Massive Scalar Particles Research Articles

The effect of the GUP on massive vector and scalar particles tunneling from a warped DGP gravity black hole

This paper discusses the effects of the mass and the angular momentum of massive vector and scalar particles on the Hawking temperature manifested under the effects of the generalized uncertainty principle (GUP). In particular, we calculate the Hawking temperature of a black hole in a warped DGP gravity model in the framework of the quantum tunneling method. We use the modified Proca and Klein-Gordon equations previously determined from the GUP Lagrangian in the spacetime background of a warped Dvali-Gabadadze-Porrati (DGP) metric, with the help of Hamilton-Jacobi (HJ) and semiclassical (WKB) approximation methods. We find that as a special case of a warped DGP black hole solution, the Hawking temperature of a Schwarzschild-de Sitter (SdS) black hole can be determined. Furthermore, the Hawking temperature is influenced by the mass and the angular momentum of vector and scalar particles and depends on which of those types of particles is being emitted by the black hole. We conclude that the nonthermal nature of the Hawking spectrum leads to Planck-scale nonthermal correlations, shedding light on the information paradox in black hole evaporation.

Hawking Radiation of Scalar and Vector Particles from 5D Myers-Perry Black Holes

In the present paper we explore the Hawking radiation as a quantum tunneling effect from a rotating 5 dimensional Myers-Perry black hole (5D-MPBH) with two independent angular momentum components. First, we investigate the Hawking temperature by considering the tunneling of massive scalar particles and spin-1 vector particles from the 5D-MPBH in the Painlev\'{e} coordinates and then in the corotating frames. More specifically, we solve the Klein-Gordon and Proca equations by applying the WKB method and Hamilton-Jacobi equation in both cases. Finally, we recover the Hawking temperature and show that coordinates systems do not affect the Hawking temperature.

The Klein–Gordon–Fock equation in the curved spacetime of the Kerr–Newman (anti) de Sitter black hole

Exact solutions of the Klein–Gordon–Fock (KGF) general relativistic equation that describe the dynamics of a massive, electrically charged scalar particle in the curved spacetime geometry of an electrically charged, rotating Kerr–Newman–(anti) de Sitter black hole are investigated. In the general case of a rotating, charged, cosmological black hole the solution of the KGF equation with the method of separation of variables results in Fuchsian differential equations for the radial and angular parts which for most of the parameter space contain more than three finite singularities and thereby generalise the Heun differential equations. For particular values of the physical parameters (i.e. mass of the scalar particle) these Fuchsian equations reduce to the case of the Heun equation and the closed form analytic solutions we derive are expressed in terms of Heun functions. For other values of the parameters some of the extra singular points are false singular points. We derive the conditions on the coefficients of the generalised Fuchsian equation such that a singular point is a false point. In such a case the exact solution of the Fuchsian equation can in principle be simplified and expressed in terms of Heun functions. This is the generalisation of the case of a Heun equation with a false singular point in which the exact solution of Heun’s differential equation is expressed in terms of Gauß hypergeometric function. We also derive the exact solutions of the radial and angular equations for a charged massive scalar particle in the Kerr–Newman spacetime. The analytic solutions are expressed in terms of confluent Heun functions. Moreover, we derived the constraints on the parameters of the theory such that the solution simplifies and expressed in terms of confluent Kummer hypergeometric functions. We also investigate the radial solutions in the KN case in the regions near the event horizon and far from the black hole. Finally, we construct several expansions of the solutions of the Heun equation in terms of generalised hypergeometric functions of Lauricella–Appell.

GUP assisted Hawking radiation of rotating acoustic black holes

Recent studies [J. Steinhauer, Nature Phys., $\textbf{10}$, 864 (2014); Phys. Rev. D $\textbf{92}$, 024043 (2015)] provide compelling evidences that Hawking radiation could be experimentally proven by using an analogue black hole. In this paper, taking this situation into account we study the quantum gravitational effects on the Hawking radiation of rotating acoustic black holes. For this purpose, we consider the generalized uncertainty principle (GUP) in the phenomenon of quantum tunneling. We firstly take the modified commutation relations into account to compute the GUP modified Hawking temperature when the massive scalar particles tunnel from this black hole. Then, we find a remarkably instructive expression for the GUP entropy to derive the quantum gravity corrected Hawking temperature of the rotating acoustic black hole.

Hawking Radiation of Mass Generating Particles from Dyonic Reissner–Nordström Black Hole

The Hawking radiation is considered as a quantum tunneling process, which can be studied in the framework of the Hamilton-Jacobi method. In this study, we present the wave equation for a mass generating massive and charged scalar particle (boson). In sequel, we analyze the quantum tunneling of these bosons from a generic 4-dimensional spherically symmetric black hole. We apply the Hamilton-Jacobi formalism to derive the radial integral solution for the classically forbidden action which leads to the tunneling probability. To support our arguments, we take the dyonic Reissner-Nordstr\"{o}m black hole as a test background. Comparing the tunneling probability obtained with the Boltzmann formula, we succeed to read the standard Hawking temperature of the dyonic Reissner-Nordstr\"{o}m black hole.

