22 research outputs found
PT-symmetry from Lindblad dynamics in a linearized optomechanical system
We analyze a lossy linearized optomechanical system in the red-detuned regime under the rotating wave approximation. This so-called optomechanical state transfer protocol provides effective lossy frequency converter (quantum beam-splitter-like) dynamics where the strength of the coupling between the electromagnetic and mechanical modes is controlled by the optical steady-state amplitude. By restricting to a subspace with no losses, we argue that the transition from mode-hybridization in the strong coupling regime to the damped-dynamics in the weak coupling regime, is a signature of the passive parity-time (PT) symmetry breaking transition in the underlying non-Hermitian quantum dimer. We compare the dynamics generated by the quantum open system (Langevin or Lindblad) approach to that of the PT-symmetric Hamiltonian, to characterize the cases where the two are identical. Additionally, we numerically explore the evolution of separable and correlated number states at zero temperature as well as thermal initial state evolution at room temperature. Our results provide a pathway for realizing non-Hermitian Hamiltonians in optomechanical systems at a quantum level
Non-local scattering control in coupled resonator networks
We demonstrate scattering control of Gaussian-like wave packets propagating
with constant envelope velocity and invariant waist through coupled resonator
optical waveguides (CROW) via an external resonator coupled to multiple sites
of the CROW. We calculate the analytical reflectance and transmittance using
standard scattering methods from waveguide quantum electrodynamics and show it
is possible to approximate them for an external resonator detuned to the CROW.
Our analytical and approximate results are in good agreement with numerical
simulations. We engineer various configurations using an external resonator
coupled to two sites of a CROW to show light trapping with effective
exponential decay between the coupling sites, wave packet splitting into two
pairs of identical Gaussian-like wave packets, and a non-local Mach-Zehnder
interferometer.Comment: 20 pages, 7 figure