12,224 research outputs found
Bohmian mechanics in relativistic quantum mechanics, quantum field theory and string theory
I present a short overview of my recent achievements on the Bohmian
interpretation of relativistic quantum mechanics, quantum field theory and
string theory. This includes the relativistic-covariant Bohmian equations for
particle trajectories, the problem of particle creation and destruction, the
Bohmian interpretation of fermionic fields and the intrinsically Bohmian
quantization of fields and strings based on the De Donder-Weyl covariant
canonical formalism.Comment: 6 pages, talk given at Third International Workshop DICE2006,
Piombino, Italy, September 11-15, 200
A general-covariant concept of particles in curved background
A local current of particle density for scalar fields in curved background is
constructed. The current depends on the choice of a two-point function. There
is a choice that leads to local non-conservation of the current in a
time-dependent gravitational background, which describes local particle
production consistent with the usual global description based on the Bogoliubov
transformation. Another choice, which might be the most natural one, leads to
the local conservation of the current.Comment: 9 pages, the paper is modified such that it includes the corrections
that will be published in the erratu
-brane type I superstring background fields in terms of type IIB ones by canonical method and T-duality approach
We consider type IIB superstring theory with embedded -brane and choose
boundary conditions which preserve half of the initial supersymmetry. In the
canonical approach that we use, boundary conditions are treated as canonical
constraints. The effective theory, obtained from the initial one on the
solution of boundary conditions, has the form of the type I superstring theory
with embedded -brane. We obtain the expressions for -brane background
fields of type I theory in terms of the -brane background fields of type
IIB theory. We show that beside known even fields, they contain
squares of odd ones, where is world-sheet parity
transformation, . We relate result of this paper and
the results of [1] using T-dualities along four directions orthogonal to
-brane
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Modelling and optimisation of design of non-conventional instrument transformers
In this paper, we have proposed, modelled and optimised several designs of non-conventional instrument transformer (NCIT) for high voltage overhead transmission lines (400kV). We have discussed several parameters and investigated how they influence the sensitivity of our NCIT, consisting of magnetic shape memory (MSM) element, magnetic circuit and an LVDT (linear variable differential transformer). One of the most used conductors in these lines, 528-Al1/69-ST1A ACSR conductor (old code MOOSE), was modelled together with the MSM element and the magnetic circuit in ANSYS APDL. Based on the obtained results we have given suggestions on how NCIT could be designed taking into account a choice of the most appropriate material for this application. The way how the model was developed was presented as well as calculations of errors in the model in ANSYS APDL for electromagnetic problems
Practopoiesis: Or how life fosters a mind
The mind is a biological phenomenon. Thus, biological principles of
organization should also be the principles underlying mental operations.
Practopoiesis states that the key for achieving intelligence through adaptation
is an arrangement in which mechanisms laying a lower level of organization, by
their operations and interaction with the environment, enable creation of
mechanisms lying at a higher level of organization. When such an organizational
advance of a system occurs, it is called a traverse. A case of traverse is when
plasticity mechanisms (at a lower level of organization), by their operations,
create a neural network anatomy (at a higher level of organization). Another
case is the actual production of behavior by that network, whereby the
mechanisms of neuronal activity operate to create motor actions. Practopoietic
theory explains why the adaptability of a system increases with each increase
in the number of traverses. With a larger number of traverses, a system can be
relatively small and yet, produce a higher degree of adaptive/intelligent
behavior than a system with a lower number of traverses. The present analyses
indicate that the two well-known traverses-neural plasticity and neural
activity-are not sufficient to explain human mental capabilities. At least one
additional traverse is needed, which is named anapoiesis for its contribution
in reconstructing knowledge e.g., from long-term memory into working memory.
The conclusions bear implications for brain theory, the mind-body explanatory
gap, and developments of artificial intelligence technologies.Comment: Revised version in response to reviewer comment
Type I background fields in terms of type IIB ones
We choose such boundary conditions for open IIB superstring theory which
preserve N=1 SUSY. The explicite solution of the boundary conditions yields
effective theory which is symmetric under world-sheet parity transformation
. We recognize effective theory as closed type I
superstring theory. Its background fields,beside known even fields of
the initial IIB theory, contain improvements quadratic in odd ones.Comment: 4 revtex pages, no figure
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