Susil Parida - Academia.edu (original) (raw)

Papers by Susil Parida

$Research paper thumbnail of Generation and characterization in a laboratory of C^{2}⊗C^{d} states of flying electrons and ions with negative or positive partial transpose possessing free or bound entanglement$

Generation and characterization in a laboratory of C^{2}⊗C^{d} states of flying electrons and ions with negative or positive partial transpose possessing free or bound entanglement

Physical Review A, 2012

ABSTRACT In this paper, we show that bipartite states of an electronic qubit and ionic qudit, pro... more ABSTRACT In this paper, we show that bipartite states of an electronic qubit and ionic qudit, produced in a laboratory in as simple an experiment as photoionization in electric dipole approximation, can be separable or can possess either free or bound entanglement. The dimension of the Hilbert space of the qudit depends upon the electronic state |1+〉 of the residual photoion A1+: In the absence of spin-orbit interaction (SOI), when Russell-Saunders coupling is applicable, it is equal to the spin multiplicity of |1+〉, but becomes (2J+1) in j-j coupling, where J is the total angular momentum of |1+〉 when SOI is taken into account. In the case of L-S coupling, all the properties (relevant to a study in quantum information) of a qubit-qudit state can readily be predicted merely with a knowledge of the spins of the atomic target and of the residual photoion which can experimentally be verified by measuring them using an entanglement witness, or any other such protocols, or by doing a full quantum-state tomography.

Physical Review A, 2009

A scheme for generating states of three free electrons entangled with respect to their spins is s... more A scheme for generating states of three free electrons entangled with respect to their spins is suggested. It consists of sequential ejection of two Auger electrons ͑e 2 and e 3 ͒ in the nonradiative decay of an inner-shell vacancy created due to the emission of photoelectron e 1 from an atom, say A. In the absence of spin-orbit interaction, the entanglement among the spin angular momenta of the flying ͑e 1 , e 2 , e 3 ͒ is generated simply by the Coulomb interaction experienced by them inside A. Their states are classified according to the hierarchic structure suggested by Dür, Cirac, and Tarrach ͓Phys. Rev. Lett. 83, 3562 ͑1999͒; Dür and Cirac, Phys. Rev. A 61, 042314 ͑2000͔͒. The generation of fully separable, 1-electron biseparable, fully inseparable, or "1 → 2 entangled" tripartite ͑in addition to various kinds of bipartite͒ states is shown to be completely determined only by the spin multiplicities of the electronic states of A and of its ionic species ͑A + ‫ء‬ , A 2+ ‫ء‬ , A 3+ ͒ participating in the suggested scheme. The entanglement of three electrons is Greenberger-Horne-Zeilinger type. The experimental characterization of these states is fully achieved merely by the measurements of the energies of ͑e 1 , e 2 , e 3 ͒, without requiring any entanglement witness or other similar protocols hitherto developed in quantum information.

Inner-shell ionization of rotating linear molecules in the presence of spin-dependent interactions: Entanglement between a photoelectron and an auger electron

The European Physical Journal Special Topics, 2009

This paper reports results of a theoretical study of angle- and spin-resolved photo-Auger electro... more This paper reports results of a theoretical study of angle- and spin-resolved photo-Auger electron coincident spectroscopy in the form of entanglement between these two particles emitted from a linear molecule. First, we develop an expression for a density matrix needed for studying spin-entanglement between a photoelectron and an Auger electron. In order to properly represent the molecular symmetries, nuclear rotation,

The European Physical Journal D, 2011

The simultaneous emission of two electrons in photoionization, or in the non-radiative spontaneou... more The simultaneous emission of two electrons in photoionization, or in the non-radiative spontaneous decay of an inner-shell vacancy, are two of the best known examples of the failure of the independentparticle model of atoms and molecules. The later of these provides also one of the two competitive processes, following inner-shell photoionization, for producing three flying electrons which can, for example, be used in implementing many protocols hitherto developed in quantum information. The correlation properties of the three-particle system consisting of these two electrons plus the photoelectron are analyzed using methods from quantum information theory. The entanglement of the consequent tripartite spin-state is shown to be completely independent of the mechanism(s) which may be responsible for the emission of these three electronic qubits in two different steps in the absence of spin-orbit interaction. Our analysis shows that the tripartite state formed in the present case is more like a |W class of states possessing pairwise entanglement. The experimental characterization of these states is fully achieved merely by the measurements of the energies of three flying electrons, without requiring any entanglement witness or other similar protocols hitherto developed in quantum information. Changes in these entanglement properties of a tripartite state of electronic qubits on the inclusion of the spin-orbit interaction have also been discussed.

Sequential double Auger decay in atoms: A quantum informatic analysis

Physics Letters A, 2009

ABSTRACT We theoretically show that the process of inner-shell photoionization in an atom A, foll... more ABSTRACT We theoretically show that the process of inner-shell photoionization in an atom A, followed by the spontaneous sequential emission of two Auger electrons, produces various kinds of spin-entangled states of three flying electronic qubits. All properties of these states are completely pre-determined by the total spin quantum numbers of the electronic states of four atomic species (i.e., A, A+∗, A2+∗, A3+) participating in this process in the Russell–Saunders coupling. These tripartite states are readily characterized experimentally by measuring only energies of the three emitted electrons, without requiring any entanglement witness or other such protocols.