120550582
Hawking radiation via tunnelling from black holes with topological defects
In this paper, we extend Parikh's recent work to two kinds of the black holes whose ADM mass is no longer identical to its mass parameter, each with a topological defect, one being a global monopole black hole and another a cosmic string black hole. We view Hawking radiation as a tunnelling process across the event horizon and calculate the tunnelling probability. From the tunnelling probability we also find a leading correction to the semiclassical emission rate. The results are consistent with an underlying unitary theory.
119744936
Neutrino Oscillation in the Space-Time with a Global Monopole
The mass neutrino interference phase in a global monopole space time along the null trajectory and the geodesic is studied, and we find that the conserved energy changes a factor when a particle travels along the geodesic, if compared with the energy in the space time without the global monopole. The oscillation phase is increased by a factor due to the correction of the global monopole, comparing with the case in Schwarzschild space time. We obtain that the type-I phase along both the null and geodesic has a difference of a factor of 1−8πη2, and that the phase along the geodesic is the double of that along the null.
119336471
Tunnelling Effect of Two Horizons from a Gibbons-Maeda Black Hole
We study the thermal characters of the inner horizon of a Gibbons–Maeda black hole. In order to satisfy the Nernst theorem of the third law, the entropy of the black hole with two horizons must depend not only on the area of the outer horizon but also on the area of the inner horizon. Then the temperature of the inner horizon is calculated. Lastly, the tunnelling effect including the inner horizon of a Gibbons–Maeda black hole is investigated. We also calculate the tunnelling rate of the outer horizon Γ+ and the inner horizon Γ-. The total tunnelling rate Γ should be the product of the rates of the outer and inner horizon, Γ = Γ+ Γ-. It is found that the total tunnelling rate is in agreement with the Parikh's standard result, Γ → exp(ΔSBH), and there is no information loss.
117555639
Hawking Radiation via Tunnelling from Arbitrarily Dimensional Schwarzschild Black Holes
We extend Parikh's recent work to the arbitrarily dimensional Schwarzschild black holes whose Arnowitt–Deser–Misner (ADM) mass is identical to its mass parameter. We view Hawking radiation as a tunnelling process across the event horizon. From the tunnelling probability we also find a leading correction to the semiclassical emission rate. The result consists with an underlying unitary theory.
123206975
Neutrino Oscillations in the Robertson-Walker Metric and the Cosmological Blue Shift of the Oscillation Length
The Doppler effect of the neutrino oscillation length in the flat space is discussed. When the observer travels away from the source, the oscillation length decreases. Moreover, the mass neutrino oscillation in the Robertson-Walker metric is studied, and the general equations of the oscillation phases are given. We obtain the relation between the phase and the scale factor. The expansion of the universe leads to the reduction of the oscillation length (blue shift), which is contrary to the red shift of the light ray.
124059954
Hawking radiation of a uniformly accelerating black hole
In this paper, we study the Hawking radiation via tunnelling from a uniformly accelerating black hole. Although the Bekenstein–Hawking entropy is proportional also to the area of the event horizon, the radius of it, rH, is a function of θ, which leads to the difficulties in the calculation of the emission rate. In order to overcome the mathematical difficulties, we propose a new technique to calculate the emission rate and the result obtained is reasonable.
54201703
Higgs gravitational interaction, weak boson scattering, and Higgs inflation in Jordan and Einstein frames
We study gravitational interaction of Higgs boson through the unique dimension-4 operator xi(HHR)-H-dagger, with H the Higgs doublet and R the Ricci scalar curvature. We analyze the effect of this dimensionless nonminimal coupling xi on weak gauge boson scattering in both Jordan and Einstein frames. We explicitly establish the longitudinal-Goldstone equivalence theorem with nonzero xi coupling in both frames, and analyze the unitarity constraints. We study the xi-induced weak boson scattering cross sections at O(1 30) TeV scales, and propose to probe the Higgs-gravity coupling via weak boson scattering experiments at the LHC (14 TeV) and the next generation pp colliders (50 100 TeV). We further extend our study to Higgs inflation, and quantitatively derive the perturbative unitarity bounds via coupled channel analysis, under large field background at the inflation scale. We analyze the unitarity constraints on the parameter space in both the conventional Higgs inflation and the improved models in light of the recent BICEP2 data.
