arXiv subjects

Prasanta K. Panigrahi

Publications and source records attributed to Prasanta K. Panigrahi.

285 records · Page 16Linked to original sources

arXiv2003

A Unified Algebraic Approach to Few and Many-Body Correlated Systems

The present article is an extended version of the paper {\it Phys. Rev.} {\bf B 59}, R2490 (1999), where, we have established the equivalence of the Calogero-Sutherland model to decoupled oscillators. Here, we first employ the same approach for finding the eigenstates of a large class of Hamiltonians, dealing with correlated systems. A number of few and many-body interacting models are studied and the relationship between their respective Hilbert spaces, with that of oscillators, is found. This connection is then used to obtain the spectrum generating algebras for these systems and make an algebraic statement about correlated systems. The procedure to generate new solvable interacting models is outlined. We then point out the inadequacies of the present technique and make use of a novel method for solving linear differential equations to diagonalize the Sutherland model and establish a precise connection between this correlated system's wave functions, with those of the free particles on a circle. In the process, we obtain a new expression for the Jack polynomials. In two dimensions, we analyze the Hamiltonian having Laughlin wave function as the ground-state and point out the natural emergence of the underlying linear $W_{1+\infty}$ symmetry in this approach.

cond-mat↗

arXiv2002

A Study of Quantum Many-Body Systems With Nearest And Next-to-Nearest Neighbour Long-Range Interactions

The scattering and bound states of the many-body systems, related to the short-range Dyson model, are studied. First, we show that the scattering states can be realized as coherent states and the scattering Hamiltonian can be connected to a free system. Unlike the closely related Calogero-Moser model, only a part of the partial waves acquire energy independent phase shifts, after scattering. The cause of the same is traced to the reduction in the degeneracies. The bound state Hamiltonian for the full-line problem is also studied and the relationship of its Hilbert space with that of the decoupled oscillators elucidated. Finally, we analyze the related models on circle and construct a part of the excitation spectrum through symmetry arguments.

cond-mat.str-el↗

arXiv2002

Solving Single and Many-body Quantum Problems: A Novel Approach

A unified approach, for solving a wide class of single and many-body quantum problems, commonly encountered in literature is developed based on a recently proposed method for finding solutions of linear differential equations. Apart from dealing with exactly and quasi-exactly solvable problems, the present approach makes transparent various properties of the familiar orthogonal polynomials and also the construction of their respective ladder operators. We illustrate the procedure for finding the approximate eigenvalues and eigenfunctions of non-exactly solvable problems.

quant-ph↗

arXiv2002

Linear Differential Equations and Orthogonal Polynomials: A Novel Approach

A novel method, connecting the space of solutions of a linear differential equation, of arbitrary order, to the space of monomials, is used for exploring the algebraic structure of the solution space. Apart from yielding new expressions for the solutions of the known differential equations, the procedure enables one to derive various properties of the orthogonal polynomials and functions, in a unified manner. The method of generalization of the present approach to the multi-variate case is pointed out and also its connection with the well-known factorization technique. It is shown that, the generating functions and Rodriguez formulae emerge naturally in this method.

math-ph↗

arXiv1999

Free harmonic oscillators, Jack polynomials and Calogero-Sutherland systems

The algebraic structure and the relationships between the eigenspaces of the Calogero-Sutherland model (CSM) and the Sutherland model (SM) on a circle are investigated through the Cherednik operators. We find an exact connection between the simultaneous non-symmetric eigenfunctions of the $A_{N-1}$ Cherednik operators, from which the eigenfunctions of the CSM and SM are constructed, and the monomials. This construction, not only, allows one to write down a harmonic oscillator algebra involving the Cherednik operators, which yields the raising and lowering operators for both of these models, but also shows the connection of the CSM with free oscillators and the SM with free particles on a circle. We also point out the subtle differences between the excitations of the CSM and the SM.

hep-th↗

arXiv1999

Equivalence of the Sutherland Model to Free Particles on a Circle

A method is developed to construct the solutions of one and many variable, linear differential equations of arbitrary order. Using this, the $N$-particle Sutherland model, with pair-wise inverse sine-square interactions among the particles, is shown to be equivalent to free particles on a circle. Applicability of our method to many other few and many-body problems is also illustrated.

hep-th↗

arXiv1999

A novel realization of the Calogero-Moser scattering states as coherent states

A novel realization is provided for the scattering states of the $N$-particle Calogero-Moser Hamiltonian. They are explicitly shown to be the coherent states of the singular oscillators of the Calogero-Sutherland model. Our algebraic treatment is straightforwardly extendable to a large number of few and many-body interacting systems in one and higher dimensions.

