UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

An order parameter for impurity systems at quantum criticality

Bayat, A; Johannesson, H; Bose, S; Sodano, P; (2014) An order parameter for impurity systems at quantum criticality. Nature Communications , 5 , Article 3784. 10.1038/ncomms4784. Green open access

[thumbnail of ncomms4784.pdf]
Preview
PDF
ncomms4784.pdf

Download (419kB)

Abstract

A quantum phase transition may occur in the ground state of a system at zero temperature when a controlling field or interaction is varied. The resulting quantum fluctuations which trigger the transition produce scaling behaviour of various observables, governed by universal critical exponents. A particularly interesting class of such transitions appear in systems with quantum impurities where a non-extensive term in the free energy becomes singular at the critical point. Curiously, the notion of a conventional order parameter that exhibits scaling at the critical point is generically missing in these systems. Here we explore the possibility to use the Schmidt gap, which is an observable obtained from the entanglement spectrum, as an order parameter. A case study of the two-impurity Kondo model confirms that the Schmidt gap faithfully captures the scaling behaviour by correctly predicting the critical exponent of the dynamically generated length scale at the critical point.

Type: Article
Title: An order parameter for impurity systems at quantum criticality
Open access status: An open access version is available from UCL Discovery
DOI: 10.1038/ncomms4784
Publisher version: http://dx.doi.org/10.1038/ncomms4784
Language: English
Additional information: © 2014 This work is licensed under a Creative Commons Attribution 3.0 Unported License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/3.0/ PubMed ID: 24807201
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI: https://discovery.ucl.ac.uk/id/eprint/1435182
Downloads since deposit
112Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item