2005/10/31 by J. Vidal, Julien Vidal, S. Dusuel +1 · 7 citations
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Critical exponent #Critical point (mathematics) #Energy (signal processing) #Hamiltonian (control theory) #Nonlinear system #Quantum and electron transport phenomena #Quantum many-body systems #Scaling #Widom scaling #cond-mat.stat-mech #quant-ph
paper · pdf · doi:10.1209/epl/i2006-10041-9
published as Europhys. Lett. 74, 817 (2006) · 4 pages, published version
openalex publication_date 2006/05/02 · arxiv created 2006/05/18 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We consider the finite-size corrections in the Dicke model and determine the scaling exponents at the critical point for several quantities such as the ground-state energy or the gap. Therefore, we use the Holstein-Primakoff representation of the angular momentum and introduce a canonical transformation to diagonalize the Hamiltonian in the normal phase. As already observed in several systems, these corrections turn out to be singular at the transition point and thus lead to nontrivial exponents. We show that for the atomic observables, these exponents are the same as in the Lipkin-Meshkov-Glick model, in agreement with numerical results. We also investigate the behavior of the order parameter related to the radiation mode and show that it is driven by the same scaling variable as the atomic one.