Flow equation approach to heavy fermion systems

Abstract

We use Wegner's flow equation method to investigate the infinite-U periodic Anderson model. We show that this method poses a new approach to the description of heavy fermion behaviour. Within this scheme we derive an effective Hamiltonian in which the c and f degrees of freedom are decoupled. By evaluating one-particle energies as well as correlation functions we find an electronic structure which comprises two gapped quasiparticle bands. We also address the lattice Kondo temperature, which shows a typical exponential dependence on the hybridisation energy. This energy scale exhibits a significant decrease compared to that of the single impurity Anderson model.

Deep inelastic scattering on the quark-gluon plasma

“…We also remark that Eqs. (35-36) could be averaged analytically over the direction of q using Legendre polynomials, along the lines of [23]. This could prove numerically advantageous in calculations performed on lattices with a large spatial volume.…”

Lattice calculation of the hadronic leading order contribution to the muon g − 2

“…Therefore, stochastic methods are applied which, despite being numerically quite efficient, introduce stochastic noise in addition to the statistical fluctuations due to the Monte Carlo integration over the gauge ensemble. Several methods have been devised to combat stochastic noise, such as performing a hopping parameter expansion of the propagator [52,53], low-mode deflation [54], hierarchical probing and Hadamard vectors [55], as well as the use of a Lorentz covariant coordinate space formulation [56] instead of the spatially summed vector correlator.…”