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Background The clobetasol propionate cream formulations (CLBCr) belong to the “strongest” group, and are used widely. In addition, those formulations are often used as a mixture with moisturizer. Recently, we evaluated pharmaceutical properties of the CLBCr using near infrared (NIR) spectroscopy, and characteristic NIR spectra depending on the formulation were observed. In the present study, we attempted to evaluate the more diverse pharmaceutical properties of CLBCr, including the stability of mixture of CLBCr and moisturizer. Method Pharmaceutical properties of CLBCr were evaluated using from rheological characteristics, microscopic observation, dye permeability observations, electrical conductivity method, thermogravimetry-differential thermal analysis (TG-DTA) and near infrared (NIR) spectroscopy. Stability of mixtures of CLBCr and moisturizer were evaluated using from dye method and NIR spectroscopy. Results The hardness of Dermovate® (DRM), Glydil® (GDL), and Myalone® (MYA) was greater than that of CLBCr. High concentrations of white beeswax were considered the reason for the hardness of DRM and GDL. On the other hand, the hardness of MYA may be due to the presence of macrogol 6000. After storage of the cream formulations discharged from the tube at room temperature, mass reduction and attenuation of the peak reflecting water of NIR spectroscopy occurred in a time-dependent manner, except for GDL and MYA. Only GDL was shown to be a w/o-type formulation by dye and electric conductivity measurements, which suggested that this was the reason for the lack of changes in the mass or NIR spectrum of samples after storage. In the NIR spectrum of MYA, the peak reflecting water slightly increased in a time-dependent manner, suggesting the water absorption of macrogol 6000. TG-DTA provided curves indicating the presence of water in each formulation, except for MYA, which was consistent with water quantification previously reported. Finally, when mixing the CLBCr with a moisturizer, in any CLBCr, the stability of the mixture with w/o-type moisturizer varies greatly depending on the each CLBCr. Conclusion Thus, even for cream formulations with the same active pharmaceutical ingredient, pharmaceutical properties and stability of mixture with moisturizer may different significantly.

Optical approaches to AI acceleration have gained intense interest recently due to the potentially breakthrough advantages of photonics: high bandwidth, low power consumption, and efficient data movement. We overview leading photonic AI platforms based on beamsplitter mesh networks, weight banks, and photoelectric multiplication. While the theoretical performance can be orders of magnitude beyond current state of the art, practical issues of chip area, input / output, and crosstalk paint a more nuanced near-term picture of photonic AI acceleration. Both fundamental and near-term limitations to energy efficiency are addressed, and bandwidth limitations due to temporal crosstalk are analyzed.

Substandard medicine is a type of substandard/spurious/falsely labeled/falsified/counterfeit (SSFFC) drug as defined by the WHO that has permeated the distribution of drugs on the Internet, and is accessible without prescription. An influx of substandard medicines is thus a serious matter in many developed countries. Here, Lipitor and its generic drugs containing atorvastatin calcium (ATC), used for the treatment of hyperlipidemia worldwide, were selected as a model prescription drug. Six brands of ATC tablets were purchased from four Japanese-language web sites. Raman spectroscopy and powder X-ray diffraction (PXRD) were employed to determine ATC and ingredients in the tablets. Although PXRD measurements showed no diffraction peaks of ATC because of its low content, a handheld Raman spectrometer detected ATC in unmodified tablets (without crushing). The tablets were assayed for drug content and dissolution profile according to the Japanese Pharmacopoeia, and one product showed an obviously slower drug release. X-ray computed tomography (CT) showed the interior of the tablet in detail and suggested that massive agglomerations caused slow disintegration of the tablet. This is the first report applying X-ray CT to tablets obtained on the Internet and indicates that unqualified prescription drugs are easily distributed on the Internet without any quality assurance.

