20,397 research outputs found
Higher-spin Gauge and Trace Anomalies in Two-dimensional Backgrounds
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
arXiv:0710.0456.Comment: 23 page
Modification of Gravitational Anomaly Method in Hawking Radiation
We discuss an ambiguity of the derivation of the Hawking radiation through
the gravitational anomaly method and propose modifications of this method such
that it reproduces the correct thermal fluxes. In this modified gravitational
anomaly method, we employ the two-dimensional conformal field theory technique.Comment: 14 pages, clarifications added. Version to appear in Physics Letters
Stochastic Equations in Black Hole Backgrounds and Non-equilibrium Fluctuation Theorems
We apply the non-equilibrium fluctuation theorems developed in the
statistical physics to the thermodynamics of black hole horizons. In
particular, we consider a scalar field in a black hole background. The system
of the scalar field behaves stochastically due to the absorption of energy into
the black hole and emission of the Hawking radiation from the black hole
horizon. We derive the stochastic equations, i.e. Langevin and Fokker-Planck
equations for a scalar field in a black hole background in the limit with the Hawking temperature fixed.
We consider two cases, one confined in a box with a black hole at the center
and the other in contact with a heat bath with temperature different from the
Hawking temperature. In the first case, the system eventually becomes
equilibrium with the Hawking temperature while in the second case there is an
energy flow between the black hole and the heat bath. Applying the fluctuation
theorems to these cases, we derive the generalized second law of black hole
thermodynamics. In the present paper, we treat the black hole as a constant
background geometry. Since the paper is also aimed to connect two different
areas of physics, non-equilibrium physics and black holes physics, we include
pedagogical reviews on the stochastic approaches to the non-equilibrium
fluctuation theorems and some basics of black holes physics.Comment: 53 page
Explicit Relation of Quantum Hall Effect and Calogero-Sutherland Model
Explicit relation between Laughlin state of the quantum Hall effect and
one-dimensional(1D) model with long-ranged interaction () is discussed.
By rewriting lowest Landau level wave functions in terms of 1D representation,
Laughlin state can be written as a deformation of the ground state of
Calogero-Sutherland model. Corresponding to Laughlin state on different
geometries, different types of 1D interaction models are derived.Comment: 10 page
Applying formal methods to standard development: the open distributed processing experience
Since their introduction, formal methods have been applied in various ways to different standards. This paper gives an account of these applications, focusing on one application in particular: the development of a framework for creating standards for Open Distributed Processing (ODP). Following an introduction to ODP, the paper gives an insight into the current work on formalising the architecture of the
Reference Model of ODP (RM-ODP), highlighting the advantages to be gained. The different approaches currently being taken are shown, together with their associated advantages and disadvantages. The paper concludes that there is no one all-purpose approach which can be used
in preference to all others, but that a combination of approaches is desirable to best fulfil the potential of formal methods in developing an architectural semantics for OD
RG-improvement of the effective action with multiple mass scales
Improving the effective action by the renormalization group (RG) with several
mass scales is an important problem in quantum field theories. A method based
on the decoupling theorem was proposed in \cite{Bando:1992wy} and
systematically improved \cite{Casas:1998cf} to take threshold effects into
account. In this paper, we apply the method to the Higgs-Yukawa model,
including wave-function renormalizations, and to a model with two real scalar
fields . In the Higgs-Yukawa model, even at one-loop level,
Feynman diagrams contain propagators with different mass scales and decoupling
scales must be chosen appropriately to absorb threshold corrections. On the
other hand, in the two-scalar model, the mass matrix of the scalar fields is a
function of their field values and the resultant running
couplings obey different RGEs on a different point of the field space. By
solving the RGEs, we can obtain the RG improved effective action in the whole
region of the scalar fields.Comment: 22 pages, 6 figure
Chiral Anomaly and Ginsparg-Wilson Relation on the Noncommutative Torus
We evaluate chiral anomaly on the noncommutative torus with the overlap Dirac
operator satisfying the Ginsparg-Wilson relation in arbitrary even dimensions.
Utilizing a topological argument we show that the chiral anomaly is combined
into a form of the Chern character with star products.Comment: 19 pages, uses ptptex.cls and ptp-prep.clo, references added, typo
corrected, the final version to appear in Prog.Theor.Phy
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