Spin geometry of entangled qubits under bilocal decoherence modes

TL;DR

This paper explores how specific bilocal decoherence modes affect entangled two-qubit states, using spin geometry to visualize the evolution of quantum correlations under these decoherence processes.

Contribution

It introduces a detailed analysis of bilocal decoherence modes generated by projection operators and unitary rotations, with a focus on maximally entangled Bell states and their geometric evolution.

Findings

Decoherence modes can be visualized in spin geometry, illustrating correlation decay.

The evolution depends only on the relative angle between bilocal rotations under certain conditions.

Conditions are identified where the path depends solely on the relative rotation angle.

Abstract

The Lindblad generators of the master equation define which kind of decoherence happens in an open quantum system. We are working with a two qubit system and choose the generators to be projection operators on the eigenstates of the system and unitary bilocal rotations of them. The resulting decoherence modes are studied in detail. Besides the general solutions we investigate the special case of maximally entangled states - the Bell singlet states. The results are depicted in the so-called spin geometry picture which allows to illustrate the evolution of the (nonlocal) correlations stored in a certain state. The question for which conditions the path traced out in the geometric picture depends only on the relative angle between the bilocal rotations is addressed.