arXiv subjects

R. P. Malik

Publications and source records attributed to R. P. Malik.

At least 109 records · Page 6Linked to original sources

arXiv2008

A field-theoretic model for Hodge theory

We demonstrate that the four (3 + 1)-dimensional free Abelian 2-form gauge theory presents a tractable field theoretical model for the Hodge theory where the well-defined symmetry transformations correspond to the de Rham cohomological operators of differential geometry. The conserved charges, corresponding to the above continuous symmetry transformations, obey an algebra that is reminiscent of the algebra obeyed by the cohomological operators. The discrete symmetry transformation of the theory represents the realization of the Hodge duality operation that exists in the relationship between the exterior and co-exterior derivatives of differential geometry. Thus, we provide the realizations of all the mathematical quantities, associated with the de Rham cohomological operators, in the language of the symmetries of the present 4D free Abelian 2-form gauge theory.

hep-th↗

arXiv2008

Nilpotent symmetry invariance in the superfield formulation: the (non-)Abelian 1-form gauge theories

We capture the off-shell as well as the on-shell nilpotent Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetry invariance of the Lagrangian densities of the four (3 + 1)-dimensional (4D) (non-)Abelian 1-form gauge theories within the framework of the superfield formalism. In particular, we provide the geometrical interpretations for (i) the above nilpotent symmetry invariance, and (ii) the above Lagrangian densities, in the language of the specific quantities defined in the domain of the above superfield formalism. Some of the subtle points, connected with the 4D (non-)Abelian 1-form gauge theories, are clarified within the framework of the above superfield formalism where the 4D ordinary gauge theories are considered on the (4, 2)-dimensional supermanifold parametrized by the four spacetime coordinates x^μ(with μ= 0, 1, 2, 3) and a pair of Grassmannian variables θand \barθ. One of the key results of our present investigation is a great deal of simplification in the geometrical understanding of the nilpotent (anti-)BRST symmetry invariance.

hep-th↗

arXiv2008

(Anti-)dual-BRST symmetries: Abelian 2-form gauge theory

We derive the absolutely anticommuting (anti-)dual-BRST symmetry transformations for the appropriate Lagrangian densities of the (3 + 1)-dimensional (4D) free Abelian 2-form gauge theory, under which, the total gauge-fixing term remains invariant. These symmetry transformations are the analogue of the co-exterior derivative of differential geometry, in the same sense, as the absolutely anticommuting (anti-)BRST symmetry transformations are the analogue of the exterior derivative. A bosonic symmetry transformation is shown to be the analogue of the Laplacian operator. The algebraic structures of these symmetry transformations are derived and they are demonstrated to be the reminiscent of the algebra obeyed by the de Rham cohomological operators of differential geometry.

hep-th↗

arXiv2008

Free Abelian 2-Form Gauge Theory: BRST Approach

We discuss various symmetry properties of the Lagrangian density of a four (3 + 1)-dimensional (4D) free Abelian 2-form gauge theory within the framework of Becchi-Rouet-Stora-Tyutin (BRST) formalism. The present free Abelian gauge theory is endowed with a Curci-Ferrari type condition which happens to be a key signature of the 4D non-Abelian 1-form gauge theory. In fact, it is due to the above condition that the nilpotent BRST and anti-BRST symmetries of the theory are found to be absolutely anticommuting in nature. For our present 2-form gauge theory, we discuss the BRST, anti-BRST, ghost and discrete symmetry properties of the Lagrangian densities and derive the corresponding conserved charges. The algebraic structure, obeyed by the above conserved charges, is deduced and the constraint analysis is performed with the help of the physicality criteria where the conserved and nilpotent (anti-)BRST charges play completely independent roles. These physicality conditions lead to the derivation of the above Curci-Ferrari type restriction, within the framework of BRST formalism, from the constraint analysis.

hep-th↗

arXiv2007

One-Form Abelian Gauge Theory As The Hodge Theory

We demonstrate that the two (1 + 1)-dimensional (2D) free 1-form Abelian gauge theory provides an interesting field theoretical model for the Hodge theory. The physical symmetries of the theory correspond to all the basic mathematical ingredients that are required in the definition of the de Rham cohomological operators of differential geometry. The conserved charges, corresponding to the above continuous symmetry transformations, constitute an algebra that is reminiscent of the algebra obeyed by the de Rham cohomological operators. The topological features of the above theory are discussed in terms of the BRST and co-BRST operators. The super de Rham cohomological operators are exploited in the derivation of the nilpotent (anti-)BRST, (anti-)co-BRST symmetry transformations and the equations of motion for all the fields of the theory, within the framework of the superfield formulation. The derivation of the equations of motion, by exploiting the super Laplacian operator, is a completely new result in the framework of the superfield approach to BRST formalism. In an Appendix, the interacting 2D Abelian gauge theory (where there is a coupling between the U(1) gauge field and the Dirac fields) is also shown to provide a tractable field theoretical model for the Hodge theory.

