Use this URL to cite or link to this record in EThOS:
Title: Topics in estimation of quantum channels
Author: O'Loan, Caleb J.
ISNI:       0000 0004 2718 8613
Awarding Body: University of St Andrews
Current Institution: University of St Andrews
Date of Award: 2010
Availability of Full Text:
Access from EThOS:
Access from Institution:
A quantum channel is a mapping which sends density matrices to density matrices. The estimation of quantum channels is of great importance to the field of quantum information. In this thesis two topics related to estimation of quantum channels are investigated. The first of these is the upper bound of Sarovar and Milburn (2006) on the Fisher information obtainable by measuring the output of a channel. Two questions raised by Sarovar and Milburn about their bound are answered. A Riemannian metric on the space of quantum states is introduced, related to the construction of the Sarovar and Milburn bound. Its properties are characterized. The second topic investigated is the estimation of unitary channels. The situation is considered in which an experimenter has several non-identical unitary channels that have the same parameter. It is shown that it is possible to improve estimation using the channels together, analogous to the case of identical unitary channels. Also, a new method of phase estimation is given based on a method sketched by Kitaev (1996). Unlike other phase estimation procedures which perform similarly, this procedure requires only very basic experimental resources.
Supervisor: Jupp, Peter E. Sponsor: Engineering and Physical Sciences Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Quantum statistics ; Phase estimation ; Quantum channels ; Riemannian metrics ; QC174.43O6 ; Quantum statistics ; Metric spaces