Quantum-Atom optics and dynamical simulations of fermionic many-body systems

Georg Lenz, Pierre Meystre

Sebastian Will, Deepak Iyer, Marcos Rigol

Quantum simulation with ultracold atoms has become a powerful technique to gain insight into interacting many-body systems. In particular, the possibility to study nonequilibrium dynamics offers a unique pathway to understand correlations and excitations in strongly interacting quantum matter. So far, coherent nonequilibrium dynamics has exclusively been observed in ultracold many-body systems of bosonic atoms. Here we report on the observation of coherent quench dynamics of fermionic atoms. A metallic state of ultracold spin-polarized fermions is prepared along with a Bose–Einstein condensate in a shallow three-dimensional optical lattice. After a quench that suppresses tunnelling between lattice sites for both the fermions and the bosons, we observe long-lived coherent oscillations in the fermionic momentum distribution, with a period that is determined solely by the Fermi–Bose interaction energy. Our results show that coherent quench dynamics can serve as a sensitive probe for correlations in delocalized fermionic quantum states and for quantum metrology. In ultracold quantum gases, coherent nonequilibrium dynamics has been observed for bosons, but remained elusive in fermionic systems. Here, Will et al. demonstrate coherent quench dynamics in a hybrid quantum system composed of a metallic state of fermionic atoms and a Bose–Einstein condensate.

Philipp M. Preiss

Y. H. Zhang, Xin-Chi Zhou, Bao‐Zong Wang +1 more

The fermionic t-J model has been widely recognized as a canonical model for broad range of strongly correlated phases, particularly the high-T_{c} superconductor. Simulating this model with controllable quantum platforms offers new possibilities to probe high-T_{c} physics, yet suffers challenges. Here we propose a novel scheme to realize a highly tunable extended t-J model in a programmable Rydberg-dressed tweezer array. Through engineering the Rydberg-dressed dipole-dipole interaction and intertweezer couplings, the fermionic t-J model with independently tunable exchange and hopping couplings is achieved. With the high tunability, we explore quantum many-body dynamics in the large J/t limit, a regime well beyond the conventional optical lattices and cuprates, and predict an unprecedented many-body self-pinning effect related to the local quantum entanglement with emergent conserved quantities. The self-pinning effect leads to novel nonthermal quantum many-body dynamics, which violates eigenstate thermalization hypothesis in Krylov subspace. Our prediction opens a new horizon in exploring exotic quantum many-body physics with t-J model, and shall also make a step toward simulating the high-T_{c} physics in neutral atom systems.

Francesco Pederiva

Erez Zohar, Alessandro Farace, Benni Reznik +1 more

We propose a scheme for digital quantum simulation of lattice gauge theories with dynamical fermions. Using a layered optical lattice with ancilla atoms that can move and interact with the other atoms (simulating the physical degrees of freedom), we obtain a stroboscopic dynamics which yields the four-body plaquette interactions, arising in models with (2+1) and higher dimensions, without the use of perturbation theory. As an example we show how to simulate a Z_{2} model in (2+1) dimensions.