Coherence evolution in two-qubit system going through amplitude damping channel

TL;DR

This paper investigates how quantum coherence evolves in a two-qubit system subjected to amplitude damping channels, identifying conditions for coherence freezing and deriving equations for output states.

Contribution

It provides a detailed analysis of coherence dynamics in two-qubit systems under amplitude damping, including conditions for coherence freezing and explicit state evolution equations.

Findings

Coherence can freeze if one subsystem is incoherent and a specific auxiliary condition is met.

Both subsystems must be incoherent for coherence freezing when both go through the channel.

Derived explicit equations for the output states after damping processes.

Abstract

In this paper, we analyze the evolution of quantum coherence in a two-qubit system going through the amplitude damping channel. After they have gone through this channel many times, we analyze the systems with respect to the coherence of their output states. When only one subsystem goes through the channel, frozen coherence occurs if and only if this subsystem is incoherent and an auxiliary condition is satisfied for the other subsystem. When two subsystems go through this quantum channel, quantum coherence can be frozen if and only if the two subsystems are both incoherent. We also investigate the evolution of coherence for maximally incoherent-coherent states and derive an equation for the output states after one or two subsystems have gone through the amplitude damping channel.