489 research outputs found
Ray transfer matrix for a spiral phase plate
We present a ray transfer matrix for a spiral phase plate. Using this matrix,
we determine the stability of an optical resonator made of two spiral phase
plates, and trace stable ray orbits in the resonator. Our results should be
relevant to laser physics, optical micromanipulation, quantum information and
optomechanics.Comment: 5 pages, 3 figure
Polarization control of single photon quantum orbital angular momentum states
The orbital angular momentum of photons, being defined in an infinitely
dimensional discrete Hilbert space, offers a promising resource for
high-dimensional quantum information protocols in quantum optics. The biggest
obstacle to its wider use is presently represented by the limited set of tools
available for its control and manipulation. Here, we introduce and test
experimentally a series of simple optical schemes for the coherent transfer of
quantum information from the polarization to the orbital angular momentum of
single photons and vice versa. All our schemes exploit a newly developed
optical device, the so-called "q-plate", which enables the manipulation of the
photon orbital angular momentum driven by the polarization degree of freedom.
By stacking several q-plates in a suitable sequence, one can also access to
higher-order angular momentum subspaces. In particular, we demonstrate the
control of the orbital angular momentum degree of freedom within the
subspaces of and per photon. Our experiments prove
that these schemes are reliable, efficient and have a high fidelity.Comment: 9 pages, 8 figure
CNOT and Bell-state analysis in the weak-coupling cavity QED regime
We propose an interface between the spin of a photon and the spin of an
electron confined in a quantum dot embedded in a microcavity operating in the
weak coupling regime. This interface, based on spin selective photon reflection
from the cavity, can be used to construct a CNOT gate, a multi-photon entangler
and a photonic Bell-state analyzer. Finally, we analyze experimental
feasibility, concluding that the schemes can be implemented with current
technology.Comment: 4 pages, 2 figure
Experimental demonstration of fractional orbital angular momentum entanglement of two photons
The singular nature of a non-integer spiral phase plate allows easy
manipulation of spatial degrees of freedom of photon states. Using two such
devices, we have observed very high dimensional (D > 3700) spatial entanglement
of twin photons generated by spontaneous parametric down-conversion.Comment: submitted to Phys. Rev. Let
Coronary Vulnerability
This thesis aims to improve risk stratification of patients with coronary artery disease. Parts 1 and 2, respectively known as âVulnerable Bloodâ and âVulnerable Periodâ aimed at elucidating the role of various serum biomarkers, and repeated measurements thereof, in order to identify patients at increased risk of myocardial infarction, and more specifically to identify the specific timeframe of that increased risk.
Part 3, âVulnerable Plaqueâ is focused on invasive coronary imaging (coronary angiography, intravascular ultrasound and near-infrared spectroscopy) and the detection of prognostic plaque characteristics, as well as the relation between plaque components and serum biomarkers.
Part 4 âIntervention Studiesâ describes the search for those patient subsets to derive most benefit from current (pharmacologic) interventions in coronary artery disease
Individualized AngiotensinâConverting Enzyme (ACE)âInhibitor Therapy in Stable Coronary Artery Disease Based on Clinical and Pharmacogenetic Determinants: The PERindopril GENEtic (PERGENE) Risk Model
Patients with stable coronary artery disease (CAD) constitute a heterogeneous group in which the treatment benefits by angiotensin-converting enzyme (ACE)-inhibitor therapy vary between individuals. Our objective was to integrate clinical and pharmacogenetic determinants in an ultimate combined risk prediction model.Clinical, genetic, and outcomes data were used from 8726 stable CAD patients participating in the EUROPA/PERGENE trial of perindopril versus placebo. Multivariable analysis of phenotype data resulted in a clinical risk score (range, 0-21 points). Three single-nucleotide polymorphisms (rs275651 and rs5182 in the angiotensin-II type I-receptor gene and rs12050217 in the bradykinin type I-receptor gene) were used to construct a pharmacogenetic risk score (PGXscore; range, 0-6 points). Seven hundred eighty-five patients (9.0%) experienced the primary endpoint of cardiovascular mortality, nonfatal myocardial infarction or resuscitated cardiac arrest, during 4.2 years of follow-up. Absolute risk reductions ranged from 1.2% to 7.5% in the 73.5% of patients with PGXscore of 0 to 2. As a consequence, estimated annual numbers needed to treat ranged from as low as 29 (clinical risk score â„10 and PGXscore of 0) to 521 (clinical risk score â€6 and PGXscore of 2). Furthermore, our data suggest that long-term perindopril prescription in patients with a PGXscore of 0 to 2 is cost-effective.Both baseline clinical phenotype, as well as genotype determine the efficacy of widely prescribed ACE inhibition in stable CAD. Integration of clinical and pharmacogenetic determinants in a combined risk prediction model demonstrated a very wide range of gradients of absolute treatment benefit
Generation of hybrid polarization-orbital angular momentum entangled states
Hybrid entangled states exhibit entanglement between different degrees of
freedom of a particle pair and thus could be useful for asymmetric optical
quantum network where the communication channels are characterized by different
properties. We report the first experimental realization of hybrid
polarization-orbital angular momentum (OAM) entangled states by adopting a
spontaneous parametric down conversion source of polarization entangled states
and a polarization-OAM transferrer. The generated quantum states have been
characterized through quantum state tomography. Finally, the violation of
Bell's inequalities with the hybrid two photon system has been observed.Comment: 6 pages, 3 figure
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