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Quantum metrology in open systems: Dissipative cramer-rao bound
, Article Physical Review Letters ; Volume 112, Issue 12 , 2014 ; 00319007 (ISSN) ; Mehboudi, M ; Rezakhani, A. T ; Sharif University of Technology
American Physical Society
2014
Abstract
Estimation of parameters is a pivotal task throughout science and technology. The quantum Cramér-Rao bound provides a fundamental limit of precision allowed to be achieved under quantum theory. For closed quantum systems, it has been shown how the estimation precision depends on the underlying dynamics. Here, we propose a general formulation for metrology scenarios in open quantum systems, aiming to relate the precision more directly to properties of the underlying dynamics. This feature may be employed to enhance an estimation precision, e.g., by quantum control techniques. Specifically, we derive a Cramér-Rao bound for a fairly large class of open system dynamics, which is governed by a...
Review of Thermalization in Closed Quantum Systems
, M.Sc. Thesis Sharif University of Technology ; Rezakhani, Ali (Supervisor)
Abstract
For a physical system, equilibrium is defined as a state in which the values of macroscopic quantities describing the system do not change in time. We observe systems around us reaching equilibrium every day. Describing such a seemingly simple phenomena has remained as one of the important challenges in theoretical physics. So far, various explanations for thermalization (approach to equilibrium) have been offered within classical and quantum thermodynamics. In classical statistical mechanics, the microcanonical ensemble provides a suitable prediction of the thermal behavior of a closed system. In this ensemble, using ergodic hypothesis and chaos theory one can assume that all microstates...