quant-ph↗

arXiv1999

Quantum equivalent of the Bertrand's theorem

A procedure for constructing bound state potentials is given. We show that, under the natural conditions imposed on a radial eigenvalue problem, the only special cases of the general central potential, which are exactly solvable and have infinite number of energy eigenvalues, are the Coulomb and harmonic oscillator potentials.

quant-ph↗

arXiv1999

Compacton-like Solutions for Modified KdV and other Nonlinear Equations

We present compacton-like solution of the modified KdV equation and compare its properties with those of the compactons and solitons. We further show that, the nonlinear Schr{ö}dinger equation with a source term and other higher order KdV-like equations also possess compact solutions of the similar form.

solv-int↗

arXiv1999

A Unified Algebraic Approach to Few and Many-Body Hamiltonians having Linear Spectra

We develop an algebraic approach for finding the eigenfunctions of a large class of few and many-body Hamiltonians, in one and higher dimensions, having linear spectra. The method presented enables one to exactly map these interacting Hamiltonians to decoupled oscillators, thereby, giving a precise correspondence between the oscillator eigenspace and the wavefunctions of these quantum systems. The symmetries behind the degeneracy structure and the commuting constants of motion responsible for the quantum integrability of some of these models are made transparent. Apart from analysing a number of well-known dynamical systems like planar oscillators with commensurate frequencies, both with or without singular inverse-square terms and generalized Calogero-Sutherland type models, we also point out a host of other examples where the present approach can be profitably employed. We further study Hamiltonians having Laughlin wavefunction as the ground-state and establish their equivalence to free oscillators. This reveals the underlying linear $W_{1+\infty}$ symmetry algebra unambiguously and establishes the Laughlin wavefunction as the highest weight vector of this algebra.

cond-mat↗

arXiv1997

Degeneracy Structure of the Calogero-Sutherland Model: an Algebraic Approach

The degeneracy structure of the eigenspace of the N-particle Calogero-Sutherland model is studied from an algebraic point of view. Suitable operators satisfying SU(2) algebras and acting on the degenerate eigenspace are explicitly constructed for the two particle case and then appropriately generalized to the N-particle model. The raising and lowering operators of these algebras connect the states, in a subset of the degenerate eigenspace, with each other.

hep-th↗

arXiv1995

Laughlin Wave Function and One-Dimensional Free Fermions

Making use of the well-known phase space reduction in the lowest Landau level(LLL), we show that the Laughlin wave function for the $ν= {1\over m}$ case can be obtained exactly as a coherent state representation of an one dimensional $(1D)$ wave function. The $1D$ system consists of $m$ copies of free fermions associated with each of the $N$ electrons, confined in a common harmonic well potential. Interestingly, the condition for this exact correspondence is found to incorporate Jain's parton picture. We argue that, this correspondence between the free fermions and quantum Hall effect is due to the mapping of the $1D$ system under consideration, to the Gaussian unitary ensemble in the random matrix theory.

cond-mat↗

arXiv1994

$B \wedge F$ Term by Spontaneous Symmetry Breaking in a generalized Abelian Higgs Model

We show that the topological $B \wedge F$ term in $3+1$ dimensions can be generated via spontaneous symmetry breaking in a generalized Abelian Higgs model. Further, we also show that even in $D$ dimensions $ ( D \geq 3 ) $, a $B \wedge F$ term gives rise to the topological massive excitations of the Abelian gauge field and that such a $B \wedge F$ term can also be generated via Higgs mechanism.

hep-th↗

arXiv1993

Inter-Relations of Solvable Potentials

Solvable Natanzon potentials in nonrelativistic quantum mechanics are known to group into two disjoint classes depending on whether the Schrödinger equation can be reduced to a hypergeometric or a confluent hypergeometric equation. All the potentials within each class are connected via point canonical transformations. We establish a connection between the two classes with appropriate limiting procedures and redefinition of parameters, thereby inter-relating all known solvable potentials.

hep-th↗

arXiv1993

An Alternate Approach to Transition Potentials

We analyze transition potentials $(V(r) \stackrel{r\sim 0}{\rightarrow} {αr^{-2}})$ in non-relativistic quantum mechanics using the techniques of supersymmetry. For the range $-1/4 < α< 3/4$, the eigenvalue problem becomes ill-defined (since it is not possible to choose a unique eigenfunction based on square integrability and boundary conditions). It is shown that supersymmetric quantum mechanics (SUSYQM) provides a natural prescription for a unique determination of the spectrum. Interestingly, our SUSYQM based approach picks out the same "less singular" wave functions as the conventional approach, and thus provides a simple justification for the usual practice in the literature. Two examples (the Pöschl-Teller II potential and a two anyon system on the plane) have been worked out for illustrative purposes.

hep-th↗