Quantum Fisher information of fermionic cavity modes in an accelerated motion

TL;DR

This paper studies how relativistic motion affects the quantum Fisher information of fermionic cavity modes, revealing invariance for pure states and periodic degradation for Werner states during acceleration.

Contribution

It introduces a perturbative analysis of quantum Fisher information in relativistic cavities, highlighting differences between pure entangled and Werner states under acceleration.

Findings

Quantum Fisher information of pure states remains invariant under motion.

Werner states exhibit periodic degradation of quantum Fisher information.

Quantum Fisher information distribution varies between Alice's and Rob's cavities.

Abstract

We investigate the effect of the inertial and non-inertial segments of relativistic motion on the quantum Fisher information of (1+1) Dirac field modes confined to cavities. %For this purpose, a bipartite system comprising of Alice's and Rob's cavities with appropriate boundary conditions is prepared. For the purpose, we consider the situation that Rob's cavity, initially inertial, accelerates uniformly with respect to its proper time and then again becomes inertial while Alice's cavity remains inertial. The acceleration is assumed to be very small and its effects were analyzed in a perturbative regime. For analysis, we consider $\theta$ parameterized two-qubit pure entangled state and a Werner state. In contrast to the degradation of entanglement due to the relativistic motion between the cavities, the quantum Fisher information of the pure composite system $\mathcal{F}_\theta$ with respect to parameter $\theta$ is found to be invariant under the same conditions. However, in the case of the Werner state, the quantum Fisher information displays periodic degradation, due to the inertial and non-inertial segments of motion. Further, we investigate how this evolution process affects the quantum Fisher information distribution over the subsystems of Alice's and Rob's cavities. We find that the quantum Fisher information over the Rob's cavity shows the periodic degradation behavior depending upon the parameter $\theta$ as well as the uniform acceleration for both the two qubit pure state and Werner state. The quantum Fisher information over Alice's cavity remains invariant throughout the motion of Rob's cavity for the two qubit pure state whereas for Werner state it is affected by the mixing parameter of the Werner state.