English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

How measurement reversal could erroneously suggest the capability to discriminate the preparation basis of a quantum ensemble

MPS-Authors
/persons/resource/persons189116

Singh,  Rajeev
Max Planck Institute for the Physics of Complex Systems, Max Planck Society;

External Resource
No external resources are shared
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Goyal, S. K., Singh, R., & Ghosh, S. (2016). How measurement reversal could erroneously suggest the capability to discriminate the preparation basis of a quantum ensemble. Physical Review A, 93(1): 012114. doi:10.1103/PhysRevA.93.012114.


Cite as: http://hdl.handle.net/11858/00-001M-0000-0029-B5B7-3
Abstract
Mixed states of a quantum system, represented by density operators, can be decomposed as a statistical mixture of pure states in a number of ways where each decomposition can be viewed as a different preparation recipe. However the fact that the density matrix contains full information about the ensemble makes it impossible to estimate the preparation basis for the quantum system. Here we present a measurement scheme to (seemingly) improve the performance of unsharp measurements. We argue that in some situations this scheme is capable of providing statistics from a single copy of the quantum system, thus making it possible to perform state tomography from a single copy. One of the by-products of the scheme is a way to distinguish between different preparation methods used to prepare the state of the quantum system. However, our numerical simulations disagree with our intuitive predictions. We show that a counterintuitive property of a biased classical random walk is responsible for the proposed mechanism not working.