# Preservation of quantum Fisher information and geometric phase of a single qubit system in a dissipative reservoir through the addition of qubits

## TL;DR

This paper demonstrates that adding noninteracting qubits can effectively preserve quantum Fisher information and geometric phase of a single qubit in a dissipative environment, enhancing quantum information stability.

## Contribution

It introduces a method to protect quantum Fisher information and geometric phase using additional qubits in a dissipative reservoir, applicable in both Markovian and non-Markovian regimes.

## Key findings

- Quantum Fisher information is fully protected with more added qubits.
- QFI decay can be monotonic or oscillatory depending on qubit number.
- Geometric phase robustness increases with additional qubits.

## Abstract

In this paper, we have investigated the preservation of quantum Fisher information of a single-qubit system coupled to a common zero temperature reservoir through the addition of noninteracting qubits. The results show that, the QFI is completely protected in both Markovian and non-Markovian regimes by increasing the number of additional qubits. Besides, the phenomena of QFI display monotonic decay or non-monotonic with revival oscillations depending on the number of additional qubits in a common dissipative reservoir. Moreover, we extend this model to investigate the effect of additional qubits N-1 and the initial conditions of the system on the geometric phase. It is found that, the robustness of GP against the dissipative reservoir has been demonstrated by increasing gradually the number of additional qubits. Besides, the GP is sensitive to the initial parameter theta, and possesses symmetric in a range regime 0,2 pi.