3,085 research outputs found
Searching for Doubly-Charged Higgs Bosons at Future Colliders
Doubly-charged Higgs bosons () appear in several
extensions to the Standard Model and can be relatively light. We review the
theoretical motivation for these states and present a study of the discovery
reach in future runs of the Fermilab Tevatron for pair-produced doubly-charged
Higgs bosons decaying to like-sign lepton pairs. We also comment on the
discovery potential at other future colliders.Comment: 6 pages, full postscript file also available via anonymous ftp at
ftp://ucdhep.ucdavis.edu/gunion/hmm_sm96.ps To appear in ``Proceedings of the
1996 DPF/DPB Summer Study on New Directions for High Energy Physics'
Optimizing Quantum Models of Classical Channels: The reverse Holevo problem
Given a classical channel---a stochastic map from inputs to outputs---the
input can often be transformed to an intermediate variable that is
informationally smaller than the input. The new channel accurately simulates
the original but at a smaller transmission rate. Here, we examine this
procedure when the intermediate variable is a quantum state. We determine when
and how well quantum simulations of classical channels may improve upon the
minimal rates of classical simulation. This inverts Holevo's original question
of quantifying the capacity of quantum channels with classical resources. We
also show that this problem is equivalent to another, involving the local
generation of a distribution from common entanglement.Comment: 13 pages, 6 figures;
http://csc.ucdavis.edu/~cmg/compmech/pubs/qfact.htm; substantially updated
from v
Extreme Quantum Advantage for Rare-Event Sampling
We introduce a quantum algorithm for efficient biased sampling of the rare
events generated by classical memoryful stochastic processes. We show that this
quantum algorithm gives an extreme advantage over known classical biased
sampling algorithms in terms of the memory resources required. The quantum
memory advantage ranges from polynomial to exponential and when sampling the
rare equilibrium configurations of spin systems the quantum advantage diverges.Comment: 11 pages, 9 figures;
http://csc.ucdavis.edu/~cmg/compmech/pubs/eqafbs.ht
A procedure for assessing aircraft turbulence- penetration performance
Subsonic transport aircraft performance assessment during atmospheric turbulenc
Increased HCO production in the outer disk around HD 163296
Three formaldehyde lines were observed (HCO 3--2, HCO
3--2, and HCO 3--2) in the protoplanetary disk
around the Herbig Ae star HD 163296 with ALMA at 0.5 arcsecond (60 AU) spatial
resolution. HCO 3--2 was readily detected via imaging, while
the weaker HCO 3--2 and HCO 3--2 lines
required matched filter analysis to detect. HCO is present throughout most
of the gaseous disk, extending out to 550 AU. An apparent 50 AU inner radius of
the HCO emission is likely caused by an optically thick dust continuum. The
HCO radial intensity profile shows a peak at 100 AU and a secondary bump at
around 300 AU, suggesting increased production in the outer disk. Different
parameterizations of the HCO abundance were compared to the observed
visibilities with minimization, using either a characteristic
temperature, a characteristic radius or a radial power law index to describe
the HCO chemistry. Similar models were applied to ALMA Science Verification
data of CO. In all modeling scenarios, fits to the HCO data show an
increased abundance in the outer disk. The overall best-fit HCO model shows
a factor of two enhancement beyond a radius of 27020 AU, with an inner
abundance of . The HCO emitting region has a lower
limit on the kinetic temperature of K. The CO modeling suggests
an order of magnitude depletion in the outer disk and an abundance of in the inner disk. The increase in HCO outer disk emission
could be a result of hydrogenation of CO ices on dust grains that are then
sublimated via thermal desorption or UV photodesorption, or more efficient
gas-phase production beyond about 300 AU if CO is photodisocciated in this
region
Active localization of virtual sounds
