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- A R R Carvalho, R L de Matos Filho, L Davidovich
- Physical review. E, Statistical, nonlinear, and…
- 2004

We discuss the roles of the macroscopic limit and different system-environment interactions in a quantum-classical transition for a chaotic system. We consider the kicked harmonic oscillator subject to reservoirs that correspond in the classical case to purely dissipative or purely diffusive behavior, a situation that can be implemented in ion trap… (More)

- André R R Carvalho, Florian Mintert, Andreas Buchleitner
- Physical review letters
- 2004

We study the dynamics of multipartite entanglement under the influence of decoherence. A suitable generalization of concurrence reveals distinct scaling of the entanglement decay rate of Greenberger-Horne-Zeilinger and W states, for various environments.

- A R Carvalho, P Milman, R L de Matos Filho, L Davidovich
- Physical review letters
- 2001

We present a proposal for protecting states against decoherence, based on the engineering of pointer states. We apply this procedure to the vibrational motion of a trapped ion, and show how to protect qubits, squeezed states, approximate phase eigenstates, and superpositions of coherent states.

We investigate the time evolution of entanglement for bipartite systems of arbitrary dimensions under the influence of decoherence. For qubits, we determine the precise entanglement decay rates under different system-environment couplings, including finite temperature effects. For qudits, we show how to obtain upper bounds for the decay rates and also… (More)

- B Bentley, A R R Carvalho, J J Hope
- 2015

3 Fast gate formalism 3 3.1 Ideal gate and two-qubit conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.2 Gate schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.2.1 GZC scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.2.2 Fast Robust Antisymmetric Gate scheme . . . . . . . .… (More)

- André R R Carvalho, Marc Busse, Olivier Brodier, Carlos Viviescas, Andreas Buchleitner
- Physical review letters
- 2007

We show that, for experimentally relevant systems, there is an optimal measurement strategy to monitor the time evolution of entanglement under open system dynamics. This suggests an efficient, dynamical characterization of the entanglement of composite, open quantum systems.

- André R R Carvalho, Andreas Buchleitner
- Physical review letters
- 2004

We show that heating of harmonically trapped ions by periodic delta kicks is dramatically enhanced at isolated values of the Lamb-Dicke parameter. At these values, quasienergy eigenstates localized on island structures undergo avoided crossings with extended web states.

- Ignacio García-Mata, André R R Carvalho, Florian Mintert, Andreas Buchleitner
- Physical review letters
- 2007

We show that nonlinear resonances in a classically mixed phase space allow us to define generic, strongly entangled multipartite quantum states. The robustness of their multipartite entanglement increases with the particle number, i.e., in the semiclassical limit, for those classes of diffusive noise which assist the quantum-classical transition.

- Stuart S Szigeti, Andre R R Carvalho, James G Morley, Michael R Hush
- Physical review letters
- 2014

A "no-knowledge" measurement of an open quantum system yields no information about any system observable; it only returns noise input from the environment. Surprisingly, performing such a no-knowledge measurement can be advantageous. We prove that a system undergoing no-knowledge monitoring has reversible noise, which can be canceled by directly feeding… (More)

- Jessica K. Eastman, Joseph J. Hope, André R. R. Carvalho
- Scientific reports
- 2017

Environment-induced decoherence has long been recognised as being of crucial importance in the study of chaos in quantum systems. In particular, the exact form and strength of the system-environment interaction play a major role in the quantum-to-classical transition of chaotic systems. In this work we focus on the effect of varying monitoring strategies,… (More)