arXiv subjects

G. D. de Moraes Neto

Publications and source records attributed to G. D. de Moraes Neto.

24 records · Page 2Linked to original sources

arXiv2014

Upper-bounded and sliced Jaynes- and anti-Jaynes-Cummings Hamiltonians and Liouvillians in cavity quantum electrodynamics

In this paper, we present a protocol to engineer upper-bounded and sliced Jaynes-Cummings and anti-Jaynes-Cummings Hamiltonians in cavity quantum electrodynamics. In the upper-bounded Hamiltonians, the atom-field interaction is confined to a subspace of Fock states ranging from $\left\vert 0\right\rangle $ up to $\left\vert 4\right\rangle $, while in the sliced interaction the Fock subspace ranges from $\left\vert M\right\rangle $ up to $\left\vert M+4\right\rangle $. We also show how to build upper-bounded and sliced Liouvillians irrespective of engineering Hamiltonians. The upper-bounded and sliced Hamiltonians and Liouvillians can be used, among other applications, to generate steady Fock states of a cavity mode and for the implementation of a quantum-scissors device for optical state truncation.

quant-ph↗

arXiv2014

Steady entanglements in bosonic dissipative networks

In this letter we propose a scheme for the preparation of steady entanglements in bosonic dissipative networks. We describe its implementation in a system of coupled cavities interacting with an engineered reservoir built up of three-level atoms. Emblematic bipartite ($Bell$ and $NOON$) and multipartite $W$-class states can be produced with high fidelity and purity.

quant-ph↗

arXiv2014

Slicing the Fock space for state production and protection

In this letter we present a protocol to engineer interactions confined to subspaces of the Fock space in trapped ions: we show how to engineer upper-, lower-bounded and sliced Jaynes-Cummings (JC) and anti-Jaynes-Cummings (AJC) Hamiltonians. The upper-bounded (lower-bounded) interaction acting upon Fock subspaces ranging from $\left\vert 0\right\rangle $ to $\left\vert M\right\rangle $ ($\left\vert N\right\rangle $ to$\ \infty$), and the sliced one confined to Fock subspace ranging from $\left\vert M\right\rangle $ to $\left\vert N\right\rangle $, whatever $M<N$. Whereas the upper-bounded JC or AJC interactions is shown to drive any initial state to a steady Fock state $\left\vert N\right\rangle $, the sliced one is shown to produce steady superpositions of Fock states confined to the sliced subspace $\left\{ \left\vert N\right\rangle \text{,}\left\vert N+1\right\rangle \right\} $.

quant-ph↗

arXiv2014

Quantum atomic lithography via cross-cavity optical Stern-Gerlach setup

We present a fully quantum scheme to perform 2D atomic lithography based on a cross-cavity optical Stern-Gerlach setup: an array of two mutually orthogonal cavities crossed by an atomic beam perpendicular to their optical axes, which is made to interact with two identical modes. After deriving an analytical solution for the atomic momentum distribution, we introduce a protocol allowing us to control the atomic deflection by manipulating the amplitudes and phases of the cavity field states.

quant-ph↗

arXiv2014

An exact master equation for the system-reservoir dynamics under the strong coupling regime and non-Markovian dynamics

In this paper we present a method to derive an exact master equation for a bosonic system coupled to a set of other bosonic systems, which plays the role of the reservoir, under the strong coupling regime, i.e., without resorting to either the rotating-wave or secular approximations. Working with phase-space distribution functions, we verify that the dynamics are separated in the evolution of its center, which follows classical mechanics, and its shape, which becomes distorted. This is the generalization of a result by Glauber, who stated that coherent states remain coherent under certain circumstances, specifically when the rotating-wave approximation and a zero-temperature reservoir are used. We show that the counter-rotating terms generate fluctuations that distort the vacuum state, much the same as thermal fluctuations.Finally, we discuss conditions for non-Markovian dynamics.

quant-ph↗

arXiv2014

Steady Fock states via atomic reservoir

In this letter we present a strategy that combines the action of cavity damping mechanisms with that of an engineered atomic reservoir to drive an initial thermal distribution to a Fock equilibrium state. The same technique can be used to slice probability distributions in the Fock space, thus allowing the preparation of a variety of nonclassical equilibrium states.

quant-ph↗