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Satoru Saito

Publications and source records attributed to Satoru Saito.

At least 19 recordsLinked to original sources
arXiv2026

Big Crunch on Julia and Anti-Julia Sets in the Integrable Limit

The Julia set is defined by the closure of repelling periodic points in chaotic systems. Why does this structure not appear in integrable systems? In this paper, we address this question by demonstrating the existence of the closure of divergences of the periodic equations, which we designate as the "anti-Julia set." We also call the sets before taking the closures the pre-Julia and pre-anti-Julia sets, respectively. We illustrate the transition mechanism by considering a complex map that interpolates between integrable and non-integrable dynamics, by introducing a real deformation parameter $a$. For $0<a\le 1/2$, we show that the Julia set and the anti-Julia set coincide in the complex plane, although the pre-Julia and pre-anti-Julia sets remain completely disjoint. At the integrable limit $a\to 0$, these two dual structures undergo a critical collision and subsequent annihilation, reminiscent of a cosmological Big Crunch. When $1/2<a<1$, on the other hand, the boundary of the pre-anti-Julia set includes the Julia set. We analytically characterize these phenomena, focusing in particular on the asymptotic behavior of the pre-anti-Julia set as it approaches the integrable limit, and provide numerical visualizations that elucidate the underlying mechanisms of this Big Crunch phenomenon.

math-ph↗
arXiv2020

Dynamic Logic of Quantum Field Theory

Although logic of quantum mechanics has been studied for a long time, logic of QFT has not been studied before. We formulate logic of QFT by introducing the perspective of dynamic logic, because the nature of two fundamental operators in QFT, namely creation and annihilation operators, is dynamic in the sense of logic. After we formulate dynamic logic of QFT, we give a dynamic logical interpretation of fermions, the so-called vacuum state, the zero vector and propagators in QFT. We also emphasize that only a tautology $\top$ and a contradiction $\bot$ are atomic formulas of our logic. Finally, we show how Aharonov-Bohm effect can be explained naturally from our dynamic logic of QFT. This paper should be the beginning of studying logic of QFT from a dynamical point of view.

quant-ph↗
arXiv2015

Derivation of Invariant Varieties of Periodic Points from Singularity Confinement in the case of Toda Map

In our previous work we have shown that the invariant varieties of periodic points (IVPP) of all periods of the 3 dimensional Lotka-Volterra map can be derived, iteratively, from the singularity confinement (SC). The method developed there can be applied to any integrable maps of dimension $d$ only when the number of the invariants $p$ equals to $d-1$. We propose, in this note, a new algorithm of the derivation which can be used in the cases ${d\over 2}\le p\le d-2$. Applying this algorithm to the 3 point Toda map, we derive a series of its IVPP's.

math-ph↗
arXiv2013

Singularity Confinement and Projective Resolution of Triangulated Category

We proposed, in our previous paper, to characterize the Hirota-Miwa equation by means of the theory of triangulated category. We extend our argument in this paper to support the idea. In particular we show in detail how the singularity confinement, a phenomenon which was proposed to characterize integrable maps, can be associated with the projective resolution of the triangulated category.

math-ph↗
arXiv2013

Degeneration of the Julia set to singular loci of algebraic curves

We show that, when a non-integrable rational map changes to an integrable one continuously, a large part of the Julia set of the map approach indeterminate points (IDP) of the map along algebraic curves. We will see that the IDPs are singular loci of the curves.

nlin.SI↗
arXiv2006

Invariant Varieties of Periodic Points for the Discrete Euler Top

The behaviour of periodic points of discrete Euler top is studied. We derive invariant varieties of periodic points explicitly. When the top is axially symmetric they are specified by some particular values of the angular velocity along the axis of symmetry, different for each period.

math-ph↗
arXiv2006

Invariant varieties of periodic points for some higher dimensional integrable maps

By studying various rational integrable maps on $\mathbf{\hat C}^d$ with $p$ invariants, we show that periodic points form an invariant variety of dimension $\ge p$ for each period, in contrast to the case of nonintegrable maps in which they are isolated. We prove the theorem: {\it `If there is an invariant variety of periodic points of some period, there is no set of isolated periodic points of other period in the map.'}

math-ph↗
arXiv2005

The nature of manifolds of periodic points for higher dimensional integrable maps

By studying periodic points for rational maps on $\bm{C}^d$ with $p$ invariants, we show that they form an invariant variety of dimension $p$ if the periodicity conditions are `fully correlated', and a set of isolated points if the conditions are `uncorrelated'. We present many examples of the invariant varieties in the case of integrable maps. Moreover we prove that an invariant variety and a set of isolated points do not exist in one map simultaneously.

math-ph↗
arXiv2005

Intersecting D-brane states derived from the KP theory

A general scheme to find tachyon boundary states is developed within the framework of the theory of KP hierarchy. The method is applied to calculate correlation function of intersecting D-branes and rederived the results of our previous works as special examples. A matrix generalization of this scheme provides a method to study dynamics of coincident multi D-branes.

hep-th↗
arXiv2004

D-brane correlators as solutions of Hirota-Miwa equation

We present a tachyon field, which simply connects to the calculus of the tachyon condensation. The tachyon field acts on any bare boundary state: the Neumann or the Dirichlet state, and generates the boundary state suggested by S.P. de Alwis, which leads to the correct ratio between D-brane tensions. On the other hand we generalize the Hirota-Miwa equation to the case where there are two boundaries. We show that correlation functions made from only the integrand of the tachyon field satisfy the generalized Hirota-Miwa equation. Using the formulation based on this evidence, we suggest that the coordinates in which there exist tachyons on an unstable D-brane be identified as the soliton coordinates in integrable systems. We also evaluate these correlation functions, which have not yet been integrated, to obtain the local information about the tachyons on unstable D-branes. We further see how these amplitudes are affected through the tachyon condensation by integrating the correlators over the tachyon momenta and taking the on-shell limit.

hep-th↗
arXiv2004

Nambu-Hamiltonian flows associated with discrete maps

For a differentiable map $(x_1,x_2,..., x_n)\to (X_1,X_2,..., X_n)$ that has an inverse, we show that there exists a Nambu-Hamiltonian flow in which one of the initial value, say $x_n$, of the map plays the role of time variable while the others remain fixed. We present various examples which exhibit the map-flow correspondence.

math-ph↗
arXiv2003

Soliton equations solved by the boundary CFT

Soliton equations are derived which characterize the boundary CFT a la Callan et al. Soliton fields of classical soliton equations are shown to appear as a neutral bound state of a pair of soliton fields of BCFT. One soliton amplitude under the influence of the boundary is calculated explicitly and is shown that it is frozen at the Dirichlet limit.

hep-th↗
arXiv2001

A Characterization of Discrete Time Soliton Equations

We propose a method to characterize discrete time evolution equations, which generalize discrete time soliton equations, including the $q$-difference Painlevé IV equations discussed recently by Kajiwara, Noumi and Yamada.

nlin.SI↗