Quantum detector tomography applied to the human visual system: a feasibility study.

We show that quantum detector tomography can be applied to the human visual system to explore human perception of photon number states. In detector tomography, instead of using very hard-to-produce photon number states, the response of a detector to light pulses with known photon statistics of varying intensity is recorded, and a model is fitted to the experimental outcomes, thereby inferring the detector's photon number state response. Generally, light pulses containing a Poisson-distributed number of photons are utilized, which are very easy to produce in the lab.

Treating gout - can hypouricemia produced by moderate doses of combined oral treatment give early treatment success? Preliminary observations.

Six male patients with gout were treated with combined oral medication (febuxostat, 120 mg/d, and benzbromarone, 50 or 100 mg/d), aiming at a more rapid success of uric acid lowering treatment (ULT) compared to guideline suggestions. By combined oral medication in moderate dosage, the sUA was reduced to <2 mg/dl in all cases. We conclude that, by the treatment schedule outlined, the majority of patients with gout can be cured within 1 - 2 years, with uricase treatment being necessary very rarely only.

Realignment-free cryogenic macroscopic optical cavity coupled to an optical fiber.

We present a cryogenic setup where an optical Fabry-Perot resonator is coupled to a single-mode optical fiber with coupling efficiency above 90% at mK temperatures without realignment during cooling down. The setup is prealigned at room temperature to compensate for the thermal contraction and change of the refractive index of the optical components during cooling down. The high coupling efficiency is achieved by keeping the setup rotation-symmetric around the optical axis.

Artificial Coherent States of Light by Multiphoton Interference in a Single-Photon Stream.

Coherent optical states consist of a quantum superposition of different photon number (Fock) states, but because they do not form an orthogonal basis, no photon number states can be obtained from it by linear optics. Here we demonstrate the reverse, by manipulating a random continuous single-photon stream using quantum interference in an optical Sagnac loop, we create engineered quantum states of light with tunable photon statistics, including approximate weak coherent states. We demonstrate this experimentally using a true single-photon stream produced by a semiconductor quantum dot in an optical microcavity, and show that we can obtain light with g^{(2)}(0)→1 in agreement with our theory, which can only be explained by quantum interference of at least 3 photons.

Stimulated Raman Adiabatic Passage in Optomechanics.

In multimode optomechanical systems, the mechanical modes can be coupled via the radiation pressure of the common optical mode, but the fidelity of the state transfer is limited by the optical cavity decay. Here we demonstrate stimulated Raman adiabatic passage (STIRAP) in optomechanics, where the optical mode is not populated during the coherent state transfer between the mechanical modes avoiding this decay channel. We show a state transfer of a coherent mechanical excitation between vibrational modes of a membrane in a high-finesse optical cavity with a transfer efficiency of 86%.

Refractory gout - does it exist?

Refractory gout (RG) has been increasingly recognized to be a major problem in clinical care. Patients diagnosed with RG have been assumed to be non-adherent, or under-dosed, to the greater part. In a minority, pathophysiological mechanisms have been discussed.

Electro-optic polarization tuning of microcavities with a single quantum dot.

We present an oxide aperture microcavity with embedded quantum dots which utilizes a three-contact design to independently tune the quantum dot wavelength and birefringence of the cavity modes. A polarization splitting tuning of ∼5  GHz is observed. For a typical microcavity polarization splitting, the method can be used to achieve perfect polarization degeneracy that is required for many polarization-based implementations of photonic quantum gates.

Observation of the Unconventional Photon Blockade.

We observe the unconventional photon blockade effect in quantum dot cavity QED, which, in contrast to the conventional photon blockade, operates in the weak coupling regime. A single quantum dot transition is simultaneously coupled to two orthogonally polarized optical cavity modes, and by careful tuning of the input and output state of polarization, the unconventional photon blockade effect is observed. We find a minimum second-order correlation g^{(2)}(0)≈0.

Pyogenic arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome: differential diagnosis of septic arthritis by regular detection of exceedingly high synovial cell counts.

Pyogenic arthritis, pyoderma gangrenosum and acne syndrome was diagnosed in a 42-year-old patient, after an unusual persistency of high synovial cell counts had been noticed. Clinical peculiarities and problems with diagnosing septic versus non-septic arthritis are discussed.

Purification of a single-photon nonlinearity.

Single photon nonlinearities based on a semiconductor quantum dot in an optical microcavity are a promising candidate for integrated optical quantum information processing nodes. In practice, however, the finite quantum dot lifetime and cavity-quantum dot coupling lead to reduced fidelity. Here we show that, with a nearly polarization degenerate microcavity in the weak coupling regime, polarization pre- and postselection can be used to restore high fidelity.

Observation of Four-Photon Orbital Angular Momentum Entanglement.

We demonstrate genuine multipartite quantum entanglement of four photons in their orbital angular momentum degrees of freedom, where a high-dimensional discrete Hilbert space is attached to each photon. This can encode more quantum information compared to the qubit case, but it is a long-standing problem to entangle more than two such photons. In our experiment we use pulsed spontaneous parametric down-conversion to produce the photon quadruplets, which allows us to detect about one four-photon event per second.

Homodyne detection of coherence and phase shift of a quantum dot in a cavity.

