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21.
The recent observation of the cosmic microwave background anisotropy by the WMAP confirmed that the lower multipoles are considerably suppressed. From the standpoint of the cosmic variance, it is nothing but a statistical accident. Alternatively, one can attribute the deficit of fluctuation on the large scale to the cosmic history, which might be explained in the context of the inflationary physics. In this Letter, we show that it is possible to explain the suppressed lower multipoles in the hybrid new inflation model. 相似文献
22.
We reconsider the evolution of strongly degenerate neutrinos in the early universe. Our chief concern is the validity of the entropy conservation after the neutrino annihilation process has frozen out (so that the establishment of chemical equilibrium is not trivial). We argue that the entropy indeed conserves because elastic scattering keeps the neutrino and antineutrino distribution functions in the equilibrium form and the sum of their chemical potential keeps zero even after the neutrino annihilation freeze-out. We also simulate the evolution of the degenerate neutrino spectrum to support the argument. We conclude that the change in the neutrino degeneracy parameter when the relativistic degrees of freedom in the universe decreases is calculated using the entropy conservation and the lepton number conservation without worrying about at what temperature the neutrino annihilation process freezes out. 相似文献
23.
M. Andachi T. Nakayama M. Kawasaki S. Kurokawa H.-P. Loock 《Applied physics. B, Lasers and optics》2007,88(1):131-135
Visible and near-infrared laser light pulses were coupled into two different types of optical fiber cavities. One cavity consisted
of a short strand of fiber waveguide that contained two identical fiber Bragg gratings. Another cavity was made using a loop
of optical fiber. In either cavity ∼40 ps laser pulses, which were generated using a custom-built gain-switched diode laser,
circulated for a large number of round trips. The optical loss of either cavity was determined from the ring-down times. Cavity
ring-down spectroscopy was performed on 200 pL volumes of liquid samples that were injected into the cavities using a 100 μm
gap in the fiber loop. A detection limit of 20 ppm of methylene blue dye in aqueous solution, corresponding to a minimum absorptivity
of εC<6 cm-1, was realized.
PACS 42.62.Fi; 42.81.-i 相似文献
24.
Abe K Adachi I Aihara H Arinstein K Asano Y Aulchenko V Aushev T Aziz T Bakich AM Balagura V Barbero M Bedny I Bitenc U Bizjak I Bondar A Bracko M Brodzicka J Browder TE Chao Y Chen A Cheon BG Chistov R Choi SK Choi Y Choi YK Chuvikov A Cole S Dalseno J Danilov M Dash M Drutskoy A Eidelman S Epifanov D Fratina S Gabyshev N Gershon T Gokhroo G Golob B Ha HC Haba J Hasegawa Y Hayasaka K Hayashii H Hazumi M Hinz L Hoshi Y Hou S Hou WS Hsiung YB Iijima T Ishikawa A Iwasaki M Iwasaki Y Kapusta P 《Physical review letters》2007,98(8):082001
We report the first observation of a charmoniumlike state recoiling from the J/psi in the inclusive process e+e- -->J/psi+anything at a mass of (3.943+/-0.006+/-0.006) GeV/c{2}. We also observe the decay of this state into D*D[over ] and determine its intrinsic width to be less than 52 MeV/c{2} at the 90% C.L. These results are obtained from a 357 fb{-1} data sample collected with the Belle detector near the Upsilon(4S) resonance, at the KEKB asymmetric-energy e+e- collider. 相似文献
25.
Measurement Accuracy in Phase-Shifting Point Diffraction Interferometer with Two Optical Fibers 总被引:1,自引:0,他引:1
Toshiaki Matsuura Satoru Okagaki Takaaki Nakamura Yasushi Oshikane Haruyuki Inoue Motohiro Nakano Toshihiko Kataoka 《Optical Review》2007,14(6):401-405
A phase-shifting point diffraction interferometer (PS/PDI) with point sources of two single mode optical fibers has been developed,
which will be appropriate for the surface figure measurement of large aperture optics on a sub-nanometer scale. To reduce
the measurement error factors, a fiber optic plate (FOP) is used as a projection plane for interference pattern. Errors caused
by imperfection of optical alignment, such as position of point sources and tilt of FOP, are minimized by analyzing the measured
phase data with an original method. Measurement accuracy in the PS/ PDI is estimated with the interference pattern produced
by the two optical fiber sources. If inhomogeneity of the FOP and a systematic error of the PS/PDI are eliminated, the measurement
accuracy of the present system is estimated to be less than 4nm P-V and 0.7nm rms, respectively, at a measurement wavelength
of 632.8 nm. 相似文献
26.
27.
Junichi Kinoshita Yoshihisa Ikeda Yuji Takeda Misaki Ueno Yoji Kawasaki Yoshiaki Matsuba Atsushi Heike 《Optical Review》2012,19(6):427-431
The speckle contrast of blue light emission out of high-brightness white lamps using phosphors excited by InGaN/GaN blue laser diodes is evaluated as a measure of coherence. As a result, speckle contrast of as low as 1.7%, the same level as a blue light emitting diode, is obtained. This implies that the original blue laser light can be converted into incoherent light through lamp structures without any dynamic mechanisms. This unique speckle-free performance is considered to be realized by multiple scattering inside the lamp structure, the multi-longitudinal mode operation of the blue laser diodes, and the use of multiple laser diodes. Such almost-incoherent white lamps can be applied for general lighting without any nuisance of speckle noise and should be categorized as lamps rather than lasers in terms of laser safety regulation. 相似文献
28.
Brodzicka J Palka H Adachi I Aihara H Aulchenko V Bakich AM Barberio E Bay A Bedny I Bitenc U Bondar A Bracko M Browder TE Chang MC Chang P Chen A Chen WT Cheon BG Chiang CC Chistov R Cho IS Choi SK Choi Y Dalseno J Danilov M Dash M Drutskoy A Eidelman S Gabyshev N Go A Gokhroo G Golob B Ha H Haba J Hara T Hayasaka K Hayashii H Hazumi M Heffernan D Hoshi Y Hou WS Hyun HJ Iijima T Ikado K Inami K Ishikawa A Ishino H Itoh R Iwasaki M Iwasaki Y Joshi NJ Kah DH Kang JH Kawai H Kawasaki T Kichimi H 《Physical review letters》2008,100(9):092001
We report the observation of a new DsJ meson produced in B+-->D0DsJ-->D0D0K+. This state has a mass of M=2708+/-9(-10)(+11) MeV/c2, a width Gamma=108+/-23(-31)(+36) MeV/c2 and a 1- spin-parity. The statistical significance of this observation is 8.4 sigma. The results are based on an analysis of 449 x 10(6) BB events collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. 相似文献
29.
A single-atom-sized gold wire was successfully observed in real time by a newly developed defocus-image modulation processing electron microscope. Because of phase retrieval processing with spherical aberration correction, the single-atom strand wire was observed with high contrast and without contrast blurring. By carefully looking at the atomic distance, the contrast, and the dynamic behavior of the wire, we recognized that there are two stages of the wire. In the first stage the wire maintained the atomic distance in the bulk crystal, but in the second stage the wire showed the atomic distance of the nearest-neighbor atoms with weaker contrast. The gold wire was rather stable for a few seconds under strong electron beam illumination. 相似文献
30.