A practical closed recirculation aquaculture system (CRAS) for seed production has been developed by Fisheries Research Agency (FRA) in Yashima Laboratory. This system consists of a culturing tank, reservoir tank (with filter treatment by collection nets), foam separation unit, biofiltration unit, UV disinfection unit, water level control tank, and recirculation pump. The foam separation unit is the most important equipment in CRAS for seed production. This is because CRAS has a high ability to remove suspended matter in the water by using microbubbles. Optimum control conditions of CRAS for seed production have been shown efficient biofilter materials and recirculation rate in biofilter and total system. Seed production using CRAS is more advanced than the flow-through system. Using CRAS, the advantages of low salinity seed production of tiger puffer, Takifugu rubripes, and high density culturing (20,000 fishes/kL of 25 mm in TL) for red sea bream, Pagrus major, seed production were demonstrated. Preventing diseases such as VNN was proved in seed production for red-spotted grouper, Epinephelus akaara, using CRAS in Kagawa Prefectural Fisheries Experimental Station.

A quantum simulator is a purposeful quantum machine that can address complex quantum problems in a controllable setting and an efficient manner. This chapter introduces a solid-state quantum simulator platform based on exciton-polaritons, which are hybrid light-matter quantum quasi-particles. We describe the physical realization of an exciton-polariton quantum simulator in semiconductor materials (hardware) and discuss a class of problems, which the exciton-polariton quantum simulators can address well (software). A current status of the experimental progress in building the quantum machine is reviewed, and potential applications are considered.

We review the national projects on quantum information science and technology in Japan over the past 30 years. The main funding agencies for this field have been the Japan Science and Technology Agency, the National Institute of Information and Communications Technology, the Japan Society for the Promotion of Science, and the Cabinet Office of the Government of Japan. The total investment in the quantum information science and technology field from these funding agencies for the past 15 years amounts to US$250 million. A similar amount of investment has been put in parallel by industry. As a result, new science frontiers have been created, and some service prototypes, such as quantum key distribution systems and coherent Ising machines, have been delivered to user premises. Recently, Japan has launched new initiatives to advance quantum information science and technology to the next phase, and to make full use of them for the resolution of societal problems.

Differences in local topography (micro-elevation) within a paddy field that constitute a source of variability in agronomical indicators have not been considered thoroughly as a block factor in weed studies. This study investigated and evaluated the performance of weeding machines (weeders) in two herbicide-free paddy fields that contained micro-elevations. The plant density of Monochoria vaginalis, a typical and harmful paddy weed unless controlled with herbicides, was used as the indicator of the efficacy of the weeders. Among the three weeders that were tested, one suppressed M. vaginalis dramatically at low elevations and the others were less sensitive to micro-elevation. For comparison across the fields, micro-elevations at weed sampling locations were converted to the initial depth of water by using the records of hydrographs that had been set in each field. The relationship between the initial depth of water and the plant density of M. vaginalis was very clear with the use of the elevation-sensitive weeder. Moreover, this relationship was valid, even with the less-sensitive weeders. The finding that the greater the depth of water, the less the plant density was significant, even for M. vaginalis, a difficult aquatic paddy weed that was controlled with any of the weeders tested. Thus, micro-elevation within a paddy field needs to be treated as a crucial block factor in weed-sampling studies. A coarse survey of the level of a field and the installation of a hydrograph are recommended for a clear analysis of the background of weed control practices.

Conventional semiconductor laser emission relies on stimulated emission of photons1, 2, which sets stringent requirements on the minimum amount of energy necessary for its operation3, 4. In comparison, exciton–polaritons in strongly coupled quantum well microcavities5 can undergo stimulated scattering that promises more energy-efficient generation of coherent light by ‘polariton lasers’3, 6. Polariton laser operation has been demonstrated in optically pumped semiconductor microcavities at temperatures up to room temperature7, 8, 9, 10, 11, 12, and such lasers can outperform their weak-coupling counterparts in that they have a lower threshold density12, 13. Even though polariton diodes have been realized14, 15, 16, electrically pumped polariton laser operation, which is essential for practical applications, has not been achieved until now. Here we present an electrically pumped polariton laser based on a microcavity containing multiple quantum wells. To prove polariton laser emission unambiguously, we apply a magnetic field and probe the hybrid light–matter nature of the polaritons. Our results represent an important step towards the practical implementation of polaritonic light sources and electrically injected condensates, and can be extended to room-temperature operation using wide-bandgap materials.

