19 research outputs found
Convenient Versus Unique Effective Action Formalism in 2D Dilaton-Maxwell Quantum Gravity
The structure of one-loop divergences of two-dimensional dilaton-Maxwell
quantum gravity is investigated in two formalisms: one using a convenient
effective action and the other a unique effective action. The one-loop
divergences (including surface divergences) of the convenient effective action
are calculated in three different covariant gauges: (i) De Witt, (ii)
-degenerate De Witt, and (iii) simplest covariant. The on-shell
effective action is given by surface divergences only (finiteness of the
-matrix), which yet depend upon the gauge condition choice.
Off-shell renormalizability is discussed and classes of renormalizable
dilaton and Maxwell potentials are found which coincide in the cases of
convenient and unique effective actions. A detailed comparison of both
situations, i.e. convenient vs. unique effective action, is given. As an
extension of the procedure, the one-loop effective action in two-dimensional
dilaton-Yang-Mills gravity is calculated.Comment: 25 pages, LaTeX file, HUPD-93-0
Vacuum instability in external fields
We study particles creation in arbitrary space-time dimensions by external
electric fields, in particular, by fields, which are acting for a finite time.
The time and dimensional analysis of the vacuum instability is presented. It is
shown that the distributions of particles created by quasiconstant electric
fields can be written in a form which has a thermal character and seems to be
universal. Its application, for example, to the particles creation in external
constant gravitational field reproduces the Hawking temperature exactly.Comment: 36 pages, LaTe
Trace anomaly induced effective action and 2d black holes for dilaton coupled supersymmetric theories
The action for 2d dilatonic supergravity with dilaton coupled matter and
dilaton multiplets is constructed. Trace anomaly and anomaly induced effective
action (in components as well as in supersymmetric form) for matter
supermultiplet on bosonic background are found. The one-loop effective action
and large- effective action for quantum dilatonic supergravity are also
calculated. Using induced effective action one can estimate the back-reaction
of dilaton coupled matter to the classical black hole solutions of dilatonic
supergravity. That is done on the example of supersymmetric CGHS model with
dilaton coupled quantum matter where Hawking radiation which turns out to be
zero is calculated. Similar 2d analysis maybe used to study spherically
symmetric collapse for other models of 4d supergravity.Comment: 21 pages, LaTeX, NDA-FP-3
Inference Rules in Nelson’s Logics, Admissibility and Weak Admissibility
© 2015, Springer Basel. Our paper aims to investigate inference rules for Nelson’s logics and to discuss possible ways to determine admissibility of inference rules in such logics. We will use the technique offered originally for intuitionistic logic and paraconsistent minimal Johannson’s logic. However, the adaptation is not an easy and evident task since Nelson’s logics do not enjoy replacement of equivalences rule. Therefore we consider and compare standard admissibility and weak admissibility. Our paper founds algorithms for recognizing weak admissibility and admissibility itself – for restricted cases, to show the problems arising in the course of study
Inconsistency-tolerant description logic. Part II: A tableau algorithm for CALCC
AbstractIn the first part of this paper, we motivated and defined three systems of constructive and inconsistency-tolerant description logic. The variety of arising systems is conditioned by the variety of approaches to defining modalities in the constructive setting. We also presented sound and complete tableau calculi for the logics under consideration. Whereas these calculi were not meant to give rise to tableau algorithms, in the present second part of the paper, after providing some motivation and recalling the main definitions, we adapt methods developed by R. Dyckhoff and by I. Horrocks and U. Sattler in order to define a tableau algorithm for our basic four-valued constructive description logic CALCC. Notice that among the three logics defined in the first part of the paper, CALCC is the only logic which lends itself to applications, because for the other logics it is unknown whether they are elementarily decidable. The presented algorithm for CALCC is the first example of an elementary decision procedure for a constructive description logic