Publication detail

Postprocessing of quantum instruments

LEPPÄJÄRVI, L. SEDLÁK, M.

Original Title

Postprocessing of quantum instruments

Type

journal article in Web of Science

Language

English

Original Abstract

Studying sequential measurements is of the utmost importance to both the foundational aspects of quantum theory and the practical implementations of quantum technologies, with both of these applications being abstractly described by the concatenation of quantum instruments into a sequence of certain length. In general, the choice of instrument at any given step in the sequence can be conditionally chosen based on the classical results of all preceding instruments. For two instruments in a sequence we consider the conditional second instrument as an effective way of post-processing the first instrument into a new one. This is similar to how a measurement described by a positive operator-valued measure (POVM) can be post-processed into another by way of classical randomization of its outcomes using a stochastic matrix. In this work we study the post-processing relation of instruments and the partial order it induces on their equivalence classes. We characterize the greatest and the least element of this order, give examples of post-processings between different types of instruments and draw connections between post-processings of some of these instruments and their induced POVMs.

Keywords

quantum measurement, quantum instrument, sequence of measurements, POVM

Authors

LEPPÄJÄRVI, L.; SEDLÁK, M.

Released

24. 2. 2021

ISBN

2469-9926

Periodical

Physical Review A

Year of study

103

Number

2

State

United States of America

Pages from

1

Pages to

13

Pages count

13

URL

https://journals.aps.org/pra/pdf/10.1103/PhysRevA.103.022615

BibTex

@article{BUT168548,
  author="Leevi {Leppäjärvi} and Michal {Sedlák}",
  title="Postprocessing of quantum instruments",
  journal="Physical Review A",
  year="2021",
  volume="103",
  number="2",
  pages="1--13",
  doi="10.1103/PhysRevA.103.022615",
  issn="2469-9926",
  url="https://journals.aps.org/pra/pdf/10.1103/PhysRevA.103.022615"
}