Although exciton–polariton lasers have been experimentally demonstrated in a variety of material systems, robust practical implementations are still challenging. Similarities with atomic Bose–Einstein condensates make the system suitable for chip-based quantum simulators for non-trivial many-body physics.

In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates -- sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity -- have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband whereas many remain elusive. Understanding the observation will lead to a development in non-equilibrium many-body physics., 18 pages, 5 figures + 23 pages, 9 figures

An optical parametric oscillator network driven by a quantum measurement-feedback circuit, composed of optical homodyne detectors, analog-to-digital conversion devices and field programmable gate arrays (FPGA), is proposed and analysed as a scalable coherent Ising machine. The new scheme has an advantage that a large number of optical coupling paths, which is proportional to the square of a problem size in the worst case, can be replaced by a single quantum measurement-feedback circuit. There is additional advantage in the new scheme that a three body or higher order Ising interaction can be implemented in the FPGA digital circuit. Noise associated with the measurement-feedback process is governed by the standard quantum limit. Numerical simulation based on c-number coupled Langevin equations demonstrate a satisfying performance of the proposed Ising machine against the NP-hard MAX-CUT problems.

We develop reduced models that describe half-harmonic generation in a synchronously-pumped optical parametric oscillator above threshold, where nonlinearity, dispersion, and group-velocity mismatch are all relevant. These models are based on (1) an eigenmode expansion for low pump powers, (2) a simulton-like sech-pulse ansatz for intermediate powers, and (3) dispersionless box-shaped pulses for high powers. Analytic formulas for pulse compression, degenerate vs. nondegenerate operation, and stability are derived and compared to numerical and experimental results., Comment: 22 pages, 24 figures. Submitted to Phys. Rev. A

Combinatorial optimization problems are ubiquitous in our modern life. The classic examples include the protein folding in biology and medicine, the frequency assignment in wireless communications, traffic control and routing in air and on surface, microprocessor circuit design, computer vision and graph cut in machine learning, and social network control. They often belong to NP, NP-complete and NP-hard classes, for which modern digital computers and future quantum computers cannot find solutions efficiently, i.e. in polynomial time [1].

The application of pulsed cavity ring-down spectroscopy (CRDS) was demonstrated for the measurement of nitrogen dioxide (NO2) in automotive exhaust gas. The transition of the ν 3 vibrational band assigned to the antisymmetric stretching mode of NO2 was probed with a thermoelectrically cooled, pulsed, mid-infrared, distributed feedback, quantum cascade laser (QCL) at 6.13 μm. The measurement of NO2 in the exhaust gas from two diesel vehicles equipped with different aftertreatment devices was demonstrated using a CRDS-based NO2 sensor, which employs a HEPA filter and a membrane gas dryer to remove interference from water as well as particulates in the exhaust gas. Stable and sensitive measurement of NO2 in the exhaust gas was achieved for more than 30 minutes with a time resolution of 1 s.

Devices based on group II-VI semiconductors, and in particular ZnSe, show several advantages for single-photon sources in comparison to group III-V and group IV devices. Additionally, the spin system of the neutral 19 F donor has strong potential as a quantum memory. Here, we summarize these advantages and some initial demonstrations of the promise of 19 F:ZnSe for quantum information, including the observation of the interference of photons from independent single 19 F:ZnSe emitters and the fabrication of 19 F-doped microdisk cavities showing low-threshold lasing.