119190318
Analytic fermionic Green’s functions from holography
We find exact, analytic solutions of the Dirac equation for a charged, massless fermion in the background of a charged, dilatonic black hole in AdS_5. The black hole descends from type IIB supergravity, where it describes D3-branes with equal angular momenta in two of the three independent planes of rotation orthogonal to the world-volume. The Green's function near the Fermi surface for a strongly coupled fermionic system can be extracted holographically from an exact solution of the Dirac equation at zero frequency but nonzero momentum. There can be several Fermi momenta, and they take the form k_F=q-n-1/2 (in units of the chemical potential), where q is the charge of the spinor, and n is a non-negative integer that labels the Fermi surfaces. Much as for holographic Fermi surfaces based on the Reissner-Nordstrom-AdS_5 solution, the dispersion relation of the excitations near the Fermi surface is determined by the geometry close to the horizon, and one can obtain Fermi liquid, marginal Fermi liquid, and non-Fermi liquid behaviors depending on the value of k_F.
118752433
Higgs Partner Searches and Dark Matter Phenomenology in a Classically Scale Invariant Higgs Boson Sector
In a previous work, a classically scale invariant extension of the standard model was proposed, as a potential candidate for resolving the hierarchy problem, by minimally introducing a complex gauge singlet scalar, and generating radiative electroweak symmetry breaking by means of the Coleman- Weinberg Mechanism. Postulating the singlet sector to respect the CP-symmetry, the existence of a stable pseudoscalar dark matter candidate with a mass in the TeV range was demonstrated. More- over, the model predicted the presence of another physical CP-even Higgs boson (with suppressed tree-level couplings), in addition to the 125 GeV scalar discovered by the LHC. The viable region of the parameter space was determined by various theoretical and experimental considerations. In this work, we continue to examine the phenomenological implications of the proposed minimal sce- nario by considering the constraints from the dark matter relic density, as determined by the Planck collaboration, as well as the direct detection bounds from the LUX experiment. Furthermore, we investigate the implications of the collider Higgs searches for the additional Higgs boson. Our results are comprehensively demonstrated in unified exclusion plots, which analyze the viable region of the parameter space from all relevant angles, demonstrating the testability of the proposed scenario.
118652689
The spin of holographic electrons at nonzero density and temperature
A bstractWe study the Green’s function of a gauge invariant fermionic operator in a strongly coupled field theory at nonzero temperature and density using a dual gravity description. The gravity model contains a charged black hole in four dimensional anti-de Sitter space and probe charged fermions. In particular, we consider the effects of the spin of these probe fermions on the properties of the Green’s function. There exists a spin-orbit coupling between the spin of an electron and the electric field of a Reissner-Nordstrom black hole. On the field theory side, this coupling leads to a Rashba like dispersion relation. We also study the effects of spin on the damping term in the dispersion relation by considering how the spin affects the placement of the fermionic quasinormal modes in the complex frequency plane in a WKB limit. An appendix contains some exact solutions of the Dirac equation in terms of Heun polynomials.
102507809
Natural electroweak symmetry breaking from scale invariant Higgs mechanism
We construct a minimal viable extension of the standard model (SM) with classical scale symmetry. Its scalar sector contains a complex singlet in addition to the SM Higgs doublet. The scale-invariant and CP-symmetric Higgs potential generates radiative electroweak symmetry breaking ` a la Coleman-Weinberg, and gives a natural solution to the hierarchy problem, free from fine-tuning. Besides the 125 GeV SM-like Higgs particle, it predicts a new CP-even Higgs (serving as the pseudo-Nambu-Goldstone boson of scale symmetry breaking) and a CP-odd scalar singlet (providing the dark matter candidate) at weak scale. We systematically analyze experimental constraints from direct LHC Higgs searches and electroweak precision tests, as well as theoretical bounds from unitarity, triviality and vacuum stability. We demonstrate the viable parameter space, and discuss implications for new Higgs and dark matter (DM) searches at the upcoming LHC runs and for the on-going direct detections of DM.