arXiv subjects

Shinsuke Nishigaki

Publications and source records attributed to Shinsuke Nishigaki.

4 recordsLinked to original sources

arXiv2024

Eigenphase distributions of unimodular circular ensembles

Motivated by the study of Polyakov lines in gauge theories, Hanada and Watanabe recently presented a conjectured formula for the distribution of eigenphases of Haar-distributed random SU(N) matrices ($β$=2), supported by explicit examples at small N and by numerical samplings at larger N. In this note, I spell out a concise proof of their formula, and present its orthogonal and symplectic counterparts, i.e. the eigenphase distributions of Haar-random unimodular symmetric ($β$=1) and selfdual ($β$=4) unitary matrices parametrizing SU(N)/SO(N) and SU(2N)/Sp(2N), respectively.

math-ph↗

arXiv1995

Renormalization group flow in one- and two-matrix models

Large-$N$ renormalization group equations for one- and two-matrix models are derived. The exact renormalization group equation involving infinitely many induced interactions can be rewritten in a form that has a finite number of coupling constants by taking account of reparametrization identities. Despite the nonlinearity of the equation, the location of fixed points and the scaling exponents can be extracted from the equation. They agree with the spectrum of relevant operators in the exact solution. A linearized $β$-function approximates well the global phase structure which includes several nontrivial fixed points. The global renormalization group flow suggests a kind of $c$-theorem in two-dimensional quantum gravity.

hep-th↗

arXiv1993

Scaling Violation in O(N) Vector Models

We investigate $O(N)$-symmetric vector field theories in the double scaling limit. Our model describes branched polymeric systems in $D$ dimensions, whose multicritical series interpolates between the Cayley tree and the ordinary random walk. We give explicit forms of residual divergences in the free energy, analogous to those observed in the strings in one dimension.

hep-th↗

arXiv1993

Nonlinear Renormalization Group Equation for Matrix Models

An exact renormalization group equation is derived for the free energy of matrix models. The renormalization group equation turns out to be nonlinear for matrix models, as opposed to linear for vector models. An algorithm for determining the critical coupling constant and the critical exponent is obtained. As concrete examples, one-matrix models with one and two coupling constants are analyzed and the exact values of the critical coupling constant and the associated critical exponent are found.

hep-th↗