Quantum-state comparison and discrimination
TLDR
In this article, the authors investigate the performance of discrimination strategy in the comparison task of known quantum states and find that the discrimination strategy is not optimal except for the minimum-error case.Abstract:
We investigate the performance of discrimination strategy in the comparison task of known quantum states. In the discrimination strategy, one infers whether or not two quantum systems are in the same state on the basis of the outcomes of separate discrimination measurements on each system. In some cases with more than two possible states, the optimal strategy in minimum-error comparison is that one should infer the two systems are in different states without any measurement, implying that the discrimination strategy performs worse than the trivial "no-measurement" strategy. We present a sufficient condition for this phenomenon to happen. For two pure states with equal prior probabilities, we determine the optimal comparison success probability with an error margin, which interpolates the minimum-error and unambiguous comparison. We find that the discrimination strategy is not optimal except for the minimum-error case.read more
Citations
More filters
Journal ArticleDOI
Limit of Gaussian operations and measurements for Gaussian state discrimination and its application to state comparison
David E. Roberson,Shuro Izumi,Wojciech Roga,Jonas S. Neergaard-Nielsen,Masahiro Takeoka,Ulrik L. Andersen +5 more
TL;DR: In this article, the optimal method of discriminating and comparing quantum states from a certain class of multimode Gaussian states and their mixtures when arbitrary global Gaussian operations and general Gaussian measurements are allowed is determined.
Journal ArticleDOI
Generalized quantum process discrimination problems
Kenji Nakahira,Kentaro Kato +1 more
TL;DR: In this paper, a broad class of quantum process discrimination problems is studied, where each process can consist of multiple time steps and can have an internal memory, and the task is to find a discrimination strategy, which may be adaptive and/or entanglement assisted, that maximizes a given objective function subject to given constraints.
References
More filters
Journal ArticleDOI
Quantum computation and quantum information
TL;DR: This special issue of Mathematical Structures in Computer Science contains several contributions related to the modern field of Quantum Information and Quantum Computing, with a focus on entanglement.
Journal ArticleDOI
A single quantum cannot be cloned
TL;DR: In this article, the linearity of quantum mechanics has been shown to prevent the replication of a photon of definite polarization in the presence of an excited atom, and the authors show that this conclusion holds for all quantum systems.
Book
Quantum detection and estimation theory
TL;DR: In this article, the optimum procedure for choosing between two hypotheses, and an approximate procedure valid at small signal-to-noise ratios and called threshold detection, are presented, and a quantum counterpart of the Cramer-Rao inequality of conventional statistics sets a lower bound to the mean-square errors of such estimates.
Journal ArticleDOI
How to differentiate between non-orthogonal states
TL;DR: In this article, a generalized measurement can be constructed which performs this task better than any combination of standard quantum measurements, and it is shown that the generalized measurement performs better than a combination of quantum measurements.
Journal ArticleDOI
How to differentiate between non-orthogonal states
TL;DR: An infinite sequence of generalized measurements, recently proposed by Ivanovic, can be performed in a single step as mentioned in this paper, and it is shown that the final result is the optimal one, regardless of the number of measurements.