Atom-optics approach to studying transport phenomena

Abstract

We present a simple experimental scheme, based on standard atom optics techniques, to design highly versatile model systems for the study of single particle quantum transport phenomena. The scheme is based on a discrete set of free-particle momentum states that are coupled via momentumchanging two-photon Bragg transitions, driven by pairs of interfering laser beams. In the effective lattice models that are accessible, this scheme allows for single-site detection, as well as site-resolved and dynamical control over all system parameters. We discuss two possible implementations, based on state-preserving Bragg transitions and on state-changing Raman transitions, which respectively allow for the study of nearly arbitrary single particle Abelian U(1) and non-Abelian U(2) lattice models. -for the quantum simulation of myriad physical phenomena, especially those related to condensed matter [4,5].For the study of single electron transport phenomena, photonic [6][7][8][9][10][11] and cold atom [12][13][14][15][16][17][18][19][20] simulators have made great progress in the experimental exploration of disordered and topological systems, while offering largely complementary capabilities and challenges. Photonic simulators generally permit control of system parameters and the detection of probability distributions at the microscopic, site-resolved level. However, the use of real materials as the medium for light transport makes these systems susceptible to inherent disorder in sample preparation [21] and to absorption in the material [22], and makes simulations in higher spatial dimensions and timedependent control of system parameters non-trivial. For cold atoms, pristine and dynamically variable potential landscapes can be constructed based on their interaction with laser light. However, a microscopic control over system parameters is difficult to realize in atomic systems. Moreover, finite temperatures and the absence of hardwall system boundaries have limited the observation of topological phenomena.Here, we propose an atom optics-based [23][24][25][26] approach to the study of coherent transport phenomena, which incorporates many of the desired features of atomic and photonic experimental platforms. The scheme we describe is motivated in spirit by magnetic resonance-based * bgadway@illinois.edu techniques for local manipulation via global field addressing [27,28]. In the context of studying transport phenomena, however, we consider an inhomogeneous landscape of site energies, with unique energy differences between neighboring sites, which defines unique tunneling resonances for each site-to-site link. Combined with global field addressing that can drive transitions between neighboring sites, and in particular by simultaneous driving of many such transitions in an amplitude, frequency, and phase-controlled manner, this would allow for local control over the parameters of a discrete lattice model relevant to myriad coherent transport phenomena.Atom optics offers a natural candidate system featuring a quadratic energy lan...

Engineering a Flux-Dependent Mobility Edge in Disordered Zigzag Chains

“…A more detailed description of this momentum-space lattice scheme can be found in Refs. [17][18][19][20].…”

Engineering tunable local loss in a synthetic lattice of momentum states

“…We validate this picture of effective loss by comparing numerical simulations of both the full dynamics (with tunneling coefficients t sys , t link , and t res ) and the effective dynamics (with equivalent inter-well tunneling coefficient t sys and effective right well loss coefficient t t eff link 2 res G = ). Moreover, we experimentally validate this protocol by realizing a tunable effective loss from one well of a synthetic double well of momentum states [50,59]. The experiment begins by loading a three-dimensional magneto-optical trap (MOT) of rubidium-87 atoms, employing a 2D-MOT transfer to 3D-MOT setup.…”

“…. This scheme can easily be implemented in the context of momentum-space lattices [50,59]. We now compare the dynamics under two lossy Hamiltonians: one 'full' version that features a loss term G  acting only on ñ | , and an 'effective' Hamiltonian that includes only ñ | , but with effective, site-dependent loss coefficients j , G  .…”

Correlated Dynamics in a Synthetic Lattice of Momentum States

“…There has been recent interest in extending quantum simulation studies from real-space potentials to synthetic lattice systems composed of discrete internal [3,4] or external [5] states. These synthetic dimensions enable many unique capabilities for quantum simulation, including new approaches to engineering nontrivial topology [4,6], access to higher dimensions [3], and potential insensitivity to finite motional temperature.The recent development of momentum-space lattices (MSLs), based on the use of discrete momentum states as effective sites, has introduced a fully synthetic approach to simulating lattice dynamics [7][8][9][10][11]. As compared to partially synthetic systems [12,13], fully synthetic lattices offer complete microscopic control of system parameters.…”

“…The recent development of momentum-space lattices (MSLs), based on the use of discrete momentum states as effective sites, has introduced a fully synthetic approach to simulating lattice dynamics [7][8][9][10][11]. As compared to partially synthetic systems [12,13], fully synthetic lattices offer complete microscopic control of system parameters.…”