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Lunchakorn Tannukij

Publications and source records attributed to Lunchakorn Tannukij.

At least 19 recordsLinked to original sources

Schwarzschild-de Sitter black hole as a correlated qubit system via entropic identification

The thermodynamic behaviours of multi-horizon black holes such as a Schwarzschild-de Sitter black hole have been one of the long-standing mysteries in gravitational physics since they involve quantum natures in gravitational systems and that the search for quantum gravity has not reached its conclusion. In this work, we seeked for a possibility of realising the Schwarzschild-de Sitter black hole as a correlated qubit system, where each of the event horizon is treated as a qubit and both of them are correlated in a way that two qubits could be. By identifying the entropies of subsystems to those of qubits, we successfully constructed the reduced density matrices of the two subsystems as well as the density matrix for the Schwarzschild-de Sitter black hole, modelled as 2-correlating qubits. Moreover, our results suggested that when the gravitational effect has its role in the qubit systems, supposedly like black holes, the correlation between qubits are constrained with a lower bound more stringent than the so-called Araki-Lieb triangle inequality.

gr-qc↗

Restoration of the Lorentz symmetry of particle propagator in the ghost condensate model

The ghost condensate model has been proposed to protect the vacuum state of the cosmological phantom model yielding the gradient instability regime and the spontaneous Lorentz symmetry breaking in the quantum level with the dispersion relation $ω^2\sim k^4$. In this paper, we point out that the Lorentz symmetry in the propagator can be restored if the explicit Lorentz symmetry-breaking process is promoted. The particle excitation of the phantom field can propagate through spacetime with the Lorentzian dispersion relation $ω^2=k^2$ in arbitrary background value. Moreover, the tree-level gradient instability regime can be removed under the characteristic Lorentz violation source of ultraviolet physics.

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A Multiplicative Formulation of the Higgs Lagrangian and the Fermion Mass Hierarchy between the charged leptons and heavy quarks

We propose a multiplicative formulation of the Higgs Lagrangian, derived from the inverse problem in the calculus of variations, as an alternative framework to investigate the fermion mass hierarchy. In this setup, fermion masses emerge as discrete quantities determined by a finite set of scaling factors, thereby allowing the observed charged-lepton and heavy-quark masses to be accommodated without introducing arbitrarily small parameters. In addition, this framework admits specific solutions where the Yukawa couplings of the charged leptons and heavy quarks converge to a universal value, approximately coinciding with the Higgs self-coupling. This numerical coincidence provides a potential hint of an underlying dynamical structure that correlates the Higgs sector with the fermion masses. Furthermore, the background-dependent Higgs self-interactions are found to decrease asymptotically, ensuring perturbative consistency in the large-field regime and suggesting possible extensions toward ultraviolet completion.

hep-th↗

Thermodynamics of Black Holes with Rényi Entropy from Classical Gravity

The nonextensive nature of black holes is one of the most intriguing discoveries. In fact, the black hole entropy is a nonextensive quantity that scales by its surface area at the event horizon. In our work, we extend the thermodynamic phase space of black holes by treating the nonextensive parameter of the Rényi entropy as the thermodynamic variable. Using Euler's theorem for a homogeneous function of the black holes' mass, the compatible Smarr formula and the first law of black hole thermodynamics can be obtained. It is also demonstrated that, by keeping the same form of the black hole mass, the Rényi temperature is straightforwardly defined as proposed in the literature. Since many different types of black holes can indeed be successfully treated with such a procedure, our consideration is fairly general. It is worthwhile to argue that the black hole thermodynamics in Rényi statistics is rooted from the relation among geometric quantities in the same way as the standard approach corresponding to the Gibbs-Boltzmann statistics. Even though our results are based on classical gravity, they may pave the way to derive the Rényi temperature using the notion of quantum field in curved spacetime.

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Neutrino mass mechanisms from a nonstandard Higgs Lagrangian and implications for flavor hierarchies

We present an alternative framework to establish the neutrino mass scale from the Higgs mechanism in a minimalist approach, which does not introduce new scalar bosons or extend the symmetry group of the standard model (SM). A nonstandard form of the Higgs Lagrangian, constructed via the inverse problem of calculus of variations, is proposed. Only one dimensionful parameter in the TeV scale is incorporated into the SM Lagrangian. The multiplicative Lagrangian model of the Higgs field plays an essential role in explaining the vast mass difference between charged fermions and Dirac neutrinos, while the Yukawa couplings for these two groups of particles naturally fall within the same scale. On the other hand, if the neutrino mass term has both Dirac and Majorana components, the mass of the mostly right-handed neutrinos in the Type-I seesaw mechanism can range from the keV scale up to slightly below the grand unification scale without requiring extremely small Yukawa couplings outside the SM regime. Furthermore, we discuss the potential of this mechanism to explain the hierarchical structure in the Yukawa couplings between first- and third-generation particles.

