# Preservation of dynamics in coupled cavity system using second order nonlinearity

## TL;DR

This paper investigates how second-order nonlinearity and time-dependent coupling in a coupled cavity system can preserve quantum dynamics and entanglement, regardless of initial states, with implications for quantum information processing.

## Contribution

It introduces a method using harmonic time dependence on non-linear coupling to preserve system dynamics and entanglement in coupled cavities with two-level systems.

## Key findings

- Preservation period is independent of initial state.
- Time-dependent coupling maintains entanglement.
- Dynamics depend on initial state despite preservation.

## Abstract

We study two coupled cavities with a single two-level system in each and a second-order non-linear process in one of the cavities. Introduction of a harmonic time dependence on the non-linear coupling is utilized for the preservation of dynamics. It is observed that, even though the preservation period is independent of the initial state, the preserved dynamics depends on the initial state. We calculated the von Neumann entropy and mutual information to study the entanglement present between the subsystems. From which it is found that the time-dependent coupling also preserves the entanglement produced in the system.