. Using a quantum gas in a modulated optical lattice, we show experimentally that inhomogeneity of the applied force leads to a rich new variety of dynamical behaviors controlled by the drive phase, from self-parametrically-modulated Bloch epicycles to adaptive driving of transport against a force gradient to modulation-enhanced monopole modes. Matching experimental observations to fit-parameter-free numerical predictions of time-dependent band theory, we show that these phenomena can be quantitatively understood as manifestations of an underlying inhomogeneity-induced phase space structure, in which topological classification of stroboscopic Poincaré orbits controls the transport dynamics.

Super-Bloch oscillations with parametric modulation of a parabolic trap

“…A quick large space spreading has also observed in experiments with 7 Li atoms where the lattice amplitude is modulated in the presence of a static trap with displaced origin [36]. Here, we find that opposite to a modulation of the lattice, the modulation of the force provides an easy visualization of the modulation effects on wavepacket dynamics by monitoring the dynamics in k-space.…”

“…Here, we find that opposite to a modulation of the lattice, the modulation of the force provides an easy visualization of the modulation effects on wavepacket dynamics by monitoring the dynamics in k-space. As in [36] the dynamics occur on a larger spatial scale, the phenomenon shown here would result in more pronounced losses. Therefore we use in our analysis the parameters of an experiment performed with 87 Rb atoms [37], for which BOs have been shown [26].…”

Six-dimensional time-space crystalline structures

“…In the present letter, we demonstrate the notion of time-space crystals (TSC) that support both spatial and temporal periodic structures simultaneously [41][42][43][44][45][46][47]. We begin with a single particle moving in a one-dimensional (1D) spatially periodic potential.…”

Two-dimensional Thouless pumping in time-space crystalline structures

“…Recent systematic studies resulted in a growing list of condensed-matter phases reproduced or generalized in the time domain: Anderson and manybody localization, Mott insulator, topological and other phases have been reported [6][7][8][9][10][11][12][13][14][15][16]. Another extension was provided by the fresh proposal of time-space crystalline structures [17], see also [18][19][20][21][22][23][24][25], that combine periodicity in time and in space. Viewed as an introduction of synthetic dimensions, such time-space lattices pave the way to potential doubling of the number of dimensions.…”