Abstract: Exciting peculiarities of Planck-scale physics have immediate effects on the Bekenstein-Hawking radiation emitted from black holes (BHs). In this paper, using the tunneling formalism, we determine the Bekenstein-Hawking temperature for the vector particles from a back-reacted black hole (BBH) constructed from a conformal scalar field surrounded by a BTZ (Banados-Teitelboim-Zanelli) BH. Then, under the effect of the generalized uncertainty principle, we extend our calculations for scalar particles to understand the effects of quantum gravity. Then, we calculate an evaporation time for the BBH, the total number of Bekenstein-Hawking particles, and the quantum corrections of the number. We observe that remnants of the BH evaporation occur and that they affect the Bekenstein-Hawking temperature of the BBH as well as the total number of Bekenstein-Hawking particles. PubDate: Sun, 20 Aug 2017 09:47:38 +000

Abstract: We study massive and massless conical defects in Minkowski and de Sitter spaces in various space-time dimensions. The energy momentum of a defect, considered as an (extended) relativistic object, is completely characterized by the holonomy of the connection associated with its space-time metric. The possible holonomies are given by Lorentz group elements, which are rotations and null rotations for massive and massless defects, respectively. In particular, if we fix the direction of propagation of a massless defect in -dimensional Minkowski space, then its space of holonomies is a maximal Abelian subgroup of the AN group, which corresponds to the well known momentum space associated with the -dimensional -Minkowski noncommutative space-time and -deformed Poincaré algebra. We also conjecture that massless defects in -dimensional de Sitter space can be analogously characterized by holonomies belonging to the same subgroup. This shows how group-valued momenta related to four-dimensional deformations of relativistic symmetries can arise in the description of motion of space-time defects. PubDate: Thu, 17 Aug 2017 00:00:00 +000

Abstract: We present a review of the measurements of elliptic flow () of light nuclei (, , , , and ) from the RHIC and LHC experiments. Light (anti)nuclei have been compared with that of (anti)proton. We observed a similar trend in light nuclei to that in identified hadron with respect to the general observations such as dependence, low mass ordering, and centrality dependence. We also compared the difference of nuclei and antinuclei with the corresponding difference of of proton and antiproton at various collision energies. Qualitatively they depict similar behavior. We also compare the data on light nuclei to various theoretical models such as blast-wave and coalescence. We then present a prediction of for and using coalescence and blast-wave models. PubDate: Tue, 15 Aug 2017 09:54:55 +000

Abstract: Considering the Einstein field equations in Lyra manifold and applying the unified first law of thermodynamics as well as the Clausius relation to the apparent horizon of FRW universe, we find the entropy of apparent horizon in Lyra manifold. In addition, the validity of second law of thermodynamics and its generalized form are also studied. Finally, we use the first law of thermodynamics in order to find the horizon entropy of static spherically symmetric spacetimes. Some results of considering (anti)de-Sitter and Schwarzschild metrics have also been addressed. PubDate: Mon, 14 Aug 2017 07:05:59 +000

Abstract: In the last decades, noncommutative spacetimes and their deformed relativistic symmetries have usually been studied in the context of field theory, replacing the ordinary Minkowski background with an algebra of noncommutative coordinates. However, spacetime noncommutativity can also be introduced into single-particle covariant quantum mechanics, replacing the commuting operators representing the particle’s spacetime coordinates with noncommuting ones. In this paper, we provide a full characterization of a wide class of physically sensible single-particle noncommutative spacetime models and the associated deformed relativistic symmetries. In particular, we prove that they can all be obtained from the standard Minkowski model and the usual Poincaré transformations via a suitable change of variables. Contrary to previous studies, we find that spacetime noncommutativity does not affect the dispersion relation of a relativistic quantum particle, but only the transformation properties of its spacetime coordinates under translations and Lorentz transformations. PubDate: Thu, 10 Aug 2017 00:00:00 +000

