Vibrational Mechanics in an Optical Lattice: Controlling Transport via Potential Renormalization

Abstract

We demonstrate theoretically and experimentally the phenomenon of vibrational resonance in a periodic potential, using cold atoms in an optical lattice as a model system. A high-frequency (HF) drive, with a frequency much larger than any characteristic frequency of the system, is applied by phase modulating one of the lattice beams. We show that the HF drive leads to the renormalization of the potential. We used transport measurements as a probe of the potential renormalization. The very same experiments also demonstrate that transport can be controlled by the HF drive via potential renormalization.

Site-selective particle deposition in periodically driven quantum lattices

“…Thereby, it has been shown that the interplay of a spatially periodic lattice potential and a driving force leads to a plethora of interesting nonequilibrium phenomena, a paradigmatic example being the celebrated "ratchet effect" where particles undergo directed motion despite the absence of any mean forces [9][10][11][12]. Besides that and triggered particularly by the upcoming ultracold atom experiments, the inclusion of a driving force has been used for the renormalization of the tunneling rates between adjacent lattice sites [13] or for the engineering of so-called artificial gauge fields [14,15], While the main focus has so far been on global driving forces that are the same everywhere in space, it has recently been shown how local modulations of the driving allow for extensive manipulations of the particles' classical dynamics leading to phenomena such as site-dependent particle trap ping [16,17], the spontaneous formation of density waves, or the emergence of order by the combination of disorder and driving [18][19][20].…”

Freezing, accelerating, and slowing directed currents in real time with superimposed driven lattices

“…We believe that our dynamical control of directed currents can be realized in experimental setups using cold atoms in driven optical lattices where the periodic potential is generated by counterpropagating laser beams of perpendicular polarization [12,18,20,31]. The resulting lattice can be driven by phase modulation using acousto-optical modulators and radio frequency generators which also allow to keep both lattices in phase and to implement a driving amplitude on length scales of the order of L [12,20].…”

“…The lateral oscillation of both lattices can be achieved by phase modulating both laser beams using standard techniques like acousto-optical modulators and radio frequency generators (see e.g. [18,31]). …”

Symmetries and transport in site-dependent driven quantum lattices

“…Because, originally these systems relied on the rectification of thermal noise they were seen as realizations of Brownian motors the corresponding research field being highly active (see [1] and references therein). As one of the many considered experimental playgrounds for ratchets physics, cold atoms loaded into driven optical lattices have proven to be particularly insightful since they allow for a precise control over the systems parameters [2][3][4][5][6]. While some of these experiments are carried out at moderate temperatures and allow for a classical treatment [2][3][4], others could reach ultracold temperatures and demonstrated the accessibility of Hamiltonian ratchet setups operating deep in the quantum regime [5,6].…”

“…As one of the many considered experimental playgrounds for ratchets physics, cold atoms loaded into driven optical lattices have proven to be particularly insightful since they allow for a precise control over the systems parameters [2][3][4][5][6]. While some of these experiments are carried out at moderate temperatures and allow for a classical treatment [2][3][4], others could reach ultracold temperatures and demonstrated the accessibility of Hamiltonian ratchet setups operating deep in the quantum regime [5,6]. The experimental advancements concerning these newly realized 'quantum ratchets' were accompanied by a substantial body of theoretical works (see [7][8][9][10][11][12][13][14] and references therein).…”