3,898 research outputs found

    Teleportation improvement by inconclusive photon subtraction

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    Inconclusive photon subtraction (IPS) is a conditional measurement scheme to force nonlinear evolution of a given state. In IPS the input state is mixed with the vacuum in a beam splitter and then the reflected beam is revealed by ON/OFF photodetection. When the detector clicks we have the (inconclusive) photon subtracted state. We show that IPS on both channels of an entangled twin-beam of radiation improves the fidelity of coherent state teleportation if the energy of the incoming twin-beam is below a certain threshold, which depends on the beam splitter transmissivity and the quantum efficiency of photodetectors. We show that the energy threshold diverges when the transmissivity and the efficiency approach unit and compare our results with that of previous works on {\em conclusive} photon subtraction.Comment: slightly revised version, to appear in PR

    Radiation to atom quantum mapping by collective recoil in Bose-Einstein condensate

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    We propose an experiment to realize radiation to atom continuous variable quantum mapping, i.e. to teleport the quantum state of a single mode radiation field onto the collective state of atoms with a given momentum out of a Bose-Einstein condensate. The atoms-radiation entanglement needed for the teleportation protocol is established through the interaction of a single mode with the condensate in presence of a strong far off-resonant pump laser, whereas the coherent atomic displacement is obtained by the same interaction with the radiation in a classical coherent field. In principle, verification of the protocol requires a joint measurement on the recoiling atoms and the condensate, however, a partial verification involving populations, i.e. diagonal matrix elements may be obtained through counting atoms experiments

    Public health approach to prevent cervical cancer in HIV-infected women in Kenya : issues to consider in the design of prevention programs

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    Women living with HIV in Africa are at increased risk to be co-infected with Human Papilloma Virus (HPV), persistent high risk (HR) HPV infection and bacterial vaginosis (BV), which compounds HPV persistence, thereby increasing the risk for cervical dysplasia. New guidance from WHO in 2014 advocating for a "screen and treat" approach in resource poor settings is becoming a more widely recommended screening tool for cervical cancer prevention programs in such contexts. This review article summarizes the risk factors to be considered when designing a primary and secondary cervical prevention program in a post-vaccination era for HIV-infected women in Kenya. This review article is based on our prior research on the epidemiology of pHR/HR-HPV genotypes in HIV-infected women and CIN 2+ in Kenya and other sub-Saharan contexts. In order to contextualize the findings, a literature search was carried out in March 2017 by means of four electronic databases: PUBMED, EMBASE, SCOPUS, and PROQUEST. Risk factors for potential (pHR)/HR HPV acquisition, including CD4 count, HAART initiation, Female Sex Worker status (FSW) and BV need to be considered. Furthermore, there may be risk factors for abnormal cytology, including FSW status, multiple potential (p) HR/HR HPV genotypes, which may require that HIV-infected women be subjected to screening at more frequent intervals than the three year recommended by the WHO. The quadruple synergistic interaction between HIV, HPV and BV and its related cervicitis may need to be reflected within a larger prevention framework at the community level. The opportunities brought forth by the roll out of HAART could lead to task shifting of HIV-HPV-BV care to nurses, which may increase access in poorly-served areas
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