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Subir Ghosh

Publications and source records attributed to Subir Ghosh.

At least 127 records · Page 7Linked to original sources
arXiv2002

Covariantly Quantized Spinning Particle and its Possible Connection to Non-Commutative Space-Time

Covariant quantization of the Nambu-Goto spinning particle in 2+1-dimensions is studied. The model is relevant in the context of recent activities in non-commutative space-time. From a technical point of view also covariant quantization of the model poses an interesting problem: the set of second class constraints (in the Dirac classification scheme) is {\it reducible}. The reducibility problem is analyzed from two contrasting approaches: (i) the auxiliary variable method [bn] and (ii) the projection operator method [blm]. Finally in the former scheme, a Batalin-Tyutin quantization has been done. This induces a mapping between the non-commutative and the ordinary space-time. BRST quantization programme in the latter scheme has also been discussed.

hep-th↗
arXiv2002

Noncommutativity in open string: New results in a gauge independent analysis

Noncommutativity in an open string moving in a background Neveu-Schwarz field is investigated in a gauge independent Hamiltonian approach, leading to new results. The noncommutativity is shown to be a direct consequence of the non-trivial boundary conditions, which, contrary to several approaches, are not treated as constraints. We find that the noncommutativity persists for all string points. In the conformal gauge our results reduce to the usual noncommutativity at the boundaries only.

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arXiv2002

Seiberg Witten Map and the Axial Anomaly in Noncommutative Field Theory

Using the point-splitting regularisation, we calculate the axial anomaly in an arbitrary even dimensional Non-Commutative (NC) field theory. Our result is (star) gauge invariant in its {\it unintegrated} form, to the leading order in the NC parameter. Exploiting the Seiberg Witten map, this result gets transformed to the familiar Adler-Bell-Jackiw anomaly in ordinary space-time. Furthermore, using this map, we derive an expression for the unintegrated axial anomaly for constant fields in NC space-time, that is valid to all finite orders of the NC parameter.

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arXiv2001

Integrability in Fluid Dynamics

3+1-dimensional free inviscid fluid dynamics is shown to satisfy the criteria for exact integrability, i.e. having an infinite set of independent, conserved quantities in involution, with the Hamiltonian being one of them. With (density dependent) interaction present, distinct infinite serieses of conserved quantities in involution are discovered. Clebsch parametrization of the velocity field is used in the the latter analysis. Relativistic generalization of the free system is also shown to be integrable.

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arXiv2001

Unified Study of Planar Field Theories

A "Master" gauge theory is constructed in 2+1-dimensions through which various gauge invariant and gauge non-invariant theories can be studied. In particular, Maxwell-Chern-Simons, Maxwell-Proca and Maxwell-Chern-Simons -Proca models are considered here. The Master theory in an enlarged phase space is constructed both in Lagrangian (Stuckelberg) and Hamiltonian (Batalin-Tyutin) frameworks, the latter being the more general one, which includes the former as a special case. Subsequently, BRST quantization of the latter is performed. Lastly, the master Lagrangian, constructed by Deser and Jackiw (Phys. Lett. B139, (1984) 371), to show the equivalence between the Maxwell-Chern-Simons and the self-dual model, is also reproduced from our Batalin-Tyutin extended model. Symplectic quantization procedure for constraint systems is adopted in the last demonstration.

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arXiv2001

Batalin-Tyutin Quantisation of the Spinning Particle Model

The Spinning Particle Model for anyon is analysed in the Batalin-Tyutin scheme of quantisation in extended phase space. Here additional degrees of freedom are introduced in the phase space such that all the constraints in the theory are rendered First Class that is commuting in the sense of Poisson Brackets. Thus the theory can be studied without introducing the Dirac Brackets which appear in the presence of non-commuting or Second Class constraints. In the present case the Dirac Brackets make the configuration space of the anyon non-canonical and also being dynamical variable dependent, poses problems for the quantisation programme. We show that previously obtained results, (e.g. gyromagnetic ratio of anyon being 2), are recovered in the Batalin-Tyutin variable independent sector in the extended space. The Batalin-Tyutin variable contributions are significant and are computable in a straightforward manner. The latter can beunderstood as manifestations of the non-commutative space-time in the enlarged phase space.

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arXiv2001

Gauge Theoretic Approach to Fluid Dynamics

The Hamiltonian dynamics of a compressible inviscid fluid is formulated as a gauge theory. The idea of gauge equivalence is exploited to unify the study of apparantly distinct physical problems and solutions of new models can be generated from known fluid velocity profiles.