Investigating the jet activity accompanying the production at the LHC of a massive scalar particle decaying into photons

We study the jet activity that accompanies the production by gluon fusion of a new physics scalar particle decaying into photons at the LHC. In the considered scenarios, both the production and decay mechanisms are governed by loop-induced interactions involving a heavy colored state. We show that the presence of large new physics contributions to the inclusive diphoton invariant-mass spectrum always implies a significant production rate of non-standard diphoton events containing extra hard jets. We investigate the existence of possible handles that could provide a way to obtain information on the underlying physics behind the scalar resonance, and this in a wide mass window.

Annihilation of the scalar pair into a photon in a de Sitter universe

The annihilation of massive scalar particles in one photon in de Sitter expanding universe is studied, using perturbative QED. The amplitude and probability corresponding to this process is computed using the exact solutions of the Klein–Gordon and Maxwell equations on de Sitter geometry. Our results show that the expression of the total probability of photon emission is a function dependent on the ratio mass/expansion factor. We perform a graphical study of the total probability in terms of the parameter mass/expansion factor, showing that this effect is significant only in strong gravitational fields. We also obtain that the total probability for this process vanishes in the Minkowski limit.

Quantum gravitational decoherence of light and matter

Real world quantum systems are open to perpetual influence from the wider environment. Quantum gravitational fluctuations provide a most fundamental source of the environmental influence through their universal interactions with all forms of energy and matter causing decoherence. This may have subtle implications on precision laboratory experiments and astronomical observations and could limit the ultimate capacities for quantum technologies prone to decoherence. To establish the essential physical mechanism of decoherence under weak spacetime fluctuations, we carry out a sequence of analytical steps utilizing the Dirac constraint quantization and gauge invariant influence functional techniques, resulting in a general master equation of a compact form, that describes an open quantum gravitational system with arbitrary bosonic fields. An initial application of the theory is illustrated by the implied quantum gravitational dissipation of light as well as (non)relativistic massive or massless scalar particles. Related effects could eventually lead to important physical consequences including those on a cosmological scale and for a large number of correlated particles.

Comparative Aspects of Spin-Dependent Interaction Potentials for Spin-1/2 and Spin-1 Matter Fields

This paper sets out to establish a comparative study between classes of spin- and velocity-dependent potentials for spin-1/2 and spin-1 matter currents/sources in the nonrelativistic regime. Both (neutral massive) scalar and vector particles are considered to mediate the interactions between (pseudo-)scalar sources or (pseudo-)vector currents. Though our discussion is more general, we contemplate specific cases in which our results may describe the electromagnetic interaction with a massive (Proca-type) photon exchanged between two spin-1/2 or two spin-1 carriers. We highlight the similarities and peculiarities of the potentials for the two different types of charged matter and also focus our attention on the comparison between the particular aspects of two different field representations for spin-1 matter particles. We believe that our results may contribute to a further discussion of the relation between charge, spin, and extensibility of elementary particles.

SU(N)gauge invariant currents and hadronization

The fermion and total currents generated by a gauge field are derived in the framework of a self-consistent consideration of the Dirac and Yang-Mills equations. Under the condition of gauge invariance, the obtained currents are found to be expressible in terms of the massive vector field generated by the initial gauge field. The mass of this vector field depends strongly on the occupancy numbers of the fermion subsystem, whereas the arisen mass term holds the gauge invariance of the modified Lagrangian. We show that such a modified Lagrangian can be reduced to the pure gluodynamic Lagrangian containing a mass term. By breaking the initial $SU(N)$ symmetry, we derive the Lagrangian governing the dynamics of the massive scalar particles, which can be treated as the octet of the pseudoscalar mesons. The contribution of both the quark-gluon interaction and the self-interaction gluon field to the masses of the octet particles is considered. Provided that the hadronization of the confinement matter into the pion triplet occurs, the QCD coupling constant is evaluated in this case in the developed model.

A relativistic spin zero particle in a spherical cavity

The problem of a relativistic massive scalar particle trapped in an infinite potential spherical well is pedagogically addressed in this paper. The wave function solutions and probability density of the Klein–Gordon equation in spherical coordinates are derived, as well as the energy levels. The results are compared with the non-relativistic solutions of the Schrödinger equation for different values of the particle’s mass. As expected, for very large masses the non-relativistic results are recovered. For illustration, these results are discussed in the specific case of the standard model Higgs field constrained inside a proton, in the quadratic approximation of the Higgs potential around the expectation value.

