U(infinity) Gauge Theory from Higher Dimensions

We show that classical U(infinity) gauge theories can be obtained from the dimensional reduction of a certain class of higher-derivative theories. In general, the exact symmetry is attained in the limit of degenerate metric; otherwise, the infinite-dimensional symmetry can be taken as spontaneously broken. Monopole solutions are examined in the model for scalar and gauge fields. An extension to gravity is also discussed.Comment: 13 pages, no figur

Attainability of Carnot Efficiency with Autonomous Engines

The maximum efficiency of autonomous engines with finite chemical potential difference is investigated. We show that without a particular type of singularity autonomous engines cannot attain the Carnot efficiency. In addition, we demonstrate that a special autonomous engine with the singularity attains the Carnot efficiency even if it is macroscopic. Our results clearly illustrate that the singularity plays a crucial role for the maximum efficiency of autonomous engines.Comment: 11 pages, 8 figure

Hausdorff dimension of the scaling limit of loop-erased random walk in three dimensions

Let $M_{n}$ be the length (number of steps) of the loop-erasure of a simple random walk up to the first exit from a ball of radius $n$ centered at its starting point. It is shown in [18] that there exists $\beta \in (1, \frac{5}{3}]$ such that $E (M_{n} )$ is of order $n^{\beta}$ in 3 dimensions. In the present article, we show that the Hausdorff dimension of the scaling limit of the loop-erased random walk in 3 dimensions is equal to $\beta$ almost surely.Comment: 39 pages, 1 figur

Anomalous System Size Dependence of Large Deviation Functions for Local Empirical Measure

We study the large deviation function for the empirical measure of diffusing particles at one fixed position. We find that the large deviation function exhibits anomalous system size dependence in systems that satisfy the following conditions: (i) there exists no macroscopic flow, and (ii) their space dimension is one or two. We investigate this anomaly by using a contraction principle. We also analyze the relation between this anomaly and the so-called long-time tail behavior on the basis of phenomenological arguments.Comment: 14 page

Two-sided random walks conditioned to have no intersections

Let $S^{1},S^{2}$ be independent simple random walks in $\mathbb{Z}^{d}$ ($d=2,3$) started at the origin. We construct two-sided random walk paths conditioned that $S^{1}[0,\infty) \cap S^{2}[1, \infty) = \emptyset$.Comment: 25 page

Wilson Loops in Open String Theory

Wilson loop elements on torus are introduced into the partition function of open strings as Polyakov's path integral at one-loop level. Mass spectra from compactification and expected symmetry breaking are illustrated by choosing the correct weight for the contributions from annulus and M\"obius strip. We show that Jacobi's imaginary transformation connects the mass spectra with the Wilson loops. The application to thermopartition function and cosmological implications are briefly discussed.Comment: 5 pages, no figur

Growth exponent for loop-erased random walk in three dimensions

We show the existence of the growth exponent for loop-erased random walk in three dimensions.Comment: 59 pages, 3 figure

Degenerate Fermions and Wilson Loop in 1+11+1 Dimensions

We investigate the effect of finite fermion density on symmetry breaking by Wilson loops in $(1+1)$ dimensions. We find the breaking and restoration of symmetry at finite density in the models with $SU(2)$ and $SU(3)$ gauge symmetries, in the presence of the adjoint fermions. The transition can occur at a finite density of fermions, regardless of the periodic or antiperiodic boundary condition of the fermion field; this is in contrast to the finite-temperature ease examined by Ho and Hosotani (Nucl. Phys. B345 (1990) 445) where the boundary condition of fractional twist is essential to the occurrence of the phase transition.Comment: 8 pages, 4 figure

Finite-time thermodynamic uncertainty relation do not hold for discrete-time Markov process

Discrete-time counterpart of thermodynamic uncertainty relation (conjectured in P. Pietzonka, et.al., arXiv:1702.07699 (2017)) with finite time interval is considered. We show that this relation do not hold by constructing a concrete counterexample to this. Our finding suggests that the proof of thermodynamic uncertainty relation with finite time interval, if true, should strongly rely on the fact that the time is continuous.Comment: 3 page

Hosotani model in closed-string theory

The Hosotani mechanism in the closed-string theory with current algebra symmetry is described by the (old covariant) operator method. We compare the gauge symmetry breaking mechanism in a string theory which contains SU(2) symmetry originated from current algebra with the one in an equivalent compactified closed-string theory. We also investigate the difference between the Hosotani mechanism and the Higgs mechanism in closed-string theories by calculation of a four-point amplitude of `Higgs' bosons at tree level.Comment: 16 pages, no figur