Quantum-state estimation
نویسندگان
چکیده
منابع مشابه
Bhattacharyya inequality for quantum state estimation
Using higher-order derivative with respect to the parameter, we will give lower bounds for variance of unbiased estimators in quantum estimation problems. This is a quantum version of the Bhattacharyya inequality in the classical statistical estimation. Because of non-commutativity of operator multiplication, we obtain three different types of lower bounds; Type S, Type R and Type L. If the par...
متن کاملIntensity and State Estimation in Quantum Cryptography
This paper describes how the communicating parties can employ intensity and state estimation to detect if the eavesdropper has siphoned off and injected photons in the received communication. This is of relevance in quantum cryptography based on random rotations of photon polarizations. Introduction The paper investigates the use of state and intensity measurements by Alice and Bob to detect th...
متن کاملQuantum state estimation and large deviations
In this paper we propose a method to estimate the density matrix ρ of a d-level quantum system by measurements on the N-fold system in the joint state ρ . The scheme is based on covariant observables and representation theory of unitary groups and it extends previous results concerning the estimation of the spectrum of ρ. We show that it is consistent (i.e. the original input state ρ is recover...
متن کاملInvariant information and quantum state estimation.
The invariant information, introduced by C. Brukner and A. Zeilinger [Phys. Rev. Lett. 83, 3354 (1999)], is reconsidered from the point of view of quantum state estimation. We show that this quantity is directly related to the mean error of the standard reconstruction from the measurement of a complete set of mutually complementary observables. We give its generalization in terms of the Fisher ...
متن کاملAsymptotic quantum cloning is state estimation.
The impossibility of perfect cloning and state estimation are two fundamental results in quantum mechanics. It has been conjectured that quantum cloning becomes equivalent to state estimation in the asymptotic regime where the number of clones tends to infinity. We prove this conjecture using two known results of quantum information theory: the monogamy of quantum correlations and the propertie...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Physical Review A
سال: 1997
ISSN: 1050-2947,1094-1622
DOI: 10.1103/physreva.55.r1561