Robustness of Interferometric Power to Sudden Death

TL;DR

The paper demonstrates that interferometric power (IP), a discord-like quantum correlation measure, remains nonzero asymptotically under several Markovian noise channels where entanglement can undergo sudden death. By comparing IP with concurrence across phase damping, generalized amplitude damping, and depolarizing channels, the authors show IP's superior robustness as a resource for quantum metrology. They derive explicit dynamics for specific initial states (e.g., Werner and Bell-like states) and show IP's occasional sudden-change behavior in some channels, while entanglement vanishes in finite time in others. The findings suggest IP-based metrology offers practical resilience against decoherence in noisy quantum information processing.

Abstract

We study the dissipative dynamics of interferometric power as a discordlike measure in Markovian environments, such as dephasing, depolarizing, and generalized amplitude damping. Moreover, we compare the dynamics of interferometric power and entanglement by choosing proper initial conditions. Our study shows that in all cases where the sudden death of entanglement appears, interferometric power decays asymptotically. Therefore, quantum metrology based on interferometric power is more robust than entanglement.

Figures (4)

• Figure 1: Dynamics of (a) concurrence and (b) IP as functions of $\alpha$ and $\gamma$, under phase damping channel.
• Figure 2: Dynamics of (a) and (c) concurrence and (b) and (d) IP as functions of $\alpha$ and $\gamma$, under generalized amplitude damping channel.
• Figure 3: Dynamics of (a) concurrence and (c) IP as functions of $\alpha$ and $\gamma$, under depolarizing noise channel.
• Figure 4: Dynamics of (a) concurrence and (b) IP as functions of $\alpha$ and $\gamma$, under dephasing and generalized amplitude damping ($q=1$) channels acted simultaneously.