Combined quantum state preparation and laser cooling of a continuous beam of cold atoms

We use two-laser optical pumping on a continuous atomic fountain in order to prepare cold cesium atoms in the same quantum ground state. A first laser excites the F=4 ground state to pump the atoms toward F=3 while a second pi-polarized laser excites the F=3 -> F'=3 transition of the D2 line to produce Zeeman pumping toward m=0. To avoid trap states, we implement the first laser in a 2D optical lattice geometry, thereby creating polarization gradients. This configuration has the advantage of simultaneously producing Sisyphus cooling when the optical lattice laser is tuned between the F=4 -> F'=4 and F=4 -> F'=5 transitions of the D2 line, which is important to remove the heat produced by optical pumping. Detuning the frequency of the second pi-polarized laser reveals the action of a new mechanism improving both laser cooling and state preparation efficiency. A physical interpretation of this mechanism is discussed.Comment: Minor changes according to the recommendations of the referee: - Corrected Fig.1. - Split the graph of Fig.6 for clarity. - Added one reference. - Added two remarks in the conclusion. - Results unchange

Theoretical analysis of aliasing noises in cold atom Mach-Zehnder interferometers

We present a theoretical analysis of aliasing noises that might appear in cold atom Mach-Zehnder interferometers used for the measurement of various physical quantities. We focus more specifically on single cold atom gyroscopes. To evaluate the level of aliasing noises, we have developed a model based on the power spectral densities of the different identified noise sources as input parameters and which makes use of a servo-loop to realize a precise measurement of the rotation rate. The model allows one to take into account different modes of operation, like a continuous as well as a pulsed or even a multi-ball operation. For monokinetic atoms, we show that the intermodulation noise can be completely filtered out with a continuous mode of operation and an optimum modulation scheme for any modulation frequency but also with a pulsed operation however only for specific launching frequencies. In the case of a real continuous atomic beam having a velocity distribution, it comes out that a high attenuation can be reached which indicates clearly the potential stability improvement that can be expected from a continuous operatio

A large sample study of spin relaxation and magnetometric sensitivity of paraffin-coated Cs vapor cells

We have manufactured more than 250 nominally identical paraffin-coated Cs vapor cells (30 mm diameter bulbs) for multi-channel atomic magnetometer applications. We describe our dedicated cell characterization apparatus. For each cell we have determined the intrinsic longitudinal, \sGamma{01}, and transverse, \sGamma{02}, relaxation rates. Our best cell shows \sGamma{01}/2\pi\approx 0.5 Hz, and \sGamma{02}/2\pi\approx 2 Hz. We find a strong correlation of both relaxation rates which we explain in terms of reservoir and spin exchange relaxation. For each cell we have determined the optimal combination of rf and laser powers which yield the highest sensitivity to magnetic field changes. Out of all produced cells, 90% are found to have magnetometric sensitivities in the range of 9 to 30 fTHz. Noise analysis shows that the magnetometers operated with such cells have a sensitivity close to the fundamental photon shot noise limit

Role of regular physical activity in neuroprotection against acute ischemia

One of the major obstacles that prevents an effective therapeutic intervention against ischemic stroke is the lack of neuroprotective agents able to reduce neuronal damage; this results in frequent evolution towards a long-term disability with limited alternatives available to aid in recovery. Nevertheless, various treatment options have shown clinical efficacy. Neurotrophins such as brain-derived neurotrophic factor (BDNF), widely produced throughout the brain, but also in distant tissues such as the muscle, have demonstrated regenerative properties with the potential to restore damaged neural tissue. Neurotrophins play a significant role in both protection and recovery of function following neurological diseases such as ischemic stroke or traumatic brain injury. Unfortunately, the efficacy of exogenous administration of these neurotrophins is limited by rapid degradation with subsequent poor half-life and a lack of blood–brain-barrier permeability. Regular exercise seems to be a therapeutic approach able to induce the activation of several pathways related to the neurotrophins release. Exercise, furthermore, reduces the infarct volume in the ischemic brain and ameliorates motor function in animal models increasing astrocyte proliferation, inducing angiogenesis and reducing neuronal apoptosis and oxidative stress. One of the most critical issues is to identify the relationship between neurotrophins and myokines, newly discovered skeletal muscle-derived factors released during and after exercise able to exert several biological functions. Various myokines (e.g., Insulin-Like Growth Factor 1, Irisin) have recently shown their ability to protects against neuronal injury in cerebral ischemia models, suggesting that these substances may influence the degree of neuronal damage in part via inhibiting inflammatory signaling pathways. The aim of this narrative review is to examine the main experimental data available to date on the neuroprotective and anti-ischemic role of regular exercise, analyzing also the possible role played by neurotrophins and myokines

Quantum marking and quantum erasure for neutral kaons

Entangled K0 anti-K0 pairs are shown to be suitable to discuss extensions and tests of Bohr's complementarity principle through the quantum marking and quantum erasure techniques suggested by M. O. Scully and K. Druehl [Phys. Rev. A 25, 2208 (1982)]. Strangeness oscillations play the role of the traditional interference pattern linked to wave-like behaviour, whereas the distinct propagation in free space of the K_S and K_L components mimics the two possible interferometric paths taken by particle-like objects.Comment: 4 RevTeX page

Application of clinical indexes in ulcerative colitis patients in regular follow-up visit. correlation with endoscopic 'mucosal healing' and implication for management

OBJECTIVE: Ulcerative Colitis (UC) is a chronic inflammatory disease of the colon of unknown etiology. Several clinical indexes have been proposed for UC disease activity evaluation, but none have been properly validated. Moreover, the reference parameter for the scores and their prognostic value is not clear. Mucosal healing has been recently proposed as an important end-point. Aim of the present study was to evaluate the correlation of four clinical indexes with objective diagnostic tools for UC evaluation, the discriminative ability in identifying patients with endoscopic mucosal healing, and to analyze the possible prognostic indication for disease course in 1 year of follow-up. PATIENTS AND METHODS: We analyzed data of 75 patients recorded in regular follow-up visit in IBD clinic at S. Andrea Hospital, Rome, between 2007-2011. We recorded clinical data and lab tests at the time of the visit, and endoscopic/ histological repor ts performed within 1 month. Clinical indexes (Seo' activity index, Simple Clinical Colitis Activity Index, partial Mayo score and Endoscopic-Clinical Correlation Index) were calculated and correlation to endoscopic and histologic activity, and to C-reactive protein increment, was assessed by mean of Spearman's rank correlation. Discriminative ability of the indexes for patients with and without endoscopic mucosal healing was tested by calculation of area under ROC curve (AUC). Patients with low and high clinical scores were compared for number of flares and increment of therapy during 1 year of follow-up. RESULTS: Clinical indexes had a good correlation with endoscopic activity (mean r = 0.73 ± 0.06), a fair correlation with CRP-increment (mean r = 0.55 ± 0.01) and a poor one with histologic activity (mean r = 0.35 ± 0.01). The discriminatory ability of the indexes for endoscopic mucosal healing was good for all the indexes (mean AUC = 0.87 ± 0.05). Patients with high clinical score had more flares and required more frequently increase of therapy at 1 year of follow up compared with patients with low score. CONCLUSIONS: Clinical indexes have a good correlation with endoscopic activity and can discriminate patients with and without mucosal healing. Patients with low and high score have different risk of disease flare and of need to increase therapy at 1 year. Clinical indexes may represent a useful tool for disease assessment in clinical practice in UC outpatients with mildmoderate disease