Searcharxiv⌕ Search

arXiv subjects

Shingo Takeuchi

Publications and source records attributed to Shingo Takeuchi.

At least 37 records · Page 2Linked to original sources
arXiv2020

Numerical and analytical analyses of a matrix model with non-pairwise contracted indices

We study a matrix model that has $ϕ_a^i\ (a=1,2,\ldots,N,\ i=1,2,\ldots,R)$ as its dynamical variable, whose lower indices are pairwise contracted, but upper ones are not always done so. This matrix model has a motivation from a tensor model for quantum gravity, and is also related to the physics of glasses, because it has the same form as what appears in the replica trick of the spherical $p$-spin model for spin glasses, though the parameter range of our interest is different. To study the dynamics, which in general depends on $N$ and $R$, we perform Monte Carlo simulations and compare with some analytical computations in the leading and the next-leading orders. A transition region has been found around $R\sim N^2/2$, which matches a relation required by the consistency of the tensor model. The simulation and the analytical computations agree well outside the transition region, but not in this region, implying that some relevant configurations are not properly included by the analytical computations. With a motivation coming from the tensor model, we also study the persistent homology of the configurations generated in the simulations, and have observed its gradual change from $S^1$ to higher dimensional cycles with the increase of $R$ around the transition region.

hep-th↗
arXiv2019

D-dependence of gap between critical temperatures in one-dimensional gauge theories

We investigate the dimensional dependence (D-dependence) of the difference (gap) between the critical temperatures associated with the uniform/non-uniform and non-uniform/gapped transitions in the large-N bosonic gauge theories with D matrix scalar fields on a circled space. We use the equations describing these critical temperatures given in the 1/D expansion arXiv:0910.4526. These transitions are related with Gregory-Laflamme instabilities in the gravities and Rayleigh-Plateau instabilities in the fluid dynamics, and qualitative similarities between these are expected. We find that the tendency in the D-dependence of the gap is opposite from those in the gravity and fluid side. This is interesting as a counterexample to the gauge/gravity and gauge/fluid correspondences.

hep-th↗
arXiv2019

Two double-angle formulas of generalized trigonometric functions

With respect to generalized trigonometric functions, since the discovery of double-angle formula for a special case by Edmunds, Gurka and Lang in 2012, no double-angle formulas have been found. In this paper, we will establish new double-angle formulas of generalized trigonometric functions in two special cases.

math.CA↗
arXiv2019

Applications of generalized trigonometric functions with two parameters II

Generalized trigonometric functions (GTFs) are simple generalization of the classical trigonometric functions. GTFs are deeply related to the $p$-Laplacian, which is known as a typical nonlinear differential operator. Compared to GTFs with one parameter, there are few applications of GTFs with two parameters to differential equations. We will apply GTFs with two parameters to studies on the inviscid primitive equations of oceanic and atmospheric dynamics, new formulas of Gaussian hypergeometric functions, and the $L^q$-Lyapunov inequality for the one-dimensional $p$-Laplacian.

math.CA↗
arXiv2019

Applications of generalized trigonometric functions with two parameters

Generalized trigonometric functions (GTFs) are simple generalization of the classical trigonometric functions. GTFs are deeply related to the $p$-Laplacian, which is known as a typical nonlinear differential operator, and there are a lot of works on GTFs concerning the $p$-Laplacian. However, few applications to differential equations unrelated to the $p$-Laplacian are known. We will apply GTFs with two parameters to nonlinear nonlocal boundary value problems without $p$-Laplacian. Moreover, we will give integral formulas for the functions, e.g. Wallis-type formulas, and apply the formulas to the lemniscate function and the lemniscate constant.

math.CA↗
arXiv2019

Violation of the KSS Bound in Holographic Bjorken-Flow

In a system with a Bjorken-flow (BF), considering the inside of a BF as a subsystem for the reason explained in the body text, we compute entanglement entropy appearing in our side holographically . BF consists of many concentrically scattering quark-gluon plasmas created by colliding two masses of hadrons. Our BF is defined in the boundary space in an asymptoticly five-dimensional Anti de-Sitter space with a growing Schwartzshild black hole. %, where its Hawking temperature diminishes with time. In our analysis we can get a parameter prescribing our bulk space-time in terms of the boundary QCD's variables. Using this, we find that the $η/s$ dips from $1/4π$ just for a moment before asymptoting to $1/4π$ at infinitely large time. Since $1/4π$ is the KSS bound, this result is intriguing as an example of violation of the KSS bound.

