Quantum Simulation in many-body cavity QED systems

Ultracold atoms coupled inside optical cavities have been used as quantum simulation platforms with long-range interatomic interactions. With a transversally pumped atomic ensemble coupled in an optical cavity, the coherent photon scatterings between pump beam and cavity mode effectively generate long-range atom-atom interaction and lead to crystallization of atoms, featuring structural phase transitions. The inherent dissipation of the optical cavity brings in dissipative couplings and drives non-Hermitian dynamics, which is connected to the concept of dissipative time crystal and, in the case of oscillating structural phases, a spontaneous charge (atom) pump. However, the cavity-mediated interaction is naturally an all-to-all interaction, which is an advantage for applications like spin-squeezing generation but a limitation for quantum simulation with finite-range interactions. We are developing a quantum simulation machine with tweezer array of Ytterbium atoms coupled in an optical cavity mode. The site-resolved transverse pump beams enable tailored finite range atom-atom interactions and any-to-any connected qubit networks. Such a system is promising for realizing multiple-qubit entanglement and exploring the crossover from few-to many-body cavity QED systems.