Runaway evaporation for optically dressed atoms

Forced evaporative cooling in a far-off-resonance optical dipole trap is proved to be an efficient method to produce fermionic- or bosonic-degenerated gases. However in most of the experiences, the reduction of the potential height occurs with a diminution of the collision elastic rate. Taking advantage of a long-living excited state, like in two-electron atoms, I propose a new scheme, based on an optical knife, where the forced evaporation can be driven independently of the trap confinement. In this context, the runaway regime might be achieved leading to a substantial improvement of the cooling efficiency. The comparison with the different methods for forced evaporation is discussed in the presence or not of three-body recombination losses

Quantum control of the hyperfine-coupled electron and nuclear spins in alkali atoms

We study quantum control of the full hyperfine manifold in the ground-electronic state of alkali atoms based on applied radio frequency and microwave fields. Such interactions should allow essentially decoherence-free dynamics and the application of techniques for robust control developed for NMR spectroscopy. We establish the conditions under which the system is controllable in the sense that one can generate an arbitrary unitary on the system. We apply this to the case of $^{133}$Cs with its $d=16$ dimensional Hilbert space of magnetic sublevels in the $6S_{1/2}$ state, and design control waveforms that generate an arbitrary target state from an initial fiducial state. We develop a generalized Wigner function representation for this space consisting of the direct sum of two irreducible representation of SU(2), allowing us to visualize these states. The performance of different control scenarios is evaluated based on the ability to generate high-fidelity operation in an allotted time with the available resources. We find good operating points commensurate with modest laboratory requirements.Comment: 14 pages, 7 figures; corrected typo

Towards high-speed optical quantum memories

Quantum memories, capable of controllably storing and releasing a photon, are a crucial component for quantum computers and quantum communications. So far, quantum memories have operated with bandwidths that limit data rates to MHz. Here we report the coherent storage and retrieval of sub-nanosecond low intensity light pulses with spectral bandwidths exceeding 1 GHz in cesium vapor. The novel memory interaction takes place via a far off-resonant two-photon transition in which the memory bandwidth is dynamically generated by a strong control field. This allows for an increase in data rates by a factor of almost 1000 compared to existing quantum memories. The memory works with a total efficiency of 15% and its coherence is demonstrated by directly interfering the stored and retrieved pulses. Coherence times in hot atomic vapors are on the order of microsecond - the expected storage time limit for this memory.Comment: 13 pages, 5 figure

Efficient and long-lived quantum memory with cold atoms inside a ring cavity

Quantum memories are regarded as one of the fundamental building blocks of linear-optical quantum computation and long-distance quantum communication. A long standing goal to realize scalable quantum information processing is to build a long-lived and efficient quantum memory. There have been significant efforts distributed towards this goal. However, either efficient but short-lived or long-lived but inefficient quantum memories have been demonstrated so far. Here we report a high-performance quantum memory in which long lifetime and high retrieval efficiency meet for the first time. By placing a ring cavity around an atomic ensemble, employing a pair of clock states, creating a long-wavelength spin wave, and arranging the setup in the gravitational direction, we realize a quantum memory with an intrinsic spin wave to photon conversion efficiency of 73(2)% together with a storage lifetime of 3.2(1) ms. This realization provides an essential tool towards scalable linear-optical quantum information processing.Comment: 6 pages, 4 figure

Delay of Squeezing and Entanglement using Electromagnetically Induced Transparency in a Vapour Cell

We demonstrate experimentally the delay of squeezed light and entanglement using Electromagnetically Induced Transparency (EIT) in a rubidium vapour cell. We perform quadrature amplitude measurements of the probe field and find no appreciable excess noise from the EIT process. From an input squeezing of 3.1 dB at low sideband frequencies, we observed the survival of 2 dB of squeezing at the EIT output. By splitting the squeezed light on a beam-splitter, we generated biased entanglement between two beams. We transmit one of the entangled beams through the EIT cell and correlate the quantum statistics of this beam with its entangled counterpart. We experimentally observed a 2 $\mu$s delay of the biased entanglement and obtained a preserved degree of wavefunction inseparability of 0.71, below the unity value for separable states.Comment: 8 pages, 5 figure

Factors contributing to patient safety incidents in primary care: a descriptive analysis of patient safety incidents in a French study using CADYA (categorization of errors in primary care)

Abstract Background Patient safety incidents (PSIs) frequently occur in primary care and are often considered to be preventable. Better knowledge of factors contributing to PSIs is required to build safer care. The aim of this work was to describe the underlying factors, specifically the human factors, that are associated with PSIs in primary care using CADYA (“CAtégorisation des DYsfonctionnements en Ambulatoire” or “Categorization of Errors in Primary Care”). Methods We followed a mixed method with content analysis and coding in CADYA of PSIs reported in the ESPRIT study, a French cross-sectional survey of primary care. For each incident, a main contributing factor (MD) and, if applicable, a secondary contributing factor (SD) were identified. Several descriptive keywords from an incremental glossary have been suggested to describe each identified human factor (attitudes or behaviours). A descriptive statistical analysis was then conducted. Results Among the 482 PSIs reported in the ESPRIT study, from 13,438 acts reported by 127 participating general practitioners (GPs), we identified 590 contributing factors (482 MDs and 178 SDs). Overall, 35% were related to the care process, 30% to human factors, 22% to the healthcare environment and 13% to technical factors. The contributing factors, in decreasing order of frequency, were communication errors (13.7%), human factors related to healthcare providers (12.9%) and human factors related to patients (12.9%). The human factors were mainly related to ‘lack of attention’, ‘stress’, ‘anger’ and ‘fatigue’. Conclusions Our results tend to prove that human factors are often involved in PSIs in primary care, with GPs and patients being equally responsible. Beyond the identification of communication errors, often found in other international research, we have described the attitudes and behaviours contributing to unsafe care. Further research exploring the links between working conditions and human factors is required

Adhésion médicamenteuse des patients ayant initié un traitement par isotrétinoïne orale.

International audienc