83 research outputs found
Information processing among high-performance managers
O propósito deste estudo foi avaliar o processamento da informação de 43 gestores empresariais de desempenho superior. No seu enquadramento teórico recorremos a três modelos: a Teoria dos Papéis Gerenciais de Henry Mintzberg, a Teoria do Processamento da Informação e o Modelo de Processo de Resposta ao Rorschach de John Exner. A ava-liação dos sujeitos recorreu ao método do Rorschach. Os resultados deste estudo mos-traram que esses gerentes são capazes de recolher dados, avaliá-los e estabelecer ran-kings de maneira adequada. Ao mesmo tempo, verifica-se que são capazes de ser objeti-vos e precisos na avaliação dos problemas. Este estilo de processamento de informação possibilita uma interpretação do mundo a partir de um modo de processamento ou de um estilo cognitivo, próprio e característico.The purpose of this study was to evaluate the information processing of 43 business managers with a professional superior performance. The theoretical framework consid-ers three models: the Theory of Managerial Roles of Henry Mintzberg, the Theory of In-formation Processing, and Process Model Response to Rorschach by John Exner. The participants have been evaluated by Rorschach method. The results show that these managers are able to collect data, evaluate them and establish rankings properly. At same time they are capable of being objective and accurate in the problems assessment. This information processing style permits an interpretation of the world around on basis of a very personal and characteristic processing way or cognitive style.Fundação para a Ciência e a Tecnologia (FCT), no âmbito do Fundo de Apoio à Comunidade Científica - Edição de Publicações Periódicas de Natureza Científica
Generation of decoherence-free displaced squeezed states of radiation fields and a squeezed reservoir for atoms in cavity QED
We present a way to engineer an effective anti-Jaynes-Cumming and a
Jaynes-Cumming interaction between an atomic system and a single cavity mode
and show how to employ it in reservoir engineering processes. To construct the
effective Hamiltonian, we analyse considered the interaction of an atomic
system in a \{Lambda} configuration, driven by classical fields, with a single
cavity mode. With this interaction, we firstly show how to generate a
decoherence-free displaced squeezed state for the cavity field. In our scheme,
an atomic beam works as a reservoir for the radiation field trapped inside the
cavity, as employed recently by S. Pielawa et al. [Phys. Rev. Lett. 98, 240401
(2007)] to generate an Einstein-Podolsky-Rosen entangled radiation state in
high-Q resonators. In our scheme, all the atoms have to be prepared in the
ground state and, as in the cited article, neither atomic detection nor precise
interaction times between the atoms and the cavity mode are required. From this
same interaction, we can also generate an ideal squeezed reservoir for atomic
systems. For this purpose we have to assume, besides the engineered atom-field
interaction, a strong decay of the cavity field (i.e., the cavity decay must be
much stronger than the effective atom-field coupling). With this scheme, some
interesting effects in the dynamics of an atom in a squeezed reservoir could be
tested
Quantum correlations in a few-atom spin-1 Bose-Hubbard model
We study the thermal quantum correlations and entanglement in spin-1 Bose-Hubbard model with two and three particles. While we use negativity to calculate entanglement, more general non-classical correlations are quantified using a new measure based on a necessary and sufficient condition for zero-discord state. We demonstrate that the energy level crossings in the ground state of the system are signalled by both the behavior of thermal quantum correlations and entanglement
Conditions for the freezing phenomena of geometric measure of quantum discord for arbitrary two-qubit X states under non-dissipative dephasing noises
We study the dynamics of geometric measure of quantum discord (GMQD) under
the influences of two local phase damping noises. Consider the two qubits
initially in arbitrary X-states, we find the necessary and sufficient
conditions for which GMQD is unaffected for a finite period. It is further
shown that such results also hold for the non-Markovian dephasing process.Comment: 4 pages, 2 figure
Geometric measure of quantum discord and the geometry of a class of two-qubit states
We investigate the geometric picture of the level surfaces of quantum
entanglement and geometric measure of quantum discord (GMQD) of a class of
X-states, respectively. This pictorial approach provides us a direct
understanding of the structure of entanglement and GMQD. The dynamic evolution
of GMQD under two typical kinds of quantum decoherence channels is also
investigated. It is shown that there exists a class of initial states for which
the GMQD is not destroyed by decoherence in a finite time interval.
Furthermore, we establish a factorization law between the initial and final
GMQD, which allows us to infer the evolution of entanglement under the
influences of the environment.Comment: 10 pages, 4 figures, comments are welcom
Experimental investigation of classical and quantum correlations under decoherence
It is well known that many operations in quantum information processing
depend largely on a special kind of quantum correlation, that is, entanglement.
However, there are also quantum tasks that display the quantum advantage
without entanglement. Distinguishing classical and quantum correlations in
quantum systems is therefore of both fundamental and practical importance. In
consideration of the unavoidable interaction between correlated systems and the
environment, understanding the dynamics of correlations would stimulate great
interest. In this study, we investigate the dynamics of different kinds of
bipartite correlations in an all-optical experimental setup. The sudden change
in behaviour in the decay rates of correlations and their immunity against
certain decoherences are shown. Moreover, quantum correlation is observed to be
larger than classical correlation, which disproves the early conjecture that
classical correlation is always greater than quantum correlation. Our
observations may be important for quantum information processing.Comment: 7 pages, 4 figures, to appear in Nature Communication
Frozen and Invariant Quantum Discord under Local Dephasing Noise
In this chapter, we intend to explore and review some remarkable dynamical
properties of quantum discord under various different open quantum system
models. Specifically, our discussion will include several concepts connected to
the phenomena of time invariant and frozen quantum discord. Furthermore, we
will elaborate on the relation of these two phenomena to the non-Markovian
features of the open system dynamics and to the usage of dynamical decoupling
protocols.Comment: 29 pages, 8 figure
Quantum Discord and entropic measures of quantum correlations: Optimization and behavior in finite spin chains
We discuss a generalization of the conditional entropy and one-way
information deficit in quantum systems, based on general entropic forms. The
formalism allows to consider simple entropic forms for which a closed
evaluation of the associated optimization problem in qudit-qubit systems is
shown to become feasible, allowing to approximate that of the quantum discord.
As application, we examine quantum correlations of spin pairs in the exact
ground state of finite spin chains in a magnetic field through the quantum
discord and information deficit. While these quantities show a similar
behavior, their optimizing measurements exhibit significant differences, which
can be understood and predicted through the previous approximations. The
remarkable behavior of these quantities in the vicinity of transverse and
non-transverse factorizing fields is also discussed.Comment: 10 pages, 3 figure
Quantum discord evolution of three-qubit states under noisy channels
We investigated the dissipative dynamics of quantum discord for correlated
qubits under Markovian environments.
The basic idea in the present scheme is that quantum discord is more general,
and possibly more robust and fundamental, than entanglement. We provide three
initially correlated qubits in pure Greenberger-Horne-Zeilinger (GHZ) or W
state and analyse the time evolution of the quantum discord under various
dissipative channels such as:
Pauli channels , , and , as well as
depolarising channels. Surprisingly, we find that under the action of Pauli
channel , the quantum discord of GHZ state is not affected by
decoherence. For the remaining dissipative channels, the W state is more robust
than the GHZ state against decoherence. Moreover, we compare the dynamics of
entanglement with that of the quantum discord under the conditions in which
disentanglement occurs and show that quantum discord is more robust than
entanglement except for phase flip coupling of the three qubits system to the
environment.Comment: 17 pages, 4 figures, accepted for publication in EPJ
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