Unambiguous comparison of ensembles of quantum states

Abstract

We present a solution of the problem of the optimal unambiguous comparison of two ensembles of unknown quantum states (psi_1)^k and (psi_2)^l. We consider two cases: 1) The two unknown states psi_1 and psi_2 are arbitrary states of qudits. 2) Alternatively, they are coherent states of a harmonic oscillator. For the case of coherent states we propose a simple experimental realization of the optimal "comparison" machine composed of a finite number of beam-splitters and a single photodetector.

arXiv comment7 pages, 3 figures

References in corpus (5)

• Experimentally realizable quantum comparison of coherent states and its applications
• Comparison of two unknown pure quantum states
• Reexamination of optimal quantum state estimation of pure states
• Unambiguous comparison of the states of multiple quantum systems
• On the generalization of quantum state comparison

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• Quantum learning of coherent states
• Multi-copy programmable discrimination of general qubit states
• Unambiguous comparison of unitary channels
• Unambiguous identification of coherent states II: Multiple resources
• An agnostic-Dolinar receiver for coherent states classification
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• Optimal quantum discrimination of single-qubit unitary gates between two candidates
• Optimal unambiguous comparison of two unknown squeezed vacua
• Knowledge-Concealing Evidencing of Knowledge about a Quantum State
• Nonexistence of a universal quantum machine to examine the precision of unknown quantum states
• Probability-based comparison of quantum states
• Unambiguous Examining the Orthogonality of Multiple Quantum States
• Dealing with ignorance: universal discrimination, learning and quantum correlations