A Complete Set of Invariants for LU-Equivalence of Density Operators

We show that two density operators of mixed quantum states are in the same local unitary orbit if and only if they agree on polynomial invariants in a certain Noetherian ring for which degree bounds are known in the literature. This implicitly gives a finite complete set of invariants for local unit...

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Veröffentlicht in:Symmetry, Integrability and Geometry: Methods and Applications
Datum:2017
Hauptverfasser: Turner, J., Morton, J.
Format: Artikel
Sprache:English
Veröffentlicht: Інститут математики НАН України 2017
Online Zugang:https://nasplib.isofts.kiev.ua/handle/123456789/148619
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Назва журналу:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Zitieren:A Complete Set of Invariants for LU-Equivalence of Density Operators / J. Turner, J. Morton // Symmetry, Integrability and Geometry: Methods and Applications. — 2017. — Т. 13. — Бібліогр.: 52 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-148619
record_format dspace
spelling Turner, J.
Morton, J.
2019-02-18T16:42:50Z
2019-02-18T16:42:50Z
2017
A Complete Set of Invariants for LU-Equivalence of Density Operators / J. Turner, J. Morton // Symmetry, Integrability and Geometry: Methods and Applications. — 2017. — Т. 13. — Бібліогр.: 52 назв. — англ.
1815-0659
2010 Mathematics Subject Classification: 20G05; 20G45; 81R05; 20C35; 22E70
DOI:10.3842/SIGMA.2017.028
https://nasplib.isofts.kiev.ua/handle/123456789/148619
We show that two density operators of mixed quantum states are in the same local unitary orbit if and only if they agree on polynomial invariants in a certain Noetherian ring for which degree bounds are known in the literature. This implicitly gives a finite complete set of invariants for local unitary equivalence. This is done by showing that local unitary equivalence of density operators is equivalent to local GL equivalence and then using techniques from algebraic geometry and geometric invariant theory. We also classify the SLOCC polynomial invariants and give a degree bound for generators of the invariant ring in the case of n-qubit pure states. Of course it is well known that polynomial invariants are not a complete set of invariants for SLOCC.
The authors would like to acknowledge the helpful comments of the reviewers which greatly improved and strengthened this paper. J. Turner would like to thank Llu´ıs Vena for helpful discussions. The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013) / ERC grant agreement No 339109.
en
Інститут математики НАН України
Symmetry, Integrability and Geometry: Methods and Applications
A Complete Set of Invariants for LU-Equivalence of Density Operators
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title A Complete Set of Invariants for LU-Equivalence of Density Operators
spellingShingle A Complete Set of Invariants for LU-Equivalence of Density Operators
Turner, J.
Morton, J.
title_short A Complete Set of Invariants for LU-Equivalence of Density Operators
title_full A Complete Set of Invariants for LU-Equivalence of Density Operators
title_fullStr A Complete Set of Invariants for LU-Equivalence of Density Operators
title_full_unstemmed A Complete Set of Invariants for LU-Equivalence of Density Operators
title_sort complete set of invariants for lu-equivalence of density operators
author Turner, J.
Morton, J.
author_facet Turner, J.
Morton, J.
publishDate 2017
language English
container_title Symmetry, Integrability and Geometry: Methods and Applications
publisher Інститут математики НАН України
format Article
description We show that two density operators of mixed quantum states are in the same local unitary orbit if and only if they agree on polynomial invariants in a certain Noetherian ring for which degree bounds are known in the literature. This implicitly gives a finite complete set of invariants for local unitary equivalence. This is done by showing that local unitary equivalence of density operators is equivalent to local GL equivalence and then using techniques from algebraic geometry and geometric invariant theory. We also classify the SLOCC polynomial invariants and give a degree bound for generators of the invariant ring in the case of n-qubit pure states. Of course it is well known that polynomial invariants are not a complete set of invariants for SLOCC.
issn 1815-0659
url https://nasplib.isofts.kiev.ua/handle/123456789/148619
citation_txt A Complete Set of Invariants for LU-Equivalence of Density Operators / J. Turner, J. Morton // Symmetry, Integrability and Geometry: Methods and Applications. — 2017. — Т. 13. — Бібліогр.: 52 назв. — англ.
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