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Soon-Tae Hong

Publications and source records attributed to Soon-Tae Hong.

At least 19 recordsLinked to original sources
arXiv2026

Equation of State Parameters for Fluid of Stringy Extended Objects in Cosmology with Cosmological Constant

We construct the strong energy conditions (SECs) for both massive and massless stringy extended objects in the higher dimensional cosmology (HDC) with cosmological constant $\Lambda$. Exploiting these conditions, we find the equation of state (EoS) parameters \mbox{$w\geq -(D-4)/D$} for both the massive and massless stringy extended objects in $D$ {$(D\geq 5)$} dimensional cosmology. The stringy SECs impose a universal constraint on $w$ that remains valid across both radiation- and matter-dominated eras. We elucidate the relations between the EoS parameter in the HDC with cosmological constant and that of Hawking--Penrose limit for the massive and massless point particles in the four dimensions. We evaluate the EoS parameters in terms of the contributions from the point particle property, cosmological constant, and extended object degrees of freedom, respectively. We also investigate the weak energy condition for the massive and massless stringy extended objects in the HDC, and those for the massive and massless point particles in the four dimensions,~respectively.

gr-qc↗
arXiv2025

Statistical Entropy Based on the Generalized-Uncertainty-Principle-Induced Effective Metric

We investigate the statistical entropy of black holes within the framework of the generalized uncertainty principle (GUP) by employing effective metrics that incorporate leading-order and all-orders quantum gravitational corrections. We construct three distinct effective metrics induced by the GUP, which are derived from GUP-corrected temperature, entropy, and all-orders GUP corrections, and analyze their impact on black hole entropy using 't Hooft's brick wall method. Our results show that, despite the differences in the effective metrics and the corresponding ultraviolet cutoffs, the statistical entropy consistently satisfies the Bekenstein-Hawking area law when expressed in terms of an invariant (coordinate-independent) distance near the horizon. Furthermore, we demonstrate that the GUP naturally regularizes the ultraviolet divergence in the density of states, eliminating the need for artificial cutoffs and yielding finite entropy even when counting quantum states only in the vicinity of the event horizon. These findings highlight the universality and robustness of the area law under GUP modifications and provide new insights into the interplay between quantum gravity effects and black hole thermodynamics.

gr-qc↗
arXiv2025

Rough estimates of solar system gravitomagnetic effects in post-Newtonian gravity

In order to describe properly the gravity interactions including the mass currents, in the gravitomagnetism we construct four Maxwell type gravitational equations which are shown to be analogs of the Maxwell equations in the electromagnetism. Next, exploiting the Maxwell type gravitational equations, we explicitly predict the mass magnetic fields for both the isolated system of the spinning Moon orbiting the spinning Earth and that of the Sun and solar system planets orbiting the spinning Sun, whose phenomenological values have not been evaluated in the precedented Newtonian gravity formalisms. In the gravitomagnetism we also phenomenologically investigate the mass magnetic general relativity (GR) forces associated with the mass magnetic fields, to find that they are extremely small but non-vanishing compared to the corresponding mass electric Newtonian forces. Moreover, the directions of the mass magnetic GR forces for the solar system planets except Venus and Uranus are shown to be anti-parallel to those of their mass electric Newtonian forces. Next we investigate the mass magnetic dipole moment related with the B-ring of Saturn, to evaluate $\vec{m}_{M}(Ring)=-1.141\times 10^{4}~{\rm m^{3}~sec^{-1}}~\hat{\omega}$ with $\hat{\omega}$ being the unit vector along the axis direction of the spinning B-ring. The predicted value of $\vec{m}_{M}(Ring)$ is shown to be directly related with the Cassini data on the total mass of the rings of Saturn.

gr-qc↗
arXiv2024

Tidal effects based on GUP-induced effective metric

In this paper, we study tidal forces in the Schwarzschild black hole whose metric includes explicitly a generalized uncertainty principle (GUP) effect. We also investigate interesting features of the geodesic equations and tidal effects dependent on the GUP parameter $\alpha$ related to a minimum length. Then, by solving geodesic deviation equations explicitly with appropriate boundary conditions, we show that $\alpha$ in the effective metric affects both the radial and angular components of the geodesic equation, particularly near the singularities.

