426 research outputs found
On the equivalence between topologically and non-topologically massive abelian gauge theories
We analyse the equivalence between topologically massive gauge theory (TMGT)
and different formulations of non-topologically massive gauge theories (NTMGTs)
in the canonical approach. The different NTMGTs studied are St\"uckelberg
formulation of (A) a first order formulation involving one and two form fields,
(B) Proca theory, and (C) massive Kalb-Ramond theory. We first quantise these
reducible gauge systems by using the phase space extension procedure and using
it, identify the phase space variables of NTMGTs which are equivalent to the
canonical variables of TMGT and show that under this the Hamiltonian also get
mapped. Interestingly it is found that the different NTMGTs are equivalent to
different formulations of TMGTs which differ only by a total divergence term.
We also provide covariant mappings between the fields in TMGT to NTMGTs at the
level of correlation function.Comment: One reference added and a typos corrected. 15 pages, To appear in
Mod. Phys. Lett.
'Schwinger Model' on the Fuzzy Sphere
In this paper, we construct a model of spinor fields interacting with
specific gauge fields on fuzzy sphere and analyze the chiral symmetry of this
'Schwinger model'. In constructing the theory of gauge fields interacting with
spinors on fuzzy sphere, we take the approach that the Dirac operator on
q-deformed fuzzy sphere is the gauged Dirac operator on fuzzy
sphere. This introduces interaction between spinors and specific one parameter
family of gauge fields. We also show how to express the field strength for this
gauge field in terms of the Dirac operators and alone. Using the path
integral method, we have calculated the point functions of this model and
show that, in general, they do not vanish, reflecting the chiral non-invariance
of the partition function.Comment: Minor changes, typos corrected, 18 pages, to appear in Mod. Phys.
Lett.
Role of oxygen transients in the facile scission of C–O bonds of alcohols on Zn surfaces
The alkoxy species produced by the interaction of alcohols with Zn surfaces undergoes C–O bond scission at 150 K giving hydrocarbon species, but this transformation occurs even at 80 K when alcohol–oxygen mixtures are coadsorbed, due to the oxygen transients
Dual Linearised Gravity in Arbitrary Dimensions
We construct dual formulation of linearised gravity in first order tetrad
formalism in arbitrary dimensions within the path integral framework following
the standard duality algorithm making use of the global shift symmetry of the
tetrad field. The dual partition function is in terms of the (mixed symmetric)
tensor field in {\it frame-like}
formulation. We obtain in d-dimensions the dual Lagrangian in a closed form in
terms of field strength of the dual frame-like field. Next by coupling a source
with the (linear) Riemann tensor in d-dimensions, dual generating functional is
obtained. Using this an operator mapping between (linear) Riemann tensor and
Riemann tensor corresponding to the dual field is derived and we also discuss
the exchange of equations of motion and Bianchi identity.Comment: 14 pages, typos corrected, Published version: Class. Quantum Grav.
22(2005)538
A Review of Noncommutative Field Theories
We present a brief review of selected topics in noncommutative field theories
ranging from its revival in string theory, its influence on quantum field
theories, its possible experimental signatures and ending with some
applications in gravity and emergent gravity.Comment: Talk presented at the XIV Mexican School on Particles and Fields,
Morelia, Mexico, November 9-11, 2010; 8 pages. V2 reference adde
INCOIS-GODAS-MOM: Ocean Analysis for the Indian Ocean: Configuration, Validation and Product Dissemination
The ocean covers approximately 71% of the earth surface and it significantly influences the global and regional climates and the weather and monsoon systems. Climate
variability and its socio-economic impact clearly emphasizes the need to understand the system to enable better forecasts. Unlike land, where the operational networks of meteorological observations placed all over the world have enabled us to monitor changes in the global atmosphere, the global coverage of the subsurface observations in the ocean is largely under sampled. With the advent of Argo and moored buoy programs, there was a
considerable increase in the amount of oceanic data during the last decade. However, the data is still inadequate to understand the dynamics and thermodynamics of the ocean on different spatial and temporal scale
A projective Dirac operator on CP^2 within fuzzy geometry
We propose an ansatz for the commutative canonical spin_c Dirac operator on
CP^2 in a global geometric approach using the right invariant (left action-)
induced vector fields from SU(3). This ansatz is suitable for noncommutative
generalisation within the framework of fuzzy geometry. Along the way we
identify the physical spinors and construct the canonical spin_c bundle in this
formulation. The chirality operator is also given in two equivalent forms.
Finally, using representation theory we obtain the eigenspinors and calculate
the full spectrum. We use an argument from the fuzzy complex projective space
CP^2_F based on the fuzzy analogue of the unprojected spin_c bundle to show
that our commutative projected spin_c bundle has the correct
SU(3)-representation content.Comment: reduced to 27 pages, minor corrections, minor improvements, typos
correcte
Quantum equivalence between the self-dual and the Maxwell-Chern-Simons models nonlinearly coupled to U(1) scalar fields
The use of master actions to prove duality at quantum level becomes
cumbersome if one of the dual fields interacts nonlinearly with other fields.
This is the case of the theory considered here consisting of U(1) scalar fields
coupled to a self-dual field through a linear and a quadratic term in the
self-dual field. Integrating perturbatively over the scalar fields and deriving
effective actions for the self-dual and the gauge field we are able to
consistently neglect awkward extra terms generated via master action and
establish quantum duality up to cubic terms in the coupling constant. The
duality holds for the partition function and some correlation functions. The
absence of ghosts imposes restrictions on the coupling with the scalar fields.Comment: 13 pages, no figure
The Central Charge of the Warped AdS^3 Black Hole
The AdS/CFT conjecture offers the possibility of a quantum description for a
black hole in terms of a CFT. This has led to the study of general AdS^3 type
black holes with a view to constructing an explicit toy quantum black hole
model. Such a CFT description would be characterized by its central charge and
the dimensions of its primary fields. Recently the expression for the central
charges (C_L, C_R) of the CFT dual to the warped AdS^3 have been determined
using asymptotic symmetry arguments. The central charges depend, as expected,
on the warping factor. We show that topological arguments, used by Witten to
constrain central charges for the BTZ black hole, can be generalized to deal
with the warped AdS^3 case. Topology constrains the warped factor to be
rational numbers while quasinormal modes are conjectured to give the dimensions
of primary fields. We find that in the limit when warping is large or when it
takes special rational values the system tends to Witten's conjectured unique
CFT's with central charges that are multiples of 24.Comment: 6 pages, Latex fil
Nitrogen-containing carbon nanotubes
Carbon nanotubes containing small amounts of nitrogen are produced by the pyrolysis of aza-aromatics such as pyridine, methylpyrimidine and triazine over cobalt nanoparticles in an Ar atmosphere; good yields of such nanotubes are obtained by carrying out the pyrolysis of a mixture of pyridine and Fe(CO)5 in flowing Ar+H2
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