Bound States in Minkowski Space in 2 + 1 Dimensions

The Nakanishi perturbative integral representation of the Bethe–Salpeter amplitude in three-dimensions (2 + 1) is used to solve the corresponding homogeneous Bethe–Salpeter equation in Minkowski space. The projection of this equation onto the null-plane, as reported here, leads to a bound-state equation for the Nakanishi weight function. The explicit forms of the integral equation for the Nakanishi weight function are shown in the ladder approximation. In addition, the valence light-front wave function is presented. The formal steps of the formalism are illustrated to some extend, with the resulting equation being applied to a bound state system composed by two identical scalar particles of mass m, interacting through the exchange of another massive scalar particle of mass μ. The results reported in this contribution show quite good agreement between our calculations obtained from the Bethe–Salpeter amplitude with the Nakanishi weight function with direct solutions obtained in the Euclidean space.

Scalar fields in the Lense-Thirring background with a cosmic string and Hawking radiation

We analyze the influence of the gravitational field produced by a slowly rotating black hole with a cosmic string along the axis of symmetry on a massive scalar field. Exact solutions of both angular and radial parts of the Klein-Gordon equation in this spacetime are obtained, and are given in terms of the confluent Heun functions. We emphasize the role of the presence of the cosmic string in these solutions. We also investigate the solutions in regions near and far from the event horizon. From the radial solution, we obtain the exact wave solutions near the exterior horizon of the black hole, and discuss the Hawking radiation of massive scalar particles.

Resonance scattering and the passage to bound states in the field of near-black-hole objects

In this paper, we examine the spectrum of a massive scalar particle interacting with the strong gravitational field of a static, spherically symmetric object which is not quite massive enough to be a black hole. As was found in the case of massless particles, there exists a dense spectrum of long lived resonances (meta-stable states), which leads to an energy-averaged cross-section for particle capture which approaches the absorption cross-section for a Schwarzschild black hole. However, the generalization to nonzero mass introduces new phenomena, along with important qualitative changes to the scattering properties. In contrast to the massless case, there exists a spectrum of bound states with almost identical structure to that of the resonances, allowing for the possibility of radiative transitions and particle capture. The resonance lifetimes for elastic processes are parametrically larger than for massless particles, meaning the absorption cross-section approaches the black hole case faster than for massless scalars.

Scattering equations and BCJ relations for gauge and gravitational amplitudes with massive scalar particles

We generalize the scattering equations to include both massless and massive particles. We construct an expression for the tree-level n-point amplitude with n-2 gluons or gravitons and a pair of massive scalars in arbitrary spacetime dimension as a sum over the (n-3)! solutions of the scattering equations, a la Cachazo, He, and Yuan. We derive the BCJ relations obeyed by these massive amplitudes.

Dwarf spheroidal galaxies and Bose-Einstein condensate dark matter

We constrain the parameters of a self-interacting massive dark matter scalar particle in a condensate using the kinematics of the eight brightest dwarf spheroidal satellites of the Milky Way. For the case of a repulsive self-interaction the condensate develops a mass density profile with a characteristic scale radius that is closely related to the fundamental parameters of the theory. We find that the velocity dispersion of dwarf spheroidal galaxies suggests a scale radius of the order of 1 kpc, in tension with previous results found using the rotational curve of low-surface-brightness and dwarf galaxies. The new value is however favored marginally by the constraints coming from the number of relativistic species at Big-Bang nucleosynthesis. We discuss the implications of our findings for the particle dark matter model and argue that while a single classical coherent state can correctly describe the dark matter in dwarf spheroidal galaxies, it cannot play, in general, a relevant role for the description of dark matter in bigger objects.

On the transition from the quantum to the classical regime for massive scalar particles: A spatiotemporal approach