We present a simple method to create an in-plane lateral potential in a semiconductor microcavity using a metal thin-film. Two types of potential are produced: a circular aperture and a one-dimensional (1D) periodic grating pattern. The amplitude of the potential induced by a 24 nm – 6 nm Au/Ti film is on the order of a few hundreds of μeV measured at 6–8 K. Since the metal layer makes the electromagnetic fields to be close to zero at the metal–semiconductor interface, the photon mode is confined more inside of the cavity. As a consequence, the effective cavity length is reduced under the metal film, and the corresponding cavity resonance is blue-shifted. Our experimental results are in a good agreement with theoretical estimates. In addition, by applying a DC electric voltage to the metal film, we are able to modify the quantum well exciton mode due to the quantum confined Stark effect, inducing a ∼1 meV potential at ∼20 kV/cm. Our method produces a controllable in-plane spatial trap potential for lower exciton-polaritons (LPs), which can be a building block towards 1D arrays and 2D lattices of LP condensates. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The magnetization and the coercivity of Co and Fe thin films in the thickness range 10–200 nm deposited onto GaAs(0 0 1) substrate were studied. Coercivity of Co and Fe thin films increases with increase in film thickness. Coercivity increased from 10 to 80 Oe as thickness of Co films increased from 50 to 100 nm. In the Fe/GaAs system, coercivity increased from 30 to 180 Oe as thickness of Fe films increased from 40 to 100 nm. The surface roughness measurements of Fe films indicate that enhancement of coercivity is due to surface roughness of the film. On the other hand, it was observed from the AFM study that the enhancement of coercivity was not due to surface roughness of Co film. It is speculated that the enhanced coercivity of Co/GaAs is due to a special interaction between Co film and GaAs substrate, since the enhancement of coercivity did not appear in Co films deposited on Si(0 0 1) substrate.

We summarize our earlier research showing how the radiative properties of an individual InAs quantum dot exciton state can be altered by their spatial and spectral position with respect to a discrete semiconductor microcavity mode. The InAs quantum dot is formed epitaxially in GaAs, and the microcavity is processed from a one-wavelength distributed Bragg reflector planar microcavity of GaAs and AlAs to form a sub-micrometer diameter pillar. Two states are tuned through a discrete cavity mode through sample temperature changes and show a spontaneous emission enhancement of 4. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Quantum key distribution (QKD) offers an unconditionally secure means of communication based on the laws of quantum mechanics. Currently, a major challenge is to achieve a QKD system with a 40 dB channel loss, which is required if we are to realize global scale QKD networks using communication satellites. Here we report the first QKD experiment in which secure keys were distributed over 42 dB channel loss and 200 km of optical fibre. We employed the differential phase shift quantum key distribution (DPS-QKD) protocol implemented with a 10-GHz clock frequency, and superconducting single photon detectors (SSPD) based on NbN nanowire. The SSPD offers a very low dark count rate (a few Hz) and small timing jitter (60 ps full width at half maximum). These characteristics allowed us to construct a 10-GHz clock QKD system and thus distribute secure keys over channel loss of 42 dB. In addition, we achieved a 17 kbit/s secure key rate over 105 km of optical fibre, which is two orders of magnitude higher than the previous record, and a 12.1 bit/s secure key rate over 200 km of optical fibre, which is the longest terrestrial QKD yet demonstrated. The keys generated in our experiment are secure against both general collective attacks on individual photons and a specific collective attack on multi-photons, known as a sequential unambiguous state discrimination (USD) attack., 15 pages, 5 figures. Original version

本研究では，各種ゴム支承を対象として速度ベース載荷法を用いる実時間ハイブリッド実験システムを開発し，一連の高速・実時間ハイブリッド実験を行った．研究の目的は，新たに開発された実験システムの性能を検証するとともに，この実験法により免震ゴム支承の地震時応答を直接的に確認することである．天然ゴム系支承(NR)および高減衰ゴム支承(HDR)と,より減衰性能を高めたHDR-S を対象に，実時間サブストラクチャ・ハイブリッド実験を行い，これらのゴム支承を設置した免震橋梁の地震時応答を検討した．その結果，ゴム支承の免震性能の相違をより実現象に近い状態で評価することが可能であることを確認するとともに，HDR 支承より減衰性能の高いHDR-S 支承の方が免震効果が高くなることを明らかにした．

