4,014 research outputs found
Particle Propagator of Spin Calogero-Sutherland Model
Explicit-exact expressions for the particle propagator of the spin 1/2
Calogero-Sutherland model are derived for the system of a finite number of
particles and for that in the thermodynamic limit. Derivation of the expression
in the thermodynamic limit is also presented in detail. Combining this result
with the hole propagator obtained in earlier studies, we calculate the spectral
function of the single particle Green's function in the full range of the
energy and momentum space. The resultant spectral function exhibits power-law
singularity characteristic to correlated particle systems in one dimension.Comment: 43 pages, 6 figure
A Frictional Cooling Demonstration Experiment with Protons
Muon cooling is the main technological obstacle in the building of a muon
collider. A muon cooling scheme based on Frictional Cooling holds promise in
overcoming this obstacle. An experiment designed to demonstrate the Frictional
Cooling concept using protons was undertaken. Although the results were
inconclusive in the observation of cooling, the data allowed for the
qualification of detailed simulations which are used to simulate the
performance of a muon collider.Comment: 24 Pages 16 figures 2 table
The Distribution of H2O Maser Emission in the Nucleus of NGC 4945
We present the first interferometer map of the water maser emission in the
active nucleus of NGC 4945. Although the declination of the galaxy is about -49
degrees, we were able to make the observations with the southernmost antennas
of the Very Long Baseline Array. Strong maser emission is present in three
velocity ranges, one near the systemic velocity and two shifted roughly
symmetrically by +/-(100-150) km/s. This is the first detection of highly
blue-shifted water emission in NGC 4945. We determined the position of the
maser to be RA(B1950)= 13 02 32.28 +/- 0.02 ; Dec(B1950)= -49 12 01.9 +/- 0.1.
The uncertainties in earlier estimates are at least several arcseconds. The
maser lies within 2'' (36 pc at a distance of 3.7 Mpc) of the peaks in 1.4 GHz
continuum and 1.6 micron emission from the nucleus. The mappable maser emission
is distributed roughly linearly over about 40 milliarcseconds (0.7 pc) at a
position angle of about 45 degrees, which is close to the 43 +/- 2 degree
position angle of the galactic disk. The red and blue-shifted emission
symmetrically stradle the systemic emission on the sky, which suggests material
in edge-on circular motion around a central object. The position-velocity
structure indicates a binding mass of about one million Suns, within a volume
of radius about 0.3 pc. This implies that the central engine radiates on the
order of 10% of its Eddington luminosity.Comment: 18 pages, including 5 Postscript figures. Accepted for publication in
ApJ Letter
First-principles study on dielectric properties of NaCl crystal and ultrathin NaCl films under finite external electric field
We present a first-principles study on the dielectric properties of an NaCl
crystal and ultrathin NaCl films under a finite external electric field. Our
results show that the high-frequency dielectric constant of the films is not
affected by the finite size effect from crystal surfaces and is close to that
of the crystal, whereas the static one is sensitive to the thickness of the
film due to the difference in the atomic configurations between the surface and
inside of the film.Comment: 11 pages and 4 figure
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