119178235
Electromagnetic Duality in Dyonic RN/CFT Correspondence
The area law of Bekenstein-Hawking entropy of the black hole suggests that the black hole should have a lower-dimensional holographic description. It has been found recently that such holographic pictures could be set up from the study of the thermodynamics of both outer and inner horizons for a large class of rotating and charged black holes. For a four-dimensional dyonic Reissner-Nordström black hole, its thermodynamics indicates that it has multiple holographic pictures not only the electric and magnetic ones corresponding to the conserved electric and magnetic charges carried by the black hole, but also the more generic ones generated by the SL(2, Z) transformations. We show that this SL(2, Z) group originates from the underlying electromagnetic duality symmetry in the Einstein-Maxwell theory. It turns out that the thermodynamics of the black hole not only encodes the information of holographic pictures; moreover it could reflect the symmetries of the underlying theory. PACS numbers: 04.70.Dy, 11.25.Hf
118544209
Holographic Rényi entropy for CFT with W symmetry
A bstractIn this paper we investigate the holographic Rényi entropy of two disjoint intervals on complex plane with small cross ratio x for conformal field theory with W symmetry in the ground state, which could be dual to a higher spin AdS3 gravity. We focus on the cases of W3 and W4 symmetries. In order to see the nontrivial contributions from the W fields, we calculate the Rényi entropy in the expansion of x to order x8 in both the gravity and the CFT sides. In the gravity side the classical contributions to the entanglement entropy is still given by the Ryu-Takayanagi area formula under the reasonable assumption, while the 1-loop quantum corrections have to take into account of the contributions not only from massless gravitons, but also from massless higher spin fields. In the CFT side we still use the operator product expansion of twist operators in the small interval limit, but now we need to consider the quasiprimary fields constructed from W fields, besides the ones from Virasoro Verma module. In the large central charge limit, we obtain the classical, 1-loop, 2-loop, and 3-loop parts of the Rényi entropy. The classical and 1-loop results in the gravity and the CFT sides are in exact match. This confirms the higher spin gravity/CFT correspondence, and also supports the holographic computation of Rényi entanglement entropy, including the quantum correction, in both the AdS3 gravity and the higher spin AdS3 gravity.
119188234
Notes on Self-dual Warped dS$_3$ Spacetime
In this paper, we investigate the warped dS/CFT correspondence of the self-dual warped dS$_3$ spacetime, which is a solution of three-dimensional topologically massive gravity (TMG) with a positive cosmological constant. We discuss its thermodynamics at two cosmological horizons. We propose that the self-dual warped dS$_3$ spacetime is holographically dual to a chiral conformal field theory. We analytically calculate the quasinormal modes of scalar, vector, tensor, and spinor perturbations under the self-dual warped dS$_3$ spacetime. It turns out that the frequencies of the quasinormal modes could be identified with the poles in the thermal boundary-boundary correlators.
118385893
On short interval expansion of Rényi entropy
A bstractRényi entanglement entropy provides a new window to study the AdS/CFT correspondence. In this paper we consider the short interval expansion of Rényi entanglement entropy in two-dimensional conformal field theory. This amounts to do the operator product expansion of the twist operators. We focus on the vacuum Verma module and consider the quasiprimary operators constructed from the stress tensors. After obtaining the expansion coefficients of the twist operators to level 6 in vacuum Verma module, we compute the leading contributions to the Rényi entropy, to order 6 in the short interval expansion. In the case of one short interval on cylinder, we reproduce the first several leading contributions to the Rényi entropy. In the case of two short disjoint intervals with a small cross ratio x, we obtain not only the classical and 1-loop quantum contributions to the Rényi entropy to order x6, both of which are in perfect match with the ones found in gravity, but also the leading 1/c contributions, which corresponds to 2-loop corrections in the bulk.
118496902
Note on thermodynamics method of black hole/CFT correspondence
A bstractIn the paper we further refine the thermodynamics method of black hole/CFT correspondence. We show that one can derive the central charges of different holographic pictures directly from the entropy product S+S− if it is mass-independent, for a black hole in the Einstein gravity or the gravity without diffeomorphism anomaly. For a general black hole in the Einstein gravity that admits holographic descriptions, we show that the thermodynamics method and asymptotic symmetry group (ASG) analysis can always give consistent results in the extreme limit. Furthermore, we discuss the relation between black hole thermodynamics and the hidden conformal symmetry. We show that the condition T+A+ = T−A−, with A± being the outer and inner horizon areas, is the necessary, but not sufficient, condition for a black hole to have the hidden conformal symmetry. In particular, for the Einstein(-Maxwell) gravity T+A+ = T−A− is just the condition T+S+ = T−S−, with S± being the outer and inner horizon entropies, which is the condition for the entropy product S+S− being mass-dependent. When there exists the hidden conformal symmetry in the low-frequency scattering off the generic non-extremal black hole, it always leads to the same temperatures of dual CFT as the ones got from the thermodynamics method.
