Entanglement robustness in trace decreasing quantum dynamics caused by depolarization and polarization dependent losses

TL;DR

This paper investigates how certain quantum states maintain entanglement under trace decreasing noise, using the quantum Sinkhorn theorem to optimize initial states for robust quantum communication.

Contribution

It introduces a method to find optimal initial entangled states for noisy quantum channels using the quantum Sinkhorn theorem, focusing on trace decreasing dynamics.

Findings

Optimal states are not maximally entangled for longest entanglement lifetime.

Quantum Sinkhorn theorem effectively finds robust entangled states under noise.

Trace decreasing maps can be as physically relevant as trace preserving ones.

Abstract

Trace decreasing dynamical maps are as physical as trace preserving ones; however, they are much less studied. Here we overview how the quantum Sinkhorn theorem can be successfully applied to find a two-qubit entangled state which has the strongest robustness against local noises and losses of quantum information carriers. We solve a practically relevant problem of finding an optimal initial encoding to distribute entangled polarized qubits though communication lines with polarization dependent losses and extra depolarizing noise. The longest entanglement lifetime is shown to be attainable with a state that is not maximally entangled.