We describe a virtual sound display built around a 12 MHz 80286 microcomputer and special purpose analog hardware. The display implements most of the primary cues for sound localization in the ear-level plane. Static information about direction is conveyed by interaural time differences and, for frequencies above 1800 Hz, by head sound shadow (interaural intensity differences) and pinna sound shadow. Static information about distance is conveyed by variation in sound pressure (first power law) for all frequencies, by additional attenuation in the higher frequencies (simulating atmospheric absorption), and by the proportion of direct to reverberant sound. When the user actively locomotes, the changing angular position of the source occasioned by head rotations provides further information about direction and the changing angular velocity produced by head translations (motion parallax) provides further information about distance. Judging both from informal observations by users and from objective data obtained in an experiment on homing to virtual and real sounds, we conclude that simple displays such as this are effective in creating the perception of external sounds to which subjects can home with accuracy and ease
Uniformity of V minus Near Infrared Color Evolution of Type Ia Supernovae, and Implications for Host Galaxy Extinction Determination
From an analysis of SNe 1972E, 1980N, 1981B, 1981D, 1983R, 1998bu, 1999cl,
and 1999cp we find that the intrinsic V-K colors of Type Ia SNe with
multi-color light curve shape (MLCS) parameter -0.4 < Delta < +0.2 suggest a
uniform color curve. V-K colors become bluer linearly with time from roughly
one week before B-band maximum until one week after maximum, after which they
redden linearly until four weeks after maximum. V-H colors exhibit very similar
color evolution. V-J colors exhibit slightly more complex evolution, with
greater scatter. The existence of V minus near infrared color relations allows
the construction of near infrared light curve templates that are an improvement
on those of Elias et al. (1985).
We provide optical BVRI and infrared JHK photometry of the Type Ia supernovae
1999aa, 1999cl, and 1999cp. SN 1999aa is an overluminous "slow decliner" (with
Delta = -0.47 mag). SN 1999cp is a moderately bright SN unreddened in its host.
SN 1999cl is extremely reddened in its host. The V minus near infrared colors
of SN 1999cl yield A_V = 2.01 +/- 0.11 mag. This leads to a distance for its
host galaxy (M 88) in agreement with other distance measurements for members of
the Virgo cluster.Comment: 57 pages, 13 postscript figures, to appear in the August 20, 2000,
issue of the Astrophysical Journal. Contains updated references and a number
of minor corrections dealt with when page proofs were correcte
Expanding Institutional Arrangements for Acquiring Water for Environmental Purposes: Transactions Evidence for the Western United States
Market purchases of water rights for environmental purposes in the western United States have involved purchases by public agencies of at least 88 850 acre feet of water over the last five years. Annual water leasing for environmental purposes has been more active, with 1.72 million acre feet leased in the western United States. The most frequent reasons for these transactions are for wildlife (primarily waterfowl), recreation and fisheries. The average price paid for a water right is 30 per acre foot for an annual water lease. As evidenced by the ability of government agencies to purchase water in voluntary transactions, environmental uses of water are often competitive with many low-value agricultural crops in the western United States
Expanding Institutional Arrangements for Acquiring Water for Environmental Purposes: Transactions Evidence for the Western United States
Market purchases of water rights for environmental purposes in the western United States have involved purchases by public agencies of at least 88 850 acre feet of water over the last five years. Annual water leasing for environmental purposes has been more active, with 1.72 million acre feet leased in the western United States. The most frequent reasons for these transactions are for wildlife (primarily waterfowl), recreation and fisheries. The average price paid for a water right is 30 per acre foot for an annual water lease. As evidenced by the ability of government agencies to purchase water in voluntary transactions, environmental uses of water are often competitive with many low-value agricultural crops in the western United States
Coupled Oscillators with Chemotaxis
A simple coupled oscillator system with chemotaxis is introduced to study
morphogenesis of cellular slime molds. The model successfuly explains the
migration of pseudoplasmodium which has been experimentally predicted to be
lead by cells with higher intrinsic frequencies. Results obtained predict that
its velocity attains its maximum value in the interface region between total
locking and partial locking and also suggest possible roles played by partial
synchrony during multicellular development.Comment: 4 pages, 5 figures, latex using jpsj.sty and epsf.sty, to appear in
J. Phys. Soc. Jpn. 67 (1998
- …