Density-Dependent Synthetic Gauge Fields Using Periodically Modulated Interactions

Abstract

We show that density-dependent synthetic gauge fields may be engineered by combining periodically modulated interactions and Raman-assisted hopping in spin-dependent optical lattices. These fields lead to a density-dependent shift of the momentum distribution, may induce superfluid-to-Mott insulator transitions, and strongly modify correlations in the superfluid regime. We show that the interplay between the created gauge field and the broken sublattice symmetry results, as well, in an intriguing behavior at vanishing interactions, characterized by the appearance of a fractional Mott insulator. DOI: 10.1103/PhysRevLett.113.215303 PACS numbers: 67.85.-d, 03.65.Vf, 03.75.Lm, 37.10.Jk The emulation of synthetic electromagnetism in cold neutral gases has attracted major interest [1,2]. Artificial electric and magnetic fields have been induced using lasers [3][4][5]. Moreover, these setups may be extended to generate non-Abelian fields, and in particular, spin-orbit coupling [6][7][8][9][10][11][12][13]. Synthetic fields may be generated as well in optical lattices, and recent experiments have created artificial staggered [14][15][16] and uniform [17,18] magnetic fields. These fields are, however, static, as they are not influenced by the atoms.The dynamical feedback between matter and gauge fields plays an important role in various areas of physics, ranging from condensed matter [19] to quantum chromodynamics [20], and its realization in cold lattice gases is attracting growing attention [21]. Schemes have been recently proposed for multicomponent lattice gases, such that the low-energy description of these systems is that of relevant quantum field theories [22][23][24][25][26][27][28][29][30][31]. The backaction of the atoms on the value of a synthetic gauge field is expected to lead to interesting physics, including statistically induced phase transitions and anyons in 1D lattices [32], and chiral solitons in Bose-Einstein condensates [33].Periodically modulated optical lattices open interesting possibilities for the engineering of lattice gases [16][17][18][34][35][36][37][38][39][40]. In particular, periodic lattice shaking results in a modified hopping rate [34][35][36], which has been employed to drive the superfluid (SF) to Mott insulator (MI) transition [37], to simulate frustrated classical magnetism [38], and to create tunable gauge potentials [16]. Interestingly, a periodically modulated magnetic field may be employed in the vicinity of a Feshbach resonance to induce periodically modulated interactions, which result in a nonlinear hopping rate that depends on the occupation differences at neighboring sites [41][42][43].In this Letter, we show that combining periodic interactions and Raman-assisted hopping may induce a densitydependent gauge field in 1D lattices. The created field results in a density-dependent shift of the momentum distribution that may be probed in time-of-flight (TOF) experiments. Moreover, contrary to the Peierls phase induced in shaken lattices [16], the created field cannot be ga...

Binary matter-wave compactons induced by inter-species scattering length modulations

“…Experimentally, this phenomenon has been recently observed in BEC in deep OL with periodic time modulatations of the interactions [10]. We also remark that the SNM of the scattering lengths is presently used to investigate several interesting physical phenomena related to new quantum phases [11,12], artificial gauge fields and spin-orbit couplings [13,14], in BEC systems.…”

Topological phases of lattice bosons with a dynamical gauge field

“…[18][19][20][21][22]. An intermediate step might be the realization of simpler but nevertheless dynamical gauge fields, engineering an occupation number-dependent tunneling term [23][24][25][26][27][28][29][30].…”

Casting New Light on Atomic Interactions

“…The oscillating scattering length drives parity-conserving transitions to the second excited state in the vertical trap at 890(10) Hz and the second excited band of the optical lattice at 8.18 (2) kHz. This demonstrates that the plentiful theoretical proposals [1][2][3][4][5][6][7] which require rapid oscillation of scattering length in the bulk or in the lattice are well within reach of our scheme.…”

“…We perform these experiments either in the bulk, with the vertical trap frequency ω z increased to 2π × 470 Hz, or in a weak one-dimensional optical lattice in the horizontal plane with spacing 532 nm and lattice depth h × 9.28 kHz, in which the system remains a superfluid [45]. For this experiment only, we introduce the optical lattice in order to test the consequences of modulated interactions in a lattice gas, as discussed in many theoretical proposals [1,2,7]. Combining the experiments in both geometries, we observe a variety of resonance features over a wide range of time scales, as shown in Fig.…”

“…DOI: 10.1103/PhysRevLett.115.155301 PACS numbers: 67.85.-d, 03.75.Kk, 34.50.-s Spatiotemporal control of interactions should bring a plethora of new quantum-mechanical phenomena into the realm of ultracold atom research. Temporal modulation of interactions is theoretically proposed as a route for creating anyonic statistics in optical lattices [1,2] as well as new types of quantum liquids [3,4] and excitations [5][6][7]. Spatial modulation should grant access to unusual soliton behavior [8,9], controlled interfaces between quantum phases [10], stable nonlinear Bloch oscillations [11], and even the dynamics of acoustic black holes [12].…”