On the theory of polarization transfer in inhomogeneous magnetized plasmas

Polarization transfer theory in inhomogeneous magnetized plasmas with mode couplin

Anharmonicity Induced Resonances for Ultracold Atoms and their Detection

When two atoms interact in the presence of an anharmonic potential, such as an optical lattice, the center of mass motion cannot be separated from the relative motion. In addition to generating a confinement-induced resonance (or shifting the position of an existing Feshbach resonance), the external potential changes the resonance picture qualitatively by introducing new resonances where molecular excited center of mass states cross the scattering threshold. We demonstrate the existence of these resonances, give their quantitative characterization in an optical superlattice, and propose an experimental scheme to detect them through controlled sweeping of the magnetic field.Comment: 6 pages, 5 figures; expanded presentatio

Quantum Teleportation from a Propagating Photon to a Solid-State Spin Qubit

The realization of a quantum interface between a propagating photon used for transmission of quantum information, and a stationary qubit used for storage and manipulation, has long been an outstanding goal in quantum information science. A method for implementing such an interface between dissimilar qubits is quantum teleportation, which has attracted considerable interest not only as a versatile quantum-state-transfer method but also as a quantum computational primitive. Here, we experimentally demonstrate transfer of quantum information carried by a photonic qubit to a quantum dot spin qubit using quantum teleportation. In our experiment, a single photon in a superposition state of two colors -- a photonic qubit is generated using selective resonant excitation of a neutral quantum dot. We achieve an unprecedented degree of indistinguishability of single photons from different quantum dots by using local electric and magnetic field control. To teleport a photonic qubit, we generate an entangled spin-photon state in a second quantum dot located 5 meters away from the first and interfere the photons from the two dots in a Hong-Ou-Mandel set-up. A coincidence detection at the output of the interferometer heralds successful teleportation, which we verify by measuring the resulting spin state after its coherence time is prolonged by an optical spin-echo pulse sequence. The demonstration of successful inter-conversion of photonic and semiconductor spin qubits constitute a major step towards the realization of on-chip quantum networks based on semiconductor nano-structures.Comment: 12 pages, 3 figures, Comments welcom

Cryopreservation of Coffea liberica Seeds and Embryos following desiccation and freezing treatments

Desiccation of Coffea liberica seeds for 6 days in an air-conditioned room reduced seed and attached emltryo moisture from 52.58% and 47.49% to 14.58% and 12.56% respectively. Seed germination and viability of the attached emltryo were maintained at moderate levels of 66% and 38% respectively. However, none of the desiccated seeds or embryos survived freezing in liquid nitrogen. Excised emltryos desiccated in the lamina flow cabinet lost their moisture very rapidly from 36.8% to 9.27% within 1.5 hours. More than 70% of these emltryos survived the desiccation. Moreover, partially desiccated emltryos at 17.17% moisture or less survived subfreezing temperatures. Between 35% to 50% survived slow freezing to -3ffC, but this was reduced to approximately 30% when they were subsequently plunged into liquid nitrogen. Fast freezing by direct plunge into liquid nitrogen also resulted in 10% to 35% survival. Desiccation ofexcised coffee embryos for 0.5h to 17.17% moisture was optimal for eryopreservation, irrespective of the speed offreezing. Differential thermal analyses of seed tissues suggest that the absence of freezable water is an important factor for successful eryopreservation of excised coffee emltryos. However, the importance of initial vigour, moisture variation and recovery media is also discussed

Large-Scale Gravitational Instability and Star Formation in the Large Magellanic Cloud

Large-scale star formation in disk galaxies is hypothesized to be driven by global gravitational instability. The observed gas surface density is commonly used to compute the strength of gravitational instability, but according to this criterion star formation often appears to occur in gravitationally stable regions. One possible reason is that the stellar contribution to the instability has been neglected. We have examined the gravitational instability of the Large Magellanic Cloud (LMC) considering the gas alone, and considering the combination of collisional gas and collisionless stars. We compare the gravitationally unstable regions with the on-going star formation revealed by Spitzer observations of young stellar objects. Although only 62% of the massive young stellar object candidates are in regions where the gas alone is unstable, some 85% lie in regions unstable due to the combination of gas and stars. The combined stability analysis better describes where star formation occurs. In agreement with other observations and numerical models, a small fraction of the star formation occurs in regions with gravitational stability parameter Q > 1. We further measure the dependence of the star formation timescale on the strength of gravitational instability, and quantitatively compare it to the exponential dependence expected from numerical simulations.Comment: Accepted for publication in ApJ, 10 pages, 5 figure

AST/RO Observations of CO J=4-3 Emission from the N44 Complex in the Large Magellanic Cloud

We present Antarctic Submillimeter Telescope and Remote Observatory (AST/RO) observations of 12CO J=4-3 and C I emission in the N44 H II complex in the Large Magellanic Cloud. We detected strong 12CO J=4-3 emission toward the H II region called as N44BC, which is located on the rim of an expanding giant shell in the N44 region. Analysis with a photodissociation region (PDR) model showed that the 12CO J=4-3 emitting cloud is very dense, with n ~ 10^5 cm^-3. We also note that there is a high-velocity component associated with the 12CO J=4-3 emission. This probably originates from molecular material accelerated as a result of the motion induced by the expanding giant shell surrounding LH47 in the N44 complex. We found that the kinetic energy of this high-velocity gas observed in the CO J=4-3 emission toward the rim of the expanding H II shell is at least an order of magnitude higher than the kinetic energy derived for the H I and H II gas in this region.Comment: 11 pages, 5 figures, submitted to Ap