hep-th↗
arXiv2017

Kerr/CFT correspondence in a 4D extremal rotating regular black hole with a non-linear magnetic monopole

We carry out the Kerr/CFT correspondence in a four-dimensional extremal rotating regular black hole with a non-linear magnetic monopole (NLMM). One problem in this study would be whether our geometry can be a solution or not. We search for the way making our rotating geometry into a solution based on the fact that the Schwarzschild regular black hole geometry with a NLMM can be a solution. However, in the attempt to extend the Schwarzschild case that we can naturally consider, it turns out that it is impossible to construct a model in which our geometry can be a exact solution. We manage this problem by making use of the fact that our geometry can be a solution approximately in the whole space-time except for the black hole's core region. As a next problem, it turns out that the equation to obtain the horizon radii is given by a fifth-order equation due to the regularization effect. We overcome this problem by treating the regularization effect perturbatively. As a result, we can obtain the near-horizon extremal Kerr (NHEK) geometry with the correction of the regularization effect. Once obtaining the NHEK geometry, we can obtain the central charge and the Frolov-Thorne temperature in the dual CFT. Using these, we compute its entropy through the Cardy formula, which agrees with the one computed from the Bekenstein-Hawking entropy.

hep-th↗
arXiv2016

Hawking fluxes and Anomalies in Rotating Regular Black Holes with a Time-Delay

Based on the anomaly cancellation method we are going to compute the Hawking fluxes (the Hawking thermal flux and the total flux of energy-momentum tensor) from a four-dimensional rotating regular black hole with a time-delay. To this purpose, in the three metrics proposed in arXiv:1510.08828, we try to perform the dimensional reduction in which the anomaly cancellation method is feasible at the near-horizon region in a general scalar field theory. As a result we can demonstrate that the dimensional reduction is possible in two of those metrics. Hence we perform the anomaly cancellation method and compute the Hawking fluxes in those two metrics. Our Hawking fluxes involve the three effects: 1) the quantum gravity effect regularizing the core of the black holes, 2) rotation of the black hole, 3) the time-delay. Further in this paper toward the metric in which the dimensional could not be performed, we argue that it would be some problematic metric, and mention its cause. The Hawking fluxes we compute in this study could be considered to correspond to more realistic Hawking fluxes. Further what Hawking fluxes can be obtained from the anomaly cancellation method would be interesting in terms of the relation between a consistency of quantum field theories and black hole thermodynamics.

gr-qc↗
arXiv2016

Multiple-angle formulas of generalized trigonometric functions with two parameters

Generalized trigonometric functions with two parameters were introduced by Drábek and Manásevich to study an inhomogeneous eigenvalue problem of the $p$-Laplacian. Concerning these functions, no multiple-angle formula has been known except for the classical cases and a special case discovered by Edmunds, Gurka and Lang, not to mention addition theorems. In this paper, we will present new multiple-angle formulas which are established between two kinds of the generalized trigonometric functions, and apply the formulas to generalize classical topics related to the trigonometric functions and the lemniscate function.

math.CA↗
arXiv2015

Complete $(p,q)$-elliptic integrals with application to a family of means

The complete elliptic integrals are generalized by using the generalized trigonometric functions with two parameters. It is shown that a particular relation holds for the generalized integrals. Moreover, as an application of the integrals, an alternative proof of a result for a family of means by Bhatia and Li, which involves the logarithmic mean and the arithmetic-geometric mean, is given.

math.CA↗
arXiv2015

Unruh effect in a real scalar field with the Higgs type potential on the de Sitter space

