92 citations · 1.3k across the 98 of their papers we have counts for
48 papers · 1 filter
Quantum phase transition in an effective three-mode model of interacting bosons
H. M. Frazão, J. G. Peixoto de Faria, G. Q. Pellegrino +1
In this work we study an effective three-mode model describing interacting bosons. These bosons can be considered as exciton-polaritons in a semiconductor microcavity at the magic…
Two proposals to protect a qubit using CQED techniques: inequality between atomic velocity dispersion and losses of a quantum memory
J. L. Santos, J. G. G. de Oliveira, J. G. Peixoto de Faria +1
We present in this work an analysis of the damage imposed by the atom on the field state inside a lossy superconducting cavity. To access such effects, we propose two procedures to…
Universality of finite time disentanglement
Raphael C. Drumond, Cristhiano Duarte, Marcelo Terra Cunha +1
In this paper we investigate how common is the phenomenon of Finite Time Disentanglement (FTD) with respect to the set of quantum dynamics of bipartite quantum states with finite d…
Atomic Focusing by Quantum Fields: Entanglement Properties
I. G. da Paz, H. M. Frazão, M. C. Nemes +1
The coherent manipulation of the atomic matter waves is of great interest both in science and technology. In order to study how an atom optic device alters the coherence of an atom…
Parametric Competition in non-autonomous Hamiltonian Systems
L. A. M. Souza, J. G. P. Faria, M. C. Nemes
In this work we use the formalism of chord functions (\emph{i.e.} characteristic functions) to analytically solve quadratic non-autonomous Hamiltonians coupled to a reservoir compo…
Quantum Properties of a Which-Way Detector
J. S. Oliveira Filho, R. Rossi, M. C. Nemes
We explore quantum properties of a which-way detector using three versions of an idealized two slit arrangements. Firstly we derive complementarity relations for the detector; seco…
Stochastic coupling in two modes systems: the weak-strong coupling transition
Dagoberto S. Freitas, M. C. Nemes
We investigate the weak-strong coupling transition of two linearly coupled systems under the influence of a phase fluctuating coupling. In the weak coupling regime the exponential…
Preparation of Schrödinger cat states of a cavity field via coupling to a superconducting charge qubit
Dagoberto S. Freitas, M. C. Nemes
We extend the approach of Ref. [Yu-xi Liu, L. F. Wei, and F. Nori, Europhys. Lett. 67, 941 (2004)] for preparing superposition states of a cavity field interacting with a supercond…
Multipartite Quantum Eraser
R. Rossi, J. P. Souza, L. A. M. de Souza +1
We study the dynamical entanglement distribution in a multipartite system. The initial state is a maximally entangled two level atom with a single photon field. Next a sequence of…
Mixedness and entanglement for two-mode Gaussian states
L. A. M. Souza, R. C. Drumond, M. C. Nemes +1
We analytically exploit the two-mode Gaussian states nonunitary dynamics. We show that in the zero temperature limit, entanglement sudden death (ESD) will always occur for symmetri…
Continuous Monitoring of Dynamical Systems and Master Equations
L. F. Lopes Oliveira, R. Rossi, A. R. Bosco de Magalhaes +2
We illustrate the equivalence between the non-unitary evolution of an open quantum system governed by a Markovian master equation and a process of continuous measurements involving…
Geometry in the entanglement dynamics of the double Jaynes-Cummings model
A. R. Vieira, J. G. G. de Oliveira Junior, J. G. Peixoto de Faria +1
We report on the geometric character of the entanglement dynamics of to pairs of qubits evolving according to the double Jaynes-Cummings model. We show that the entanglement dynami…
Degree of information accessibility: a precursor of the quantum--classical transition
J. G. Oliveira Junior, J. G. Peixoto de Faria, M. C. Nemes
One of the fundamental problems with the interpretation of Quantum Mechanics, according to Bohr, is the fact that "our usual description of physical phenomena is based entirely on…
Experimental proposal for measuring the Gouy phase of matter waves
I. G. da Paz, P. L. Saldanha, M. C. Nemes +1
The Schrödinger equation for an atomic beam predicts that it must have a phase anomaly near the beam waist analogous to the Gouy phase of an electromagnetic beam. We propose here a…
Residual entanglement and sudden death: A direct connection
J. G. Oliveira Junior, J. G. Peixoto de Faria, M. C. Nemes
We explore the results of [V. Coffman, et al., Phys. Rev. A 61 (2000) 052306] derived for general tripartite states in a dynamical context. We study a class of physically motivated…
Semiclassical Dynamics from Zeno-Like measurements
R. Rossi, K. M. Fonseca, Romero M. C. Nemes
The usual semiclassical approximation for atom-field dynamics consists in substituting the field operators by complex numbers related to the (supposedly large enough) intensity of…
Multipartite entanglement control via Quantum Zeno Effect
J. G. Oliveira, R. Rossi, M. C. Nemes
We develop a protocol based on 2M pairwise interacting qubits, which through Quantum Zeno Effect controls the entanglement distribution of the system. We also show that if the coup…
Control of state and state entanglement with a single auxiliary subsystem
R. Rossi, A. R. Bosco de Magalhães, J. G. Peixoto de Faria +1
We present a strategy to control the evolution of a quantum system. The novel aspect of this protocol is the use of a \emph{single auxiliary subsystem}. Two applications are given,…
Protecting, Enhancing and Reviving Entanglement
J. G. Oliveira, R. Rossi, M. C. Nemes
We propose a strategies not only to protect but also to enhance and revive the entanglement in a double Jaynes-Cummings model. We show that such surprising features arises when Zen…
Indirect evidence for the Gouy phase for matter waves
I. G. da Paz, M. C. Nemes, C. H. Monken +2
We show that the well known geometric phase, the Gouy phase in optics can be defined for matter waves in vacuum as well. In particular we show that the underlying physics for the "…
Quantifying the decay of quantum properties in single-mode states
L. A. M. Souza, M. C. Nemes, M. França Santos +1
The dissipative dynamics of Gaussian squeezed states (GSS) and coherent superposition states (CSS) are analytically obtained and compared. Time scales for sustaining different quan…
Characteristic Time and Maximum Mixedness: Single Mode Gaussian States in Dissipative Channels
Leonardo A. M. Souza, M. C. Nemes
We derive an upper limit for the mixedness of single bosonic mode gaussian states propagating in dissipative channels. It is a function of the initial squeezing and temperature of…
An analytical relation between entropy production and quantum Lyapunov exponents for Gaussian bipartite systems
K. M. Fonseca Romero, J. E. Parreira, L. A. M. Souza +2
We study and compare the information loss of a large class of Gaussian bipartite systems. It includes the usual Caldeira-Leggett type model as well as Anosov models (parametric osc…
Atomic detection in microwave cavity experiments: a dynamical model
R. Rossi, M. C. Nemes, J. G. Peixoto de Faria
We construct a model for the detection of one atom maser in the context of cavity Quantum Electrodynamics (QED) used to study coherence properties of superpositions of electromagne…