Renormalization group flow for fermionic superfluids at zero temperature - Condensed Matter > Strongly Correlated ElectronsReportar como inadecuado




Renormalization group flow for fermionic superfluids at zero temperature - Condensed Matter > Strongly Correlated Electrons - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We present a comprehensive analysis of quantum fluctuation effects in thesuperfluid ground state of an attractively interacting Fermi system, employingthe attractive Hubbard model as a prototype. The superfluid order parameter,and fluctuations thereof, are implemented by a bosonic Hubbard-Stratonovichfield, which splits into two components corresponding to longitudinal andtransverse Goldstone fluctuations. Physical properties of the system arecomputed from a set of approximate flow equations obtained by truncating theexact functional renormalization group flow of the coupled fermion-bosonaction. The equations capture the influence of fluctuations on non-universalquantities such as the fermionic gap, as well as the universal infraredasymptotics present in every fermionic superfluid. We solve the flow equationsnumerically in two dimensions and compute the asymptotic behavior analyticallyin two and three dimensions. The fermionic gap \Delta is reduced significantlycompared to the mean-field gap, and the bosonic order parameter \alpha, whichis equivalent to \Delta in mean-field theory, is suppressed to values below\Delta by fluctuations. The fermion-boson vertex is only slightly renormalized.In the infrared regime, transverse order parameter fluctuations associated withthe Goldstone mode lead to a strong renormalization of longitudinalfluctuations: the longitudinal mass and the bosonic self-interaction vanishlinearly as a function of the scale in two dimensions, and logarithmically inthree dimensions, in agreement with the exact behavior of an interacting Bosegas.



Autor: P. Strack, R. Gersch, W. Metzner

Fuente: https://arxiv.org/







Documentos relacionados