# Retrieving the lost fermionic entanglement by partial measurement in noninertial frames

## TL;DR

This paper demonstrates that partial measurement techniques can fully recover or amplify fermionic entanglement degraded by the Unruh effect in noninertial frames, highlighting a novel approach in relativistic quantum information.

## Contribution

It introduces a method to completely eliminate Unruh-induced entanglement degradation using partial measurement and reversal, a novel application in relativistic quantum information.

## Key findings

- Entanglement can be fully recovered using optimal partial measurement.
- Recovery depends on whether the reversed measurement strength is state-independent or state-dependent.
- Partial measurement can amplify entanglement beyond initial levels.

## Abstract

The initial entanglement shared between inertial and accelerated observers degrades due to the influence of the Unruh effect. Here, we show that the Unruh effect can be completely eliminated by the technique of partial measurement. The lost entanglement could be entirely retrieved or even amplified, which is dependent on whether the optimal strength of reversed measurement is \emph{state-independent} or \emph{state-dependent}. Our work provides a novel and unexpected method to recover the lost entanglement under Unruh decoherence and exhibits the ability of partial measurement as an important technique in relativistic quantum information.