Practical quantum communication between remote quantum memories rely on single photons at telecom wavelengths. Although spin-photon entanglement has been demonstrated in atomic and solid-state qubit systems, the produced single photons at short wavelengths and with polarization encoding are not suitable for long-distance communication, because they suffer from high propagation loss and depolarization in optical fibres. Establishing entanglement between remote quantum nodes would further require the photons generated from separate nodes to be indistinguishable. Here, we report the observation of correlations between a quantum-dot spin and a telecom single photon across a 2-km fibre channel based on time-bin encoding and background-free frequency downconversion. The downconverted photon at telecom wavelengths exhibits two-photon interference with another photon from an independent source, achieving a mean wavepacket overlap of greater than 0.89 despite their original wavelength mismatch (900 and 911 nm). The quantum-networking operations that we demonstrate will enable practical communication between solid-state spin qubits across long distances., Quantum communication requires quantum correlations between the information processing units and the information carrying units. Here, the authors use time-bin encoding and frequency downconversion to telecom wavelengths to achieve kilometre-scale spin-photon correlations.

A two-site Ising model is implemented as an injection-locked laser network consisting of a single master laser and two mutually coupled slave lasers. We observed ferromagnetic and antiferromagnetic orders in the in-phase and out-of-phase couplings between the two slave lasers. Their phase difference is locked to either 0 or p even if the coupling path is continuously modulated. The system automatically selects the oscillation frequency to satisfy the in-phase or out-of-phase coupling condition, when the mutual coupling dominates over the injection-locking by the master laser., 12 pages, 9 figures

We investigate optical spin pumping of self-assembled p-type δ-doped InAs quantum dots as well as site-controlled InP nanowire quantum dots and find that they are both promising for scalable quantum information processing platforms., CLEO: QELS - Fundamental Science, CLEO_QELS 2015, 10 May 2015 through 15 May 2015

We theoretically investigate a new type of lateral trap that can be used to confine quantum well excitons. By sending an ultrahigh frequency bulk acoustic wave from the substrate of III–V semiconductors such as GaAs or GaN, an oscillating piezoelectric field is generated. The effective potential induced by the oscillating piezoelectric field implements a type I lateral trap. Such a controllable quantum confinement is essential in many semiconductor nano-electronics and nano-photonics applications.

Photonic crystal cavities can localize light into nanoscale volumes with high quality factors. This permits a strong interaction between light and matter, which is important for the construction of classical light sources with improved properties (e.g., low threshold lasers) and of nonclassical light sources (such as single and entangled photon sources) that are crucial pieces of hardware of quantum information processing systems. This article will review some of our recent experimental and theoretical results on the interaction between single quantum dots and photonic crystal cavity fields, and on the integration of multiple photonic crystal devices into functional circuits for quantum information processing., 6 pages, 6 figures; replaced with revised version

In recent years, high damping rubber (HDR) bridge bearings have become widely used because of the excellent ability to provide high damping as well as flexibility. However, there are few systematic studies on the deterioration problems of HDRs during their service life, and usually the long-term performance was not considered in the design stage. In this research, through accelerated thermal oxidation tests on HDR blocks, the property variations inside the HDR bridge bearing are examined. A deterioration prediction model is developed to estimate the property profiles. Then using a constitutive model and carrying out FEM analysis, the behavior of a HDR bridge bearing during its lifespan is clarified. A design procedure is proposed that takes the long-term performance in the site environment into consideration.

We examine the photoluminescence of highly-excited exciton-polariton condensates in semiconductor microcavities. Under strong pumping, exciton-polariton condensates have been observed to undergo a lasing transition where strong coupling between the excitons and photons is lost. We discuss an alternative high-density scenario, where the strong coupling is maintained. We find that the photoluminescence smoothly transitions between the lower polariton energy to the cavity photon energy. An intuitive understanding of the change in spectral characteristics is given, as well as differences to the photoluminescence characteristics of the lasing case., Comment: 5 pages, 4 figures

Micromachining of magnetic materials is becoming a crucial technology for future magnetic systems/devices such as high-density magnetic recording heads, high-density patterned media, magnetic quantum devices, and micro-magnetic smart systems. NiFe alloy, one of the typical ferromagnetic materials, can be deposited and fabricated using current thin film and micromachining technologies, and it has found various applications in microsensors, microactuators, and microsystems. In our recent work, Ni45Fe55 alloy with the highest saturation magnetic-flux density was selected as the micro-magnet for an all-silicon quantum computer. The micro-magnet was designed to create a large magnetic field gradient and to distinguish 29 Si nuclear spins arranged as chains in a 28 Si matrix with Larmor frequencies. This paper reports the micromachining of a Ni45Fe55 alloy mesa structure for an all-silicon quantum computer and the preliminary evaluation of its effectiveness using a magnetic force microscope (MFM) an da superconducting quantum interference device (SQUID). (Some figures in this article are in colour only in the electronic version)

