1,433,681 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
Welfare Competition in Norway
Local redistribution policy creates incentives for welfare migration that may result in 'underprovision' or even a 'race to the bottom'. This paper evaluates the empirical importance of welfare competition. Our contribution is to separate between the policy decision and the actual welfare benefit payments and to introduce income distribution as a determinant of welfare policy. Utilizing spatial econometric methods we find statistical significant strategic interaction between local governments for both the welfare benefit norm decided by the local council and the expected welfare benefits of a standardized person. No robust relationship is found between inequality and welfare benefits and thus we offer no strong support for the Romer-Meltzer-Richard hypothesis. We conclude that there is a geographic pattern in welfare benefits. This does not necessarily imply underprovision, since the grant financing of the local governments may generate overall excessive public spending.
A smooth-transition model of the Australian unemployment rate
Models of the aggregate unemployment rate have traditionally been estimated from structural models of the labour market or in a linear single-equation framework. However, theory as well as evidence suggest that the unemployment rate is asymmetric and should be modelled in a non-linear framework. In this paper the unemployment rate in Australia is modelled as a non-linear function of aggregate demand and real wages. Negative changes in aggregate demand cause the unemployment rate to rise rapidly, while real wage rigidity contributes its to slow adjustment back towards a lower level of unemployment. The model is developed by exploiting recent developments in automated model-selection procedures.unemployment;non-linearity;dynamic modelling;aggregate demand;real wages
Financial incentives and study duration in higher education
The current paper investigates to which extent students in higher education respond to financial incentives by adjusting their study behavior. Students in Norway who completed certain graduate study programs between 1991 and 1995 on stipulated time were entitled to a restitution (of approximately 3,000 USD) from the Norwegian State Educational Loan Fund. Using a difference-in-difference approach, we find that the fraction of students graduating on time during the reform period increased by 10 percent, relative to a base probability of about 25 percent. The estimated effect for fully treated students (students who were aware of the reform from the start of their studies) is much higher, at 50 percent.
Designing Integrated Conservation and Development Projects (ICDPs): Illegal hunting, wildlife conservation and the welfare of the local people
This paper develops a bio-economic model to explore the effect on illegal hunting, wildlife conservation and human welfare of the most common instruments of existing ICDPs. It is demonstrated that stimulating working opportunities in the formal sector has the potential of promoting conservation, while money transfers and distribution of game meat to the local people fail, if not explicitly linked to the conservation objective. The analysis shows that such links, modelled as a risk of being excluded from the project if caught in illegal hunting, may be a more durable mean for ICDPs to reach its goal of improved wildlife conservation and human welfare. The model is illustrated by numerical calculations with data from Serengeti, Tanzania.
Iso-array rewriting P systems with context-free iso-array rules
A new computing model called P system is a highly distributed and
parallel theoretical model, which is proposed in the area of membrane computing. Ceterchi et al. initially proposed array rewriting P systems by extending the notion of string rewriting P systems to arrays (2003). A theoretical model for picture generation using context-free iso-array grammar rules and puzzle iso-array grammar rules are introduced by Kalyani et al. (2004, 2006). Also iso-array rewriting P systems for iso-picture languages have been studied by Annadurai et al. (2008). In this paper we consider the context-free iso-array rules and context-free puzzle iso-array rules in iso-array rewriting P systems and examine the generative powers
of these P systems
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