Quantum measurement with minimal state alteration

Authors

  • Janus B. Advincula National Institute of Physics, University of the Philippines Diliman
  • Eric A. Galapon National Institute of Physics, University of the Philippines Diliman

Abstract

We construct a positive-operator valued measurement (POVM) that only minimally changes the state of the quantum system. The problem is delimited to a 2-element POVM and 2-dimensional Hilbert space. The elements are given by M= √αA and M2 = U √I − αAA. If the measurement outcome is M1, then the system is unaltered. However, if the outcome is M2, the state is altered. We focus on the unitary operator U that will minimize ‖ρf − ρ0‖. The minimum of this function is zero for a = 0 , which is trivial, and nonzero, otherwise. We conclude that there are no unitary operators that will leave a state completely unaltered. However, we were able to find a unitary operator that will minimize state alteration.

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Article ID

SPP-2015-3B-04

Section

Theoretical and Computational Physics

Published

2015-06-03

How to Cite

[1]
JB Advincula and EA Galapon, Quantum measurement with minimal state alteration, Proceedings of the Samahang Pisika ng Pilipinas 33, SPP-2015-3B-04 (2015). URL: https://proceedings.spp-online.org/article/view/1149.