hep-th↗

arXiv2007

Noncommutativity In A Simple Toy Model

We discuss various symmetry properties of the reparametrization invariant toy model of a free non-relativistic particle and show that its commutativity and noncommutativity (NC) properties are the artifact of the underlying symmetry transformations. For the case of the symmetry transformations corresponding to the noncommutative geometry, the mass parameter of the toy model turns out to be noncommutative in nature. By exploiting the Becchi-Rouet-Stora-Tyutin (BRST) symmetry transformations, we demonstrate the existence of the NC and show its cohomological equivalence with its commutative counterpart. A connection between the usual gauge symmetry transformations corresponding to the commutative geometry and the quantum groups, defined on the phase space, is also established for the present model at the level of Poisson bracket structure. We show that, for the NC geometry, such a kind of quantum group connection does not exist.

hep-th↗

arXiv2007

An Alternative To The Horizontality Condition In Superfield Approach To BRST Symmetries

We provide an alternative to the gauge covariant horizontality condition which is responsible for the derivation of the nilpotent (anti-)BRST symmetry transformations for the gauge and (anti-)ghost fields of a (3 + 1)-dimensional (4D) interacting 1-form non-Abelian gauge theory in the framework of the usual superfield approach to Becchi-Rouet-Stora-Tyutin (BRST) formalism. The above covariant horizontality condition is replaced by a gauge invariant restriction on the (4, 2)-dimensional supermanifold, parameterized by a set of four spacetime coordinates x^μ(μ= 0, 1, 2, 3) and a pair of Grassmannian variables θand \barθ. The latter condition enables us to derive the nilpotent (anti-)BRST symmetry transformations for all the fields of an interacting 4D 1-form non-Abelian gauge theory where there is an explicit coupling between the gauge field and the Dirac fields. The key differences and striking similarities between the above two conditions are pointed out clearly.

hep-th↗

arXiv2007

A Generalization Of The Horizontality Condition In The Superfield Approach To Nilpotent Symmetries For QED With Complex Scalar Fields

We provide a generalization of the horizontality condition of the usual superfield approach to Becchi-Rouet-Stora-Tyutin (BRST) formalism to obtain the nilpotent (anti-)BRST symmetry transformations for all the fields of a four (3 + 1)-dimensional interacting 1-form U(1) gauge theory (QED) within the framework of the augmented superfield formalism. In the above interacting gauge theory, there is an explicit coupling between the 1-form U(1) gauge field and the complex scalar fields. This interacting gauge theory is considered on the (4, 2)-dimensional supermanifold parametrized by the four even spacetime variables x^μ(with μ= 0, 1, 2, 3) and a pair of odd Grassmannian variables θand \barθ. The above (anti-)BRST symmetry transformations are obtained due to the imposition of a gauge (i.e. BRST) invariant restriction on the (4, 2)-dimensional supermanifold. This restriction owes its origin to the (super) covariant derivatives and their intimate connections with the 2-form (super) curvatures. The results obtained, due to the application of the horizontality condition alone, are contained in the results obtained due to the imposition of the gauge (i.e. BRST) invariant restriction on the above supermanifold.

hep-th↗

arXiv2007

Interacting Relativistic Particle: Time-Space Noncommutativity And Symmetries

We discuss the symmetry properties of the reparametrization invariant model of an interacting relativistic particle where the electromagnetic field is taken as the constant background field. The direct coupling between the relativistic particle and the electromagnetic {\it gauge} field is a special case of the above with a specific set of subtleties involved in it. For the above model, we demonstrate the existence of a time-space noncommutativity (NC) in the spacetime structure from the symmetry considerations alone. We further show that the NC and commutativity properties of this model are different aspects of a unique continuous {\it gauge} symmetry that is derived from the non-standard gauge-type symmetry transformations by requiring their consistency with (i) the equations of motion, and (ii) the expressions for the canonical momenta, derived from the Lagrangians. We provide a detailed discussion on the noncommutative deformation of the Poincar{é} algebra.

hep-th↗

arXiv2007

Augmented Superfield Approach To Unique Nilpotent Symmetries For Complex Scalar Fields In QED

