45,271 research outputs found
Calculations for mosaics with plane and curved grating elements quarterly progress report no. 4
Review of calculations of plane grating mosaic for photon energ
Inelastic neutron scattering signal from deconfined spinons in a fractionalized antiferromagnet
We calculate the contribution of deconfined spinons to inelastic neutron
scattering (INS) in the fractionalized antiferromagnet (AF*), introduced
elsewhere. We find that the presence of free spin-1/2 charge-less excitations
leads to a continuum INS signal above the Neel gap. This signal is found above
and in addition to the usual spin-1 magnon signal, which to lowest order is the
same as in the more conventional confined antiferromagnet. We calculate the
relative weights of these two signals and find that the spinons contribute to
the longitudinal response, where the magnon signal is absent to lowest order.
Possible higher-order effects of interactions between magnons and spinons in
the AF* phase are also discussed.Comment: 9 page
Rocket study of the X-ray background
The X-ray optical detection system flown on Aerobee 17.08 is described in detail, and the preliminary results of the 24 June 1971 flight are discussed. The optical design, fabrication and parabolic nature of the mirrors, effective aperture of mirror array, and X-ray detectors are considered. Preliminary analysis of data from the flight confirms the extended nature and complex structure of the X-ray source in Virgo. A core of X-ray emission is indicated which is approximately 0.5 deg in diameter and surrounded by an emitting region at least 2 deg across. The Virgo source spectrum is observed to have few low energy photons
Quantum critical phenomena of long-range interacting bosons in a time-dependent random potential
We study the superfluid-insulator transition of a particle-hole symmetric
system of long-range interacting bosons in a time-dependent random potential in
two dimensions, using the momentum-shell renormalization-group method. We find
a new stable fixed point with non-zero values of the parameters representing
the short- and long-range interactions and disorder when the interaction is
asymptotically logarithmic. This is contrasted to the non-random case with a
logarithmic interaction, where the transition is argued to be first-order, and
to the Coulomb interaction case, where either a first-order transition or
an XY-like transition is possible depending on the parameters. We propose that
our model may be relevant in studying the vortex liquid-vortex glass transition
of interacting vortex lines in point-disordered type-II superconductors.Comment: 10 pages, 3 figure
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