Indistinguishability of identical bosons from a quantum information theory perspective

Fuente: arXiv
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Hauptverfasser: Englbrecht, Matthias, Kraft, Tristan, Dittel, Christoph, Buchleitner, Andreas, Giedke, Geza, Kraus, Barbara
Format: Preprint
Veröffentlicht: 2023
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author Englbrecht, Matthias
Kraft, Tristan
Dittel, Christoph
Buchleitner, Andreas
Giedke, Geza
Kraus, Barbara
author_facet Englbrecht, Matthias
Kraft, Tristan
Dittel, Christoph
Buchleitner, Andreas
Giedke, Geza
Kraus, Barbara
contents Using tools from quantum information theory, we present a general theory of indistinguishability of identical bosons in experiments consisting of passive linear optics followed by particle number detection. Our results do neither rely on additional assumptions on the input state of the interferometer, such as, for instance, a fixed mode occupation, nor on any assumption on the degrees of freedom that potentially make the particles distinguishable. We identify the expectation value of the projector onto the $N$-particle symmetric subspace as an operationally meaningful measure of indistinguishability, and derive tight lower bounds on it that can be efficiently measured in experiments. Moreover, we present a consistent definition of perfect distinguishability and characterize the corresponding set of states. In particular, we show that these states are diagonal in the computational basis up to a permutationally invariant unitary. Moreover, we find that convex combinations of states that describe partially distinguishable and perfectly indistinguishable particles can lead to perfect distinguishability, which itself is not preserved under convex combinations.
format Preprint
id arxiv_https___arxiv_org_abs_2307_06626
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Indistinguishability of identical bosons from a quantum information theory perspective
Englbrecht, Matthias
Kraft, Tristan
Dittel, Christoph
Buchleitner, Andreas
Giedke, Geza
Kraus, Barbara
Quantum Physics
Using tools from quantum information theory, we present a general theory of indistinguishability of identical bosons in experiments consisting of passive linear optics followed by particle number detection. Our results do neither rely on additional assumptions on the input state of the interferometer, such as, for instance, a fixed mode occupation, nor on any assumption on the degrees of freedom that potentially make the particles distinguishable. We identify the expectation value of the projector onto the $N$-particle symmetric subspace as an operationally meaningful measure of indistinguishability, and derive tight lower bounds on it that can be efficiently measured in experiments. Moreover, we present a consistent definition of perfect distinguishability and characterize the corresponding set of states. In particular, we show that these states are diagonal in the computational basis up to a permutationally invariant unitary. Moreover, we find that convex combinations of states that describe partially distinguishable and perfectly indistinguishable particles can lead to perfect distinguishability, which itself is not preserved under convex combinations.
title Indistinguishability of identical bosons from a quantum information theory perspective
topic Quantum Physics
url https://arxiv.org/abs/2307.06626