This article reviews recent work on non-classical light generation using semiconductor quantum dots. Experimental results for single-photon generation are presented, including suppression of the two-photon probability, coherence properties and two-photon interference. An experiment demonstrating generation of polarization-correlated photon pairs from biexciton recombination is also reviewed.

We review our recent observation of exciton-polariton lasing and discuss new time-resolved spectra, imaging and angular dispersion data with regards to a possible Bose-Einstein condensate of polaritons. A brief outlook on our activities towards a clearer observation of polariton lasing is given.

The experimental studies on active control of vortex shedding frequency were conducted to suppress fluid-dynamic forces of a square cylinder.Each sidewall of the cylinder consists of four vibrating side-plates equipped with piezoelectric actuators. The vortex shedding frequency was controlled by means of a lock-in phenomenon that was caused by vibrating the side-plates transversely with amplitude less than 100μm. The results are summarized as follows : (1) the spanwise synchronous excitation brings about reduction of the time-averaged drag coefficient Cd. It is reduced by approximately 20% of the natural condition. (2) When a half span of sidewall surface is vibrated with 180 degrees differential phase against the other half span, the vortices shed from each half span in the reversal phase mode. The fluctuating lift coefficient Cl' is reduced by approximately 70% of the natural condition with the reversal phase mode.

The visible light photon counter (VLPC) features high quantum efficiency (QE) and low pulse height dispersion. These properties make it ideal for efficient photon-number state detection. The ability to perform efficient photon-number state detection is important in many quantum information processing applications, including recent proposals for performing quantum computation with linear optical elements. In this paper, we investigate the unique capabilities of the VLPC. The efficiency of the detector and cryogenic system is measured at 543 nm wavelengths to be 85%. A picosecond pulsed laser is then used to excite the detector with pulses having average photon numbers ranging from 3-5. The output of the VLPC is used to discriminate photon numbers in a pulse. The error probability for number state discrimination is an increasing function of the number of photons, due to buildup of multiplication noise. This puts an ultimate limit on the ability of the VLPC to do number state detection. For many applications, it is sufficient to discriminate between 1 and more than one detected photon. The VLPC can do this with 99% accuracy.

The formation of macroscopic coherence associated with a Bose–Einstein phase transition in excitons has long been sought for. We review our recent observation of related effects of exciton–polariton lasing in a semiconductor microcavity.

We report a set of experiments designed to test the quantum indistinguishability of single photons emitted by a resonantly pumped Inas/GaAs quantum dot, embedded in a microcavity. We first performed high resolution interferometric measurements on the source to infer its coherence time. By comparison with the exciton lifetime, obtained by time-resolved spectroscopy, we found that some quantum dots were emitting almost transform-limited photons. The measured ratio of the coherence time to the pulse duration gives a lower bound on the dephasing time which agrees well with previous studies. We then directly measured the mean overlap between wave packets of consecutive photons emitted 2 ns apart, through a Hong-Ou-Mandel type two-photon interference experiment. For the best dot, an overlap as high as 0.81 was inferred. This result suggests that quantum dots could be a practical single photon source to perform quantum information processing experiments. We stress the importance of the microcavity for identical photon generation.

The emission from two InAs quantum dots is coupled to the fundamental cavity mode of a micropost cavity. The emission from each quantum dot is spectrally separated by approximately 2 nm. By adjusting the sample temperature the single exciton emission from each quantum dot is spectrally tuned in and out of resonance with the cavity mode. The ratio of the spontaneous emission decay rate at on and off resonance conditions is nearly 4 for both quantum dots.