A homodyne measurement technique is demonstrated that enables direct observation of the coherence and phase of light that passed through a coupled quantum dot (QD)-microcavity system, which in turn enables clear identification of coherent and incoherent QD transitions. As an example, we study the effect of power-induced decoherence, where the QD transition saturates and incoherent emission from the excited state dominates at higher power. Further, we show that the same technique allows measurement of the quantum phase shift induced by a single QD in the cavity, which is strongly enhanced by cavity quantum electrodynamics effects.

Eigenpolarizations for giant transverse optical beam shifts.

We show how careful control of the incident polarization of a light beam close to the Brewster angle gives a giant transverse spatial shift on reflection. This resolves the long-standing puzzle of why such beam shifts transverse to the incident plane (Imbert-Fedorov shifts) tend to be an order of magnitude smaller than the related Goos-Hänchen shifts in the longitudinal direction, which are largest close to critical incidence. We demonstrate that with the proper initial polarization the transverse displacements can be equally large, which we confirm experimentally near Brewster incidence.

Health status and utilisation of the healthcare system by homeless and non-homeless people in Vienna.

This case-control study describes the health situation, internal and external resources, and utilisation of healthcare facilities by a marginalised population consisting of homeless people in Vienna, Austria, compared with a non-homeless control population. Among the homeless group, participants lived in halfway houses (70%) or permanent housing (30%) in Vienna. Personal interviews were conducted in July 2010 with 66 homeless individuals, and their data were compared with data from non-homeless subjects from the Austrian Health Interview Survey using conditional logistic regression.

Walsh modes and radial quantum correlations of spatially entangled photons.

Orthogonal sets of 2D transverse modes are key to controlling the spatial degree of freedom of light in a classical or quantum context. In contrast to the azimuthal part, which is easily accessible using orbital angular momentum modes, control of the radial part is more difficult. We show here that simple sets of orthogonal binary sequences, the Walsh functions, provide a workable solution for exploration of the radial space with phase-only spatial light modulation.

Spatial coherence and optical beam shifts.

A beam of light, reflected at a planar interface, does not follow perfectly the ray optics prediction. Diffractive corrections lead to beam shifts; the reflected beam is displaced (spatial Goos-Hänchen type shifts) and/or travels in a different direction (angular Imbert-Fedorov type shifts), as compared to geometric optics. How does the degree of spatial coherence of light influence these shifts? We investigate this issue first experimentally and find that the degree of spatial coherence influences the angular beam shifts, while the spatial beam shifts are unaffected.

Instability of higher-order optical vortices analyzed with a multi-pinhole interferometer.

Higher-order optical vortices are inherently unstable in the sense that they tend to split up in a series of vortices with unity charge. We demonstrate this vortex-splitting phenomenon in beams produced with holograms and spatial light modulators and discuss its generic and practically unavoidable nature. To analyze the splitting phenomena in detail, we use a multi-pinhole interferometer to map the combined amplitude and phase profile of the optical field.

Observation of orbital angular momentum sidebands due to optical reflection.

We investigate how the orbital angular momentum of a paraxial light beam is affected upon reflection at a planar interface. Theoretically, the unavoidable angular spread of the beam leads to orbital angular momentum sidebands, which are found to be already significant for a modest beam spread (0.05).

Full-field quantum correlations of spatially entangled photons.

Spatially entangled twin photons allow the study of high-dimensional entanglement, and the Laguerre-Gauss modes are the most commonly used basis to discretize the single-photon mode spaces. In this basis, to date only the azimuthal degree of freedom has been investigated experimentally due to its fundamental and experimental simplicity. We show that the full spatial entanglement is indeed accessible experimentally; i.

Fiber transport of spatially entangled photons.

Entanglement in the spatial degrees of freedom of photons is an interesting resource for quantum information. For practical distribution of such entangled photons, it is desirable to use an optical fiber, which in this case has to support multiple transverse modes. Here we report the use of a hollow-core photonic crystal fiber to transport spatially entangled qubits.

Search for Hermite-Gauss mode rotation in cholesteric liquid crystals.

In theory, there are analogous transformations of light's spin and orbital angular momentum [Allen and Padgett, J. Mod. Opt.

Localized and delocalized modes in coupled optical micropillar cavities.

Optical micropillar Bragg cavities of different diameters and coupled by a small bridge have been realized experimentally by means of a focused ion beam system. The resonator modes in these coupled microcavities are either localized in one pillar or delocalized over the whole photonic structure, a fact that could be exploited to control the coupling between two spatially separated quantum dots, i.e.

Patient acceptance of diagnostic laparoscopy.

Purpose: To assess patient acceptance of diagnostic conventional laparoscopy and minilaparoscopy under sedoanalgesia.

Materials And Methods: 120 consecutive patients undergoing diagnostic laparoscopy were enrolled prospectively in this study. Within the first week after diagnostic laparoscopy the patients were asked to answer a total of eight questions with regard to the acceptance of the procedure.

Late-onset schizophrenia versus paranoid psychoses: a valid diagnostic distinction?

Objective: The authors tested the validity of the diagnostic distinction between schizophrenia and delusional disorder of late onset.

Methods: Authors examined hospital case registers.

Results: A clear distinction between these diagnostic groups is not possible, irrespective of whether a descriptive, predictive, or construct-based approach is taken.