124268406
Running Spectral Index from Noncommutativty
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.
119364316
EXACT SOLUTIONS OF EMBEDDING THE 4D UNIVERSE IN A 5D EINSTEIN MANIFOLD
One of the simplest ways to extend 4D cosmological models is to add another spatial dimension to make them 5D. In particular, it has been shown that the simplest of such 5D models, i.e. one in which the right-hand side of the Einstein equation is empty, induces a 4D nonempty universe. Accordingly, the origin of matter in a real 4D universe might be mathematically attributed to the existence of one (fictitious) extra spatial dimension. Here we consider the case of an empty 5D universe possessing a cosmological constant Λ and obtain exact solutions for both positive and negative values of the Λ. It is seen that such a model can naturally reduce to a power law ΛCDM model for the real universe. Further, it can be seen that the arbitrary constants and functions appearing in this model are endowed with definite physical meanings.
119368144
DARK VISCOUS FLUID DESCRIBED BY A UNIFIED EQUATION OF STATE IN COSMOLOGY
We generalize the ΛCDM model by introducing a unified EOS to describe the Universe contents modeled as dark viscous fluid, motivated by the fact that a single constant equation of state (EOS) p = -p0 (p0 > 0) reproduces the ΛCDM model exactly. This EOS describes the perfect fluid term, the dissipative effect, and the cosmological constant in a unique framework and the Friedmann equations can be analytically solved. Especially, we find a relation between the EOS parameter and the renormalizable condition of a scalar field. We develop a completely numerical method to perform a χ2 minimization to constrain the parameters in a cosmological model directly from the Friedmann equations, and employ the SNe data with the parameter $\mathcal{A}$ measured from the SDSS data to constrain our model. The result indicates that the dissipative effect is rather small in the late-time Universe.
119356187
Cosmological model with viscosity media (dark fluid) described by an effective equation of state
Abstract A generally parameterized equation of state (EOS) is investigated in the cosmological evolution with bulk viscosity media modelled as dark fluid, which can be regarded as a unification of dark energy and dark matter. Compared with the case of the perfect fluid, this EOS has possessed four additional parameters, which can be interpreted as the case of the non-perfect fluid with time-dependent viscosity or the model with variable cosmological constant. From this general EOS, a completely integrable dynamical equation to the scale factor is obtained with its solution explicitly given out. (i) In this parameterized model of cosmology, for a special choice of the parameters we can explain the late-time accelerating expansion universe in a new view. The early inflation, the median (relatively late time) deceleration, and the recently cosmic acceleration may be unified in a single equation. (ii) A generalized relation of the Hubble parameter scaling with the redshift is obtained for some cosmology interests. (iii) By using the SNe Ia data to fit the effective viscosity model we show that the case of matter described by p = 0 plus with effective viscosity contributions can fit the observational gold data in an acceptable level.
118756844
Observe the open universe in the sky
We first review the related works on the observable consequence of landscape and the regulation of e-foldings during inflation. We focus on a branch of observable consequence of landscape which predicts an open universe with negative curvature if e-foldings $N>62$. After discussing the observable regulation from the aspect by Kaloper, Kleban and Sorbo, we make an argument that in the non-flat background the observable $N$ is suppressed by a factor $k/\rho_{0}$. We point out that this seems to detect the information where e-foldings $N>62$ possibly. Finally, we discuss our outcomes with the recent work by Arkani-Hamed et al.
55805244
LHC constraints on a Higgs boson partner from an extended color sector
the presence of a heavy Higgs and to the detailed properties of the 125 GeV Higgs will further constrain the properties of the new heavy s scalar. Since the renormalizable coloron model may contain spectator fermions to remove anomalies, we examine several representative scenarios with different numbers of spectator fermions. Our results are summarized in plots that overlay the current exclusion limits on the s boson with the projected sensitivity of the ffiffiffi s p ¼ 14TeV LHC to the new state. We find that the upcoming LHC searches should be sensitive to an s scalar of mass less than 1 TeV for essentially all of the model parameter space in which the h state differs from the Higgs boson of the SM. More precisely, unless the mixing between the weak doublet and weak singlet gauge-eigenstate scalars is zero, the 14 TeV LHC will be sensitive to the presence of the nonstandard heavy s state that is characteristic of the renormalizable coloron model.
