1,353 research outputs found
Gauge algebra of irreducible theories in the Sp(2)-symmetric BRST formalism
An explicit solution to classical master equations of the Sp(2)-symmetric
Hamiltonian BRST quantization scheme is presented in the case of irreducible
gauge theories. A realization of the observable algebra is constructed.Comment: 12 pages, v2: typos corrected, an explicit formula and references
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Generalized BRST Quantization and Massive Vector Fields
A previously proposed generalized BRST quantization on inner product spaces
for second class constraints is further developed through applications. This
BRST method involves a conserved generalized BRST charge Q which is not
nilpotent but which satisfies Q=\delta+\delta^{\dagger}, \delta^2=0, and by
means of which physical states are obtained from the projection
\delta|ph>=\delta^{\dagger}|ph>=0. A simple model is analyzed in detail from
which some basic properties and necessary ingredients are extracted. The method
is then applied to a massive vector field. An effective theory is derived which
is close to the one of the Stueckelberg model. However, since the scalar field
here is introduced in order to have inner product solutions, a massive
Yang-Mills theory with polynomial interaction terms might be possible to
construct.Comment: 19 pages,Latexfil
Government Expenditure, Foreign Direct Investment and Economic Growth in Nigeria
Government expenditure and Foreign Direct Investment (FDI) are vital macroeconomic variables of any economy as they are strong propellant of economic growth. The need to control and monitoring government spending and the FDI so as to achieve a steady economic growth necessitated this study. The study seeks to determine the impact of government expenditure and FDI on the Nigeria economic growth. A multiple regression analysis was used to test the relationship between government expenditure (capital and recurrent expenditure) and FDI as the explanatory variables on GDP (proxy for economic growth) as the dependent variable. Our result revealed that the explanatory variables: CEXP, REXP and FDI had significant relationship with economic growth. However CEXP did not conform to expectation. Some recommendations such as a thorough and accountable management of capital and recurrent expenditures in Nigeria, adequate planning, an effective macroeconomic framework and conducive economic environment to encourage foreign direct investment is require
Gauge Consistent Wilson Renormalization Group II: Non-Abelian Case
We give a wilsonian formulation of non-abelian gauge theories explicitly
consistent with axial gauge Ward identitities. The issues of unitarity and
dependence on the quantization direction are carefully investigated. A
wilsonian computation of the one-loop QCD beta function is performed.Comment: 34 pages, 1 eps figure, latex2e. Minor changes, version to appear in
Int. J. Mod. Phy
The Hot Bang state of massless fermions
In 2002, a method has been proposed by Buchholz et al. in the context of
Local Quantum Physics, to characterize states that are locally in thermodynamic
equilibrium. It could be shown for the model of massless bosons that these
states exhibit quite interesting properties. The mean phase-space density
satisfies a transport equation, and many of these states break time reversal
symmetry. Moreover, an explicit example of such a state, called the Hot Bang
state, could be found, which models the future of a temperature singularity.
However, although the general results carry over to the fermionic case easily,
the proof of existence of an analogue of the Hot Bang state is not quite that
straightforward. The proof will be given in this paper. Moreover, we will
discuss some of the mathematical subtleties which arise in the fermionic case.Comment: 17 page
The Reeh-Schlieder property for thermal field theories
We show that the Reeh-Schlieder property w.r.t. the KMS-vector is a direct
consequence of locality, additivity and the relativistic KMS-condition. The
latter characterises the thermal equilibrium states of a relativistic quantum
field theory. The statement remains vaild even if the given equilibrium state
breaks spatial translation invariance.Comment: plain tex, 10 page
Recent Developments in Enantioselective Transition Metal Catalysis Featuring Attractive Noncovalent Interactions between Ligand and Substrate.
Enantioselective transition metal catalysis is an area very much at the forefront of contemporary synthetic research. The development of processes that enable the efficient synthesis of enantiopure compounds is of unquestionable importance to chemists working within the many diverse fields of the central science. Traditional approaches to solving this challenge have typically relied on leveraging repulsive steric interactions between chiral ligands and substrates in order to raise the energy of one of the diastereomeric transition states over the other. By contrast, this Review examines an alternative tactic in which a set of attractive noncovalent interactions operating between transition metal ligands and substrates are used to control enantioselectivity. Examples where this creative approach has been successfully applied to render fundamental synthetic processes enantioselective are presented and discussed. In many of the cases examined, the ligand scaffold has been carefully designed to accommodate these attractive interactions, while in others, the importance of the critical interactions was only elucidated in subsequent computational and mechanistic studies. Through an exploration and discussion of recent reports encompassing a wide range of reaction classes, we hope to inspire synthetic chemists to continue to develop asymmetric transformations based on this powerful concept.The EPSRC are acknowledged in manuscript as they provide a studentship to one of the authors
Speed of Light in Non--Trivial Vacua
We unify all existing results on the change of the speed of low--energy
photons due to modifications of the vacuum, finding that it is given by a
universal constant times the quotient of the difference of energy densities
between the usual and modified vacua over the mass of the electron to the
fourth power. Whether photons move faster or slower than depends only on
the lower or higher energy density of the modified vacuum, respectively.
Physically, a higher energy density is characterized by the presence of
additional particles (real or virtual) in the vacuum whereas a lower one stems
from the absence of some virtual modes. We then carry out a systematic study of
the speed of propagation of massless particles for several field theories up to
two loops on a thermal vacuum. Only low--energy massless particles
corresponding to a massive theory show genuine modifications of their speed
while remaining massless. All other modifications are mass-related, or running
mass-related. We also develop a formalism for the Casimir vacuum which
parallels the thermal one and check that photons travel faster than between
plates.Comment: 24 p., plain te
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