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A. Nersessian

Publications and source records attributed to A. Nersessian.

At least 19 recordsLinked to original sources

Second Hopf map and supersymmetric mechanics with Yang monopole

We propose to use the second Hopf map for the reduction (via SU(2) group action) of the eight-dimensional N=8 supersymmetric mechanics to five-dimensional supersymmetric systems specified by the presence of an SU(2) Yang monopole. For our purpose we develop the relevant Lagrangian reduction procedure. The reduced system is characterized by its invariance under the N=5 or N=4 supersymmetry generators (with or without an additional conserved BRST charge operator) which commute with the su(2) generators.

hep-th

Cuboctahedric Higgs oscillator from the Calogero model

We exclude the center of mass of the N-particle rational Calogero model and consider the angular part of the resulting Hamiltonian. We show that it describes the motion of the particle on (N-2)-dimensional sphere interacting with N(N-1)/2 force centers with Higgs oscillator potential. In the case of four-particle system these force centers define the vertexes of an Archimedean solid called cuboctahedron.

math-ph

N=4 supersymmetric mechanics with nonlinear chiral supermultiplet

We construct N=4 supersymmetric mechanics using the N=4 nonlinear chiral supermultiplet. The two bosonic degrees of freedom of this supermultiplet parameterize the sphere S(2) and go into the bosonic components of the standard chiral multiplet when the radius of the sphere goes to infinity. We construct the most general action and demonstrate that the nonlinearity of the supermultiplet results in the deformation of the connection, which couples the fermionic degrees of freedom with the background, and of the bosonic potential. Also a non-zero magnetic field could appear in the system.

hep-th

2k-dimensional N=8 supersymmetric quantum mechanics

We demonstrate that two-dimensional N=8 supersymmetric quantum mechanics which inherits the most interesting properties of $N=2, d=4$ SYM can be constructed if the reduction to one dimension is performed in terms of the basic object, i.e. the $N=2, d=4$ vector multiplet. In such a reduction only complex scalar fields from the $N=2, d=4$ vector multiplet become physical bosons in $d=1$, while the rest of the bosonic components are reduced to auxiliary fields, thus giving rise to the {\bf (2, 8, 6)} supermultiplet in $d=1$. We construct the most general action for this supermultiplet with all possible Fayet-Iliopoulos terms included and explicitly demonstrate that the action possesses duality symmetry extended to the fermionic sector of theory. In order to deal with the second--class constraints present in the system, we introduce the Dirac brackets for the canonical variables and find the supercharges and Hamiltonian which form a N=8 super Poincarè algebra with central charges. Finally, we explicitly present the generalization of two-dimensional N=8 supersymmetric quantum mechanics to the $2k$-dimensional case with a special Kähler geometry in the target space.

hep-th

Extended BRST quantization in general coordinates

We propose an extended BRST invariant Lagrangian quantization scheme of general gauge theories based on explicit realization of "modified triplectic algebra" in general coordinates. All the known Lagrangian quantization schemes based on the extended BRST symmetry are obtained by specifying the (free) parameters of that method.

hep-th

D-dimensional massless particle with extended gauge invariance

We propose the model of $D-$dimensional massless particle whose Lagrangian is given by the $N-$th extrinsic curvature of world-line. The system has $N+1$ gauge degrees of freedom constituting $W-$like algebra; the classical trajectories of the model are space-like curves which obey the conditions $k_{N+a}=k_{N-a}$, $k_{2N}=0$, $a=1,...,N-1$, $N\leq[(D-2)/2]$, while the first $N$ curvatures $k_i$ remain arbitrary. We show that the model admits consistent formulation on the anti-De Sitter space. The solutions of the system are the massless irreducible representations of Poincaré group with $N$ nonzero helicities, which are equal to each other.

hep-th

Particle with torsion on 3d null-curves

We consider a (2+1)-dimensional mechanical system with the Lagrangian linear in the torsion of a light-like curve. We give Hamiltonian formulation of this system and show that its mass and spin spectra are defined by one-dimensional nonrelativistic mechanics with a cubic potential. Consequently, this system possesses the properties typical of resonance-like particles.

