On the symmetry and dynamics of squeezed and correlated states

Sergey V. Prants

Alexander V. Gorokhov

Method of dynamical groups and approach of coherent states have used to calculate the squeezing and multiphoton correlations in spontaneous parametric down-conversion processes. Special case of twisted photons with orbital angular momentum is considered.

Sibel Başkal, Young S Kim, Marilyn E. Noz

B. -B. Liu, D. -Y. Wang, J. Tang +4 more

Reservoir engineering enables unidirectional energy and signal flow. We establish squeezing-induced symmetry breaking between two cavities as a guiding principle for exponentially amplifying reservoir-mediated nonreciprocity. Rather than a simple scaling of the coupling, this mechanism strategically redistributes the squeezing resources to relax experimental requirements, as single-cavity squeezing alone demands a much larger squeezing strength. Moreover, reservoir squeezing does not alter the system symmetry, but reshapes the noise correlations and thereby changes the system dynamics. The proposed mechanism improves the performance of the quantum battery by several orders of magnitude, including stored energy, charging power, and ergotropy, with the analytical expressions provided. Extending to the optical isolation, we observe a second-order exponential enhancement of the output signal. Our results open a new avenue for nonreciprocal quantum information processing and nonreciprocal quantum device design.

P. L. Knight, Vladimír Bužek

Ali Ü. C. Hardal

We investigate the Hermitian and the non-Hermitian dynamics of the mode entanglement in two identical optical cavities coupled by a chiral mirror. By employing the non-Hermitian quantum evolution, we calculate the logarithmic negativity measure of entanglement for initially Fock, coherent, and squeezed states, separately. We verify the nonconservation of mean spin for the initially coherent and squeezed states when the coupling is nonreciprocal and report the associated spin noise for each case. We examine the effects of nonconserved symmetries on the mode correlations and determine the degree of nonreciprocal coupling to establish robust quantum entanglement.