Abstract: It was recently realized that Planck-scale momentum-space curvature, which is expected in some approaches to the quantum-gravity problem, can produce dual-curvature lensing, a feature which mainly affects the direction of observation of particles emitted by very distant sources. Several gray areas remain in our understanding of dual-curvature lensing, including the possibility that it might be just a coordinate artifact and the possibility that it might be in some sense a by-product of the better studied dual-curvature redshift. We stress that data reported by the IceCube neutrino telescope should motivate a more vigorous effort of investigation of dual-curvature lensing, and we observe that studies of the recently proposed “-Minkowski noncommutative spacetime” could be valuable from this perspective. Through a dedicated -Minkowski analysis, we show that dual-curvature lensing is not merely a coordinate artifact and that it can be present even in theories without dual-curvature redshift. PubDate: Thu, 10 Aug 2017 00:00:00 +000

Abstract: Main parameters of Super proton-proton Collider (SppC) based lepton-proton colliders are estimated. For electron beam parameters, highest energy International Linear Collider (ILC) and Plasma Wake Field Accelerator-Linear Collider (PWFA-LC) options are taken into account. For muon beams, 1.5 TeV and 3 TeV center of mass energy muon collider parameters are used. In addition, ultimate collider which assumes construction of additional 50 TeV muon ring in the SppC tunnel is considered. It is shown that luminosity values exceeding can be achieved with moderate upgrade of the SppC proton beam parameters. Physics search potential of proposed lepton-proton colliders is illustrated by considering small Björken region as an example of SM physics and resonant production of color octet leptons as an example of BSM physics. PubDate: Tue, 01 Aug 2017 06:44:15 +000

Abstract: We examine the logarithmic corrections to the black hole (BH) entropy product formula of outer horizon and inner horizon by taking into account the effects of statistical quantum fluctuations around the thermal equilibrium and via conformal field theory (CFT). We argue that, in logarithmic corrections to the BH entropy product formula when calculated using CFT and taking into account the effects of quantum fluctuations around the thermal equilibrium, the formula should not be universal and it also should not be quantized. These results have been explicitly checked by giving several examples. PubDate: Sun, 30 Jul 2017 09:11:16 +000

Abstract: We propose a method to relate the holographic minimal information density to de Broglie’s wavelength at a given universe temperature . To figure this out, we assume that the thermal length of massive and massless constituents represents the cut-off scale of the holographic principle. To perform our analysis, we suppose two plausible universe volumes, that is, the adiabatic and the horizon volumes, that is, and , respectively, assuming zero spatial curvature. With these choices in mind, we evaluate the thermal lengths for massive and massless particles and we thus find two cosmological models associated with late and early cosmological epochs. We demonstrate that both models depend upon a free term which enters the temperature parametrization in terms of the redshift . For the two treatments, we show evolving dark energy terms which can be compared with the CDM quintessence paradigm when the barotropic factor takes the formal values and , respectively, for late and early eras. From our analyses, we nominate the two models as viable alternatives to dark energy determined from thermodynamics in the field of the holographic principle. PubDate: Sun, 30 Jul 2017 06:25:33 +000

Abstract: We have presented FRW cosmological model in the framework of Brans-Dicke theory. This paper deals with a new proposed form of deceleration parameter and cosmological constant . The effect of bulk viscosity is also studied in the presence of modified Chaplygin gas equation of state (). Furthermore, we have discussed the physical behaviours of the models. PubDate: Sun, 30 Jul 2017 00:00:00 +000

Abstract: We propose an efficient method to compute the vacuum polarization energy of static field configurations that do not allow decomposition into symmetric and antisymmetric channels in one space dimension. In particular, we compute the vacuum polarization energy of the kink soliton in the model. We link the dependence of this energy on the position of the center of the soliton to the different masses of the quantum fluctuations at negative and positive spatial infinity. PubDate: Sun, 30 Jul 2017 00:00:00 +000

Abstract: Depending on the value of the Higgs mass, the Standard Model acquires an unstable region at large Higgs field values due to RG running of couplings, which we evaluate at 2-loop order. For currently favored values of the Higgs mass, this renders the electroweak vacuum only metastable with a long lifetime. We argue on statistical grounds that the Higgs field would be highly unlikely to begin in the small field metastable region in the early universe, and thus some new physics should enter in the energy range of order of, or lower than, the instability scale to remove the large field unstable region. We assume that Peccei-Quinn (PQ) dynamics enters to solve the strong CP problem and, for a PQ-scale in this energy range, may also remove the unstable region. We allow the PQ-scale to scan and argue, again on statistical grounds, that its value in our universe should be of order of the instability scale, rather than (significantly) lower. Since the Higgs mass determines the instability scale, which is argued to set the PQ-scale, and since the PQ-scale determines the axion properties, including its dark matter abundance, we are led to a correlation between the Higgs mass and the abundance of dark matter. We find the correlation to be in good agreement with current data. PubDate: Thu, 27 Jul 2017 00:00:00 +000

