A minimal set of measurements for qudit-state tomography based on unambiguous discrimination

Abstract

Quantum-state tomography (QST) is a fundamental task for reconstructing unknown quantum state from statistics of measurements. We propose a qudit-state tomography based on unambiguous discrimination (UD) of d linearly independent pure states. We then prove that our proposal for QST provides a minimal set of measurements. Our proposal can be used in any finite dimension, and our strategy can be realized by a projective measurement on a system combined with a d-dimensional auxiliary system. In addition, we present another method to improve previously known UD QST of pure quantum state.