hep-ph↗

Rényi Holographic Dark Energy

In this work, the holographic dark energy model is constructed by using the non-extensive nature of the Schwarzschild black hole via the Rényi entropy. Due to the non-extensivity, the black hole can be stable under the process of fixing the non-extensive parameter. A change undergoing such a process would then motivate us to define the energy density of the Rényi holographic dark energy (RHDE). As a result, the RHDE with choosing the characteristic length scale as the Hubble radius provides the late-time expansion without the issue of causality. Remarkably, the proposed dark energy model contains the non-extensive length scale parameter additional to the standard $Λ$CDM model. The cosmic evolution can be characterized by comparing the size of the Universe to this length scale. Moreover, the preferable value of the non-extensive length scale is determined by fitting the model to recent observations. The results of this work would shed light on the interplay between the thermodynamic description of the black hole with non-extensivity and the classical gravity description of the evolution of the Universe.

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Holographic Dark Energy from the Anti-de Sitter Black Hole

The anti-de Sitter (AdS) black hole plays an important role in the holographic principle. In this study, the upper bound in energy corresponding to the mass of the Schwarzschild black hole is modified to be that of the AdS black hole. Via the correspondence between the ultraviolet (UV) and infrared (IR) cutoffs, the constant term in the energy density of the holographic dark energy (HDE) can be obtained from the negative cosmological constant from the black hole. Interestingly, the proposed dark energy model could drive the late-time expansion of the Universe without the causality violation. The cosmic evolution is investigated by choosing the Hubble and particle horizons as the IR length scales. It is found that the accelerated expansion at late time can be obtained for both cases. This result may shed light on the connection between the AdS black hole and the de Sitter (dS) spacetime in the context of cosmology.

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Thermodynamics of Asymptotically de-Sitter Black Hole in dRGT Massive Gravity from Rényi entropy

The thermodynamic properties of the de Rham-Gabadadze-Tolley (dRGT) black hole in the asymptotically de Sitter (dS) spacetime are investigated by using Rényi entropy. It has been found that the black hole with asymptotically dS spacetime described by the standard Gibbs-Boltzmann statistics cannot be thermodynamically stable. Moreover, there generically exist two horizons corresponding to two thermodynamic systems with different temperatures, leading to a nonequilibrium state. Therefore, in order to obtain the stable dRGT black hole, we use the alternative Rényi statistics to analyze the thermodynamics properties in both the separated system approach and the effective system approach. Interestingly, we found that it is possible concurrently obtain positive pressure and volume for the dRGT black hole while it is not for the Schwarzschild-de Sitter (Sch-dS) black hole. Furthermore, the bounds on the nonextensive parameter for which the black hole being thermodynamically stable are determined. In addition, the key differences between the systems described by different approaches, e.g., temperature profiles and types of the Hawking-Page phase transition are pointed out.

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The Higgs mechanism from the effective theory of the non-minimal gravity action

The spontaneous symmetry breaking for the massless scalar field naturally arises from the framework of the effective theory (the non-minimal coupling of gravity to a scalar field). A magic key ingredient is to add the large vacuum energy density, contributing to the cosmological constant, to the Lagrangian density. By applying this modified spontaneous symmetry breaking with the gauge theory (called modified Higgs mechanism), the inflation physics and the electroweak phase transition can be generated from the same framework. However, this comes with the huge price-the large cosmological constant which is known as the dark energy problem. The possible solution of this issue is also discussed.

hep-ph↗

Effective thermodynamical system of Schwarzschild-de Sitter black holes from Rényi statistics

It has been known that the Schwarzschild-de Sitter (Sch-dS) black hole may not be in thermal equilibrium and also be found to be thermodynamically unstable in the standard black hole thermodynamics. In the present work, we investigate the possibility to realize the thermodynamical stability of the Sch-dS black hole as an effective system by using the Rényi statistics, which includes the non-extensive nature of black holes. Our results indicate that the non-extensivity allows the black hole to be thermodynamically stable which gives rise to the lower bound on the non-extensive parameter. By comparing the results to ones in the separated system approach, we find that the effective temperature is always smaller than the black hole horizon temperature and the thermodynamically stable black hole in effective approach is always larger than one in separated approach at a certain temperature. There exists only the zeroth-order phase transition from the the hot gas phase to the black hole phase for the effective system while it is possible to have the transition of both the zeroth order and the first order for the separated system.