hep-th

Massive $4d$ particle with torsion and conformal mechanics

The consequences of coupling of the torsion (highest curvature) term to the Lagrangian of a massive spinless particle in four-dimensional space-time are studied. It is shown that the modified system remains spinless and possesses extended gauge invariance. Though the torsion term does not generate spin, it provides the system with a nontrivial mass spectrum, described by one-dimensional conformal mechanics. Under an appropriate choise of characteristic constants the system has solutions with a discrete mass spectrum.

hep-th

Massless particles and the geometry of curves. Classical picture

We analyze the possibility of description of D-dimensional massless particles by the Lagrangians linear on world-line curvatures k_i, {\cal S}=\sum_{i=1}^Nc_i\int k_i d{\tilde s}. We show, that the nontrivial classical solutions of this model are given by space-like curves with zero 2N-th curvature for N\leq[(D-2)/2]. Massless spinning particles correspond to the curves with constant k_{N+a}/k_{N-a} ratio. It is shown that only the system with action {\cal S}=c\int k_N d{\tilde s} leads to irreducible representation of Poincaré group. This system has maximally possible number (N+1) of gauge degrees of freedom. Its classical solutions obey the conditions k_{N+a}=k_{N-a}, a=1,..., N-1, while first N curvatures k_i remain arbitrary. This solution is specified by coinciding N weights of the massless representation of little Lorentz group, while the remaining weights vanish.

hep-th

A geometrical particle model for anyons

We consider the simplest geometrical particle model associated with light-like curves in (2+1)-dimensions. The action is proportional to the pseudo-arc length of the particle's path. We show that under quantization it yields the (2+1)-dimensional anyonic field equation supplemented with a Majorana-like relation on mass and spin, i.e., $mass \times spin =α^2$, with $α$ the coupling constant in front of the action.

hep-th

Supergeometry in Equivariant Cohomology

We analyze $S^1$ equivariant cohomology from the supergeometrical point of view. For this purpose we equip the external algebra of given manifold with equivariant even super(pre)symplectic structure, and show, that its Poincare-Cartan invariant defines equivariant Euler classes of surfaces. This allows to derive localization formulae by use of superanalog of Stockes theorem.

hep-th

The Hamiltonian Formalism for the Generalized Rigid Particles

The Hamiltonian formulation for the mechanical systems with reparametrization-invariant Lagrangians, depending on the worldline external curvatures is given, which is based on the use of moving frame. A complete sets of constraints are found for the Lagrangians with quadratic dependence on curvatures, for the lagrangians, proportional to an arbitrary curvature, and for the Lagrangians, linear on the first and second curvatures.

hep-th

Anyons, Monopole and Coulomb Problem

The monopole systems with hidden symmetry of the two-dimensional Coulomb problem are considered. One of them, the "charge-charged magnetic vortex" with a half-spin, is constructed by reducing the quantum circular oscillator with respect to the action of the parity operator. The other two systems are constructed by reduction from the two-dimensional complex space. The first system is a particle on the sphere in the presence of the exterior constant magnetic field (generated by Dirac's monopole located in its center). This system is dual to the massless (3+1)-dimensional particle with fixed energy. The second system represents the particle on the pseudosphere in the presence of exterior magnetic field and is dual to the massive relativistic anyon.

math-ph

On the Geometry of Relativistic Anyon

A twistor model is proposed for the free relativistic anyon. The Hamiltonian reduction of this model by the action of the spin generator leads to the minimal covariant model; whereas that by the action of spin and mass generators, to the anyon model with free phase space that is a cotangent bundle of the Lobachevsky plane with twisted symplectic structure. Quantum mechanics of that model is described by irreducible representations of the (2+1)-dimensional Poincare' group.

hep-th

A note on quantum Bohlin transformation

It is shown, that the reduction of the circular quantum oscillator by the $Z_2$-group action results to the two systems: a two-dimensional hydrogen atom, and a ``charge - charged magnetic vortex" one, with the spin $\frac 12$. Analogously, the $Z_N$-reduction of the two-dimensional system with the central potential $r^{2(N-1)}$ results into $N$ bound ``charge - magnetic vertex" systems with the interaction potential $r^{2(1/N-1)}$ and spins $σ=\frac kN$, $k =0,1,..., (N-1)$.

hep-th

Quantum oscillator and a bound system of two dyons

It is shown that $U(1)$--Hamiltonian reduction of a four--dimensional isotropic quantum oscillator results in a bound system of two spinless Schwinger's dyons. Its wavefunctions and spectrum are constructed.

hep-th