450 research outputs found
Towards the quantization of the non-relativistic D2-brane in the Pure Spinor Formalism
An attempt is made to apply the pure spinor formalism to the non-relativistic
IIA D2-brane. The fermionic constraints corresponding to the rescaled fermionic
coordinates are given. Two commuting spinor fields are introduced, each one
corresponding to a fermionic constraint. A BRST charge is constructed via the
ansatz proposed by N. Berkovits. The nilpotency of the BRST charge leads to a
set of constraints for the two spinor fields including pure spinor constraints.
A novel non-trivial solution is given for one of the spinor fields which can be
written as a sum of two pure spinors.Comment: 23 pages in latex, no figures; discussion added, some typos
corrected, more references adde
String Thermalization in Static Spacetimes
We study the evolution, the transverse spreading and the subsequent
thermalization of string states in the Weyl static axisymmetric spacetime. This
possesses a singular event horizon on the symmetry axis and a naked singularity
along the other directions. The branching diffusion process of string bits
approaching the singular event horizon provides the notion of temperature that
is calculated for this process. We find that the solution of the Fokker-Planck
equation in the phase space of the transverse variables of the string, can be
factored as a product of two thermal distributions, provided that the classical
conjugate variables satisfy the uncertainty principle. We comment on the
possible physical significance of this result.Comment: 16 pages, no figures, Late
New IUFRO Initiative to Improve Forest Sciences Study Programmes: the Task Force EFS (Education in Forest Sciences)
The system of higher education has been facing fundamental changes, triggered by globalization and global change, altering expectations of stakeholders and society from university graduates and novel insights of educational sciences â calling for a move from teaching to learning. Programmes of higher forest education have been challenged even more by changing societal demands, such as climate change, changing patterns of demands for ecosystem services, and novel resource governance systems. The development of forest sciences as well as of forestry curricula should adapt to or even anticipate those trends. Consequently development of forest sciences curricula should move towards: ⢠Focusing on generic and methodical competences instead of contents and descriptive approaches, enabling graduates to tackle novel, complex problems; ⢠Competences to integrate and communicate knowledge across disciplinary boarders and to analyze the existing interactions; ⢠New learning units addressing challenges such as climate change, adaptive ecosystem management, governance systems, gender issues, forests as source of energy, role of forests and forest products in rural development and poverty alleviation as well as the assessment of other environmental and social impacts. The IUFRO Task Force on Education in Forest Sciences (EFS â http://www.tf-efs.proste.pl) is an attempt to answer to the growing demand for coordination of research based knowledge and education at university level. The objective of EFS IUFRO TF is an improved practice of Education in Forest Sciences worldwide. EFS therefore aims at contributing to development of standards of Education in Forest Sciences, which meet the requirements of today, using experiences and examples of good practice in the IUFRO community and cooperation with higher education experts. Part of this is the development of a framework on required competences of graduates of education in forest sciences, to be characterized in terms of skill dimension, context, and level of mastery. This will be based, among others, on focus group discussions with higher forestry education specialists worldwide
Application of the canonical quantization of systems with curved phase space to the EMDA theory
The canonical quantization of dynamical systems with curved phase space
introduced by I.A. Batalin, E.S. Fradkin and T.E. Fradkina is applied to the
four-dimensional Einstein-Maxwell Dilaton-Axion theory. The spherically
symmetric case with radial fields is considered. The Lagrangian density of the
theory in the Einstein frame is written as an expression with first order in
time derivatives of the fields. The phase space is curved due to the nontrivial
interaction of the dilaton with the axion and the electromagnetic fields.Comment: 23 pages in late
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