Controlling chaos in the quantum regime using adaptive measurements

The continuous monitoring of a quantum system strongly influences the emergence of chaotic dynamics near the transition from the quantum regime to the classical regime. Here we present a feedback control scheme that uses adaptive measurement techniques to control the degree of chaos in the driven-damped quantum Duffing oscillator. This control relies purely on the measurement backaction on the system, making it a uniquely quantum control, and is only possible due to the sensitivity of chaos to measurement. We quantify the effectiveness of our control by numerically computing the quantum Lyapunov exponent over a wide range of parameters. We demonstrate that adaptive measurement techniques can control the onset of chaos in the system, pushing the quantum-classical boundary further into the quantum regime

Heat Resistance of Human Pathogens in Sous-Vide Products Studied in Model Nutrition Media

Sous-vide (French for ʽunder vacuum’) is a professional cooking method, by which, under oxygen-free conditions and precise temperature control, not only cooking but preservation is achieved. During the process the food matrix is vacuum-packed and undergoes a mild heat treatment, thus achieving an enhanced nutrition value and a better organoleptic character. Due to the mild heat treatment (55 to 90 °C), the high water activity, and the slight acidity of raw materials, the microbial quality assurance is a great challenge even for professionals. The heat treatment does not assure the inactivation of pathogen spores. In our experiments we used Clostridium perfringens representing the spore-forming pathogens, and Salmonella Enteritidis as a the food-borne infection bacterium. Effects of various temperatures were measured in normal and sous-vide type vacuum packaging. Higher thermal death rate in vacuum packaging was demonstrated for Salmonella Enteritidis and Clostridium perfringens

Possible modulation of dopaminergic neurotransmission function by acetyl-L-carnitine

Acetyl‐L‐Carnitine (ALC) has a putative neuroprotective effect being used in a variety of conditions. Nevertheless, the underlying molecular mechanisms, particularly regarding the induction of changes in neurotransmitter systems, are still not fully understood. We aim to contribute for the elucidation of the mechanisms by which ALC alters neurotransmitter release, using a cell line and an animal model of exposure to methamphetamine (METH). PC12 cells were incubated with several doses of ALC (0.01 to 1.0 mM) alone or in combination with METH 1.0 or 100 µM for 24h or 72h. When combined, ALC preceded METH administration in 30 minutes. Dopamine (DA) content was determined by high performance liquid chromatography. C57BL/6J mice were used for in vivo assays to assess DA striatal binding. Mice were divided into 4 groups, according to different treatments: group 1 (control), group 2 (ALC, 100 mg/kg), group 3 (METH, 10 mg/kg) and group 4 (ALC+METH). Images were acquired in a SPECT/CT scanner (NanoSPECT/CT, Mediso, Hungary) 70 minutes after 123I‐IBZM injection. Regions of interest were drawn in the striata and in the cerebellum to determine the striatal binding ratio. Increased intracellular levels of DA were observed in PC12 cells at 24h and 72h after the administration of ALC. Cells treated with METH 100 µM displayed decreased intracellular levels of DA. ALC prevented the METH‐induced decrease in DA concentration (p<0.0001). On the other hand, a single dose of 10 mg/kg of METH induced a decrease in striatal D2R binding ratios comparing to control group (between 20% and 30%). Interestingly, over time, ALC was able to reverse the decrease on the radiotracer binding induced by METH. The present study indicates a possible effect of ALC over METH‐induced DA release.info:eu-repo/semantics/publishedVersio

Quantum tunneling dynamics of an interacting Bose-Einstein condensate through a Gaussian barrier

The transmission of an interacting Bose-Einstein condensate incident on a repulsive Gaussian barrier is investigated through numerical simulation. The dynamics associated with interatomic interactions are studied across a broad parameter range not previously explored. Effective 1D Gross-Pitaevskii equation (GPE) simulations are compared to classical Boltzmann-Vlasov equation (BVE) simulations in order to isolate purely coherent matterwave effects. Quantum tunneling is then defined as the portion of the GPE transmission not described by the classical BVE. An exponential dependence of transmission on barrier height is observed in the purely classical simulation, suggesting that observing such exponential dependence is not a sufficient condition for quantum tunneling. Furthermore, the transmission is found to be predominately described by classical effects, although interatomic interactions are shown to modify the magnitude of the quantum tunneling. Interactions are also seen to affect the amount of classical transmission, producing transmission in regions where the non-interacting equivalent has none. This theoretical investigation clarifies the contribution quantum tunneling makes to overall transmission in many-particle interacting systems, potentially informing future tunneling experiments with ultracold atoms.Comment: Close to the published versio

