Thermodynamics of scalar fields is investigated in three dimensional black hole backgrounds in two approaches. One is mode expansion and direct computation of the partition sum, and the other is theâ€¦ (More)

We study two-dimensional Dirac fermions in a random non-Abelian vector potential by using lattice regularization. We consider U(N) random vector potential for large N . The ensemble average withâ€¦ (More)

In the present paper we shall study (2 + 1) dimensional ZN gauge theories on a lattice. It is shown that the gauge theories have two phases, one is a Higgs phase and the other is a confinement phase.â€¦ (More)

We study the t-J model on a ladder using the slave-fermion-CP formalism which has been used successfully in studying lightly doped high-TC cuprates. Special attention is paid to the dynamics ofâ€¦ (More)

Institute of Physics, University of Tokyo, Komaba, Tokyo, 153-8902 Japan February 29, 2008 We investigate chiral properties of the overlap lattice fermion by using solvable model in two dimensions,â€¦ (More)

In this paper, we study a 3D compact U(1) lattice gauge theory with a variety of nonlocal interactions that simulates the effects of gapless/gapful matter fields. We restrict the nonlocalâ€¦ (More)

We present a quantitative study of the charge-spin separation (CSS) phenomenon in a U(1) gauge theory of the t-J model of high-TC superconductors. We calculate the critical temperature TCSS of aâ€¦ (More)

In the previous paper we studied Dirac fermions in a non-Abelian random vector potential by using lattice supersymmetry. By the lattice regularization, the system of disordered Dirac fermions isâ€¦ (More)

In this paper we shall introduce a lattice model of unconventional superconductors (SC) like d-wave SC in order to study quantum phase transition at vanishing temperature (T ). Finite-T counterpartâ€¦ (More)

In the present paper, we shall study the 4-dimensional Z2 lattice gauge model with a random gauge coupling; the random-plaquette gauge model(RPGM). The random gauge coupling at each plaquette takesâ€¦ (More)