Abstract: We have carried out dynamical system analysis of hessence field coupling with dark matter in gravity. We have analysed the critical points due to autonomous system. The resulting autonomous system is nonlinear. So, we have applied the theory of nonlinear dynamical system. We have noticed that very few papers are devoted to this kind of study. Maximum works in literature are done treating the dynamical system as done in linear dynamical analysis, which are unable to predict correct evolution. Our work is totally different from those kinds of works. We have used nonlinear dynamical system theory, developed till date, in our analysis. This approach gives totally different stable solutions, in contrast to what the linear analysis would have predicted. We have discussed the stability analysis in detail due to exponential potential through computational method in tabular form and analysed the evolution of the universe. Some plots are drawn to investigate the behaviour of the system (this plotting technique is different from usual phase plot and that devised by us). Interestingly, the analysis shows that the universe may resemble the “cosmological constant” like evolution (i.e., CDM model is a subset of the solution set). Also, all the fixed points of our model are able to avoid Big Rip singularity. PubDate: Tue, 25 Jul 2017 08:03:56 +000

Abstract: Using the momentum space representation, we study the (2 + 1)-dimensional Duffin-Kemmer-Petiau oscillator for spin 0 particle under a magnetic field in the presence of a minimal length in the noncommutative space. The explicit form of energy eigenvalues is found, and the wave functions and the corresponding probability density are reported in terms of the Jacobi polynomials. Additionally, we also discuss the special cases and depict the corresponding numerical results. PubDate: Tue, 18 Jul 2017 00:00:00 +000

Abstract: We study the behavior of the eigenvalues of the one and two dimensions of -deformed Dirac oscillator. The eigensolutions have been obtained by using a method based on the -deformed creation and annihilation operators in both dimensions. For a two-dimensional case, we have used the complex formalism which reduced the problem to a problem of one-dimensional case. The influence of the -numbers on the eigenvalues has been well analyzed. Also, the connection between the -oscillator and a quantum optics is well established. Finally, for very small deformation , we (i) showed the existence of well-known -deformed version of Zitterbewegung in relativistic quantum dynamics and (ii) calculated the partition function and all thermal quantities such as the free energy, total energy, entropy, and specific heat. The extension to the case of Graphene has been discussed only in the case of a pure phase (). PubDate: Sun, 16 Jul 2017 00:00:00 +000

Abstract: Entropy bound for the photon gas in a noncommutative (NC) spacetime where phase space is with compact spatial momentum space, previously studied by Nozari et al., has been reexamined with the correct distribution function. While Nozari et al. have employed Maxwell-Boltzmann distribution function to investigate thermodynamic properties of photon gas, we have employed the correct distribution function, that is, Bose-Einstein distribution function. No such entropy bound is observed if Bose-Einstein distribution is employed to solve the partition function. As a result, the reported analogy between thermodynamics of photon gas in such NC spacetime and Bekenstein-Hawking entropy of black holes should be disregarded. PubDate: Thu, 13 Jul 2017 07:24:31 +000

Abstract: The van der Waals (VdW) phase transition in a hairy black hole is investigated by analogizing its charge, temperature, and entropy as the temperature, pressure, and volume in the fluid, respectively. The two-point correlation function (TCF), which is dual to the geodesic length, is employed to probe this phase transition. We find the phase structure in the temperature-thermal entropy plane besides the scale of the horizontal coordinate (geodesic length plane resembles that in the temperature). In addition, we find the equal area law (EAL) for the first-order phase transition and critical exponent of the heat capacity for the second-order phase transition in the temperature-thermal entropy plane (geodesic length plane is consistent with that in temperature), which implies that the TCF is a good probe to probe the phase structure of the back hole. PubDate: Wed, 12 Jul 2017 08:10:31 +000

