Takeshi Morita

Quantum Anomalies at Horizon and Hawking Radiations in Myers-Perry Black Holes

A new method has been developed recently to derive Hawking radiations from black holes based on considerations of gravitational and gauge anomalies at the horizon [1, 2]. In this paper, we apply the method to Myers-Perry black holes with multiple angular momenta in various dimensions by using the dimensional reduction technique adopted in the case of four-dimensional rotating black holes [3].

Higher-spin currents and thermal flux from Hawking radiation

Quantum fields near black hole horizons can be described in terms of an infinite set of d = 2 conformal fields. In this paper, by investigating transformation properties of general higher-spin currents under a conformal transformation, we reproduce the thermal distribution of Hawking radiation in both cases of bosons and fermions. As a by-product, we obtain a generalization of the Schwarzian derivative for higher-spin currents.

Hawking radiation via higher-spin gauge anomalies

We give a higher-spin generalization of the anomaly method for the Hawking radiation from black holes. In the paper [S. Iso, T. Morita, and H. Umetsu, arXiv:0710.0453.] higher-spin generalizations of the gauge (and gravitational) anomalies in d = 2 were obtained. By applying these anomalies to black hole physics, we derive the higher moments of the Hawking fluxes. We also give a higher-spin generalization of the trace anomaly method by Christensen and Fulling [S. Christensen and S. Fulling, Phys. Rev. D 15, 2088 (1977).].

Higher-spin gauge and trace anomalies in two-dimensional backgrounds

Abstract Two-dimensional quantum fields in electric and gravitational backgrounds can be described by conformal field theories, and hence all the physical (covariant) quantities can be written in terms of the corresponding holomorphic quantities. In this paper, we first derive relations between covariant and holomorphic forms of higher-spin currents in these backgrounds, and then, by using these relations, obtain higher-spin generalizations of the trace and gauge (or gravitational) anomalies up to spin 4. These results are applied to derive higher-moments of Hawking fluxes in black holes in a separate paper [S. Iso, T. Morita, H. Umetsu, Hawking radiation via higher-spin gauge anomalies, arXiv: 0710.0456 [hep-th] ].

Hagedorn Instability in Dimensionally Reduced Large-N Gauge Theories as Gregory-Laflamme and Rayleigh-Plateau Instabilities

It is expected that the Gregory-Laflamme (GL) instability in the black string in gravity is related to the Rayleigh-Plateau instability in fluid mechanics. Especially, the orders of the phase transitions associated with these instabilities depend on the number of the transverse space dimensions, and they are of first and second order below and above the critical dimension. Through the gauge-gravity correspondence, the GL instability is conjectured to be thermodynamically related to the Hagedorn instability in large-N gauge theories, and it leads to a prediction that the order of the confinement-deconfinement transition associated with the Hagedorn instability may depend on the transverse dimension. We test this conjecture in the D-dimensional bosonic D0-brane model using numerical simulation and the 1/D expansion, and confirm the expected D dependence.

Quantum quench in matrix models: dynamical phase transitions, selective equilibration and the Generalized Gibbs Ensemble

A bstractQuantum quench dynamics is considered in a one dimensional unitary matrix model with a single trace potential. This model is integrable and has been studied in the context of non-critical string theory. We find dynamical phase transitions, and study the role of the quantum critical point. In course of the time evolutions, we find evidence of selective equilibration for a certain class of observables. The equilibrium is governed by the Generalized Gibbs Ensemble (GGE) and differs from the standard Gibbs ensemble. We compute the production of entropy which is O(N) for large N matrices. An important feature of the equilibration is the appearance of an energy cascade, reminiscent of the Richardson cascade in turbulence, where we find flow of energy from initial long wavelength modes to progressively shorter wavelength excitations. We discuss possible implication of the equilibration and of GGE in string theories and higher spin theories. In another related study, we compute time evolutions in a double trace unitary matrix model, which arises s an effective theory of D2 branes in IIA string theory in the confinement phase. We find similar equilibrations and dynamical transitions in this matrix model. The dynamical transitions are related to Gregory-Laflamme transitions in string theory and are potentially connected with the issue of appearance of naked singularities.

Thermodynamics of black M-branes from SCFTs

A bstractWe discuss thermodynamics of N M2-branes at strong coupling from the ABJM theory by employing the Smilga-Wiseman method, which explains the black Dp-brane thermodynamics from the maximally supersymmetric U(N) Yang-Mills theories through a field theory analysis. As a result we obtain the free energy of the ABJM theory ~ N3/2

Nucleus from string theory

\sqrt{k}{T^3}

New States of Gauge Theories on a Circle

, which is consistent with the prediction from the eleven-dimensional supergravity. We also estimate the free energy of N M5-branes by assuming some natural properties of the 6d superconformal field theory. Remarkably we obtain the free energy ~ N3T6, which is consistent again with the supergravity prediction. This result might illuminate the low energy field theory description of the multiple M5-branes.

Super Yang-Mills Theory from a Supermatrix Model

In generic holographic QCD, we find that baryons are bound to form a nucleus, and that its radius obeys the empirically-known mass number (A) dependence r A^{1/3} for large A. Our result is robust, since we use only a generic property of D-brane actions in string theory. We also show that nucleons are bound completely in a finite volume. Furthermore, employing a concrete holographic model (derived by Hashimoto, Iizuka, and Yi, describing a multi-baryon system in the Sakai-Sugimoto model), the nuclear radius is evaluated as O(1) x A^{1/3} [fm], which is consistent with experiments.