gr-qc↗
arXiv2023

Phenomenologies in hypersphere soliton and stringy photon models

We consider the Dirac quantization in the first class formalism to investigate the hypersphere soliton model (HSM) defined on the $S^{3}$ hypersphere. To do this, we construct the first class Hamiltonian possessing the Weyl ordering correction. In the HSM, we evaluate the baryon physical quantities such as the baryon masses, magnetic moments, axial coupling constant and charge radii, most predicted values of which are in good agreement with the corresponding experimental data. Moreover, shuffling the baryon and transition magnetic moments, we find the model independent sum rules. In the HSM we also evaluate the baryon intrinsic frequencies such as $\omega_{N}=0.87\times 10^{23}~{\rm sec}^{-1}$ and $\omega_{\Delta}=1.74\times 10^{23}~{\rm sec}^{-1}$ of the nucleon and delta baryon, respectively, to yield the identity $\omega_{\Delta}=2\omega_{N}$. Next, making use of the Nambu-Goto string action and its extended rotating bosonic string theory, we formulate the stringy photon model to obtain the energy of the string configuration, which consists of the rotational and vibrational energies of the open string. Exploiting this total string energy we evaluate the photon intrinsic frequency $\omega_{\gamma}=9.00\times 10^{23}~{\rm sec}^{-1}$ which is comparable to the corresponding baryon intrinsic frequencies. We also predict the photon size $\langle r^{2}\rangle^{1/2}(\rm photon)=0.17~{\rm fm}$ which is approximately 21\% of the proton magnetic charge radius.

hep-ph↗
arXiv2023

New algorithm of measuring gravitational wave radiation from rotating binary system

In order to investigate the gravitational wave (GW) radiation, without appealing to the tensorial formalism of the linearized general relativity, we formulate the so-called modified linearized general relativity (MLGR). As an application of the MLGR, we construct a novel paradigm of measuring the GW radiation from a binary system of compact objects, to theoretically interpret their phenomenology. To do this, we formulate the mass scalar and mass vector potentials for the merging binary compact objects, from which we construct the mass magnetic field in addition to the mass electric one which also includes the mass vector potential effect. Next, defining the mass Poyinting vector in terms of the mass electric and mass magnetic fields, we construct the GW radiation intensity profile possessing a prolate ellipsoid geometry due to the merging binary compact objects source. At a given radial distance from the binary compact objects, the GW radiation intensity on the revolution axis of the binary compact objects is shown to be twice that on the equatorial plane. Moreover, we explicitly obtain the total radiation power of the GW, which has the same characteristic as that of the electromagnetic wave in the rotating charge electric dipole moment. We also find that, in no distorting limit of the merging binary compact objects, the compact objects do not yield the total GW radiation power, consistent with the result of the linearized general relativity.

physics.gen-ph↗
arXiv2023

Foliation, topology and nucleon charge profiles in hypersphere soliton model

In the hypersphere soliton model (HSM), we study the geometrical inner structures and the ensuing charge distributions of the nucleons by exploiting the aspect of the HSM where the hypersphere soliton is described by an extended object possessing the parameter $\lambda$ $(0\le\lambda<\infty)$ which corresponds to the radial distance from the center of $S^{3}$ to the foliation leaves of the hypersphere soliton. To do this, we investigate the foliation and topology related with geometry on a hypersphere described by $(\mu,\theta,\phi)$. Exploiting the so-called scanning algorithm we study geometrical relations between spherical shell foliation leave on a northern hemi-hypersphere $S^{3}_{+}$ and that on a flat equatorial solid sphere $E^{3}$ which contains the center of $S^{3}$. We then elucidate the physical meaning of $\mu$ in $S^{3}$ of radius $\lambda$ by showing that $\mu$ plays the role of an auxiliary angle to fix the radius $\lambda\sin\mu$ of the $S^{2}$ spherical shell sharing the center of $S^{3}(=S^{2}\times S^{1})$, at a given angle $\mu$. Next, using the charge density profiles of nucleons with $\mu$ dependence, we construct the nucleon fractional charges of spherically symmetric and nontrivial distributions. In the HSM we note that the proton and neutron charges do not leak out from the hypersphere soliton, and the positive and negative charges in the neutron are confined inside and outside its core, respectively. Explicitly we predict the fractional volumes and charges of the neutron. The proton and neutron are shown to be described by a topological structure of two Hopf-linked M\"obius strip type twist circles in $S^{3}$. We also note that the characteristic ratio of the hypersphere volume to the corresponding solid sphere one is given by a geometrical invariant related with hyper-compactness.