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arXiv2001

$CP^{1}$ model with Hopf interaction: the quantum theory

The $CP^1$ model with Hopf interaction is quantised following the Batalin-Tyutin (BT) prescription. In this scheme, extra BT fields are introduced which allow for the existence of only commuting first-class constraints. Explicit expression for the quantum correction to the expectation value of the energy density and angular momentum in the physical sector of this model is derived. The result shows, in the particular operator ordering that we have chosen to work with, that the quantum effect has a divergent contribution of $ {\cal O} (\hbar^2)$ in the energy expectation value. But, interestingly the Hopf term, though topological in nature, can have a finite ${\cal O} (\hbar)$ contribution to energy density in the homotopically nontrivial topological sector. The angular momentum operator, however, is found to have no quantum correction, indicating the absence of any fractional spin even at this quantum level. Finally, the extended Lagrangian incorporating the BT auxiliary fields is computed in the conventional framework of BRST formalism exploiting Faddeev-Popov technique of path integral method.

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arXiv2000

Canonical transformations and soldering

We show that the recently developed soldering formalism in the Lagrangian approach and canonical transformations in the Hamiltonian approach are complementary. The examples of gauged chiral bosons in two dimensions and self-dual models in three dimensions are discussed in details.

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arXiv1999

Self-interaction effects on screening in three-dimensional QED

We have shown that self interaction effects in massive quantum electrodynamics can lead to the formation of bound states of quark antiquark pairs. A current-current fermion coupling term is introduced, which induces a well in the potential energy profile. Explicit expressions of the effective potential and renormalized parameters are provided.

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arXiv1999

Three Dimensional Gauge Theory with Topological and Non-topological Mass: Hamiltonian and Lagrangian Analysis

Three dimensional (abelian) gauged massive Thirring model is bosonized in the large fermion mass limit. A further integration of the gauge field results in a non-local theory. A truncated version of that is the Maxwell Chern Simons (MCS) theory with a conventional mass term or MCS Proca theory. This gauge invariant theory is completely solved in the Hamiltonian and Lagrangian formalism, with the spectra of the modes determined. Since the vector field constituting the model is identified (via bosonization) to the fermion current, the charge current algebra, including the Schwinger term is also computed in the MCS Proca model.

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arXiv1999

Bosonization and Duality in 2+1-Dimensions: Applications in Gauged Massive Thirring Model

Bosonization of the gauged, massive Thirring model in 2+1-dimensions produces a Maxwell-Chern-Simons gauge theory, coupled to a dynamical, massive vector field. Exploiting the Master Lagrangian formalism, two dual theories are constructed, one of them being a gauge theory. The full two-point functions of both the interacting fields are computed in the path integral quantization scheme. Furthermore, some new dual models, derived from the original master lagrangian and valid for different regimes of coupling parameters, are constructed and analysed in details.

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arXiv1998

Bosonisation Excercise in Three Dimensions: Gauged Massive Thirring Model

Bosonisation of the massive Thirring model, with a non-minimal and non-abelian gauging is studied in 2+1-dimensions. The static abelian model is solved completely in the large fermion mass limit and the spectrum is obtained. The non-abelian model is solved for a restricted class of gauge fields. In both cases explicit expressions for bosonic currents corresponding to the fermion currents are given.

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arXiv1997

Anyon Zitterbewegung

A new model for anyon is proposed, which exhibits the classical analogue of the quantum phenomenon - Zitterbewegung. The model is derived from existing spinning particle model and retains the essential features of anyon in the non-relativistic limit.

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arXiv1997

Planar Two-particle Coulomb Interaction: Classical and Quantum Aspects

The classical and quantum aspects of planar Coulomb interactions have been studied in detail. In the classical scenario, Action Angle Variables are introduced to handle relativistic corrections, in the scheme of time-independent perturbation theory. Complications arising due to the logarithmic nature of the potential are pointed out. In the quantum case, harmonic oscillator approximations are considered and effects of the perturbations on the excited (oscillator) states have been analysed. In both the above cases, the known 3+1-dimensional analysis is carried through side by side, for a comparison with the 2+1-dimensional (planar) results.

hep-th↗
arXiv1997

Screening in Anyon Gas

Anyon gas with interparticle (retarded) Coulomb interaction has been studied. The resulting system is shown to be a collection of dressed anyons, with a screening factor introduced in their spin. Close structural similarity with the Chern-Simons construction of anyons has helped considerably in computing the screening effect. Finally the present model is compared with the conventional Chern-Simons construction.

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arXiv1996

On the Vortex-Point Charge Composite: Classical Orbits and Quantum Bound States

The possibility of composite systems arising out of a point charge interacting with a Nielsen-Olesen vortex in 2+1-dimensions is investigated. It is shown that classical bounded orbits are possible for certain ranges of parameters. Long lived metastable states are shown to exist, in a semi-classical approach, from the study of the effective potential. Loss of self-adjointness of the Hamiltonian and its subsequent self-adjoint extension in some cases leads to bound states.

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