It has been predicted that an accelerating electron performs a Brownian motion in the inertial frame. This Brownian motion in the inertial frame has its roots in the interaction with the thermal excitation given by the Unruh effect in the accelerating frame. If such a prediction is possible, we correspondingly propose a prediction in this study that the thermal radiation appears in the inertial frame from an electron heated by the Unruh effect in the accelerating frame. The point in our prediction is, although the Unruh effect is only in the accelerating frame, if the appearance of the Brownian motion rooted in the Unruh effect in the inertial frame can be predicted, the heat that the particle gets in its body by the Unruh effect in the accelerating frame could survive in the inertial frame. Based on such a prediction, in this paper we investigate phenomena in the neighborhood of an accelerating electron in the inertial frame. The model we consider is the four-dimensional Klein-Gordon real scalar field model with the Higgs type potential term at the finite temperature identified with the Unruh temperature on the de Sitter space-time. We calculate the one-loop effective potential in the inertial frame with the corrections by the thermal radiation rooted in the Unruh effect in the accelerating frame. In this calculation, we take into account that the background space-time is deformed due to the field theory's corrected one-loop effective potential. Based on such an analysis, we illustrate the restoration of the spontaneous symmetry breaking and the variation of the background space-time, and we examine the accelerating particle's world-line and the amount of the energy corresponding to the change of the acceleration.

hep-th↗
arXiv2015

Holographic Superconducting Quantum Interference Device

We present a holographic model of the SQUID (Superconducting QUantum Interference Device) in the external magnetic field. The model of the gravitational theory considered in this paper is the Einstein-Maxwell-complex scalar model on the four-dimensional Anti-de Sitter Schwarzschild black brane geometry, where one space direction is compacted into a circle and we arrange the coefficient of the time components profile so that we can model the SQUID, where the profile plays the role of the chemical potential for the cooper pair.

hep-th↗
arXiv2015

The complete $p$-elliptic integrals and a computation formula of $π_p$ for $p=4$

The complete $p$-elliptic integrals are generalizations of the complete elliptic integrals by the generalized trigonometric function $\sin_pθ$ and its half-period $π_p$. It is shown, only for $p=4$, that the generalized $p$-elliptic integrals yield a computation formula of $π_p$ in terms of the arithmetic-geometric mean. This is a $π_p$-version of the celebrated formula of $π$, independently proved by Salamin and Brent in 1976.

math.CA↗
arXiv2014

A new form of the generalized complete elliptic integrals

Generalized trigonometric functions are applied to the Legendre-Jacobi standard form of complete elliptic integrals, and a new form of the generalized complete elliptic integrals of the Borweins is presented. According to the form, it can be easily shown that these integrals have similar properties to the classical ones. In particular, it is possible to establish a computation formula of the generalized $π$ in terms of the arithmetic-geometric mean, in the classical way as the Gauss-Legendre algorithm for $π$ by Salamin and Brent. Moreover, an elementary new proof of Ramanujan's cubic transformation is also given.

math.CA↗
arXiv2014

Hagedorn Instability in Dimensionally Reduced Large-N Gauge Theories as Gregory-Laflamme and Rayleigh-Plateau Instabilities

It is expected that the Gregory-Laflamme (GL) instability in the black string in gravity is related to the Rayleigh-Plateau instability in fluid mechanics. Especially, the orders of the phase transitions associated with these instabilities depend on the number of the transverse space dimensions, and they are of first and second order below and above the critical dimension. Through the gauge-gravity correspondence, the GL instability is conjectured to be thermodynamically related to the Hagedorn instability in large-N gauge theories, and it leads to a prediction that the order of the confinement-deconfinement transition associated with the Hagedorn instability may depend on the transverse dimension. We test this conjecture in the D-dimensional bosonic D0-brane model using numerical simulation and the 1/D expansion, and confirm the expected D dependence.

hep-th↗
arXiv2013

The basis property of generalized Jacobian elliptic functions

The Jacobian elliptic functions are generalized to functions including the generalized trigonometric functions. The paper deals with the basis property of the sequence of generalized Jacobian elliptic functions in any Lebesgue space. In particular, it is shown that the sequence of the classical Jacobian elliptic functions is a basis in any Lebesgue space if the modulus $k$ satisfies $0 \le k \le 0.99$.

math.CA↗