Abstract: The natural supersymmetry (SUSY) requires light (≤1 TeV) stop quarks, light sbottom quark, and gluinos. The first generation of squarks can be effectively larger than several TeV which does not introduce any hierarchy problem in order to escape the constraints from LHC. In this paper we consider a Yukawa deflected mediation to realize the effective natural supersymmetry where the interactions between squarks and messengers are made natural under certain Froggatt-Nielsen charges. The first generation squarks obtain large and positive contribution from the Yukawa deflected mediation. The corresponding phenomenology and sparticle spectra are discussed in detail. PubDate: Mon, 10 Jul 2017 07:30:37 +000

Abstract: We argue that certain nonviolent local quantum field theory (LQFT) modification considered at the global horizon of a static spherically symmetric black hole can lead to adiabatic leakage of quantum information in the form of Hawking particles. The source of the modification is (i) smooth at and (ii) rapidly vanishing at . Furthermore, we restore the unitary evolution by introducing extra quanta which departs slightly from the generic Hawking emission without changing the experience of an infalling observer (no drama). Also, we suggest that a possible interpretation of the Bekenstein-Hawking bound as entanglement entropy may yield a nonsingular dynamical horizon behavior described by black hole thermodynamics. Hence, by treating gravity as a field theory and considering its coupling to the matter fields in the Minkowski vacuum, we derive the conjectured fluctuations of the background geometry of a black hole. PubDate: Tue, 04 Jul 2017 09:53:26 +000

Abstract: It is widely believed that the quark-gluon plasma (QGP) might be formed in the current heavy ion collisions. It is also widely recognized that the relativistic hydrodynamics is one of the best tools for describing the process of expansion and hadronization of QGP. In this paper, by taking into account the effects of thermalization, a hydrodynamic model including phase transition from QGP state to hadronic state is used to analyze the rapidity and transverse momentum distributions of identified charged particles produced in heavy ion collisions. A comparison is made between the theoretical results and experimental data. The theoretical model gives a good description of the corresponding measurements made in Au-Au collisions at RHIC energies. PubDate: Tue, 04 Jul 2017 00:00:00 +000

Abstract: The hadronic jets in a microquasar stellar system are modeled with the relativistic hydrocode PLUTO. We focus on neutrino emission from such jets produced by fast proton (nonthermal) collisions on thermal ones within the hadronic jet. We adopt a semianalytical approximation for the description of the secondary particles produced from p-p collisions and develop appropriate algorithms using the aforementioned injected protons as input. As a concrete example, we consider the SS-433 X-ray binary system for which several observations have been made the last decades. In contrast to the preset distribution of the fast protons along the jet employed in our previous works, in the present paper, we simulated it by using a power-law fast proton distribution along the PLUTO hydrocode. This distribution gradually sweeps aside the surrounding winds, during the jet advance through the computational grid. As a first step, in the present work, the neutrino energy spectrum is extracted from the model jet, facilitating a range of potential dynamical simulations in currently interesting microquasar jet systems. PubDate: Tue, 04 Jul 2017 00:00:00 +000

Abstract: We investigate the Hawking radiation of vector particles from the apparent horizon of a Friedmann-Robertson-Walker (FRW) universe in the framework of quantum tunnelling method. Furthermore we use Proca equation, a relativistic wave equation for a massive/massless spin-1 particle (massless photons, weak massive and bosons, strong massless gluons, and and mesons) together with a Painlevé space-time metric for the FRW universe. We solve the Proca equation via Hamilton-Jacobi (HJ) equation and the WKB approximation method. We recover the same result for the Hawking temperature associated with vector particles as in the case of scalar and Dirac particles tunnelled from outside to the inside of the apparent horizon in a FRW universe. PubDate: Mon, 03 Jul 2017 00:00:00 +000