If the classical structure of space-time is assumed to define an a priori scenario for the formulation of quantum theory (QT), the coordinate representation of the solutions $$\psi (\vec x,t)(\psi (\vec x_1 , \ldots ,\vec x_N ,t))$$ of the Schroedinger equation of a quantum system containing one (N) massive scalar particle has a preferred status. Let us consider all of the solutions admitting a multipolar expansion of the probability density function $$\rho (\vec x,t) = \left| {(\psi (\vec x,t)} \right|^2$$ (and more generally of the Wigner function) around a space-time trajectory $$\vec x_c (t)$$ to be properly selected. For every normalized solution $$\left( {\smallint d^3 x\rho (\vec x,t) = 1} \right)$$ there is a privileged trajectory implying the vanishing of the dipole moment of the multipolar expansion: it is given by the expectation value of the position operator $$\left\langle {\psi (t)\left| {\hat \vec x} \right|\psi (t)} \right\rangle = \vec x_c (t)$$ . Then, the special subset of solutions $$\psi (\vec x,t)$$ which satisfy Ehrenfest’s Theorem (named thereby Ehrenfest monopole wave functions (EMWF)), have the important property that this privileged classical trajectory $$\vec x_c (t)$$ is determined by a closed Newtonian equation of motion where the effective force is the Newtonian force plus non-Newtonian terms (of order ħ 2 or higher) depending on the higher multipoles of the probability distribution ρ. Note that the superposition of two EMWFs is not an EMWF, a result to be strongly hoped for, given the possible unwanted implications concerning classical spatial perception. These results can be extended to N-particle systems in such a way that, when N classical trajectories with all the dipole moments vanishing and satisfying Ehrenfest theorem are associated with the normalized wave functions of the N-body system, we get a natural transition from the 3N-dimensional configuration space to the space-time. Moreover, these results can be extended to relativistic quantum mechanics. Consequently, in suitable states of N quantum particle which are EMWF, we get the “emergence” of corresponding “classical particles” following Newton-like trajectories in space-time. Note that all this holds true in the standard framework of quantum mechanics, i.e. assuming, in particular, the validity of Born’s rule and the individual system interpretation of the wave function (no ensemble interpretation). These results are valid without any approximation (like ħ → 0, big quantum numbers, etc.). Moreover, we do not commit ourselves to any specific ontological interpretation of quantum theory (such as, e.g., the Bohmian one). We will argue that, in substantial agreement with Bohr’s viewpoint, the macroscopic description of the preparation, certain intermediate steps and the detection of the final outcome of experiments involving massive particles are dominated by these classical “effective” trajectories. This approach can be applied to the point of view of de-coherence in the case of a diagonal reduced density matrix ρ red (an improper mixture) depending on the position variables of a massive particle and of a pointer. When both the particle and the pointer wave functions appearing in ρ red are EMWF, the expectation value of the particle and pointer position variables becomes a statistical average on a classical ensemble. In these cases an improper quantum mixture becomes a classical statistical one, thus providing a particular answer to an open problem of de-coherence about the emergence of classicality.

Exact solutions of the Klein–Gordon equation in the Kerr–Newman background and Hawking radiation

This work considers the influence of the gravitational field produced by a charged and rotating black hole (Kerr–Newman spacetime) on a charged massive scalar field. We obtain exact solutions of both angular and radial parts of the Klein–Gordon equation in this spacetime, which are given in terms of the confluent Heun functions. From the radial solution, we obtain the exact wave solutions near the exterior horizon of the black hole, and discuss the Hawking radiation of charged massive scalar particles.

CCDM model from quantum particle creation: constraints on dark matter mass

In this work the results from the quantum process of matter creation have been used in order to constrain the mass of the dark matter particles in an accelerated Cold Dark Matter model (Creation Cold Dark Matter, CCDM). In order to take into account a back reaction effect due to the particle creation phenomenon, it has been assumed a small deviation ε for the scale factor in the matter dominated era of the form t2/3+ε. Based on recent H(z) data, the best fit values for the mass of dark matter created particles and the ε parameter have been found as m = 1.6× 103 GeV, restricted to a 68.3% c.l. interval of 1.5 < m < 6.3× 107) GeV and ε = -0.250+0.15-0.096 at 68.3% c.l. For these best fit values the model correctly recovers a transition from decelerated to accelerated expansion and admits a positive creation rate near the present era. Contrary to recent works in CCDM models where the creation rate was phenomenologically derived, here we have used a quantum mechanical result for the creation rate of real massive scalar particles, given a self consistent justification for the physical process. This method also indicates a possible solution to the so called ``dark degeneracy'', where one can not distinguish if it is the quantum vacuum contribution or quantum particle creation which accelerates the Universe expansion.

Hawking radiation of charged rotating AdS black holes in conformal gravity for charged massive particles, complex scalar and Dirac particles

Extending researches on Hawking radiation to conformal gravity theory, we discuss Hawking radiation of different particles across charged rotating anti-de Sitter black holes in conformal gravity, including charged massive particles, complex scalar and spin $$-1/2$$ Dirac particles. To make the study of rotating black holes’ tunneling radiation get rid of the dependence on dragging coordinate systems, we investigate the radiation without dragging coordinate transformations. The previous geodesic derivation existed some shortcomings. Not only did geodesics of massive and massless particles are derived by using quite different approaches, but also the treatment for massive case was inconsistent with the variation principle of action. Recently, Wu et al. have remedied the shortcomings. In this paper, we introduce the improved treatment in conformal gravity and derive geodesic equations of massive and massless particles in a unified and self-consistent way. Although the result that the black holes’ entropy is not one-quarter of horizon area differs from that in Einstein gravity, the tunneling probability of charged massive particles in conformal gravity is still related to the change of Bekenstein–Hawking entropy.