1,832 research outputs found
High-energy head-on collisions of particles and hoop conjecture
We investigate the apparent horizon formation for high-energy head-on
collisions of particles in multi-dimensional spacetime. The apparent horizons
formed before the instance of particle collision are obtained analytically.
Using these solutions, we discuss the feature of the apparent horizon formation
in the multi-dimensional spacetime from the viewpoint of the hoop conjecture.Comment: 4pages, 4figure
All-optical multiphoton absorption figures of merit: Polydiacetylene poly (bis para-toluene sulfonate) of 2,4-hexadiyne-1,6 diol
The all-optical switching figures of merit are reported for the single crystal PTS (polydiacetylene poly (bis para-toluene sulfonate) of 2,4-hexadiyne-1,6 diol). Included are the effects of the absorption mechanisms from linear up to four-photon over the wavelength range 1.2-2.2 mum
Aging, rejuvenation, and memory effects in short-range Ising spin glass: CuCoCl-FeCl graphite bi-intercalation compound
Non-equilibrium aging dynamics in 3D Ising spin glass
CuCoCl-FeCl GBIC has been studied by zero-field
cooled (ZFC) magnetization and low frequency AC magnetic susceptibility ( Hz), where K. The time dependence of the
relaxation rate dd for the ZFC magnetization
after the ZFC aging protocol, shows a peak at a characteristic time
near a wait time (aging behavior), corresponding to a crossover from
quasi equilibrium dynamics to non-equilibrium. The time strongly
depends on , temperature (), magnetic field (), and the
temperature shift (). The rejuvenation effect is observed in both
and under the -shift and -shift
procedures. The memory of the specific spin configurations imprinted during the
ZFC aging protocol can be recalled when the system is re-heated at a constant
heating rate. The aging, rejuvenation, and memory effects observed in the
present system are discussed in terms of the scaling concepts derived from
numerical studies on 3D Edwards-Anderson spin glass model.Comment: 14 pages, 14 figures; Eur. Phys. J. B accepted for publicatio
Interference Commensurate Oscillations in Q1D Conductors
We suggest an analytical theory to describe angular magnetic oscillations
recently discovered in quasi-one-dimensional conductor (TMTSF)2PF6 [see Phys.
Rev. B, 57, 7423 (1998)] and define the positions of the oscillation minima.
The origin of these oscillations is related to interference effects resulting
from an interplay of quasi-periodic and periodic ("commensurate") electron
trajectories in an inclined magnetic field. We reproduce via calculations
existing experimental data and predict some novel effects.Comment: 10 pages, 2 figure
Absorption spectrum in the wings of the potassium second resonance doublet broadened by helium
We have measured the reduced absorption coefficients occurring in the wings
of the potassium 4S-5P doublet lines at 404.414 nm and at 404.720 nm broadened
by helium gas at pressures of several hundred Torr. At the experimental
temperature of 900 K, we have detected a shoulder-like broadening feature on
the blue wing of the doublet which is relatively flat between 401.8 nm and
402.8 nm and which drops off rapidly for shorter wavelengths, corresponding to
absorption from the X doublet Sigma+ state to the C doublet Sigma+ state of the
K-He quasimolecule. The accurate measurements of the line profiles in the
present work will sharply constrain future calculations of potential energy
surfaces and transition dipole moments correlating to the asymptotes He-K(5p),
He-K(5s), and He-K(3d).Comment: 2 figure
Anomalous geoelectrical and geomagnetic signals observed at Southern Boso Peninsula, Japan
Geoelectrical and geomagnetic fluctuations are considered the end product of several geophysical phenomena. In
particular these signals measured in seismically active areas can be attributed to stress and strain changes associated
with earthquakes. The complexity of this problem has suggested the development of advanced sophysticated methods
to investigate the heterogeneous nature of these fluctuations. In this paper, we analyzed the time dynamics of
short-term variability of geoelectrical potential differences and geomagnetic fields obsereved at Kiyosumi (KYS),
Uchiura (UCU), and Fudago (FDG) stations, located in the southern part of Boso Peninsula, one of the most seismically
active areas in Japan. Anomalous changes in electric and magnetic fields are obeserved in mid-night on October
6, 2002. the anomalous signals observed on October 6, 2002 are different from those originated from the train
and other cultural noises according to the investigation on preferred directions of geoelectric field. The investigation
of simaltaneous geomagnetic field changes suggest that the source of the electromagnetic change might be generated
by underground current because of the polarity pattern oberved at KYS, UCU and FDG. Therefore, electrokinetic
assumption under the ground seems one of the possible solutions for the generation of anomalous signals. It is important
to understand the ULF electromagnetic environment for the study on the preparation process of crustal activity
and systematic understanding both electromagnetic and seismic phenomena
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