54 research outputs found
Flow and Radiation Analyses for Stardust Entry at High Altitude
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76603/1/AIAA-2008-1215-337.pd
High speed self-testing quantum random number generation without detection loophole
Quantum mechanics provides means of generating genuine randomness that is
impossible with deterministic classical processes. Remarkably, the
unpredictability of randomness can be certified in a self-testing manner that
is independent of implementation devices. Here, we present an experimental
demonstration of self-testing quantum random number generation based on an
detection-loophole free Bell test with entangled photons. In the randomness
analysis, without the assumption of independent identical distribution, we
consider the worst case scenario that the adversary launches the most powerful
attacks against quantum adversary. After considering statistical fluctuations
and applying an 80 Gb 45.6 Mb Toeplitz matrix hashing, we achieve a
final random bit rate of 114 bits/s, with a failure probability less than
. Such self-testing random number generators mark a critical step
towards realistic applications in cryptography and fundamental physics tests.Comment: 34 pages, 10 figure
Similarities between structural distortions under pressure and chemical doping in superconducting BaFe2As2
The discovery of a new family of high Tc materials, the iron arsenides
(FeAs), has led to a resurgence of interest in superconductivity. Several
important traits of these materials are now apparent, for example, layers of
iron tetrahedrally coordinated by arsenic are crucial structural ingredients.
It is also now well established that the parent non-superconducting phases are
itinerant magnets, and that superconductivity can be induced by either chemical
substitution or application of pressure, in sharp contrast to the cuprate
family of materials. The structure and properties of chemically substituted
samples are known to be intimately linked, however, remarkably little is known
about this relationship when high pressure is used to induce superconductivity
in undoped compounds. Here we show that the key structural features in
BaFe2As2, namely suppression of the tetragonal to orthorhombic phase transition
and reduction in the As-Fe-As bond angle and Fe-Fe distance, show the same
behavior under pressure as found in chemically substituted samples. Using
experimentally derived structural data, we show that the electronic structure
evolves similarly in both cases. These results suggest that modification of the
Fermi surface by structural distortions is more important than charge doping
for inducing superconductivity in BaFe2As2
Clinicopathological and Prognostic Significance of PRAME Overexpression in Human Cancer: A Meta-Analysis
Numerous studies have demonstrated that preferentially expressed antigen in melanoma (PRAME) is abnormally expressed in various solid tumours. However, the clinicopathological features and prognostic value of the PRAME expression in patients with cancer remain unclear. Accordingly, we performed a meta-analysis to accurately assess the association of the expression level of PRAME with clinicopathological features and cancer prognosis. Relevant study collection was performed in PubMed, Web of Science, and Embase until 28 February 2020. A total of 14 original studies involving 2,421 patients were included. Our data indicated that the PRAME expression was significantly associated with tumour stage (OR=1.99, 95% CI: 1.48–2.67, P<0.001) and positive lymph node metastasis (OR=3.14, 95% CI: 1.99–4.97, P<0.001). Pooled results showed that overexpression of PRAME is positively correlated with poor disease-free survival (HR=1.60, 95% CI: 1.36–1.88, P<0.001), progression-free survival (HR=1.88, 95% CI: 1.02–3.46, P=0.042), metastasis-free survival (HR=1.86, 95% CI: 1.05–3.31, P=0.034), and overall survival (HR=1.75, 95% CI: 1.53–1.99, P<0.001). In summary, these data are suggesting that PRAME is tumorigenic and may serve as a prognostic biomarker for cancer
Faking photon number on a transition-edge sensor
We study potential security vulnerabilities of a single-photon detector based
on superconducting transition-edge sensor. In a simple experiment, we show that
an adversary could fake a photon number result at a certain wavelength by
sending a larger number of photons at a longer wavelength. In another
experiment, we show that the detector can be blinded by bright continuous-wave
light and then, a controlled response simulating single-photon detection can be
produced by applying a bright light pulse. We model an intercept-and-resend
attack on a quantum key distribution system that exploits the latter
vulnerability and, under certain assumptions, succeeds to steal the key.Comment: Replacing incorrectly uploaded previous versions. 6 page, 5 figure
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