# Universal feedback control of two-qubit entanglement

## TL;DR

This paper develops a universal Markovian feedback control strategy to preserve and generate stationary entanglement in two-qubit systems under local dissipation and driving, independent of initial states.

## Contribution

It introduces a universal feedback protocol that optimally maintains and creates entanglement in two-qubit systems regardless of initial conditions.

## Key findings

- Optimal feedback actions preserve initial entanglement.
- Feedback creates stationary entanglement.
- Protocol is independent of initial states.

## Abstract

We consider two-qubit undergoing local dissipation and subject to local driving. We then determine the optimal Markovian feedback action to preserve initial entanglement as well as to create stationary entanglement with the help of an XY interaction Hamiltonian. Such feedback actions are worked out in a way not depending on the initial two-qubit state, whence called universal.