SUBSTITUTION OF NTO BY HTP IN A BIPROPELLANT RCS

The present article presents some theoretical considerations about the implications due the change of the oxidizer in a bipropellant propulsion system. Preliminary analysis conducted on the NTO/UDMH 400 N engine of a roll control system shows that this engine could be capable of operation with HTP90 without significant modification in the design. The new propellant combination is less toxic, can be handled more easily, has a wider operational temperature range, and yields a more amenable thermal environment from the combustion down to the exhaustion. Even with a decrease in liquid film cooling, the HTP90/UDMH engine would present a satisfactory reduction of the combustion chamber temperature and approximately the same performance level of the original NTO/UDMH engine

Frequency up- and down-conversions in two-mode cavity quantum electrodynamics

In this letter we present a scheme for the implementation of frequency up- and down-conversion operations in two-mode cavity quantum electrodynamics (QED). This protocol for engineering bilinear two-mode interactions could enlarge perspectives for quantum information manipulation and also be employed for fundamental tests of quantum theory in cavity QED. As an application we show how to generate a two-mode squeezed state in cavity QED (the original entangled state of Einstein-Podolsky-Rosen)

Proposal to produce long-lived mesoscopic superpositions through an atom-driven field interaction

We present a proposal for the production of longer-lived mesoscopic superpositions which relies on two requirements: parametric amplification and squeezed vacuum reservoir for cavity-field states. Our proposal involves the interaction of a two-level atom with a cavity field which is simultaneously subjected to amplification processes.Comment: 12 pages, title changed, text improved and refences adde

Engineering cavity-field states by projection synthesis

We propose a reliable scheme for engineering a general cavity-field state. This is different from recently presented strategies,where the cavity is supposed to be initially empty and the field is built up photon by photon through resonant atom-field interactions. Here, a coherent state is previously injected into the cavity. So, the Wigner distribution function of the desired state is constructed from that of the initially coherent state. Such an engineering process is achieved through an adaptation of the recently proposed technique of projection synthesis to cavity QED phenomena.Comment: 5 ps pages plus 3 included figure

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

PRNT de escórias na correção da acidez do solo para o cultivo da alfafa.

projeto/Plano de Ação: 0109.01.001

Reatividade de silicatos.

Projeto/Plano de Ação: 01.09.10103-04

Mean excitation numbers due to anti-rotating term (MENDART) in cavity QED under Lindbladian dephasing

We study the photon generation from arbitrary initial state in cavity QED due to the combined action of the anti-rotating term present in the Rabi Hamiltonian and Lindblad-type dephasing. We obtain a simple set of differential equations describing this process and deduce useful formulae for the moments of the photon number operator, demonstrating analytically that the average photon number increases linearly with time in the asymptotic limit.Comment: 4 page