Refractive indices of GaAs and AlAs at high temperature have been extracted by combining the high resolution X-ray diffraction and optical reflectivity measurement techniques. The comparison between the empirical formulas and experimental data on the indices of GaAs and AlAs has been made. A good agreement between them allows us to use empirical formulas to calculate the indices of GaAs and AlAs at high temperature over a wide wavelength range. The extracted data have been successfully employed in GaAs/AlAs DBR MBE growth.

Using a micropost cavity, the emission from a quantum dot (QD) is coupled to the discrete fundamental optical mode of the cavity. By adjusting the temperature of the device between 4 and 70 K, the coupling between the QD and the cavity can be tuned. The ratio of the spontaneous emission decay rate between on and off resonance is approximately 4.

We have demonstrated efficient production of triggered single photons by coupling a single semiconductor quantum dot to a three-dimensionally confined optical mode in a micropost microcavity. The efficiency of emitting single photons into a single-mode travelling wave is approximately 38%, which is nearly two orders of magnitude higher than for a quantum dot in bulk semiconductor material. At the same time, the probability of having more than one photon in a given pulse is reduced by a factor of seven as compared to light with Poissonian photon statistics.

We report 2 patients who received medical guidance during immunosuppressive therapy involving the administration of antithymocyte globulin (ATG) and cyclosporin A (CyA) for complicated aplastic anemia. In case 1, during the second administration of ATG, side effects manifested as allergic reaction and serum sickness. In case 2, the side effects after the first administration of ATG were the same as those in case 1. An antimycotic drug that can increase the blood concentration of CyA was also administered in case 1. The BUN level, which is a marker of renal function, was slightly elevated. In both cases, drug compliance for CyA was good, and the trough blood concentration of CyA remained within the objective concentration. Levels of leucocyte, neurophils and thrombocytes tended to the recover after combined administration of both drugs in the 2 patients. However, the patient's quality of life (QOL) decreased remarkably due to a deterioration of the stomatitis, since the host was immunocompromised. The patient's QOL improved by the administration of narcotic analgesics. In case 2, the stomatitis did not worsen, since infection was prevented by the use of a clean room and care of the oral cavity. This study suggests that appropriate pharmaceutical care during immunosuppressive therapy contributes to QOL maintenance in patients with aplastic anemia.

A solid-state quantum computer composed entirely of semiconductor silicon is proposed. Qubits are nuclear spins, I = 1/2, of 29Si stable isotopes in the form of atomic chains embedded in a nuclear-spin free matrix of 28Si stable isotopes. Each 29Si nuclear spin in a chain can be accessed selectively with a different resonant frequency (rf) due to a large magnetic field gradient created by a nearby micromagnet, i.e., unitary operations needed for quantum computing can be performed by fine tuning of the rf. Ensemble readout of qubits from 105 copies of the atomic chain is accomplished by magnetic resonance force microscopy.

A phase transition from a classical thermal mixed state to a quantum-mechanical pure state of exciton polaritons is observed in a GaAs multiple quantum-well microcavity from the decrease of the second-order coherence function. Supporting evidence is obtained from the observation of a nonlinear threshold behavior in the pump-intensity dependence of the emission, a polariton-like dispersion relation above threshold, and a decrease of the relaxation time into the lower polariton state. The condensation of microcavity exciton polaritons is confirmed.

We examined whether mixed allogeneic transplantation with syngeneic plus allogeneic peripheral blood stem cells (PBSCs) is sufficient to interrupt autoimmune processes in BXSB mice and confer a potential therapeutic option for the treatment of patients with autoimmune diseases. Eight-week-old BXSB mice were lethally irradiated and reconstituted with BALB/c (H-2d)+BXSB (H-2b) PBSCs, in which the number of injected allogeneic progenitor cells was 5 times that of syngeneic progenitor cells. The survival of mixed PBSC chimeras (BALB/c+BXSB→BXSB) was 80% at the age of 48 weeks, whereas that of full chimeras (BALB/c→BXSB) was 90%. Mixed PBSC transplantation (PBSCT) prevented the production of anti-DNA antibodies and the development of lupus nephritis in BXSB recipients and induced tolerance to both allogeneic and syngeneic antigens. Moreover, mixed chimeras exhibited immunological functions superior to fully allogeneic chimeras. On the other hand, increases in the number of BXSB PBSCs resulted in the transfer of lupus nephritis in BXSB+BALB/c→BALB/c mice. Thus, the number of hematopoietic progenitor cells from normal mice proved critical to the prevention of autoimmune diseases. We propose that mixed allogeneic PBSCT for the interruption of the autoimmune process can be carried out by injecting increased numbers of allogeneic normal hematopoietic progenitor cells to prevent the relapse of autoimmune diseases, although it is necessary to decide upon a minimum dose of syngeneic PBSCs to achieve the desired beneficial effects on autoimmunity.

