Entanglement measures of Majorana bound states

TL;DR

This paper investigates the entanglement properties of Majorana bound states in topological superconductors coupled to quantum dots, revealing how their energy and nonlocality influence entanglement dynamics and offering new ways to detect and utilize them in quantum information.

Contribution

It introduces a novel approach to characterize Majorana bound states through entanglement measures and dynamics, distinguishing them from trivial states and exploring their potential for quantum information applications.

Findings

Zero-energy Majorana states can destroy entanglement in the system.

Finite-energy Majorana states can generate maximal entanglement.

Controlling Majorana nonlocality can produce entanglement between MBSs and quantum dots.

Abstract

Majorana bound states emerge in topological superconductors as zero-energy edge states exhibiting spatial nonlocality. Despite the enormous advances, the detection of Majorana bound states is still challenging mainly because topologically trivial Andreev bound states produce similar signatures. In this work we consider a topological superconductor with Majorana bound states coupled to quantum dots and investigate the dynamics of their quantum correlations with the aim to explore their entanglement properties. In particular, we characterize entanglement by using concurrence and discord, which are also complemented by the entanglement dynamics and return probability. We find that Majorana bound states at truly zero energy can transform an initially entangled system into its classical state, while they can create maximally entangled states at a finite energy overlap. Interestingly, we show that the system can generate a maximally entangled state between MBSs and a quantum dot by simply controlling the Majorana nonlocality. We demonstrate that these results hold in the scenarios when the initial state is either maximally entangled or separable, albeit in the latter maximally entangled states are achieved in the long time dynamics. Furthermore, we contrast our findings with those produced by a regular fermion and obtain very distinct entanglement signatures. Our work offers an alternative approach to characterize Majorana bound states, which can be also useful towards their utilization for quantum information tasks.