Rényi entropy and quantum phase transition in the Dicke model

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• 作者：E. Romera^a ; ^{eromera@ugr.es"" rel=""nofollow} ; Á ; . Nagy^b ; ^{anagy@madget.atomki.hu"" rel=""nofollow}
• 关键词：Quantum phase transition ; Dicke model ; Ré ; nyi entropy
• 刊名：Physics Letters A
• 出版年：2011
• 出版时间：8 August 2011
• 年：2011
• 卷：375
• 期：34
• 页码：3066-3069
• 全文大小：180 K

文摘

The Rényi entropies of the Dicke model are presented. This quantum-optical model describes a single-mode bosonic field interacting with an ensemble of N two-level atoms. There is a quantum phase transition in the N→∞ limit. It is shown that there is an abrupt change in the Rényi entropy of order β at the transition point. Around the critical value of the coupling strength λ_c the Rényi entropy is proportional to the logarithm of the characteristic length and diverges as lnλ_c−λ for any order β. The pseudocapacity defined here in analogy with the heat capacity exhibits the phase transition. The critical exponent for the Dicke model is found to be 1 for any value of the parameter β.