Current quantum cryptography systems are limited by the attenuated coherent pulses they use as light sources: a security loophole is opened up by the possibility of multiple-photon pulses. By replacing the source with a single-photon emitter, transmission rates of secure information can be improved. We have investigated the use of single self-assembled InAs/GaAs quantum dots as such single-photon sources, and have seen a tenfold reduction in the multi-photon probability as compared to Poissonian pulses. An extension of our experiment should also allow for the generation of triggered, polarization-entangled photon pairs. The utility of these light sources is currently limited by the low efficiency with which photons are collected. However, by fabricating an optical microcavity containing a single quantum dot, the spontaneous emission rate into a single mode can be enhanced. Using this method, we have seen 78% coupling of single-dot radiation into a single cavity resonance. The enhanced spontaneous decay should also allow for higher photon pulse rates, up to about 3 GHz.

We previously described a unique procedure for the collection of bone marrow cells (BMCs) using a perfusion method (PM). In cynomolgus monkeys, this method resulted in lower contamination with T cells (

Excitons in semiconductors can have multiple lifetimes due to spin dependent oscillator strengths and interference between different recombination pathways. In addition, strain and symmetry effects can further modify lifetimes via the removal of degeneracies. We present a convenient formalism for predicting the optical properties of ${k=0}$ excitons with an arbitrary number of charge carriers in different symmetry environments. Using this formalism, we predict three distinct lifetimes for the neutral acceptor bound exciton in GaAs, and confirm this prediction through polarization dependent and time-resolved photoluminescence experiments. We find the acceptor bound-exciton lifetimes to be ${T_o (1,3,3/4)}$ where ${T_o = (0.61 \pm 0.12) \text{ns}}$. Furthermore, we provide an estimate of the intra-level and inter-level exciton spin-relaxation rates., 5 pages, 3 figures, supplemental information included

Exciton-polariton lasers are operated in the strong light matter coupling regime. They promise low threshold operation since population inversion is not inherently necessary. Hence they are of great interest for next generation coherent light sources. Published version

Here we summarize the advantages of excitons bound to isolated fluorine donor in ZnSe/ZnMgSe quantum well nano-structures. Devices based on these semiconductors, are particularly suited to implement concepts of the optical manipulation of quantum states in solid-state material. The fluorine donor in ZnSe provides a physical qubit with potential advantages over previously researched qubits. In this context we show several initial demonstrations of devices, such as a low-threshold microdisk laser and an indistinguishable single photon source. Additionally we demonstrate the realization of a controllable three-level-system qubit consisting of a single Fluorine donor in a ZnSe nano-pillar, which provides an optical accessible single electon spin qubit.

Despite their name polariton lasers do not rely on stimulated emission of cavity photons. The less stringent threshold conditions are the cause that bosonic polariton lasers can outperform standard lasers in terms of their threshold currents. The part-light and part-matter quasiparticles called polaritons, can undergo a condensation process into a common energy state. The radiated light from such a system shares many similarities with the light emitted from a conventional photon laser, even though the decay of the polaritons out of the finite lifetime cavity is a spontaneous process. We discuss properties of polariton condensates in GaAs based microcavities. The system’s response to an external magnetic field is used as a reliable tool to distinguish between polariton laser and conventional photon laser. In particular, we will discuss the realization of an electrically pumped polariton laser, which manifests a major step towards the exploitation of polaritonic devices in the real world. Published version