The derivation of the exact and unique nilpotent Becchi-Rouet-Stora-Tyutin (BRST)- and anti-BRST symmetries for the matter fields, present in any arbitrary interacting gauge theory, has been a long-standing problem in the framework of superfield approach to BRST formalism. These nilpotent symmetry transformations are deduced for the four (3 + 1)-dimensional (4D) complex scalar fields, coupled to the U(1) gauge field, in the framework of augmented superfield formalism. This interacting gauge theory (i.e. QED) is considered on a six (4, 2)-dimensional supermanifold parametrized by four even spacetime coordinates and a couple of odd elements of the Grassmann algebra. In addition to the horizontality condition (that is responsible for the derivation of the exact nilpotent symmetries for the gauge field and the (anti-)ghost fields), a new restriction on the supermanifold, owing its origin to the (super) covariant derivatives, has been invoked for the derivation of the exact nilpotent symmetry transformations for the matter fields. The geometrical interpretations for all the above nilpotent symmetries are discussed, too.

hep-th↗

arXiv2006

Gauge Transformations, BRST Cohomology and Wigner's Little Group

We discuss the (dual-)gauge transformations and BRST cohomology for the two (1 + 1)-dimensional (2D) free Abelian one-form and four (3 + 1)-dimensional (4D) free Abelian 2-form gauge theories by exploiting the (co-)BRST symmetries (and their corresponding generators) for the Lagrangian densities of these theories. For the 4D free 2-form gauge theory, we show that the changes on the antisymmetric polarization tensor e^{μν} (k) due to (i) the (dual-)gauge transformations corresponding to the internal symmetry group, and (ii) the translation subgroup T(2) of the Wigner's little group, are connected with each-other for the specific relationships among the parameters of these transformation groups. In the language of BRST cohomology defined w.r.t. the conserved and nilpotent (co-)BRST charges, the (dual-)gauge transformed states turn out to be the sum of the original state and the (co-)BRST exact states. We comment on (i) the quasi-topological nature of the 4D free 2-form gauge theory from the degrees of freedom count on e^{μν} (k), and (ii) the Wigner's little group and the BRST cohomology for the 2D one-form gauge theory {\it vis-{à}-vis} our analysis for the 4D 2-form gauge theory.

hep-th↗

arXiv2006

Superfield Approach To Exact And Unique Nilpotent Symmetries

In the framework of usual superfield approach, we derive the exact local, covariant, continuous and off-shell nilpotent Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetry transformations for the U(1) gauge field (A_μ) and the (anti-)ghost fields ((\bar C)C) of the Lagrangian density of a four (3 + 1)-dimensional QED by exploiting the horizontality condition defined on the six (4, 2)-dimensional supermanifold. The long-standing problem of the exact derivation of the above nilpotent symmetry transformations for the matter (Dirac) fields (\bar ψ, ψ), in the framework of superfield formulation, is resolved by a new restriction on the (4, 2)-dimensional supermanifold. This new gauge invariant restriction on the supermanifold, due to the augmented superfield formalism, owes its origin to the (super) covariant derivatives. The geometrical interpretations for all the above off-shell nilpotent transformations are provided in the framework of augmented superfield formalism.

hep-th↗

arXiv2006

Superfield Approach To Nilpotent Symmetries For QED From A Single Restriction: An Alternative To The Horizontality Condition

We derive together the exact local, covariant, continuous and off-shell nilpotent Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetry transformations for the U(1) gauge field (A_μ), the (anti-)ghost fields ((\bar C)C) and the Dirac fields (ψ, \barψ) of the Lagrangian density of a four (3 + 1)-dimensional QED by exploiting a single restriction on the six (4, 2)-dimensional supermanifold. A set of four even spacetime coordinates x^μ(μ= 0, 1, 2, 3) and two odd Grassmannian variables θand \barθparametrize this six dimensional supermanifold. The new gauge invariant restriction on the above supermanifold owes its origin to the (super) covariant derivatives and their intimate relations with the (super) 2-form curvatures (\tilde F^{(2)})F^{(2)} constructed with the help of (super) 1-form gauge connections (\tilde A^{(1)})A^{(1)} and (super) exterior derivatives (\tilde d)d. The results obtained separately by exploiting (i) the horizontality condition, and (ii) one of its consistent extensions, are shown to be a simple consequence of this new single restriction on the above supermanifold. Thus, our present endeavour provides an alternative to (and, in some sense, generalization of) the horizontality condition of the usual superfield formalism applied to the derivation of BRST symmetries.

hep-th↗

arXiv2006

Unique Nilpotent Symmetry Transformations For Matter Fields In QED: Augmented Superfield Formalism

We derive the local, covariant, continuous, anticommuting and off-shell nilpotent (anti-)BRST symmetry transformations for the interacting U(1) gauge theory of quantum electrodynamics (QED) in the framework of augmented superfield approach to BRST formalism. In addition to the horizontality condition, we invoke another gauge invariant condition on the six (4, 2)-dimensional supermanifold to obtain the exact and unique nilpotent symmetry transformations for all the basic fields, present in the (anti-)BRST invariant Lagrangian density of the physical four (3 + 1)-dimensional QED. The above supermanifold is parametrized by four even spacetime variables x^μ(with μ= 0, 1, 2, 3) and a couple of odd variables (θand \barθ) of the Grassmann algebra. The new gauge invariant condition on the supermanifold owes its origin to the (super) covariant derivatives and leads to the derivation of unique nilpotent symmetry transformations for the matter fields. The geometrical interpretations for all the above off-shell nilpotent transformations are discussed, too.

