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arXiv · 0709.3273

Detection of quantum critical points by a probe qubit

Jingfu Zhang·Xinhua Peng·Nageswaran Rajendran·Dieter Suter
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Abstract

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.

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Jingfu Zhang, Xinhua Peng, Nageswaran Rajendran, Dieter Suter. 2008-03-14. Detection of quantum critical points by a probe qubit. https://doi.org/10.1103/physrevlett.100.100501

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