Abstract: We study the radiative decay widths of vector quarkonia for the process of and (for principal quantum numbers ) in the framework of Bethe-Salpeter equation under the covariant instantaneous ansatz using a form of BSE. The parameters of the framework were determined by a fit to the mass spectrum of ground states of pseudoscalar and vector quarkonia, such as , , , and . These input parameters so fixed were found to give good agreements with data on mass spectra of ground and excited states of pseudoscalar and vector quarkonia, leptonic decay constants of pseudoscalar and vector quarkonia, two-photon decays, and two-gluon decays of pseudoscalar quarkonia in our recent paper. With these input parameters so fixed, the radiative decay widths of ground and excited states of heavy vector quarkonia ( and ) are calculated and found to be in reasonable agreement with data. PubDate: Tue, 20 Jun 2017 06:32:01 +000

Abstract: We review the realization of Starobinsky-type inflation within induced-gravity supersymmetric (SUSY) and non-SUSY models. In both cases, inflation is in agreement with the current data and can be attained for sub-Planckian values of the inflation. The corresponding effective theories retain perturbative unitarity up to the Planck scale and the inflation mass is predicted to be . The supergravity embedding of these models is achieved by employing two gauge singlet chiral superfields, a superpotential that is uniquely determined by a continuous and a discrete symmetry and several (semi)logarithmic Kähler potentials that respect these symmetries. Checking various functional forms for the noninflation accompanying field in the Kähler potentials, we identify four cases which stabilize it without invoking higher order terms. PubDate: Sun, 18 Jun 2017 08:28:21 +000

Abstract: The present works deals with gravitational collapse of cylindrical viscous heat conducting anisotropic fluid following the work of Misner and Sharp. Using Darmois matching conditions, the dynamical equations are derived and the effects of charge and dissipative quantities over the cylindrical collapse are analyzed. Finally, using the Miller-Israel-Steward causal thermodynamic theory, the transport equation for heat flux is derived and its influence on collapsing system has been studied. PubDate: Wed, 14 Jun 2017 00:00:00 +000

Abstract: We present a gravitational collapse null dust solution of the Einstein field equations. The space-time is regular everywhere except on the symmetry axis where it possesses a naked curvature singularity and admits one parameter isometry group, a generator of axial symmetry along the cylinder which has closed orbits. The space-time admits closed timelike curves (CTCs) which develop at some particular moment in a causally well-behaved manner and may represent a Cosmic Time Machine. The radial geodesics near the singularity and the gravitational lensing (GL) will be discussed. The physical interpretation of this solution, based on the study of the equation of the geodesic deviation, will be presented. It was demonstrated that this solution depends on the local gravitational field consisting of two components with amplitudes and . PubDate: Mon, 12 Jun 2017 00:00:00 +000

Abstract: A simple transformation of field variables eliminates Coulomb forces from the theory of quantum electrodynamics. This suggests that Coulomb forces may be an emergent phenomenon rather than being fundamental. This possibility is investigated in the context of reducible quantum electrodynamics. It is shown that states exist which bind free photon and free electron fields. The binding energy peaks in the long-wavelength limit. This makes it plausible that Coulomb forces result from the interaction of the electron/positron field with long-wavelength transversely polarized photons. PubDate: Tue, 06 Jun 2017 00:00:00 +000

Abstract: We calculate the particle ratios , , and for a strongly interacting hadronic matter using nonlinear Walecka model (NLWM) in relativistic mean field (RMF) approximation. It is found that interactions among hadrons modify and particle ratios, while is found to be insensitive to these interactions. PubDate: Sun, 04 Jun 2017 06:51:38 +000

Abstract: We investigate the possibility of TeV-scale scalars as low energy remnants arising in the nonsupersymmetric grand unification framework where the field content is minimal. We consider a scenario where the gauge symmetry is broken into the gauge symmetry of the Standard Model (SM) through multiple stages of symmetry breaking, and a colored and hypercharged scalar picks a TeV-scale mass in the process. The last stage of the symmetry breaking occurs at the TeV-scale where the left-right symmetry, that is, , is broken into that of the SM by a singlet scalar field of mass TeV, which is a component of an -triplet scalar field, acquiring a TeV-scale vacuum expectation value. For the LHC phenomenology, we consider a scenario where is produced via gluon-gluon fusion through loop interactions with and also decays to a pair of SM gauge bosons through in the loop. We find that the parameter space is heavily constrained from the latest LHC data. We use a multivariate analysis to estimate the LHC discovery reach of into the diphoton channel. PubDate: Tue, 30 May 2017 09:03:57 +000