Open quantum dynamics with variational non-Gaussian states and the truncated Wigner approximation.

We present a framework for simulating the open dynamics of spin-boson systems by combining variational non-Gaussian states with a quantum trajectories approach. We apply this method to a generic spin-boson Hamiltonian that has both Tavis-Cummings and Holstein type couplings and which has broad applications to a variety of quantum simulation platforms, polaritonic physics, and quantum chemistry. Additionally, we discuss how the recently developed truncated Wigner approximation for open quantum systems can be applied to the same Hamiltonian.

Rise and Fall, and Slow Rise Again, of Operator Entanglement under Dephasing.

The operator space entanglement entropy, or simply "operator entanglement" (OE), is an indicator of the complexity of quantum operators and of their approximability by matrix product operators (MPOs). We study the OE of the density matrix of 1D many-body models undergoing dissipative evolution. It is expected that, after an initial linear growth reminiscent of unitary quench dynamics, the OE should be suppressed by dissipative processes as the system evolves to a simple stationary state.

A quantum optics approach to photoinduced electron transfer in cavities.

We study a simple model for photoinduced electron transfer reactions for the case of many donor-acceptor pairs that are collectively and homogeneously coupled to a photon mode of a cavity. We describe both coherent and dissipative collective effects resulting from this coupling within the framework of a quantum optics Lindblad master equation. We introduce a method to derive an effective rate equation for electron transfer by adiabatically eliminating donor and acceptor states and the cavity mode.

Collective Dissipative Molecule Formation in a Cavity.

We propose a mechanism to realize high-yield molecular formation from ultracold atoms. Atom pairs are continuously excited by a laser, and a collective decay into the molecular ground state is induced by a coupling to a lossy cavity mode. Using a combination of analytical and numerical techniques, we demonstrate that the molecular yield can be improved by simply increasing the number of atoms, and can overcome efficiencies of state-of-the-art association schemes.

Photon Blockade with Ground-State Neutral Atoms.

We show that induced dipole-dipole interactions allow for photon blockade in subwavelength ensembles of two-level, ground-state neutral atoms. Our protocol relies on the energy shift of the single-excitation, superradiant state of N atoms, which can be engineered to yield an effective two-level system. A coherent pump induces Rabi oscillation between the ground state and a collective bright state, with at most a single excitation shared among all atoms.