Tetsuo Matsui

Parisi-Klauder algorithm for complex actions in stochastic quantization

Abstract We study the condition under which the Parisi-Klauder algorithm for complex actions works. We discuss the relations between this condition and diverging Langevin solutions.

Two-loop effective action of O(N) spin models in 1D expansion

We calculate the two-loop effective action of O(N) spin models on the lattice in a 1D expansion to order 1D2. The resulting free energy depends on β = 1T and the order parameter Φ. It matches the high and low temperature regimes and is quite reliable close to the phase transition where it has a simple Landau expansion.

Ginzburg Landau theory of resonating valence bonds and its U(1) phase dynamics

Abstract We formulate a Ginzburg Landau theory for the resonating valence bond model of antiferromagnetism and high Tc superconductivity, the order parameter of which are complex link variables. We investigate the dynamics of their phase part by Monte Carlo mothod and obtain an indication of a transition to a superconducting phase. When the doping parameter is zero, the theory becomes equivalent to a U(1) lattice gauge theory in two dimension.

Are gluons composite? A new lattice gauge model with an exact U(∞) solution

Abstract The search for an exact N → ∞ solution of U( N ) gauge theories has led us to a new lattice model in which the gauge field dynamics is generated by four fundamental tensor fields describing subgluons. Our model has the same β → 0 limit as Wilsons and the same β → ∞ limit as far as the soft weak field excitations are concerned. It allows for the introduction of colorless Hartree like collective fields and has a simple N → ∞ solution.