We report the realization of correlated, density-dependent tunneling for fermionic $^{40}\mathrm{K}$ atoms trapped in an optical lattice. By appropriately tuning the frequency difference between a pair of Raman beams applied to a spin-polarized gas, simultaneous spin transitions and tunneling events are induced that depend on the relative occupations of neighboring lattice sites. This correlated spin-flip tunneling (CSFT) is spectroscopically resolved using gases prepared in opposite spin states, and the inferred Hubbard interaction energy is compared with a tight-binding prediction. We measure the doublons created by the laser-induced correlated tunneling process using loss induced by light-assisted collisions. Furthermore, by controllably introducing vacancies to a spin-polarized gas, we demonstrate that correlated tunneling is suppressed when neighboring lattice sites are unoccupied. We explain how the CSFT quench implemented here prepares and evolves a large number of resonating-valence-bond (RVB) singlets in a Hubbard model, thus allowing exploration of RVB dynamics.We report the realization of correlated, density-dependent tunneling for fermionic $^{40}\mathrm{K}$ atoms trapped in an optical lattice. By appropriately tuning the frequency difference between a pair of Raman beams applied to a spin-polarized gas, simultaneous spin transitions and tunneling events are induced that depend on the relative occupations of neighboring lattice sites. This correlated spin-flip tunneling (CSFT) is spectroscopically resolved using gases prepared in opposite spin states, and the inferred Hubbard interaction energy is compared with a tight-binding prediction. We measure the doublons created by the laser-induced correlated tunneling process using loss induced by light-assisted collisions. Furthermore, by controllably introducing vacancies to a spin-polarized gas, we demonstrate that correlated tunneling is suppressed when neighboring lattice sites are unoccupied. We explain how the CSFT quench implemented here prepares and evolves a large number of resonating-valence-bond (RVB) singlets in a Hubbard model, thus allowing exploration of RVB dynamics.

arXiv:1711.02061Physical Review AAug 20, 201817 citations

Interacting Fermions in Optical Lattices

Tilman Esslinger

Bulletin of the American Physical SocietyMay 19, 20050 citations

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

Maxime Jamotte, Nathan Goldman, Marco Fedele Di Liberto

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 density-assisted 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, opening the door to future studies of their possible interplay with quantum fluctuations and collective excitations.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 density-assisted 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, opening the door to future studies of their possible interplay with quantum fluctuations and collective excitations.

arXiv:2104.13394Communications PhysicsJan 27, 202220 citations

Detecting the tunneling rates for strongly interacting fermions on optical lattices

Alberto Anfossi, Luca Barbiero, Arianna Montorsi

Strongly interacting fermionic atoms on optical lattices are studied through a Hubbard-like model Hamiltonian, in which tunneling rates of atoms and molecules between neighboring sites are assumed to be different. In the limit of large on-site repulsion $U$ , the model is shown to reproduce the $t$ - $J$ Hamiltonian, in which the $J$ coefficient of the Heisenberg term depends on the particle-assisted tunneling rate $g$ : explicitly, $J=4{g}^{2}/U$ . At half-filling, $g$ drives a crossover from a Brinkman-Rice paramagnetic insulator of fully localized atoms ( $g=0$ ) to the antiferromagnetic Mott insulator of the standard Hubbard case ( $g=t$ ). This is observed already in the number of doubly occupied sites under the intermediate coupling regime, thus providing a criterion for extracting from measurements the effective value of $g$ .Strongly interacting fermionic atoms on optical lattices are studied through a Hubbard-like model Hamiltonian, in which tunneling rates of atoms and molecules between neighboring sites are assumed to be different. In the limit of large on-site repulsion $U$, the model is shown to reproduce the $t$-$J$ Hamiltonian, in which the $J$ coefficient of the Heisenberg term depends on the particle-assisted tunneling rate $g$: explicitly, $J=4{g}^{2}/U$. At half-filling, $g$ drives a crossover from a Brinkman-Rice paramagnetic insulator of fully localized atoms ($g=0$) to the antiferromagnetic Mott insulator of the standard Hubbard case ($g=t$). This is observed already in the number of doubly occupied sites under the intermediate coupling regime, thus providing a criterion for extracting from measurements the effective value of $g$.

arXiv:1002.1814Physical Review AApr 26, 20101 citation

We report the realization of correlated, density-dependent tunneling for fermionic

^{40}\mathrm{K}

atoms trapped in an optical lattice. By appropriately tuning the frequency difference between a pair of Raman beams applied to a spin-polarized gas, simultaneous spin transitions and tunneling events are induced that depend on the relative occupations of neighboring lattice sites. This correlated spin-flip tunneling (CSFT) is spectroscopically resolved using gases prepared in opposite spin states, and the inferred Hubbard interaction energy is compared with a tight-binding prediction. We measure the doublons created by the laser-induced correlated tunneling process using loss induced by light-assisted collisions. Furthermore, by controllably introducing vacancies to a spin-polarized gas, we demonstrate that correlated tunneling is suppressed when neighboring lattice sites are unoccupied. We explain how the CSFT quench implemented here prepares and evolves a large number of resonating-valence-bond (RVB) singlets in a Hubbard model, thus allowing exploration of RVB dynamics.

U

, the model is shown to reproduce the

t

J

Hamiltonian, in which the

J

coefficient of the Heisenberg term depends on the particle-assisted tunneling rate

g

: explicitly,

J=4{g}^{2}/U

. At half-filling,

g

drives a crossover from a Brinkman-Rice paramagnetic insulator of fully localized atoms (

g=0

) to the antiferromagnetic Mott insulator of the standard Hubbard case (

g=t

). This is observed already in the number of doubly occupied sites under the intermediate coupling regime, thus providing a criterion for extracting from measurements the effective value of

g