Strain and pseudo-magnetic fields in optical lattices from density-assisted tunneling

Abstract

Applying time-periodic modulations is routinely used to control and design synthetic matter in quantum-engineered settings. In lattice systems, this approach is explored to engineer band structures with non-trivial topological properties, but also to generate exotic interaction processes. A prime example is density-assisted tunneling, by which the hopping amplitude of a particle between neighboring sites explicitly depends on their respective occupations. Here, we show how densityassisted tunneling can be tailored in view of simulating the effects of strain in synthetic graphene-type systems. Specifically, we consider a mixture of two atomic species on a honeycomb optical lattice: one species forms a Bose-Einstein condensate in an anisotropic harmonic trap, whose inhomogeneous density profile induces an effective uniaxial strain for the second species through density-assisted tunneling processes. In direct analogy with strained graphene, the second species experiences a pseudo magnetic field, hence exhibiting relativistic Landau levels and the valley Hall effect. Our proposed scheme introduces a unique platform for the investigation of strain-induced gauge fields and their possible interplay with quantum fluctuations and collective excitations.

Topological phonons in arrays of ultracold dipolar particles

“…Similar physics has been observed, for instance, in optical systems [85,86] where the lattice spacing can be engineered at will in the fabrication process. The simulation of strain with ultracold atoms instead has not been realized so far, although different theoretical proposals are already available [87,88]. The purpose of this section is to show how the physics of strain can be explored with dipolar particles.…”

Few-to-many vortex states of density-angular-momentum coupled Bose-Einstein condensates

“…To address this, there is a growing subfield whose aim instead is to simulate dynamical [44][45][46] gauge potentials. Then, one methodology to overcome this problem is to directly couple the gauge potential and the quantum state of the system, which naturally introduces a time-dependent feedback in the form of a densitydependent gauge potential either in the continuum [47] or for lattice based theories [48][49][50][51]. The associated phenomenology has revealed a wealth of unusual effects; in the one-dimensional context the theory violates Kohn's theorem [52,53] and possesses exact chiral soliton solutions [54][55][56][57][58], as well as exhibiting unusual transport effects when confined in double well [59] or harmonic potentials [60].…”

Formation of spontaneous density-wave patterns in DC driven lattices

“…While for AC driven Floquet systems many-body localization has been proposed for stabilization against heating, DC driven systems require Stark localization (and potentially many-body Stark localization [28]) for stabilization and our experiments show that it is promising to identify suitable regimes. Of particular interest would be extended Hubbard models in the strongly-correlated regime featuring exotic states such as topological Mott insulators [29] or other density-assisted tunneling terms for engineering artificial magnetic fields [30]. Furthermore, the DC drive could be combined with an AC drive leading to rich phenomena such as topological bandgap solitons [31] or Stark time crystals [32].…”