458 research outputs found
The first sub shot noise wide field microscope
No full textQuantum technologies promise to overcome by far the limits of the classical schemes. However, the present challenge is to overpass the limits of proof of principle demonstrations to approach real applications. In this paper, we present an experiment which aims to bridge this gap in the field of quantum enhanced imaging. In particular, we realize a sub-shot noise wide field microscope based on spatially multi-mode non-classical photon number correlations in twin beams. The microscope produces real time images of 8000 pixels at full resolution, with noise reduced to the 80% of the shot noise level (for each pixel), hence able to image faint samples at low illumination level. The noise can be further reduced (less than 30% of the shot noise level) turning down the resolution. It demonstrates the best sensitivity per incident photon ever achieved in absorption microscopy
Improving interferometers by quantum light: toward testing quantum gravity on an optical bench
No full textWe analyze in detail a system of two interferometers aimed at the detection of extremely faint phase uctuations. The idea behind is that a correlated phase-signal like the one predicted by some phenomenological theory of Quantum Gravity (QG) could emerge by correlating the output ports of the interferometers, even when in the single interferometer it confounds with the background. We demonstrated that injecting quantum light in the free ports of the interferometers can reduce the photon noise of the system beyond the shot-noise, enhancing the resolution in the phase-correlation estimation. Our results conrms the benet of using squeezed beams together with strong coherent beams in interferometry, even in this correlated case. On the other hand, our results concerning the possible use of photon number entanglement in twin beam state pave the way to interesting and probably unexplored areas of application of bipartite entanglement and, in particular, the possibility of reaching surprising uncertainty reduction exploiting new interferometric congurations, as in the case of the system described here
One- and two-mode squeezed light in correlated interferometry
No full textWe study in detail a system of two interferometers aimed at detecting extremely faint phase fluctuations.
This system can represent a breakthrough for detecting a faint correlated signal that would remain otherwise
undetectable even using the most sensitive individual interferometric devices, as in the case of so-called
holographic noise. The signature of this kind of noise emerges as a correlation between the output signals
of the interferometers. On the other hand, when holographic noise is absent one expects uncorrelated signals
since the time-averaged fluctuations due to shot noise and other independent contributions vanish (though limiting
the overall sensitivity).We showhowinjecting quantum light in the free ports of the interferometers can reduce the
photon noise of the system beyond the shot noise, enhancing the resolution in the phase-correlation estimation.We
analyze the use of both the two-mode squeezed vacuum and two independent squeezed states. Our results confirm
the benefit of using squeezed beams together with strong coherent beams in interferometry. We also investigate
the possible use of the two-mode squeezed vacuum, discovering interesting and unexplored areas of application
of bipartite entanglement, in particular the possibility of reaching in principle a surprising uncertainty reduction
Realization of a twin beam source based on four wave mixing in Cesium
No full textFour-wave mixing (4WM) is a known source of intense non-classical twin beams. It can be generated when an intense laser beam (the pump) and a weak laser beam (the seed) overlap in a ð3Þ medium (here Cesium vapor), with frequencies close to resonance with atomic transitions. The twin beams generated by 4WM have frequencies naturally close to atomic transitions, and can be intense (gain 1) even in the CW pump regime, which is not the case for PDC ð2Þ phenomenon in nonlinear crystals. So, 4WM is well suited for atom-light interaction and atombased quantum-protocols. Here, we present the ¯rst realization of a source of 4-wave mixing exploiting D2 line of Cesium atoms
The effect on post-operative pain of intravenous clonidine given before induction of anaesthesia