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.
121890616
Tunneling Effect of Two Horizons from a Reissner-Nordstrom Black Hole
The understanding of possible role played by the inner horizon of black holes in black hole thermodynamics is still somewhat incomplete. By adopting Damour-Ruffini method and the thin film model which is developed on the base of brick wall model suggested by ’t Hooft, we calculate the temperature and the entropy of the inner horizon of a R-N black hole. We conclude that the temperature of inner horizon is positive and the entropy of the inner horizon is proportional to the area of the inner horizon. In addition, the cut-off factor is 90β, which is same in calculation of the entropy of the outer horizon. So, we prove the existence of thermal characters of the inner horizon. Then, we discuss that if the contribution of the inner horizon is taken into account to the total entropy of the black hole, the Nernst theorem can be satisfied. At last, we study the tunneling effect including the inner horizon of the Reissner-Nordstrom black hole. We calculate the tunneling rate of the outer horizon Γ+ and the inner horizon Γ−. The total tunneling rate Γ should be the product of the rates of the outer and inner horizon, Γ=Γ+⋅Γ−. We find that the total tunneling rate is in agreement with the Parikh’s standard result, Γ→exp (ΔSBH), and there is no information loss.
119113213
Strongly First-Order Electroweak Phase Transition and Classical Scale Invariance
In this work, we examine the possibility of realizing a strongly first-order electroweak phase transition within the minimal classically scale invariant extension of the standard model (SM), previously proposed and analyzed as a potential solution to the hierarchy problem. By introducing one complex singlet scalar and three right-handed Majorana neutrinos, the scenario was successfully capable of achieving a radiative breaking of the electroweak symmetry (Coleman-Weinberg Mechanism), inducing non-zero masses for the SM neutrinos (seesaw mechanism), presenting a pseudoscalar dark matter candidate, and predicting the existence of a second $CP$-even boson in addition to the 125 GeV scalar. We construct the full finite-temperature one-loop effective potential of the model, including the resummed thermal daisy loops, and demonstrate that finite-temperature effects induce a first-order electroweak phase transition. Requiring the thermally-driven first-order phase transition to be sufficiently strong further constrains the model's parameter space; in particular, an $\mathcal O(0.01)$ fraction of the dark matter in the universe may be simultaneously accommodated with a strongly first-order electroweak phase transition. Moreover, such a phase transition disfavors right-handed Majorana neutrino masses above several hundreds of GeV, confines the pseudoscalar dark matter masses to $\sim 1$-2 TeV, predicts the mass of the second $CP$-even scalar to be $\sim 100$-300 GeV, and requires the mixing angle between the $CP$-even components of the SM doublet and the complex singlet to lie within the range $0.2 \lesssim \sin\omega \lesssim 0.4$. The obtained results are displayed in comprehensive exclusion plots, identifying the viable regions of the parameter space. Many of these predictions lie within the reach of the next LHC run.
118390911
Hadron collider production of massive color-octet vector bosons at next-to-leading order
This paper completes the study of the next-to-leading-order QCD corrections to massive color-octet vector boson production at the LHC and Tevatron. The massive color-octet vector bosons are generically referred to as colorons. Building on our previous calculation of quark-initiated coloron production at next-to-leading order, we use the pinch technique to investigate coloron production via gluon fusion. We demonstrate that this one-loop production amplitude is finite and find that its numerical contribution to coloron production is typically 4 orders of magnitude smaller than the contribution from quark annihilation. Coloron production via gluon fusion is therefore relevant only if the colorons are (nearly) fermiophobic. We then present extensive plots and tables of our full results for next-to-leading-order coloron production at the Tevatron and the LHC.