Quasi-sparse eigenvector diagonalization and stochastic error correction

We briefly review the diagonalization of quantum Hamiltonians using the quasi-sparse eigenvector (QSE) method. We also introduce the technique of stochastic error correction, which systematically removes the truncation error of the QSE result by stochastically sampling the contribution of the remaining basis states.Comment: 5 pages, to appear in the proceedings of the International Light-Cone Meeting on Non-Perturbative QCD and Hadron Phenomenology, Heidelberg, June 200

Lattice simulations for few- and many-body systems

We review the recent literature on lattice simulations for few- and many-body systems. We focus on methods and results that combine the framework of effective field theory with computational lattice methods. Lattice effective field theory is discussed for cold atoms as well as low-energy nucleons with and without pions. A number of different lattice formulations and computational algorithms are considered, and an effort is made to show common themes in studies of cold atoms and low-energy nuclear physics as well as common themes in work by different collaborations.Comment: 71 pages, 20 figures, published version to appear in Progress in Particle and Nuclear Physic

Ground state energy of spin-1/2 fermions in the unitary limit

We present lattice results for the ground state energy of a spin-1/2 fermion system in the unitary limit, where the effective range of the interaction is zero and the scattering length is infinite. We compute the ground state energy for a system of 6, 10, 14, 18, and 22 particles, with equal numbers of up and down spins in a periodic cube. We estimate that in the limit of large number of particles, the ground state energy is 0.25(3) times the ground state energy of the free Fermi system.Comment: 17 pages, 9 figures, expanded manuscript includes more data and cross-check

Spherical gauge fields

We introduce the spherical field formalism for free gauge fields. We discuss the structure of the spherical Hamiltonian for both general covariant gauge and radial gauge and point out several new features not present in the scalar field case. We then use the evolution equations to compute gauge-field and field-strength correlators