No full textBackground: Treatment of acute post-thoracotomy pain is particularly important not only to keep the patient comfortable but also to minimize pulmonary complications. Aim: This study was designed to test the effect of pre-induction administration of clonidine, given as a single intravenous dose, on post-operative pain scores and fentanyl consumption in patients after thoracic surgery. Setting and Design: Tertiary referral centre. Prospective, randomised, double-blind, placebo-controlled trial. Methods: Sixty patients were randomly allocated to receive clonidine (3 mcg/kg) or saline pre-operatively before induction of anaesthesia. The primary endpoint was pain on coughing (visual analogue scale (VAS) 0-100 mm) 120 min after surgery, time to first analgesic injection in the post-anaesthesia care unit (PACU) and 24-h fentanyl consumption. Statistical Analysis: For between-group comparisons, t-test and U-test were used as appropriate after checking normality of distribution. The incidence of complications between the groups was compared by Fisher′s exact test. Results: The post-operative VAS for the first 120 min and the fentanyl consumption at 24 h was significantly greater in the placebo group compared with the clonidine group (P<0.05). The sedation score was increased in the clonidine group during study drug infusion, but did not differ significantly on admission to the PACU. Conclusions: A single intravenous dose of clonidine (3 mcg/kg) given before induction of anaesthesia significantly reduced the post-operative VAS score in the initial period and fentanyl consumption during 24 h after thoracic surgery
The comparison between single atom catalysis and surface organometallic catalysis
No full textSingle atom catalysis (SAC) is a recent discipline of heterogeneous catalysis for which a single atom on a surface is able to carry out various catalytic reactions. A kind of revolution in heterogeneous catalysis by metals for which it was assumed that specific sites or defects of a nanoparticle were necessary to activate substrates in catalytic reactions. In another extreme of the spectrum, surface organometallic chemistry (SOMC), and, by extension, surface organometallic catalysis (SOMCat), have demonstrated that single atoms on a surface, but this time with specific ligands, could lead to a more predictive approach in heterogeneous catalysis. The predictive character of SOMCat was just the result of intuitive mechanisms derived from the elementary steps of molecular chemistry. This review article will compare the aspects of single atom catalysis and surface organometallic catalysis by considering several specific catalytic reactions, some of which exist for both fields, whereas others might see mutual overlap in the future. After a definition of both domains, a detailed approach of the methods, mostly modeling and spectroscopy, will be followed by a detailed analysis of catalytic reactions: hydrogenation, dehydrogenation, hydrogenolysis, oxidative dehydrogenation, alkane and cycloalkane metathesis, methane activation, metathetic oxidation, CO2 activation to cyclic carbonates, imine metathesis, and selective catalytic reduction (SCR) reactions. A prospective resulting from present knowledge is showing the emergence of a new discipline from the overlap between the two areas.
Comparison of field swept ferromagnetic resonance methods – A case study using Ni-Mn-Sn films
No full textThermotectonic evolution of the Rauer Group and Vestfold Hills in Prydz Bay: implications for Neoproterozoic assembly of the East Antarctic Shield
No full textThe Rauer Group and Vestfold Hills are critical components of the East Antarctic Shield and are believed to have been parts of the supercontinents Rodinia and Gondwana. The Rauer Group is characterized by Archean to Pan-African thermal history, while the Pan-African signature in the Vestfold Hills is restricted to its southwestern margin. The correlation between the Rauer Group and Vestfold Hills remains controversial, while the significance of amalgamation between these two terranes remains unclear. Most importantly, the precise nature and timing of the Rauer-Vestfold contact is disputed. In this review, we compare the available structural, metamorphic, geochronological and geophysical data in these two East Antarctic terranes and suggest that (i) the Rauer Group and Vestfold Hills of East Antarctica were amalgamated during the late Mesoproterozoic to early Neoproterozoic (∼1000 Ma), and (ii) the Rauer-Vestfold contact is located beneath the Sørsdal Glacier in the East Antarctic Shield. Finally, we argue that juxtaposition of the Rauer-Vestfold contiguous crustal unit with the Eastern Ghats Province (EGP)-Rayner amalgam took place in the Pan-African time (∼500 Ma).Sandro Chatterjee, Aishi Debnath, Suvankar Samantaray, Devsamridhi Arora, Soham Dey, Saibal Gupta, Naresh Chandra Pan
Amiodarone and reperfusion ventricular fibrillation
No full text[No abstract available]Ayoub CM, 2009, EUR J ANAESTH, V26, P1056, DOI 10.1097-EJA.0b013e32832f0dfb; NANAS JN, 1995, CIRCULATION, V91, P451; SAMANTARAY A, 2009, J CARDIOTHORAC VASC1
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