Multipartite entangled states in particle mixing

TL;DR

This paper explores multipartite entanglement in particle flavor mixing systems, analyzing how entanglement distribution depends on mixing parameters and CP-violation, and examines decoherence effects in neutrino oscillations.

Contribution

It introduces a global entanglement measure for flavor states, analyzing entanglement distribution and decoherence in three- and four-flavor mixing scenarios.

Findings

Entanglement concentrates in specific bipartitions depending on mixing parameters.

CP-violating phases influence entanglement distribution and decoherence.

Defined a decoherence length related to the loss of quantum interference.

Abstract

In the physics of flavor mixing, the flavor states are given by superpositions of mass eigenstates. By using the occupation number to define a multiqubit space, the flavor states can be interpreted as multipartite mode-entangled states. By exploiting a suitable global measure of entanglement, based on the entropies related to all possible bipartitions of the system, we analyze the correlation properties of such states in the instances of three- and four-flavor mixing. Depending on the mixing parameters, and, in particular, on the values taken by the free phases, responsible for the CP-violation, entanglement concentrates in preferred bipartitions. We quantify in detail the amount and the distribution of entanglement in the physically relevant cases of flavor mixing in quark and neutrino systems. By using the wave packet description for localized particles, we use the global measure of entanglement, suitably adapted for the instance of multipartite mixed states, to analyze the decoherence induced by the free evolution dynamics on the quantum correlations of stationary neutrino beams. We define a decoherence length as the distance associated with the vanishing of the coherent interference effects among massive neutrino states. We investigate the role of the CP-violating phase in the decoherence process.