Relation between nonclassical features through logical qudits

TL;DR

This paper explores how quantum coherence in logical qubits relates to quantum correlations in physical multiqubit systems, extending the understanding of nonclassical features across different quantum system dimensions.

Contribution

It generalizes a framework linking quantum coherence and correlations, showing a single nonclassicality condition detects multiple nonclassical features in diverse Hilbert spaces.

Findings

Reciprocity between nonclassical correlations and coherence.

Extension of the framework to higher-dimensional systems.

A single condition detects multiple nonclassical features.

Abstract

Scalable modern-time fault-tolerant quantum computation and quantum communication in a network employ a large number of physical qubits. For example, IBM is reported to have made a 127-qubit quantum computer. Unlike classical computation, quantum computation employs different types of logical qubits and qudits in terms of physical multiqubit and multiqudit systems respectively. Given this, of particular interest to us is to enquire on how quantum coherence in logical qubits is a manifestation of underlying quantum correlations in constituent physical multiqubit systems and vice-versa. In a recent work [Asthana, Sooryansh. New J Phys 24.5 (2022): 053026], we have shown that there is reciprocity in nonclassical correlations in physical multiqubit systems and coherence in a single logical qubit system. Subsequently, we have generalised the framework to higher dimensional quantum systems []. The crux of this study is that a single nonclassicality condition derived for quantum coherence in a logical system detects more than one type of nonclassicality in Hilbert spaces of nonidentical dimensions.