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We use the Density-Matrix Renormalization Group to study the single-particle and two-particle correlation functions of spinless fermions in the ground state of a quarter-filled ladder. This ladder consists of two chains having an in-chain…

Strongly Correlated Electrons · Physics 2009-11-07 L. G. Caron , C. Bourbonnais

The cumulant expansion is a powerful approach for including correlation effects in electronic structure calculations beyond the GW approximation. However, current implementations are incomplete since they ignore terms that lead to partial…

Strongly Correlated Electrons · Physics 2014-02-04 J. J. Kas , J. J. Rehr , L. Reining

We investigate the entanglement properties of the equilibrium and nonequilibrium quantum dynamics of 2D and 3D Fermi gases, by computing entanglement entropies of extended space regions, which generally show multiplicative logarithmic…

Statistical Mechanics · Physics 2013-03-27 Jacopo Nespolo , Ettore Vicari

Problems occurring in physically important non-trivial examples of loop calculations are discussed. A procedure of deriving expansions of two-loop self-energy diagrams with different masses is constructed. The cases of small and large…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. I. Davydychev

One of the major challenges in realizing antiferromagnetic and superfluid phases in optical lattices is the ability to cool fermions. We determine constraints on the entropy for observing these phases in two-dimensional Hubbard models. We…

Quantum Gases · Physics 2015-05-13 Thereza Paiva , Richard Scalettar , Mohit Randeria , Nandini Trivedi

A self contained analysis demonstrates that the sum of all particle-hole ladder contributions for a two dimensional, weakly coupled fermion gas with a strictly convex Fermi curve at temperature zero is bounded. This is used in our…

Mathematical Physics · Physics 2007-05-23 Joel Feldman , Horst Knoerrer , Eugene Trubowitz

Recent experiments with dilute trapped Fermi gases observed that weak interactions can drastically modify spin transport dynamics and give rise to robust collective effects including global demagnetization, macroscopic spin waves, spin…

Quantum Gases · Physics 2016-12-09 Andrew P. Koller , Michael L. Wall , Josh Mundinger , Ana Maria Rey

We calculate perturbative renormalization properties of the topological charge, using the standard lattice discretization given by a product of twisted plaquettes. We use the overlap and clover action for fermions, and the Symanzik improved…

High Energy Physics - Lattice · Physics 2009-11-11 A. Skouroupathis , H. Panagopoulos

This thesis is concerned with ground state properties of two-dimensional fermionic superfluids, in which fluctuation effects like the renormalization of the order parameter or infrared singularities are important. In the superfluid state,…

Strongly Correlated Electrons · Physics 2014-07-30 Andreas Eberlein

The overlap hypercube fermion is a variant of a chirally symmetric lattice fermion, which is endowed with a higher level of locality than the standard overlap fermion. We apply this formulation in quenched QCD simulations with light quarks.…

High Energy Physics - Lattice · Physics 2009-11-11 W. Bietenholz , S. Shcheredin

I present one-loop perturbative calculations of matching coefficients between matrix elements in continuum regulated QCD and lattice QCD with overlap fermions, with emphasis a recently-proposed variant discretization of the overlap. These…

High Energy Physics - Lattice · Physics 2016-09-01 Thomas DeGrand

We study the perturbative correction to the ground state energy eigenvalue of a 2-dimensional dilute fermi gas with weak short-range two body repulsion. From the structure of the energy shift we infer the presence of an induced two body…

Condensed Matter · Physics 2007-05-23 G. Baskaran

We consider the two-dimensional Fermi gas at finite temperature with attractive short-range interactions. Using the virial expansion, which provides a controlled approach at high temperatures, we determine the spectral function and contact…

Quantum Gases · Physics 2014-01-08 V. Ngampruetikorn , J. Levinsen , Meera M. Parish

Proceeding from the simplest field theoretical model of 2D metal, the normal phase Green functions of the weakly interacting fermions and the order parameter fluctuations (responsible for the attraction between fermions) are obtained. It is…

Condensed Matter · Physics 2007-05-23 V. P. Gusynin , V. M. Loktev , I. A. Shovkovy

We present detailed measurements of the frequency and damping of three different collective modes in an ultracold trapped Fermi gas of $^6$Li atoms with resonantly tuned interactions. The measurements are carried out over a wide range of…

The effect of ordering field phase fluctuations on the normal and superconducting properties of a simple 2D model with a local four-fermion attraction is studied. Neglecting the coupling between the spin and charge degrees of freedom an…

Superconductivity · Physics 2009-10-31 V. P. Gusynin , V. M. Loktev , R. M. Quick , S. G. Sharapov

Three aspects of symmetry structure of lattice chiral fermion in the overlap formalism are discussed. By the weak coupling expansion of the overlap Dirac operator, the axial anomaly associated to the chiral transformation proposed by…

High Energy Physics - Lattice · Physics 2009-10-31 Y. Kikukawa

A formalism based on the fermionic functional-renormalization-group approach to interacting electron models defined on a lattice is presented. One-loop flow equations for the coupling constants and susceptibilities in the particle-particle…

Strongly Correlated Electrons · Physics 2024-08-21 Lucas Désoppi , Nicolas Dupuis , Claude Bourbonnais

We discuss the momentum-space topology of 3+1 and 2+1 strongly correlated fermionic systems. For the 3+1 systems the important universality class is determined by the topologically stable Fermi points in momentum space. In the extreme limit…

Condensed Matter · Physics 2017-08-23 G. E. Volovik

We present the detailed formalism of the extremely correlated Fermi liquid theory, developed for treating the physics of the t-J model. We start from the exact Schwinger equation of motion for the Greens function for projected electrons,…

Strongly Correlated Electrons · Physics 2013-04-05 B. Sriram Shastry