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Partially massless theory as a quantum gravity candidate

We study partially massless gravity theory(PM gravity theory) and suggest an alternative way to add higher order interaction vertices to the theory. Rather than introducing self interaction vertices of the gravitational fields to the partially massless gravity action, we consider interactions with matter fields, since it is well known that addition of the self interaction terms necessarily breaks the $U(1)$ gauge symmetry that PM gravity theory enjoys. For the coupling with matter fields, we consider two different types of interaction vertices. The first one is given by an interaction Lagrangian density, $\mathcal L_{int}\sim h_{μν}T^{μν}$, where $h_{μν}$ is the PM gravity field and $T^{μν}$ is the stress-energy tensor of the matter fields. To retain the $U(1)$ gauge symmetry, the matter fields also transform accordingly and it turns out that the transform must be non-local in this case. The second type interaction is obtained by employing a gauge covariant derivative with the PM gravity field, where the PM gravity fields play a role of a gauge connection canceling the phase shift of the matter fields. We also study the actions and the equations of motion of the partially massless gravity fields. As expected, it shows 4 unitary degrees of freedom. 2 of them are traceless tensor modes and they are light like fields. The other 2 are transverse vector modes and their dispersion relation changes as background space time (de Sitter) evolutes. In the very early time, they are light like but in the very late time, their velocity become a half of speed of light. The vector mode dispersion relation shows momentum dependent behavior. In fact, the higher(lower) frequency modes show the faster(slower) velocity. We suggest their quantization, compute Hamiltonians to present their exited quanta and construct their free propagators.

hep-th↗

Resolving Hubble Tension with Quintom Dark Energy Model

Recent low-redshift observations give value of the present-time Hubble parameter $H_{0}\simeq 74~\rm{km s}^{-1}\rm{Mpc}^{-1}$, roughly 10\% higher than the predicted value $H_{0}=67.4~\rm{km s}^{-1}\rm{Mpc}^{-1}$ from Planck's observations of the Cosmic Microwave Background radiation~(CMB) and the $Λ$CDM model. Phenomenologically, we show that by adding an extra component X with negative density in the Friedmann equation, it can relieve the Hubble tension without changing the Planck's constraint on the matter and dark energy densities. For the extra negative density to be sufficiently small, its equation-of-state parameter must satisfy $1/3\leq w_{X}\leq1$. We propose a quintom model of two scalar fields that realizes this condition and potentially alleviate the Hubble tension. One scalar field acts as a quintessence while another "phantom" scalar conformally couples to matter in such a way that viable cosmological scenario can be achieved. The model depends only on two parameters, $λ_ϕ$ and $δ$ which represent rolling tendency of the self-interacting potential of the quintessence and the strength of conformal phantom-matter coupling respectively. The toy quintom model with $H_{0}=73.4~\rm{km s}^{-1}\rm{Mpc}^{-1}$~(Quintom I) gives good Supernovae-Ia luminosity fits, decent $r_{\rm BAO}$ fit, but slightly small acoustic multipole $\ell_{A}=285.54$. Full parameter scan reveals that quintom model provide better model than the $Λ$CDM model in certain region of the parameter space, $0.02<δ<0.10, Ω_{m}^{(0)}<0.31$, while significantly relieving Hubble tension even though not completely resolving it. A benchmark quintom model, Quintom II, is presented as an example.

gr-qc↗

Rotating black string in dRGT massive gravity

One of the solutions of Einstein field equation with cylindrical symmetry is known as black string solution. In this work, the rotating black string solution in dRGT massive gravity is obtained and then called rotating-dRGT black string solution. This solution is a kind of generalized version of rotating AdS/dS black sting solution containing an additional two more terms characterizing the structure of graviton mass. The horizon structures of the black string are explored. The thermodynamical properties of the black string are investigated. We found that it is possible to obtain the Hawking-Page phase transition depending on the additional structure of the graviton mass, while it is not possible for rotating-AdS/dS black string. By analyzing the free energy, we also found that the stable rotating black string is bigger than the non-rotating one.

gr-qc↗

Thermodynamics and Phase Transition of Spherically Symmetric Black Hole in de Sitter Space from Rényi Statistics

