Pulse control of sudden transition for two qubits in XY spin baths and quantum phase transition

Journal Article · Wed Dec 14 23:00:00 EST 2011 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.84.062112· OSTI ID:22095545

Luo, Da-Wei; Xu, Jing-Bo ^[1]; Lin, Hai-Qing ^[2]; Yao, Dao-Xin ^[3]

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1. Zhejiang Institute of Modern Physics and Department of Physics, Zhejiang University, Hangzhou 310027 (China)
2. Beijing Computational Science Research Center, Beijing 100084 (China)
3. State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)

We study the dynamics of two initially correlated qubits coupled to their own separate spin baths modeled by an XY spin chain and find the explicit expression of the quantum discord for the system. A sudden transition is found to exist between classical and quantum decoherence by choosing certain initial states. We show that the sudden transition happens near the critical point, which provides an alternative way to characterize the quantum phase transition. Furthermore, we propose a scheme to prolong the transition time of the quantum discord by applying the bang-bang pulses.

• OSTI ID: 22095545
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 6 Vol. 84; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
PHASE TRANSFORMATIONS
PULSES
QUANTUM DECOHERENCE
QUANTUM MECHANICS
QUBITS
SPIN