Precision atomic gravimeter based on Bragg diffraction

We present a precision gravimeter based on coherent Bragg diffraction of freely falling cold atoms. Traditionally, atomic gravimeters have used stimulated Raman transitions to separate clouds in momentum space by driving transitions between two internal atomic states. Bragg interferometers utilize only a single internal state, and can therefore be less susceptible to environmental perturbations. Here we show that atoms extracted from a magneto-optical trap using an accelerating optical lattice are a suitable source for a Bragg atom interferometer, allowing efficient beamsplitting and subsequent separation of momentum states for detection. Despite the inherently multi-state nature of atom diffraction, we are able to build a Mach-Zehnder interferometer using Bragg scattering which achieves a sensitivity to the gravitational acceleration of $\Delta g/g = 2.7\times10^{-9}$ with an integration time of 1000s. The device can also be converted to a gravity gradiometer by a simple modification of the light pulse sequence.Comment: 13 pages, 11 figure

Observation of a Modulational Instability in Bose-Einstein condensates

We observe the breakup dynamics of an elongated cloud of condensed $^{85}$Rb atoms placed in an optical waveguide. The number of localized spatial components observed in the breakup is compared with the number of solitons predicted by a plane-wave stability analysis of the nonpolynomial nonlinear Schr\"odinger equation, an effective one-dimensional approximation of the Gross-Pitaevskii equation for cigar-shaped condensates. It is shown that the numbers predicted from the fastest growing sidebands are consistent with the experimental data, suggesting that modulational instability is the key underlying physical mechanism driving the breakup.Comment: 6 pages, 5 figure

Al(OH)(3) facilitated synthesis of water-soluble, magnetic, radiolabelled and fluorescent hydroxyapatite nanoparticles

Magnetic and fluorescent hydroxyapatite nanoparticles were synthesised using Al(OH)3-stabilised MnFe2O4 or Fe3O4 nanoparticles as precursors. They were readily and efficiently radiolabelled with 18F. Bisphosphonate polyethylene glycol polymers were utilised to endow the nanoparticles with excellent colloidal stability in water and to incorporate cyclam for high affinity labelling with 64Cu

Pre-Excitation Studies for Rubidium-Plasma Generation

The key element in the Proton-Driven-Plasma-Wake-Field-Accelerator (AWAKE) project is the generation of highly uniform plasma from Rubidium vapor. The standard way to achieve full ionization is to use high power laser which can assure the over-barrier-ionization (OBI) along the 10 meters long active region. The Wigner-team in Budapest is investigating an alternative way of uniform plasma generation. The proposed Resonance Enhanced Multi Photon Ionization (REMPI) scheme probably can be realized by much less laser power. In the following the resonant pre-excitations of the Rb atoms are investigated, theoretically and the status report about the preparatory work on the experiment are presented.Comment: 8 pages, 6 figures, submitted to Nucl. Inst. and Meth. in Phys. Res.

Personal control of the indoor environment in offices: Relations with building characteristics, influence on occupant perception and reported symptoms related to the building-the officair project

Personal control over various indoor environment parameters, especially in the last decades, appear to have a significant role on occupants' comfort, health and productivity. To reveal this complex relationship, 7441 occupants of 167 recently built or retrofitted office buildings in eight European countries participated in an online survey about personal/health/work data as well as physical/psycho-social information. The relationship between the types of control available over indoor environments and the perceived personal control of the occupants was examined, as well as the combined effect of the control parameters on the perceived comfort using multilevel statistical models. The results indicated that most of the occupants have no or low control on noise. Half of the occupants declared no or low control on ventilation and temperature conditions. Almost one-third of them remarked that they do not have satisfactory levels of control for lighting and shading from sun conditions. The presence of operable windows was shown to influence occupants' control perception over temperature, ventilation, light and noise. General building characteristics, such as floor number and floor area, office type, etc., helped occupants associate freedom positively with control perception. Combined controlling parameters seem to have a strong relation with overall comfort, as well as with perception regarding amount of privacy, office layout and decoration satisfaction. The results also indicated that occupants with more personal control may have less building-related symptoms. Noise control parameter had the highest impact on the occupants' overall comfort