arXiv subjects

G. S. Djordjevic

Publications and source records attributed to G. S. Djordjevic.

10 recordsLinked to original sources

arXiv2010

Non-archimedean quantum cosmology and tachyonic inflation

We review the relevance of quantum rolling tachyons and corresponding inflation scenario in the frame of the standard, $p$-adic and adelic minisuperspace quantum cosmology. The field theory of tachyon matter proposed by Sen in a zero-dimensional version suggested by Kar leads to a model of a particle moving in a constant external field with quadratic damping. We calculate the exact quantum propagator of the model, as well as, the vacuum states and conditions necessary to construct an adelic generalization. In addition we present an overview on several important cosmological models on archimedean and nonarchimedean spaces.

gr-qc↗

arXiv2009

Education and Research in the SEENET-MTP Regional Framework for Higher Education in Physics

Southeastern European countries undergo significant changes in the demand/supply ratio on the labour market and in the structure of professional competences that are necessary for undertaking a professional activity. In addition, brain-drain process and decrease of interest for a career in basic sciences put many challenges for our community. Consequently, based on the activity of the Southeastern European Network in Mathematical and Theoretical Physics (SEENET MTP Network) in connecting groups and persons working in mathematics and theoretical physics, we investigate specific qualifications recognized in these fields in all the countries from the region, and the related competences necessary for practicing the respective occupations. A list of new possible occupations will be promoted for inclusion in the National Qualifications Register for Higher Education. Finally, we analyze the vision existing in this region on the higher education qualifications against the European vision and experience, in particular in training of Master students, PhD students, and senior teaching and research staff through the Network, i.e. multilateral and bilateral programs.

physics.ed-ph↗

arXiv2009

High School Class for Gifted Pupils in Physics and Sciences and Pupils` Skills Measured by Standard and Pisa Test

The ``High school class for students with special abilities in physics`` was founded in Nis, Serbia in 2003. The basic aim of this project has been introducing a broadened curriculum of physics, mathematics, computer science, as well as chemistry and biology. We present analysis of the pupils` skills in solving rather problem oriented test, as PISA test, and compare their results with the results of pupils who study under standard curricula. Analysis of achievement data should clarify what are benefits of introducing in school system track for gifted students. Additionally, item analysis helps in understanding and improvement of learning strategies efficacy.

physics.ed-ph↗

arXiv2008

Quantum Cosmology and Tachyons

We discuss the relevance of the classical and quantum rolling tachyons inflation in the frame of the standard, p-adic and adelic minisuperspace quantum cosmology. The field theory of tachyon matter proposed by Sen in a zero-dimensional version suggested by Kar leads to a model of a particle moving in a constant external field with quadratic damping. We calculate the exact quantum propagator of the model, as well as, the vacuum states and conditions necessary to construct an adelic generalization.

gr-qc↗

arXiv2006

Zero Dimensional Field Theory of Tachyon Matter

The first issue about the object (now) called tachyons was published almost one century ago. Even though there is no experimental evidence of tachyons there are several reasons why tachyons are still of interest today, in fact interest in tachyons is increasing. Many string theories have tachyons occurring as some of the particles in the theory. In this paper we consider the zero dimensional version of the field theory of tachyon matter proposed by A. Sen. Using perturbation theory and ideas of S. Kar, we demonstrate how this tachyon field theory can be connected with a classical mechanical system, such as a massive particle moving in a constant field with quadratic friction. The corresponding Feynman path integral form is proposed using a perturbative method. A few promising lines for further applications and investigations are noted.

hep-th↗

arXiv2004

Propagator for the Free Relativistic Particle on Archimedean and Nonarchimedean Spaces

We consider dynamics of a free relativistic particle at very short distances, treating space-time as archimedean as well as nonarchimedean one. Usual action for the relativistic particle is nonlinear. Meanwhile, in the real case, that system may be treated like a system with quadratic (Hamiltonian) constraint. We perform similar procedure in -adic case, as the simplest example of a nonarchimedean space. The existence of the simplest vacuum state is considered and corresponding Green function is calculated. Similarities and differences between obtained results on both spaces are examined and possible physical implications are discussed.

hep-th↗

arXiv2002

Adelic Path Integrals for Quadratic Lagrangians

Feynman's path integral in adelic quantum mechanics is considered. The propagator K(x'',t'';x',t') for one-dimensional adelic systems with quadratic Lagrangians is analytically evaluated. Obtained exact general formula has the form which is invariant under interchange of the number fields R and Q_p.

hep-th↗

arXiv2002

p-Adic and Adelic Minisuperspace Quantum Cosmology

We consider the formulation and some elaboration of p-adic and adelic quantum cosmology. The adelic generalization of the Hartle-Hawking proposal does not work in models with matter fields. p-Adic and adelic minisuperspace quantum cosmology is well defined as an ordinary application of p-adic and adelic quantum mechanics. It is illustrated by a few minisuperspace cosmological models in one, two and three minisuperspace dimensions. As a result of p-adic quantum effects and the adelic approach, these models exhibit some discreteness of the minisuperspace and cosmological constant. In particular, discreteness of the de Sitter space and its cosmological constant is emphasized.

gr-qc↗

arXiv2000

p-Adic Path Integrals for Quadratic Actions

The Feynman path integral in p-adic quantum mechanics is considered. The probability amplitude ${\cal K}_p (x^{\prime\prime},t^{\prime\prime}; x^\prime,t^\prime)$ for one-dimensional systems with quadratic actions is calculated in an exact form, which is the same as that in ordinary quantum mechanics.

math-ph↗

arXiv2000

p-Adic and Adelic Free Relativistic Particle

We consider spectral problem for a free relativistic particle in p-adic and adelic quantum mechanics. In particular, we found p-adic and adelic eigenfunctions. Within adelic approach there exist quantum states that exhibit discrete structure of spacetime at the Planck scale.

hep-th↗