53 citations · 382 across the 32 of their papers we have counts for
32 papers
Delocalization and superfluidity of ultracold bosonic atoms in a ring lattice
Fernanda Pinheiro, A. F. R. de Toledo Piza
Properties of bosonic atoms in small systems with a periodic quasi one-dimensional circular toroidal lattice potential subjected to rotation are examined by performing exact diagon…
Quantum entanglement of bound particles under free center of mass dispersion
Fernanda Pinheiro, A. F. R. de Toledo Piza
On the basis of the full analytical solution of the overall unitary dynamics, the time evolution of entanglement is studied in a simple bipartite model system evolving unitarily fr…
Quantum dynamics of bosons in a double-well potential: Josephson oscillations, self-trapping and ultralong tunneling times
A. N. Salgueiro, A. F. R. de Toledo Piza, G. B. Lemos +3
The dynamics of the population imbalance of bosons in a double-well potential is investigated from the point of view of many-body quantum mechanics in the framework of the two-mode…
Doorway states and the Bose-Hubbard model
A. N. Salgueiro, Chi-Yong Lin, A. F. R. de Toledo Piza +1
We introduce an efficient method to solve the Mott-Hubbard model. The Schrödinger equation is solved by the successive construction of doorway states. The ground state wavefunction…
Classification of Tripartite Entanglement with one Qubit
Marcio F. Cornelio, A. F. R. de Toledo Piza
We present a method to find the decompositions of tripartite entangled pure states which are smaller than two successive Schmidt decompositions. The method becomes very simple when…
Phases of quantum states in completely positive non-unitary evolution
J. G. Peixoto de Faria, A. F. R. de Toledo Piza, M. C. Nemes
We define an operational notion of phases in interferometry for a quantum system undergoing a completely positive non-unitary evolution. This definition is based on the concepts of…
Excitation of Triple Giant Resonances in Heavy-Ion Reactions
M. S. Hussein, B. V. Carlson, L. F. Canto +1
We calculate the cross-section for the excitation and subsequent decay of triple giant resonances(TGDR) in several nuclei excited with heavy ions.The recently developed coherent pl…
Equilibrium and stability properties of a coupled two-component Bose-Einstein condensate
Chi-Yong Lin, E. J. V. de Passos, M. S. Hussein +2
The equilibrium and stability properties of a coupled two-component BEC is studied using a variational method and the one-dimensional model of Williams and collaborators. The varia…
Stern-Gerlach Entanglement in Spinor Bose-Einstein Condensates
S. Cruz-Barrios, M. C. Nemes, A. F. R. de Toledo Piza
Entanglement of spin and position variables produced by spatially inhomogeneous magnetic fields of Stern-Gerlach type acting on spinor Bose-Einstein condensates may lead to interfe…
Sensitivity to Initial Conditions in Quantum Dynamics: an Analytical Semiclassical Expansion
K. M. Fonseca-Romero, M. C. Nemes, J. G. Peixoto de Faria +1
We construct a class of systems for which quantum dynamics can be expanded around a mean field approximation with essentially classical content. The modulus of the quantum overlap…
Anomalous anapole moment of an exotic nucleus
M. S. Hussein, A. F. R. de Toledo Piza, O. K. Vorov +1
Using the information on the nuclear structure of exotic neutron-rich halo nucleus Be, we evaluate the parity violating anapole moment in its ground state. The resulting val…
Time Evolution of tunneling and decoherence: soluble model
A. N. Salgueiro, A. F. de R. de Toledo Piza, J. G. Peixoto de Faria
Decoherence effects associated to the damping of a tunneling two-level system are shown to dominate the tunneling probability at short times in strong coupling regimes in the conte…
Manipulating decay rates by entanglement and the Zeno effect
A. F. R. de Toledo Piza, M. C. Nemes
We analyse a class of quantum dynamical processes which may lead to the hindering of the decay of a non-stationary state through appropriate entanglement with an additional two-lev…
SU(2,1) Dynamics of Multiple Giant Dipole Resonance Coulomb Excitation
M. S. Hussein, A. F. R. de Toledo Piza, O. K. Vorov
We construct a three-dimensional analytically soluble model of the nonlinear effects in Coulomb excitation of multiphonon Giant Dipole Resonances (GDR) based on the SU(2,1) algebra…
Effective Widths and Effective Number of Phonons of Multiphonon Giant Resonances
L. F. Canto, B. V. Carlson, M. S. Hussein +1
We discuss the origin of the difference between the harmonic value of the width of the multiphonon giant resonances and the smaller observed value. Analytical expressions are deriv…
Enhancement of parity violating mixing in halo nuclei and the problem of neutron weak parity nonconserving potential constant
M. S. Hussein, A. F. R. de Toledo Piza, O. K. Vorov +1
We consider the Parity Nonconserving (PNC) mixing in the ground state of exotic (halo) nuclei caused by the PNC weak interaction between outer neutron and nucleons within nuclear i…
Isospin structure of one- and two-phonon GDR excitations
A. F. R. de Toledo Piza, M. S. Hussein, B. V. Carlson +3
Isospin is included in the description of Coulomb excitation of multiple giant isovector dipole resonances. In the excitation of even-even nuclei, a relevant portion of the excitat…
Semiclassical description of multiple giant dipole resonance excitation and decay
B. V. Carlson, M. S. Hussein, A. F. R. de Toledo Piza
A semiclassical description of multiple giant resonance excitation and decay that incorporates incoherent fluctuation contributions of the Brink-Axel type is developed. Numerical c…
Nonlinear Enhancement of the Multiphonon Coulomb Excitation in Relativistic Heavy Ion Collisions
M. S. Hussein, A. F. R. de Toledo Piza, O. K. Vorov
We propose a soluble model to incorporate the nonlinear effects in the transition probabilities of the multiphonon Giant Dipole Resonances based on the SU(1,1) algebra. Analytical…
Decay theory of double giant resonances
B. V. Carlson, M. S. Hussein, A. F. R. de Toledo Piza
The decay theory of double giant resonances incorporating fluctuation contributions of the Brink-Axel type is developed. The gamma and neutron emission decay of Double Giant Dipole…
Multiphonon and ``hot''-phonon Isovector Electric-Dipole Excitations
B. V. Carlson, L. F. Canto, S. Cruz-Barrios +2
We argue that a substantial increase in the cross section for Coulomb excitation in the region of the Double Giant Dipole Resonance should be expected from Coulomb excitation of ex…
Self Consistent and Renormalized particle-particle RPA in a Schematic Model
E. J. V. de Passos, A. F. R. de Toledo Piza, F. Krmpotić
The dynamical effects of ground state correlations for excitation energies and transition strengths near the superfluid phase transition are studied in the soluble two level pairin…
Decoherence of mesoscopic states of cavity fields
K. Fonseca Romero, M. C. Nemes, J. G. Peixoto de Faria +2
We show that two-atom correlation measurements of the type involved in a recent experimental study of the evolution of a mesoscopic superposition state prepared in a definite mode…
The Hydrogen Atom as an Entangled Electron-Proton System
Paolo Tommasini, Eddy Timmermans, A. F. R. de Toledo Piza
We illustrate the description of correlated subsystems by studying the simple two-body Hydrogen atom. We study the entanglement of the electron and proton coordinates in the exact…