We present a source of entangled photons that violates a Bell inequality free of the "fair-sampling" assumption, by over 7 standard deviations. This violation is the first reported experiment with photons to close the detection loophole, and we demonstrate enough "efficiency" overhead to eventually perform a fully loophole-free test of local realism. The entanglement quality is verified by maximally violating additional Bell tests, testing the upper limit of quantum correlations. Finally, we use the source to generate "device-independent" private quantum random numbers at rates over 4 orders of magnitude beyond previous experiments.This document has been published at http://prl.aps.org/abstract/PRL/v111/i13/e130406 in Phys. Rev. Lett.PACS numbers: 03.65. Ud, 03.67.Ac, 42.50.Xa, 03.67.Bg In 1935, Einstein, Podolsky, and Rosen suggested that certain quantum mechanical states must violate one or both of the fundamental classical assumptions of locality (sufficiently distant events cannot change the outcome of a nearby measurement) and realism (the outcome probabilities of potential measurements depend only on the state of the system). These nonclassical two-particle states exhibit multiple-basis correlations (or anti-correlations), and are referred to as "entangled". Because locality and realism are so fundamental to classical intuition, a central debate in 20th century physics [1] revolved around the following question: could an alternative to quantum mechanics-a local realistic theory-explain entanglements seemingly nonclassical correlations? In 1964, John Bell devised a way to in principle answer this question experimentally, by analyzing the limit of allowed correlations between measurements made on an ensemble of any classical system [2]. If performed under sufficiently ideal conditions, a violation of Bells inequality would conclusively rule out all possible local realistic theories. Although entanglement has been experimentally demonstrated and the Bell inequality violated in a myriad of non-ideal experiments [3][4][5][6][7][8][9][10][11][12], each of these experiments fails to overcome at least one of two critical obstacles.The first obstacle-the "locality loophole"-addresses the possibility that a local realistic theory might rely on some type of signal sent from one entangled particle to its partner (e.g., a signal containing information about the specific measurement carried out on the first particle), or from the measurement apparatus to the source (known as the freedom of choice loophole). These loopholes have thus far only been closed using entangled photons [8, 13]; photons traveling in different directions can be measured at places and times which are relativistically strictly simultaneous (i.e., in a space-like separated configuration). The second obstacle-the "detection loophole"-addresses the fact that even maximally entangled particles, when measured with low-quantum-efficiency detectors, will produce experimental results that can be explained by a local realistic theory. To avoid this, almos...

Research is fundamental to the advancement of medicine and critical to identifying the most optimal therapies unique to particular societies. This is easily observed through the dynamics associated with pharmacology, surgical technique and the medical equipment used today versus short years ago. Advancements in knowledge synthesis and reporting guidelines enhance the quality, scope and applicability of results; thus, improving health science and clinical practice and advancing health policy. While advancements are critical to the progression of optimal health care, the high cost associated with these endeavors cannot be ignored. Research fundamentally needs to be evaluated to identify the most efficient methods of evaluation. The primary objective of this paper is to look at a specific research methodology when applied to the area of clinical research, especially extracorporeal circulation and its prognosis for the future.

Photons have proven to be excellent carriers of quantum information, and play essential roles in numerous quantum information processing (QIP) applications [1][2][3][4]. In particular, heralded singlephoton sources [5] via spontaneous parametric-down conversion (SPDC) have been a key technology for demonstrating small-scale QIP, yet their low generation efficiency is a critical limitation for further scaling up optical QIP technology. In order to efficiently overcome the probabilistic nature of SPDC, here we demonstrate time multiplexing [6][7][8][9][10] for up to 30 time slots of a periodically pumped heralded single-photon source, using a switchable low-loss optical storage cavity. We observe a maximum single-photon probability of 38.6±0.4% in periodic output time windows, corresponding to ∼6 times enhancement over a non-multiplexed source, but with no increase in the contribution of unwanted multi-photon events. Combining this time-multiplexing technique with a heralded source producing pure single-photon states [11][12][13] should enable larger scale optical QIP systems than ever realized.Realizing and scaling up optical QIP systems requires on-demand preparation of quantum states of light such as single-photon and definite multi-photon states. Single atoms, ions, and solid-state single-emitter sources such as colorcenters in diamond and semiconductor quantum dots can generate true single-photon states, and especially solid-state systems have great potential for integration. However, while high indistinguishability [14,15] and somewhat high (50-80%) collection efficiency [16] have been reported in different single-emitter systems, achieving both simultaneously remains a challenge. Moreover, most single-emitter sources generate single photons with narrow bandwidths (5-100 MHz) that may be unsuitable for pursuing high-speed applications (e.g., a 5-MHz bandwidth source can produce non-overlapping single-photon gaussian wavepackets-of duration 90 ns-at a maximum rate of ∼10 MHz).SPDC is another approach that has been conventionally and widely used for generating entangled photon pairs, multi-photon entangled states, and small-scale quantum algorithms [4]. A photon pair generated via SPDC can also be used for generating a "heralded" single-photon state; detecting one of the photons "heralds" the presence of the other. Moreover, current technology has realized photons with very high coupling efficiency into single-mode optical fibers [17,18] and controlled two-photon spectral shape [11,12]. However, the photon-pair generation process via SPDC is probabilistic: one cannot obtain a photon pair or a heralded single photon on demand. Unfortunately, indefinitely increasing the mean number of photon pairs per pump pulse p also increases the likelihood of unwanted k-photon pairs (∼p k ) by higher-order processes. To overcome the probabilistic nature of photon-pair generation, time-multiplexing techniques were first proposed and demonstrated by Pittman, Jacobs, and Franson [6] in 2002. The method was since extended and t...

Oxidants from cigarette smoke or those produced by phagocytes are implicated in the pathogenesis of emphysema. We reasoned that augmentation of antioxidant enzymes in cigarette smokers may be important in restricting direct and indirect oxidant damage to alveolar structures. Accordingly, we studied the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSHPx), in alveolar macrophages (AM) from cigarette smokers and from smoke-exposed hamsters. The activities of these antioxidant enzymes were compared with the activities found in AM from nonsmoking control subjects. The activities of SOD and CAT from AM of smokers and smoke-exposed hamsters were twice that found in control subjects (p less than 0.01), but there was no change in the activity of GSHPx. Using the hamster model, we found that filtration of smoke attenuated the increase in antioxidant activities, and that after smoking cessation, the increased activities had returned to those found with control subjects. An adaptive response was further suggested by prolonged survival of smoke-exposed hamsters in normobaric hyperoxia (O2 greater than 95%). Chronic smoke exposure in humans or hamsters causes increased SOD and CAT activities in AM. This augmented activity may serve as a mechanism to limit oxidant-mediated damage to alveolar structures.

Neutrophils contribute to chronic bronchitis and pulmonary emphysema associated with cigarette smoking. Nicotine was found to be chemotactic for human neutrophils but not monocytes, with a peak activity at approximately 31 micromolar. In lower concentrations (comparable to those in smokers' plasma), nicotine enhanced the response of neutrophils to two chemotactic peptides. In contrast to most other chemoattractants for neutrophils, however, nicotine did not affect degranulation or superoxide production. Nicotine thus may promote inflammation and consequent lung injury in smokers.