Witnessing entanglement by proxy

Entanglement is a ubiquitous feature of low temperature systems and believed to be highly relevant for the dynamics of condensed matter properties and quantum computation even at higher temperatures. The experimental certification of this paradigmatic quantum effect in macroscopic high temperature s...

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Detalles Bibliográficos
Autores: Bäuml, Stefan, Bruß, Dagmar|||0000-0003-4661-2267, Huber, Marcus|||0000-0003-1985-4623, Kampermann, Hermann|||0000-0002-0659-6699, Winter, Andreas|||0000-0001-6344-4870
Tipo de recurso: artículo
Fecha de publicación:2016
País:España
Institución:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:203724
Acceso en línea:https://ddd.uab.cat/record/203724
https://dx.doi.org/urn:doi:10.1088/1367-2630/18/1/015002
Access Level:acceso abierto
Palabra clave:Entanglement
Entropy
Thermodynamics
Descripción
Sumario:Entanglement is a ubiquitous feature of low temperature systems and believed to be highly relevant for the dynamics of condensed matter properties and quantum computation even at higher temperatures. The experimental certification of this paradigmatic quantum effect in macroscopic high temperature systems is constrained by the limited access to the quantum state of the system. In this paper we show how macroscopic observables beyond the mean energy of the system can be exploited as proxy witnesses for entanglement detection. Using linear and semi-definite relaxations we show that all previous approaches to this problem can be outperformed by our proxies, i.e. entanglement can be certified at higher temperatures without access to any local observable. For an efficient computation of proxy witnesses one can resort to a generalised grand canonical ensemble, enabling entanglement certification even in complex systems with macroscopic particle numbers.