Detection of quantum critical points by a probe qubit

Quantum phase transitions occur when the ground state of a quantum system undergoes a qualitative change when an external control parameter reaches a critical value. Here, we demonstrate a technique for studying quantum systems undergoing a phase transition by coupling the system to a probe qubit. I...

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Bibliographic Details
Published in:Physical review letters 2008-03, Vol.100 (10), p.100501-100501, Article 100501
Main Authors: Zhang, Jingfu, Peng, Xinhua, Rajendran, Nageswaran, Suter, Dieter
Format: Article
Language:English
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Summary:Quantum phase transitions occur when the ground state of a quantum system undergoes a qualitative change when an external control parameter reaches a critical value. Here, we demonstrate a technique for studying quantum systems undergoing a phase transition by coupling the system to a probe qubit. It uses directly the increased sensibility of the quantum system to perturbations when it is close to a critical point. Using an NMR quantum simulator, we demonstrate this measurement technique for two different types of quantum phase transitions in an Ising spin chain.
ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.100.100501