53 research outputs found
Complexification of Gauge Theories
For the case of a first-class constrained system with an equivariant momentum
map, we study the conditions under which the double process of reducing to the
constraint surface and dividing out by the group of gauge transformations
is equivalent to the single process of dividing out the initial phase space by
the complexification of . For the particular case of a phase space
action that is the lift of a configuration space action, conditions are found
under which, in finite dimensions, the physical phase space of a gauge system
with first-class constraints is diffeomorphic to a manifold imbedded in the
physical configuration space of the complexified gauge system. Similar
conditions are shown to hold in the infinite-dimensional example of Yang-Mills
theories. As a physical application we discuss the adequateness of using
holomorphic Wilson loop variables as (generalized) global coordinates on the
physical phase space of Yang-Mills theory.Comment: 25pp., LaTeX, Syracuse SU-GP-93/6-2, Lisbon DF/IST 6.9
Loop Quantum Gravity: An Inside View
This is a (relatively) non -- technical summary of the status of the quantum
dynamics in Loop Quantum Gravity (LQG). We explain in detail the historical
evolution of the subject and why the results obtained so far are non --
trivial. The present text can be viewed in part as a response to an article by
Nicolai, Peeters and Zamaklar [hep-th/0501114]. We also explain why certain no
go conclusions drawn from a mathematically correct calculation in a recent
paper by Helling et al [hep-th/0409182] are physically incorrect.Comment: 58 pages, no figure
Activated carbons with high nitrogen content by a combination of hydrothermal carbonization with activation
The work was funded by the FCT (Grants PEst-OE/QUI/UI0619/
2011 and SFRH/BD/82696/2011) with National (OE) and European
Union (FEDER, program COMPETE of QREN) funds
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