Quasi-unambiguous state discrimination for coherent states with phase fluctuation
نویسندگان
چکیده
This paper describes unambiguous state discrimination (USD) for a sequence of coherent states with fluctuating phase, while considering eavesdropping against differential-phase-shift quantum key distribution systems. A measurement system extracts a fraction of the incoming signal of coherent states, estimates the carrier phase from that fraction, and then conducts a USD measurement on the main signal based on the estimated carrier phase. In such a system, the estimated carrier phase can be different from a true value because of the phase fluctuation, and an error can occur in the USD measurement because of the error in the estimated phase. The USD performance in such a situation is formalized and simulated. & 2013 Elsevier B.V. All rights reserved.
منابع مشابه
Phase-reference monitoring in coherent-state discrimination assisted by a photon-number resolving detector
Phase estimation represents a crucial challenge in many fields of Physics, ranging from Quantum Metrology to Quantum Information Processing. This task is usually pursued by means of interferometric schemes, in which the choice of the input states and of the detection apparatus is aimed at minimizing the uncertainty in the estimation of the relative phase between the inputs. State discrimination...
متن کاملHeralded orthogonalisation of coherent states and their conversion to discrete-variable superpositions
The nonorthogonality of coherent states is a fundamental property which prevents them from being perfectly and deterministically discriminated. To circumvent this problem, we present an experimentally feasible protocol for the probabilistic orthogonalisation of a pair of coherent states, independent of their amplitude and phase. In contrast to unambiguous state discrimination, successful operat...
متن کاملUnambiguous discrimination of mixed quantum states
Quantum state discrimination is an essential problem in quantum information theory. It was first considered for pure states in the literature. One strategy of quantum state discrimination is that one is asked to distinguish the given states without error, but a non-zero probability of inconclusive answer is allowed. Such a strategy is called unambiguous discrimination. Unambiguous discriminatio...
متن کاملAnalytical calculation of optimal POVM for unambiguous discrimination of quantum states using KKT method
In the present paper, an exact analytic solution for the optimal unambiguous state discrimination(OPUSD) problem involving an arbitrary number of pure linearly independent quantum states with real and complex inner product is presented. Using semidefinite programming and Karush-Kuhn-Tucker convex optimization method, we derive an analytical formula which shows the relation between optimal solut...
متن کاملua nt - p h / 06 11 11 6 v 1 1 0 N ov 2 00 6 Quantum mechanics on a circle : Husimi phase space distributions and semiclassical coherent state propagators
We discuss some basic tools for an analysis of one-dimensional quantum systems defined on a cyclic coordinate space. The basic features of the generalized coherent states, the complexifier coherent states are reviewed. These states are then used to define the corresponding (quasi)densities in phase space. The properties of these generalized Husimi distributions are discussed, in particular thei...
متن کامل