N-chain Hubbard model in weak coupling
نویسندگان
چکیده
We present a systematic weak-coupling renormalization group ~RG! technique for studying a collection of N coupled one-dimensional interacting electron systems, focusing on the example of N-leg Hubbard ladders. For N52,3, we recover previous results, and find that also more generally broad regions of the phase space of these models are unstable to pairing, usually with approximate d-wave symmetry. We show how these instabilities can be understood in terms of a fairly conventional ‘‘gap’’ function D at the discretized Fermi surface, and describe how this function is calculated. The dimensional crossovers as N→` and as many such ladders are weakly coupled together are also discussed. @S0163-1829~97!00836-9#
منابع مشابه
Weak-coupling phase diagram of the two-chain Hubbard model.
We present a general method for determining the phase diagram of systems of a finite number of onedimensional Hubbard-like systems coupled by single-particle hopping with weak interactions. The technique is illustrated by detailed calculations for the two-chain Hubbard model, providing controlled results for arbitrary doping and interchain hopping. Of nine possible states which could occur in s...
متن کاملWeak – coupling calculation of the gap structure of doped n – leg Hubbard ladders
Weak–coupling calculation of the gap structure of doped n–leg Hubbard ladders Abstract In weak coupling, the spin gap in doped, even, n–leg periodic Hubbard ladders reflects the energy to break a pair into separate quasiparticles. Here we investigate the structure of the gap within a spin–fluctuation exchange approximation. We also calculate the amplitude for removing a singlet pair from two la...
متن کاملFailure of Fermi-liquid theory at strong coupling
We investigate quantitatively the effects of strong electron-electron coupling onto the dynamics of lattice electrons. To that purpose the selfconsistent version of the bubble-chain approximation at zero temperature and half filling of the Anderson (Hubbard) model is used. Special attention is paid to a critical region of an electron-hole correlation function shaping the transition from weak to...
متن کاملAnalytic Correlation Functions of the two-dimensional Half Filled Hubbard Model at Weak Coupling
We derive explicit spin and charge correlation functions of the N × N Hubbard model from a recently obtained weak-coupling analytic ground state |Ψ AF 〉. The spin correlation function shows an antiferromagnetic behaviour with different signs for the two sublattices and its Fourier tranform is peaked at Q = (π, π). The charge correlation function presents two valleys at 45 degrees from the axes....
متن کاملA NUMERICAL RENORMALIZATION GROUP APPROACH FOR AN ELECTRON-PHONON INTERACTION
A finite chain calculation in terms of Hubbard X-operators is explored by setting up a vibronic Harniltonian. The model conveniently transformed into a form so that in the case of strong coupling a numerical renormalization group approach is applicable. To test the technique, a one particle Green function is calculated for the model Harniltonian
متن کامل