hep-ph↗
arXiv2022

GEMS embeddings of Hayward regular black holes in massless and massive gravities

After finding a solution for the Hayward regular black hole (HRBH) in massive gravity, we embed the (3+1)-dimensional HRBHs both in massless and in massive gravities into (5+2)- and (6+3)-dimensional Minkowski spacetimes, respectively. Here, massive gravity denotes that a graviton acquires a mass holographically by broken momentum conservation in the HRBH. The original HRBH has no holographically added gravitons, which we call massless. Making use of newly found embedding coordinates, we obtain desired Unruh temperatures and compare them with the Hawking and local fiducial temperatures, showing that the Unruh effect for a uniformly accelerated observer in a higher dimensional flat spacetime is equal to the Hawking effect for a fiducial observer in a black hole spacetime. We also obtain freely falling temperatures of the HRBHs in massless and massive gravities seen by freely falling observers, which remain finite even at the event horizons while becoming the Hawking temperatures in asymptotic infinity.

gr-qc↗
arXiv2022

Dirac type relativistic quantum mechanics for massive photons

Constructing a relativistic quantum mechanics (RQM) for a massive photon, without appealing to the quantum field theoretical approach such as the massive Proca model, we find a new theoretical particle solution which allows the massive photon having either positive or negative energy as solutions. In particular, we predict the existence of the so-called anti-photon corresponding to the negative energy solution, similar to the positron in the Dirac RQM for an electron. Note that the anti-photons could be an intense radiation flare of the gamma ray burst. In this RQM for the massive photon, we construct a positive definite probability density and a nontrivial diagonal Hamiltonian, and also discuss a massless photon. Moreover we confirm the covariances of the relativistic equation of motion for the massive photon and the corresponding probability continuity equation under the Lorentz transformation.

physics.gen-ph↗
arXiv2021

GEMS embeddings of Schwarzschild and RN black holes in Painlevé-Gullstrand spacetimes

Making use of the higher dimensional global embedding Minkowski spacetime (GEMS), we embed (3+1)-dimensional Schwarzschild and Reissner-Nordström (RN) black holes written by the Painlevé-Gullstrand (PG) spacetimes, which have off-diagonal components in metrics, into (5+1)- and (5+2)-dimensional flat ones, respectively. As a result, we have shown the equivalence of the GEMS embeddings of the spacetimes with the diagonal and off-diagonal terms in metrics. Moreover, with the aid of their geodesic equations satisfying various boundary conditions in the flat embedded spacetimes, we directly obtain freely falling temperatures. We also show that freely falling temperatures in the PG spacetimes are well-defined beyond the event horizons, while they are equivalent to the Hawking temperatures, which are obtained in the original curved ones in the ranges between the horizon and the infinity. These will be helpful to study GEMS embeddings of more realistic Kerr, or rotating BTZ black holes.

gr-qc↗
arXiv2021

Photon intrinsic frequency and size in stringy photon model

Exploiting an open string which performs both rotational and pulsating motions, we investigate a photon intrinsic frequency. Explicitly evaluating the zero point fluctuation of the string which is delineated in terms of the quantum mechanical ground state energy in the vibrational mode of the string and the classical energy in the rotational mode, we find that the intrinsic frequency of the photon is given by $ω_γ=9.00\times 10^{23}~{\rm sec}^{-1}$ and comparable to those of the baryons such as nucleon and delta baryon. Next, we calculate the photon size $\langle r^{2}\rangle^{1/2}(\rm photon)=0.17~{\rm fm}$ in a phenomenological stringy photon model.

physics.gen-ph↗
arXiv2021

Dirac quantization and baryon intrinsic frequencies in hypersphere soliton model

Quantizing a soliton on a hypersphere, we obtain the first class Hamiltonian, and evaluate the baryon physical quantities which are in good agreement with the corresponding experimental data. In particular, we find that the predicted value for axial coupling constant is comparable to its experimental value. The prediction for delta baryon mass possessing the Weyl ordering correction obtained in the first class Dirac quantization is improved comparing with that in the second class canonical quantization performed on the hypersphere. Making use of the same input parameters associated with the baryon masses, we also investigate the hypersphere soliton and standard Skyrmion models to compare the corresponding predictions for the physical quantities effectively. Next, we evaluate the intrinsic frequencies of the pulsating baryons. We thus find that the intrinsic pulsating frequency of more massive particle is greater than that of the less massive one. We explicitly evaluate the intrinsic frequencies $ω_{N}=0.87\times 10^{23}~{\rm sec}^{-1}$ and $ω_Δ=1.74\times 10^{23}~{\rm sec}^{-1}$ of the nucleon and delta baryon, respectively, to yield the identity $ω_Δ=2ω_{N}$.

