title: Linked-cluster expansion for the Green's function of the infinite-U Hubbard model.
abstract: We implement a highly efficient strong-coupling expansion for the Green's function of the Hubbard model. In the limit of extreme correlations, where the onsite interaction is infinite, the evaluation of diagrams simplifies dramatically enabling us to carry out the expansion to the eighth order in powers of the hopping amplitude. We compute the finite-temperature Green's function analytically in the momentum and Matsubara frequency space as a function of the electron density. Employing Padé approximations, we study the equation of state, Kelvin thermopower, momentum distribution function, quasiparticle fraction, and quasiparticle lifetime of the system at temperatures lower than, or of the order of, the hopping amplitude. We also discuss several different approaches for obtaining the spectral functions through analytic continuation of the imaginary frequency Green's function, and show results for the system near half filling. We benchmark our results for the equation of state against those obtained from a numerical linked-cluster expansion carried out to the eleventh order.
authors.affiliation: Department of Physics, University of California, Santa Cruz, California 95064, USA and Department of Physics, University of California, Davis, California 95616, USA.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Khatami
authors.affiliation: Department of Physics, University of California, Santa Cruz, California 95064, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Perepelitsky
authors.affiliation: Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Marcos
authors.initials: M
authors.lastname: Rigol
authors.affiliation: Department of Physics, University of California, Santa Cruz, California 95064, USA.
authors.forename: B Sriram
authors.initials: BS
authors.lastname: Shastry
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D004553:Electric Conductivity; D004579:Electron Transport; D004735:Energy Transfer; D008962:Models, Theoretical; D011789:Quantum Theory