8,829 research outputs found
BRST quantization of matrix models with constraints and two-dimensional Yang-Mills theory on the cylinder
BRST quantization of the one-dimensional constrained matrix model which
describes two-dimensional Yang-Mills theory on the cylinder is performed.
Classical and quantum BRST generators and BRST-invariant hamiltonians are
constructed. Evolution operator is expressed in terms of BRST path integral.
Advantages of the BRST quantization over the reduced phase space approach
leading to the theory of free fermions are discussed.Comment: 8 page
Ostrogradski approach for the Regge-Teitelboim type cosmology
We present an alternative geometric inspired derivation of the quantum
cosmology arising from a brane universe in the context of {\it geodetic
gravity}. We set up the Regge-Teitelboim model to describe our universe, and we
recover its original dynamics by thinking of such field theory as a
second-order derivative theory. We refer to an Ostrogradski Hamiltonian
formalism to prepare the system to its quantization. Our analysis highlights
the second-order derivative nature of the RT model and the inherited
geometrical aspect of the theory. A canonical transformation brings us to the
internal physical geometry of the theory and induces its quantization
straightforwardly. By using the Dirac canonical quantization method our
approach comprises the management of both first- and second-class constraints
where the counting of degrees of freedom follows accordingly. At the quantum
level our Wheeler-De Witt Wheeler equation agrees with previous results
recently found. On these lines, we also comment upon the compatibility of our
approach with the Hamiltonian approach proposed by Davidson and coworkers.Comment: 11 pages, 2 figures, accepted for publication in Phys. Rev.
Applicability to Assignees of Doctrine of Practical Construction of Contracts
The courts resort to established rules of interpretation for assistance in solving the doubts found in ambiguous contracts. The cardinal rule of interpretation is that the court must endeavor to ascertain and give effect to the intention of the parties to the contract at the time of the making of the contract. Intention can not be proved by direct and positive evidence. It is a question of fact to be proved like any other fact, by acts, conduct and circumstances . Thus the issue, the intention of the parties to the contract at the time of the making of the contract, is an issue of fact to be proved like any other fact. Relevant evidence is admissible—irrelevant evidence is not
Characteristics of long-duration inhibitory postsynaptic potentials in rat neocortical neurons in vitro
1. The characteristics of long-duration inhibitory postsynaptic potentials (l-IPSPs) which are evoked in rat frontal neocortical neurons by local electrical stimulation were investigated with intracellular recordings from anin vitro slice preparation.
2. Stimulation with suprathreshold intensities evoked l-IPSPs with typical durations of 600–900 msec at resting membrane potential. Conductance increases of 15–60% were measured at the peak amplitude of l-IPSPs (150–250 msec poststimulus).
3. The duration of the conductance increases during l-IPSPs displayed a significant voltage dependence, decreasing as the membrance potential was depolarized and increasing with hyperpolarization.
4. The reversal potential of l-IPSPs is significantly altered by reductions in the extracellular potassium concentration. Therefore it is concluded that l-IPSPs in rat neocortical neurons are generated by the activation of a potassium conductance.
5. l-IPSPs exhibit stimulation fatigue. Stimulation with a frequency of 1 Hz produces a complete fatigue of the conductance increases during l-IPSPs after approximately 20 consecutive stimuli. Recovery from this fatigue requires minutes.
6. l-IPSPs are not blocked by bicuculline but are blocked by baclofen
Holonomy groups and W-symmetries
Irreducible sigma models, i.e. those for which the partition function does
not factorise, are defined on Riemannian spaces with irreducible holonomy
groups. These special geometries are characterised by the existence of
covariantly constant forms which in turn give rise to symmetries of the
supersymmetric sigma model actions. The Poisson bracket algebra of the
corresponding currents is a W-algebra. Extended supersymmetries arise as
special cases.Comment: pages 2
Evolution of 1612 MHz Maser Emission in Expanding Circumstellar Shells
Observations show that 1612 MHz masers of OH/IR stars can fade on a timescale
of a decade. This fading is probably associated with the switch from rapid mass
loss, which is ultimately linked with an internal He-shell flash, to the much
slower mass loss supported by more quiescent conditions. We study the observed
maser decay with a composite computational model, comprising a time-dependent
chemical model of the envelope, and a radiation transfer model which provides
the maser pumping. Our combined model is able to reproduce the rapid decay of
maser intensity, following a sudden drop in the stellar mass-loss rate. The
explanation for the rapid fall in maser emission is not a fall in the OH number
density, or the kinetic temperature in the inverted layers, but the loss of a
radiative pump route which carries population from level 1 to level 4 via
levels 16, 15 and 11. The loss of these pump routes is a result, in turn, of a
greatly reduced energy density of 53 micron radiation
AdS/SCFT in Superspace
A discussion of the AdS/CFT correspondence in IIB is given in a superspace
context. The main emphasis is on the properties of SCFT correlators on the
boundary which are studied using harmonic superspace techniques. These
techniques provide the easiest way of implementing the superconformal Ward
identities. The Ward identities, together with analyticity, can be used to give
a compelling argument in support of the non-renormalisation theorems for two-
and three-point functions, and to establish the triviality of extremal and
next-to-extremal correlation functions. The OPE in is also briefly discussed.Comment: 10 pages; talk given by PSH at 2nd Gursey Memorial Conference, June
200
Super-Yang-Mills and M5-branes
We uplift 5-dimensional super-Yang-Mills theory to a 6-dimensional gauge
theory with the help of a space-like constant vector , whose norm
determines the Yang-Mills coupling constant. After the localization of
the 6D gauge theory acquires Lorentzian invariance as well as scale invariance.
We discuss KK states, instantons and the flux quantization. The 6D theory
admits extended solutions like 1/2 BPS `strings' and monopoles.Comment: 15 pages; minor changes, to appear in JHE
Non-Perturbative Green's Functions in Theories with Extended Superconformal Symmetry
The multiplets that occur in four dimensional rigidly supersymmetric theories
can be described either by chiral superfields in Minkowski superspace or
analytic superfields in harmonic superspace. The superconformal Ward identities
for Green's functions of gauge invariant operators of these types are derived.
It is shown that there are no chiral superconformal invariants. It is further
shown that the Green's functions of analytic operators are severely restricted
by the superconformal Ward when analyticity is taken into account.Comment: 17 pages, plain tex. Some conjectures that were in the original paper
are clarifed in the light of more recent work to which we give references.
See Note added for detail
Working-Together Normative Appeals: Normative appeals motivate people to contribute to collective action problems more when they invite people to work together toward a common goal
A common method to promote behavior change, particularly in contexts related to collective action, is to reference a social norm and ask people to comply with it. We argue that such appeals will be more effective when they couch the norm as an invitation to work with others toward a common goal. In six experiments, we found that working-together normative appeals, which invited people to “join in” and “do it together,” increased interest in (Experiments 1, 4, and 5) and actual charitable giving (Experiment 2); reduced paper-towel use in public restrooms (Experiment 3); and increased interest in reducing personal carbon emissions (Experiment 6). By contrast, normative-information appeals, which included the same normative information but no reference to working together, did not affect interest or behavior. Mediation analyses suggest that working-together normative appeals were more effective because they fostered a feeling in participants that they were working together with others, which increased motivation, while inducing less social pressure, which undermined effectiveness. Results show how the very collective nature of collective action problems can be leveraged to promote personal behavior change and help solve societal problems
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