3,372 research outputs found
A Possible Spin-Orbit Misalignment in the Transiting Eccentric Planet HD 17156b
We present simultaneous photometric and spectroscopic observations of HD
17156b spanning a transit on UT 2007 November 12. This system is of special
interest because of its 21-day period (unusually long for a transiting planet)
and its high orbital eccentricity of 0.67. By modeling the Rossiter-McLaughlin
effect, we find the angle between the sky projections of the orbital axis and
the stellar rotation axis to be . Such a large
spin-orbit misalignment, as well as the large eccentricity, could be explained
as the relic of a previous gravitational interaction with other planets.Comment: 5 pages, 2 figures, 3 tables. Accepted for publication in PASJ
Letters (Vol. 60, No. 2
Single-photon emitting diode in silicon carbide
Electrically driven single-photon emitting devices have immediate
applications in quantum cryptography, quantum computation and single-photon
metrology. Mature device fabrication protocols and the recent observations of
single defect systems with quantum functionalities make silicon carbide (SiC)
an ideal material to build such devices. Here, we demonstrate the fabrication
of bright single photon emitting diodes. The electrically driven emitters
display fully polarized output, superior photon statistics (with a count rate
of 300 kHz), and stability in both continuous and pulsed modes, all at room
temperature. The atomic origin of the single photon source is proposed. These
results provide a foundation for the large scale integration of single photon
sources into a broad range of applications, such as quantum cryptography or
linear optics quantum computing.Comment: Main: 10 pages, 6 figures. Supplementary Information: 6 pages, 6
figure
Identification of antifungal molecules from novel probiotic Lactobacillus bacteria for control of Candida infection
1. Probiotic lactic acid bacteria were identified to have antifungal properties against Candida albicans.
2. The cell-free supernatant of the lactic acid bacteria was successfully fractionated and purified using fast performance liquid chromatography.
3. Eight of the 41 fractions containing the antifungal components exhibited a growth inhibitory effect against C albicans.published_or_final_versio
Single-dot spectroscopy via elastic single-electron tunneling through a pair of coupled quantum dots
We study the electronic structure of a single self-assembled InAs quantum dot
by probing elastic single-electron tunneling through a single pair of weakly
coupled dots. In the region below pinch-off voltage, the non-linear threshold
voltage behavior provides electronic addition energies exactly as the linear,
Coulomb blockade oscillation does. By analyzing it, we identify the s and p
shell addition spectrum for up to six electrons in the single InAs dot, i.e.
one of the coupled dots. The evolution of shell addition spectrum with magnetic
field provides Fock-Darwin spectra of s and p shell.Comment: 7 pages, 3 figures, Accepted for publication in Phys. Rev. Let
A silicon carbide room temperature single-photon source
Over the past few years, single-photon generation has been realized in numerous systems: single molecules 1 , quantum dots 2-4 , diamond colour centres 5 and others 6 . The generation and detection of single photons play a central role in the experimental foundation of quantum mechanics 7 and measurement theory 8 . An efficient and high-quality single-photon source is needed to implement quantum key distribution, quantum repeaters and photonic quantum information processing 9 . Here we report the identification and formation of ultrabright, room-temperature, photostable single-photon sources in a device-friendly material, silicon carbide (SiC). The source is composed of an intrinsic defect, known as the carbon antisite- vacancy pair, created by carefully optimized electron irradiation and annealing of ultrapure SiC. An extreme brightness (210 6 counts s 1 ) resulting from polarization rules and a high quantum efficiency is obtained in the bulk without resorting to the use of a cavity or plasmonic structure. This may benefit future integrated quantum photonic devices 9
Simple test for high Jc and low Rs superconducting thin films
A simple method, fishing high-Tc superconductor thin films out of liquid
nitrogen bath by a permanent magnet (field > Hc1) due to the effect of high
flux pinning, has been suggested to identify films having high critical current
density (Jc > 106 A/cm2 at 77 K) and thus a low microwave surface resistance
(Rs). We have demonstrated that a Nd-Fe-B magnet, having a maximum field of ~
0.5 T, could fish out Tl-1223 superconducting thin films on LSAT substrate with
a thickness of ~ 5000 Angstrong having Jc > 1 MA/cm2 (at 77 K) whereas it could
not fish out other films with Jc < 0.1 MA/cm2 at 77 K. The fished out films
exhibit Rs values 237 - 245 ((at 77 K and 10 GHz, which is lower than that (Rs
= 317 (() of the best YBCO film at the same temperature and frequency. On the
other hand, the non-fishable films show very high Rs values. This method is a
very simple tool to test for high Jc and good microwave properties of
superconducting films of large area which otherwise require a special and
expensive tool.Comment: 5 pages including 2 figures, to be published as Rapid Commun. in
Supercond. Sci. Techno
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