Quantum Trajectories for Quantum Optical Systems

Timo Felbinger, Stephan Schiller, J. Mlynck

Shakib Daryanoosh, Alexei Gilchrist, Ben Q. Baragiola

We study the dynamics of quantum systems interacting with a stream of entangled-qubit pairs in the weak coupling limit. For a large class of two-qubit bath states, we present a detailed framework describing conditional dynamical maps for the system, known as quantum trajectories, that arise when the qubits are measured. Depending on the measurement basis, these quantum trajectories can be jump-type or diffusive-type, and can successively transfer entanglement from the bath qubits other quantum systems. They also exhibit features not present in standard quantum optical trajectories due to the fact that collisional models are not confined by the standard white-noise limit for optical-mode baths. As an example of this formalism, we consider the case of two remote two-level systems, where jump-type quantum trajectories herald the birth and death of entanglement.

Ansh Singal, Allen Zang, Jordan Thomas +5 more

We introduce Trajectree, a quantum trajectory-based quantum circuit simulator that uses a novel, state-saving partial execution of the quantum circuits to simulate broad and deep noisy quantum circuits efficiently. Trajectree can efficiently generate a large number of Monte Carlo samples by saving partially executed trajectories. We conduct extensive performance analysis of the Trajectree approach, proving the utility of the trajectory saving scheme for simulations of open quantum systems. Using this architecture, we show that Trajectree can simulate standard benchmark noisy circuits over five times faster than Google's QSim, a part of the Cirq package. We also analyze Trajectree's performance for simulating quantum optical systems relevant to communication and computing applications. We demonstrate applications of the optical backend to simulate three optical experiments: CHSH Bell test, entanglement swapping, and optical CNOT gate. This shows Trajectree's potential for simulating noisy qudit and optical systems efficiently.

H. J. Carmichael, Roy J. Glauber, Marlan O. Scully

H. J. Carmichael, Roy J. Glauber, Marlan O. Scully