118607645
Hidden conformal symmetry of extremal black holes
We study the hidden conformal symmetry of extremal black holes. We introduce a new set of conformal coordinates to write the SL(2,R) generators. We find that the Laplacian of the scalar field in many extremal black holes, including Kerr(-Newman), Reissner-Nordstrom, warped AdS{sub 3}, and null warped black holes, could be written in terms of the SL(2,R) quadratic Casimir. This suggests that there exist dual conformal field theory (CFT) descriptions of these black holes. From the conformal coordinates, the temperatures of the dual CFTs could be read directly. For the extremal black hole, the Hawking temperature is vanishing. Correspondingly, only the left (right) temperature of the dual CFT is nonvanishing, and the excitations of the other sector are suppressed. In the probe limit, we compute the scattering amplitudes of the scalar off the extremal black holes and find perfect agreement with the CFT prediction.
118409517
Mass spectra of the heavy baryons $\Lambda_{Q}$ and $\Sigma_Q^(*)$ from QCD sum rules
We use QCD sum rule approach to calculate the masses of the ground-state Lambda_Q and Sigma_Q^(*) baryons. Contributions of the operators up to dimension six are included in operator product expansion. The resulting heavy baryonic masses from the calculations are m_{Lambda_b}=5.69 +/- 0.13 GeV, and m_{Lambda_c}=2.31 +/- 0.19 GeV for Lambda_Q; m_{Sigma_b}=5.73 +/- 0.21 GeV, m_{Sigma_b^*}=5.81 +/- 0.19 GeV, m_{Sigma_c}=2.40 +/- 0.31 GeV and m_{Sigma_c^*}=2.56 +/- 0.24 GeV for Sigma_Q^(*), respectively, which are in good agreement with the experimental values.
45784849
Past incompleteness of a bouncing multiverse
According to classical GR, Anti-de Sitter (AdS) bubbles in the multiverse terminate in big crunch singularities. It has been conjectured, however, that the fundamental theory may resolve these singularities and replace them by nonsingular bounces. This may have important implications for the beginning of the multiverse. Geodesics in cosmological spacetimes are known to be past-incomplete, as long as the average expansion rate along the geodesic is positive, but it is not clear that the latter condition is satisfied if the geodesic repeatedly passes through crunching AdS bubbles. We investigate this issue in a simple multiverse model, where the spacetime consists of a patchwork of FRW regions. The conclusion is that the spacetime is still past-incomplete, even in the presence of AdS bounces.
117031507
Preheating in a DBI Inflation Model
We study the preheating process in a model of DBI inflation with a DBI-type inflaton coupling to a canonical entropy field. At the end of inflation, the inflaton field oscillates around its vacuum which can arise from an infrared cutoff parameter on the warp factor and correspondingly the evolution of its fluctuations can be approximately described by a generalized Hill's equation in third order. We study the field fluctuations numerically and show that they could grow exponentially since the instability bands commonly exist in the DBI models if the amplitudes of background oscillations are of order or larger than the cutoff parameter. Our numerical result also reveals that the particle excitation of the matter field is more dramatic than that in usual case since the parametric resonance lasts longer when the effect of a warp factor is taken into account. Therefore, we conclude that the preheating process in the model of DBI inflation could be more efficient than that in standard inflation models.
16589327
On the Locality and Scaling of Overlap Fermions at Coarse Lattice Spacings
The overlap fermion offers the considerable advantage of exact chiral symmetry on the lattice, but is numerically intensive. This can be made affordable while still providing large lattice volumes, by using coarse lattice spacing, given that good scaling and localization properties are established. Here, using overlap fermions on quenched Iwasaki gauge configurations, we demonstrate directly that, with appropriate choice of negative Wilson's mass, the overlap Dirac operator's range is comfortably small in lattice units for each of the lattice spacings 0.20 fm, 0.17 fm, and 0.13 fm (and scales to zero in physical units in the continuum limit). In particular, our direct results contradict recent speculation that an inverse lattice spacing of 1 GeV is too low to have satisfactory localization. Furthermore, hadronic masses (available on the two coarser lattices) scale very well.
118804860
Signature of large extra dimensions from Z boson pair production at the CERN Large Hadron Collider
We study the Z boson pair production mediated by the Kaluza-Klein (KK) graviton in large extra dimensions (LED) at the CERN Large Hadron Collider (LHC). We use the partial wave unitarity to discuss the constraints on the process energy scale in order to give a self-consistent calculation. We find that the LED contributions can enhance the Z boson pair production cross sections significantly when the fundamental scale M{sub S} of the large extra dimensions is up to several TeV. We also show that the kinematic distributions of the LED signals are greatly different from the standard model ones and the LHC can probe the M{sub S} values up to 4.3-5.6 TeV at 3{sigma} level depending on the number of the extra dimensions.