Detecting Entanglement can be More Effective with Inequivalent Mutually Unbiased Bases

TL;DR

This paper demonstrates that inequivalent and unextendible mutually unbiased bases (MUBs) can enhance entanglement detection in quantum systems, offering a systematic search method and practical benefits for experimental quantum state verification.

Contribution

It introduces a systematic approach to identify inequivalent MUBs, highlighting their effectiveness in entanglement detection, especially in higher dimensions, and discusses their practical application in experiments.

Findings

Unextendible MUBs can be more effective in entanglement detection.

Inequivalent MUBs occur regularly in higher dimensions.

A systematic method for searching inequivalent MUBs is provided.

Abstract

Mutually unbiased bases (MUBs) provide a standard tool in the verification of quantum states, especially when harnessing a complete set for optimal quantum state tomography. In this work, we investigate the detection of entanglement via inequivalent sets of MUBs, with a particular focus on unextendible MUBs. These are bases for which an additional unbiased basis cannot be constructed and, consequently, are unsuitable for quantum state verification. Here, we show that unextendible MUBs, as well as other inequivalent sets in higher dimensions, can be more effective in the verification of entanglement. Furthermore, we provide an efficient and systematic method to search for inequivalent MUBs and show that such sets occur regularly within the Heisenberg-Weyl MUBs, as the dimension increases. Our findings are particularly useful for experimentalists since adding optimal MUBs to an experimental setup enables a step-by-step approach to detect a larger class of entangled states.