Fast quantum control in dissipative systems using dissipationless solutions

We report on a systematic geometric procedure, built up on solutions designed in the absence of dissipation, to mitigate the effects of dissipation in the control of open quantum systems. Our method addresses a standard class of open quantum systems modeled by non-Hermitian Hamiltonians. It provides the analytical expression of the extra magnetic field to be superimposed to the driving field in order to compensate the geometric distortion induced by dissipation, and produces an exact geometric optimization of fast population transfer. Interestingly, it also preserves the robustness properties of protocols originally optimized against noise. Its extension to two interacting spins restores a fidelity close to unity for the fast generation of Bell state in the presence of dissipation

Microscopic dynamical Casimir effect

We consider an atom in its ground state undergoing a non-relativistic oscillation in free space. The interaction with the electromagnetic quantum vacuum leads to two effects to leading order in perturbation theory. When the mechanical frequency is larger than the atomic transition frequency, the dominant effect is the motion-induced transition to an excited state with the emission of a photon carrying the excess energy. We compute the angular distribution of emitted photons and the excitation rate. On the other hand, when the mechanical frequency is smaller than the transition frequency, the leading-order effect is the parametric emission of photon pairs, which constitutes the microscopic counterpart of the dynamical Casimir effect. We discuss the properties of the microscopic dynamical Casimir effect and build a connection with the photon production by an oscillating macroscopic metallic mirror

Let there be light : light interception method update for oil palm (Elaeis guineensis Jacq.) canopies

Light interception (photosynthetically active radiation, PAR) experiments in oil palm (Elaeis guineensis Jacq.) plantations are scarce and often performed decennia ago, in Southeast Asia and without a clear methodology. This is a great opportunity for research with recent planting material in West-African growing conditions. Therefore a light inter-ception experiment was performed in Nigeria. The first objective of this study was to put forward a recommendation regarding PAR interception assessment under oil palm cano-pies. Therefore a fixed and mobile PAR interception sampling method were compared. The second objective was to reveal PAR interception distribution under an oil palm canopy. In this study, PAR interception was monitored in oil palm plots of five di erent planting den-sities (128, 143, 160, 180 and 205 palms ha−1), eleven years after oil palm planting. During the fixed sampling, PAR was measured on sixteen equidistant locations below canopy with a quantum sensor (QS5 Quantum Sensor, Delta-T Devices). During mobile sampling, mea-surements were carried out by walking along two regular paths while holding the quantum sensor by hand. PAR above canopy was measured simultaneously during sampling below canopy. This study found no significant differences between the fixed and mobile PAR interception sampling methods (p > 0.99), and this in the five different planting densities. Furthermore it was discovered that four regular fixed sampling locations below an oil palm canopy are suÿcient for an exact assessment of PAR interception. This study showed also that PAR interception was randomly distributed under the canopy without a decreasing trend of PAR interception away from the oil palm trunk. Finally, there was no significant difference in PAR interception due to the shifting position of the sun between 10 a. m. and 2 p. m. (p > 0.78). It is recommended to assess PAR interception with a fixed sampling method considering its ease, although data from both mobile and fixed methods are com-parable. The standardisation of the fixed PAR interception method is easier due to the lower probability of human error compared to the mobile PAR interception method

Saturation and Σ2\Sigma_2-transfer for ERNA

Elementary Recursive Nonstandard Analysis, in short ERNA, is a constructive system of nonstandard analysis with a PRA consistency proof, proposed around 1995 by Patrick Suppes and Richard Sommer. It is built on a previous system by Rolando Chuaqui and Patrick Suppes, which was recently reconsidered by Michal R\"ossler and Emil Je\v{r}\'{a}bek. A $\Pi_{1} principle has already been added to ERNA and the consistency of the resulting theory proved in PRA. Here, we equip ERNA with$\Sigma_{2} and a saturation principle, while keeping the consistency proof inside PRA. We show that the extended theory allows for generalized transfer, a basic tool of nonstandard analysis, and interprets several strong theories, like \Sigma_{2}$and \Sigma_{2}$