Two-time Green's functions and spectral density method in nonextensive quantum statistical mechanics

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dc.creatorCavallo, A.
dc.creatorCosenza, F.
dc.creatorDe Cesare, L.
dc.date2007-10-30
dc.date2008-09-07
dc.date.accessioned2026-07-07T10:00:48Z
dc.date.available2026-07-07T10:00:48Z
dc.descriptionWe extend the formalism of the thermodynamic two-time Green's functions to nonextensive quantum statistical mechanics. Working in the optimal Lagrangian multipliers representation, the $q$-spectral properties and the methods for a direct calculation of the two-time $q$% -Green's functions and the related $q$-spectral density ($q$ measures the nonextensivity degree) for two generic operators are presented in strict analogy with the extensive ($q=1$) counterpart. Some emphasis is devoted to the nonextensive version of the less known spectral density method whose effectiveness in exploring equilibrium and transport properties of a wide variety of systems has been well established in conventional classical and quantum many-body physics. To check how both the equations of motion and the spectral density methods work to study the $q$-induced nonextensivity effects in nontrivial many-body problems, we focus on the equilibrium properties of a second-quantized model for a high-density Bose gas with strong attraction between particles for which exact results exist in extensive conditions. Remarkably, the contributions to several thermodynamic quantities of the $q$-induced nonextensivity close to the extensive regime are explicitly calculated in the low-temperature regime by overcoming the calculation of the $q$ grand-partition function.
dc.description48 pages, no figures
dc.identifierhttps://arxiv.org/abs/0710.5695
dc.identifierhttp://arxiv.org/abs/0710.5695
dc.identifierPhys. Rev. E 77, 051110 (2008)
dc.identifierdoi:10.1103/PhysRevE.77.051110
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/168432
dc.subjectStatistical Mechanics
dc.titleTwo-time Green's functions and spectral density method in nonextensive quantum statistical mechanics
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