Schwarzschild black holes in a de Sitter background were studied in terms of their thermodynamics based on the Rényi statistics. This led to thermodynamically stable black hole configurations for some certain range of black hole radii; namely within this range the corresponding black holes have positive heat capacity. Moreover, for a certain background temperature there can exist at most three configurations of black hole; one among which is thermodynamically stable. These configurations were investigated in terms of their free energies, resulting in the moderate-sized stable black hole configuration being the most preferred configuration. Furthermore, a specific condition on the Rényi non-extensive parameter is required if a given hot spacetime were to evolve thermally into the moderate-sized stable black hole.

gr-qc↗

Particle motions and Gravitational Lensing in de Rham-Gabadadze-Tolley Massive Gravity Theory

We investigate gravitational lensing and particle motions around non-asymptotically flat black hole spacetime in non-linear, ghost-free massive gravity theory, called de Rham-Gabadadze-Tolley (dRGT) massive gravity. Deflection angle formulae are derived in terms of perihelion parameter. The deflection angle can be positive, zero or even negative with various perihelion distance. The negative angle reveals repulsive behaviour of gravity from a linear term $γ$ in the dRGT black hole solution. We also find an analytically approximated formula of deflection angle in two regimes: large and small $γ$ term regimes which are shown to be consistent with direct numerical integration. Null and timelike geodesic motions on equatorial plane are explored. Particle trajectories around the dRGT black hole are plotted and discussed in details.

gr-qc↗

Quasinormal modes of black strings in de Rham-Gabadadze-Tolley massive gravity

The effect of massive scalar perturbations on neutral black string in de Rham-Gabadadze-Tolley (dRGT) massive gravity is investigated through the study of the quasi-normal modes~(QNMs). Due to the similarity between the equation of motion of the field in the black-string and black-hole background, similar numerical and analytical techniques can be used to explore the behaviour of the QNMs. We use the asymptotic iteration method (AIM) and the WKB method to numerically calculate the QNMs of scalar perturbation in the black string background with positive cosmological constant. High-momentum behaviour of such QNMs can be analytically approximated by the first-order WKB method with excellent accuracy. For near-extremal black string with event horizon very close to the cosmological horizon, the Pöschl-Teller technique gives accurate analytic formula for the QNMs. When massive-gravity-parameter $γ$ increases, we found that the scalar modes oscillate with higher frequencies and decay faster. The QNMs of black string in spacetime with negative cosmological constant are explored in all range of possible $γ$ using the spectral method. We found the movement of the holographic sound poles to collide and form diffusive poles as $γ$ changes from positive to negative values. We observe no evidence of instability of neutral black string in both positive and negative cosmological constant cases.

gr-qc↗

Charged scalar perturbations on charged black holes in dRGT massive gravity

We explore the quasi-stationary profile of massive charged scalar field in a class of charged black hole in dRGT massive gravity. We discuss how the linear term in the metric which is a unique character of the dRGT massive gravity affects structure of the spacetime. Numerical calculations of the quasinormal modes are performed for the charged scalar field in the dRGT black hole background. For asymptotically de Sitter (dS) black hole, an improved asymptotic iteration method is used to obtain the associated quasinormal frequencies. The unstable modes are found for $\ell=0$ case and their corresponding real parts satisfy superradiant condition. For $\ell=2$, the results show that all the de Sitter black holes considered here are stable against a small perturbation. For asymptotically dRGT anti de Sitter (AdS) black hole, unstable modes are found with the frequency satisfying superradiant condition. Effects of massive gravity parameter are discussed. Analytic calculation reveals unique diffusive nature of quasinormal modes in the massive gravity model with the linear term. Numerical results confirm existence of the characteristic diffusive modes in both dS and AdS cases.

gr-qc↗

Black String in dRGT Massive Gravity

We present a cylindrically symmetric solution, both charged and uncharged, which is known as a black string solution to the nonlinear ghost-free massive gravity found by de Rham, Gabadadze, and Tolley (dRGT). This "dRGT black string" can be thought of as a generalization of the black string solution found by Lemos \cite{1}. Moreover, the dRGT black string solution also include other classes of black string solution such as the monopole-black string ones since the graviton mass contributes to the global monopole term as well as the cosmological constant term. To investigate the solution, we compute mass, temperature, and entropy of the dRGT black string. We found that the existence of the graviton mass drastically affects the thermodynamics of the black string. Furthermore, the Hawking-Page phase transition is found to be possible for the dRGT black string as well as the charged dRGT black string. In terms of their stability, the dRGT black string solution is thermodynamically stable for $r>r_c$ with negative thermodynamical potential and positive heat capacity while it is unstable for $r<r_c$ where the potential is positive.

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