hep-ph↗
arXiv2021

Quantum mechanics for relativistic bosons

We construct a relativistic quantum mechanics for a boson. To do this we exploit two component wave functions in Dirac type equations of motion. In our formalism we fix the pathological aspect of particle probability density which appears in Klein-Gordon theory. Our solutions possess a negative solution as well as a positive one. We also formulate a diagonal Hamiltonian of the relativistic quantum mechanics for the boson.

hep-th↗
arXiv2021

Baryon topology in hypersphere soliton model

Exploiting a topological soliton on a hypersphere, we construct nucleon charge profile functions and find the density distributions for proton and neutron plotted versus the hypersphere third angle $μ$. The neutron charge density is shown to possess a nontrivial $μ$ dependence, consisting of both positive and negative charge density fractions. We next investigate the inner topology of the hypersphere soliton, by making use of the schematic Möbius strips which are related with the tubular neighborhood of half-twist circle in the manifold $S^{3}$. In particular, we find that in the hypersphere soliton the nucleons are delineated in terms of a knot structure of two Möbius strip type circles in $S^{3}$. Moreover, the two Hopf-linked Möbius strip type circles in the hypersphere soliton are shown to correspond to (uu, d) in proton and (dd, u) in neutron, respectively, in the quark model.

physics.gen-ph↗
arXiv2021

Photon size in higher dimensional phantom cosmology

We study a higher dimensional cosmology with phantom field associated with a negative kinetic term. Assuming that the universe possesses the phantom field defined in $D$ dimensional spacetime, we investigate in detail the solutions involved in the higher dimensional phantom cosmology, to explicitly predict photon size and phantom field strength at present in nature. To be specific, we find that the photon size decreases drastically at the early stage of the universe after the Big Bang. Next we explicitly demonstrate the dependences of the photon size, universe size and phantom field strength on the spacetime dimensionality $D$. We observe that the size of the universe undergoes stiff explosion with different types of slope depending on $D$. Moreover the scale factor of the universe at present is shown to approach to a saturated value, which is independent of $D$ and is the same as that in the $D=4$ Friedmann-Robertson-Walker cosmology. The photon size and phantom field strength in the greater dimensionality are also shown to be larger and lower than those in the smaller one, respectively. Next the photon size at present $b_{*}$ in $D=5$ is numerically shown to be extremely small, namely $b_{*}=6.08\times 10^{-216}$ cm, comparing to $b_{*}=1.56\times 10^{-63}$ cm in $D=10$. In contrast, the phantom field strength at present $σ_{*}$ is shown to be relatively large $σ_{*}=4.72\times 10^{24}$ (dyne$)^{1/2}$ in $D=5$, comparing to $σ_{*}=1.39\times 10^{22}$ (dyne$)^{1/2}$ in $D=10$.

gr-qc↗
arXiv2021

GUP corrected entropy of the Schwarzschild black hole in holographic massive gravity

We obtain the statistical entropy of a scalar field on the Schwarzschild black hole in holographic massive gravity by considering corrections on the density of quantum states to all orders in the Planck length from a generalized uncertainty principle (GUP). As a result, we find not only the generalized Bekenstein-Hawking entropy depending on holographically massive gravitons without any artificial cutoff, but also new additional correction terms, which are proportional to surface gravity. Moreover, we also observe that all order GUP corrected entropy is improved to have smaller GUP parameter $\lambda$ than the previous results.

gr-qc↗
arXiv2020

Tidal effects in Schwarzschild black hole in holographic massive gravity

We investigate tidal effects produced in the spacetime of Schwarzschild black hole in holographic massive gravity, which has two additional mass parameters due to massive gravitons. As a result, we have obtained that massive gravitons affect the angular component of the tidal force, while the radial component has the same form with the one in massless gravity. On the other hand, by solving the geodesic deviation equations, we have found that radial components of two nearby geodesics keep tightening while falling into the black hole and after passing the event horizons get abruptly infinitely stretched due to massive gravitons. However, angular components of two nearby geodesics get stretched firstly, reach a peak and then get compressed while falling into the black hole. Moreover, we have also shown that the angular components are more easily deformed near the departure position as the mass of a black hole is smaller for a fixed graviton mass.

gr-qc↗