hep-th↗

arXiv2006

Augmented Superfield Approach To Exact Nilpotent Symmetries For Matter Fields In Non-Abelian Theory

We derive the nilpotent (anti-)BRST symmetry transformations for the Dirac (matter) fields of an interacting four (3+1)-dimensional 1-form non-Abelian gauge theory by applying the theoretical arsenal of augmented superfield formalism where (i) the horizontality condition, and (ii) the equality of a gauge invariant quantity, on the six (4, 2)-dimensional supermanifold, are exploited together. The above supermanifold is parameterized by four bosonic spacetime coordinates x^μ(with μ= 0,1,2,3) and a couple of Grassmannian variables θand \barθ. The on-shell nilpotent BRST symmetry transformations for all the fields of the theory are derived by considering the chiral superfields on the five (4, 1)-dimensional super sub-manifold and the off-shell nilpotent symmetry transformations emerge from the consideration of the general superfields on the full six (4, 2)-dimensional supermanifold. Geometrical interpretations for all the above nilpotent symmetry transformations are also discussed in the framework of augmented superfield formalism.

hep-th↗

arXiv2006

Hodge Duality Operation And Its Physical Applications On Supermanifolds

An appropriate definition of the Hodge duality $\star$ operation on any arbitrary dimensional supermanifold has been a long-standing problem. We define a working rule for the Hodge duality $\star$ operation on the $(2 + 2)$-dimensional supermanifold parametrized by a couple of even (bosonic) spacetime variables $x^μ(μ= 0, 1)$ and a couple of Grassmannian (odd) variables $θ$ and $\barθ$ of the Grassmann algebra. The Minkowski spacetime manifold, hidden in the supermanifold and parametrized by $x^μ(μ= 0, 1)$, is chosen to be a flat manifold on which a two $(1 + 1)$-dimensional (2D) free Abelian gauge theory, taken as a prototype field theoretical model, is defined. We demonstrate the applications of the above definition (and its further generalization) for the discussion of the (anti-)co-BRST symmetries that exist for the field theoretical models of 2D- (and 4D) free Abelian gauge theories considered on the four $(2 + 2)$- (and six $(4 + 2)$)-dimensional supermanifolds, respectively.

hep-th↗

arXiv2005

Nilpotent Symmetries For Matter Fields In Non-Abelian Gauge Theory: Augmented Superfield Formalism

In the framework of superfield approach to Becchi-Rouet-Stora-Tyutin (BRST) formalism, the derivation of the (anti-)BRST nilpotent symmetries for the matter fields, present in any arbitrary interacting gauge theory, has been a long-standing problem. In our present investigation, the local, covariant, continuous and off-shell nilpotent (anti-)BRST symmetry transformations for the Dirac fields $(ψ, \barψ)$ are derived in the framework of the augmented superfield formulation where the four $(3 + 1)$-dimensional (4D) interacting non-Abelian gauge theory is considered on the six $(4 + 2)$-dimensional supermanifold parametrized by the four even spacetime coordinates $x^μ$ and a couple of odd elements ($θ$ and $\barθ$) of the Grassmann algebra. The requirement of the invariance of the matter (super)currents and the horizontality condition on the (super)manifolds leads to the derivation of the nilpotent symmetries for the matter fields as well as the gauge- and the (anti-)ghost fields of the theory in the general scheme of the augmented superfield formalism.

hep-th↗

arXiv2005

Nilpotent Symmetries For A Spinning Relativistic Particle In Augmented Superfield Formalism

The local, covariant, continuous, anticommuting and nilpotent Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetry transformations for all the fields of a (0 + 1)-dimensional spinning relativistic particle are obtained in the framework of augmented superfield approach to BRST formalism. The trajectory of this super-particle is parametrized by a monotonically increasing parameter τthat is embedded in a D-dimensional flat Minkowski spacetime manifold. This physically useful one-dimensional system is considered on a three (1 + 2)-dimensional supermanifold which is parametrized by an even element τand a couple of odd elements θand \barθof the Grassmann algebra. Two anticommuting sets of (anti-)BRST symmetry transformations, corresponding to the underlying (super)gauge symmetries for the above system, are derived in the framework of augmented superfield formulation where (i) the horizontality condition, and (ii) the invariance of conserved quantities on the supermanifold, play decisive roles. Geometrical interpretations for the above nilpotent symmetries (and their generators) are provided.

hep-th↗