4,225 research outputs found
Think Different: Applying the Old Macintosh Mantra to the Computability of the SUSY Auxiliary Field Problem
Starting with valise supermultiplets obtained from 0-branes plus field
redefinitions, valise adinkra networks, and the "Garden Algebra," we discuss an
architecture for algorithms that (starting from on-shell theories and, through
a well-defined computation procedure), search for off-shell completions. We
show in one dimension how to directly attack the notorious "off-shell auxiliary
field" problem of supersymmetry with algorithms in the adinkra network-world
formulation.Comment: 28 pages, 1 figur
Studies on the Reduction of Radon Plate-Out
The decay of common radioactive gases, such as radon, produces stable
isotopes by a sequence of daughter particles with varied half-lives. These
daughter particles are a significant source of gamma, neutron, and alpha
particle backgrounds that can mimic desired signals in dark matter and
neutrinoless double beta decay experiments. In the LUMINA Laboratory at
Southern Methodist University (SMU), studies of radon plate-out onto copper
samples are conducted using one of XIA's first five UltraLo 1800 alpha
counters. We present results from investigations into various mitigation
approaches. A custom-built copper holder (in either plastic or metal) has been
designed and produced to maximize the copper's exposure to 220Rn. The 220Rn
source is a collection of camping lantern mantles. We present the current
status of control and experimental methods for addressing radon exposure
levels.Comment: 4 pages, 1 figure, Conference Proceedings for Low Radioactivity
Techniques 201
An exploration of occupation in nursing home residents with dementia
Objectives: This study evaluated the sitting room environment of two nursing homes
in Ireland, using interactive occupation and social engagement as outcome measures
and defining these rooms as occupational spaces.
Method: Snapshot observational recordings were made in the main sitting rooms
during the periods of time when the rooms were in most active use. Narrative
information was also recorded.
Results: Residents were more likely to occupy their time in the main sitting room
passively, rather than in interactive occupation and social engagement. The nursing
home residents with dementia spent approximately 70% of their daily time in the
main sitting room areas in states of occupational disengagement.
Discussion: Additional insight is provided through pragmatic narrative descriptions
of the functioning of the main sitting room environment in terms of interactive
occupation and social engagement.
Relevance: The research study demonstrates a methodology for evaluating the
sitting room areas of a care environment, using interactive occupation and social
engagement as outcome measures,which can be used for descriptive and comparative
insights into the performance of care environments
Generation of Optical Coherent State Superpositions by Number-Resolved Photon Subtraction from Squeezed Vacuum
We have created heralded coherent state superpositions (CSS), by subtracting
up to three photons from a pulse of squeezed vacuum light. To produce such CSSs
at a sufficient rate, we used our high-efficiency photon-number-resolving
transition edge sensor to detect the subtracted photons. This is the first
experiment enabled by and utilizing the full photon-number-resolving
capabilities of this detector. The CSS produced by three-photon subtraction had
a mean photon number of 2.75 -0.24/+0.06 and a fidelity of 0.59 -0.14/+0.04
with an ideal CSS. This confirms that subtracting more photons results in
higher-amplitude CSSs.Comment: Main manuscript and supplementary materia
Detection-Loophole-Free Test of Quantum Nonlocality, and Applications
We present a source of entangled photons that violates a Bell inequality free
of the "fair-sampling" assumption, by over 7 standard deviations. This
violation is the first experiment with photons to close the detection loophole,
and we demonstrate enough "efficiency" overhead to eventually perform a fully
loophole-free test of local realism. The entanglement quality is verified by
maximally violating additional Bell tests, testing the upper limit of quantum
correlations. Finally, we use the source to generate secure private quantum
random numbers at rates over 4 orders of magnitude beyond previous experiments.Comment: Main text: 5 pages, 2 figures, 1 table. Supplementary Information: 7
pages, 2 figure
Type II Supernova Light Curves and Spectra From the CfA
We present multiband photometry of 60 spectroscopically-confirmed supernovae
(SN): 39 SN II/IIP, 19 IIn, one IIb and one that was originally classified as a
IIn but later as a Ibn. Forty-six have only optical photometry, six have only
near infrared (NIR) photometry and eight have both optical and NIR. The median
redshift of the sample is 0.016. We also present 192 optical spectra for 47 of
the 60 SN. All data are publicly available. There are 26 optical and two NIR
light curves of SN II/IIP with redshifts z > 0.01, some of which may give rise
to useful distances for cosmological applications. All photometry was obtained
between 2000 and 2011 at the Fred Lawrence Whipple Observatory (FLWO), via the
1.2m and 1.3m PAIRITEL telescopes for the optical and NIR, respectively. Each
SN was observed in a subset of the bands. There are a total
of 2932 optical and 816 NIR light curve points. Optical spectra were obtained
using the FLWO 1.5m Tillinghast telescope with the FAST spectrograph and the
MMT Telescope with the Blue Channel Spectrograph. Our photometry is in
reasonable agreement with other samples from the literature. Comparison with
Pan-STARRS shows that two-thirds of our individual star sequences have
weighted-mean V offsets within 0.02 mag. In comparing our standard-system
SN light curves with common Carnegie Supernova Project objects using their
color terms, we found that roughly three-quarters have average differences
within 0.04 mag. The data from this work and the literature will provide
insight into SN II explosions, help with developing methods for photometric SN
classification, and contribute to their use as cosmological distance
indicators.Comment: Accepted to ApJS. TAR of light curves and star sequences here:
https://www.cfa.harvard.edu/supernova/fmalcolm2017/cfa_snII_lightcurvesndstars.june2017.tar
... Spectra can be found here:
https://www.cfa.harvard.edu/supernova/fmalcolm2017/cfaspec_snII.tar.gz ...
Passbands and plot of spectra can be found here:
https://www.cfa.harvard.edu/supernova/SNarchive.htm
Deep Photometry of GRB 041006 Afterglow: Hypernova Bump at Redshift z=0.716
We present deep optical photometry of the afterglow of gamma-ray burst (GRB)
041006 and its associated hypernova obtained over 65 days after detection (55
R-band epochs on 10 different nights). Our early data (t<4 days) joined with
published GCN data indicates a steepening decay, approaching F_nu ~t^{-0.6} at
early times (<<1 day) and F_nu ~t^{-1.3} at late times. The break at
t_b=0.16+-0.04 days is the earliest reported jet break among all GRB
afterglows. During our first night, we obtained 39 exposures spanning 2.15
hours from 0.62 to 0.71 days after the burst that reveal a smooth afterglow,
with an rms deviation of 0.024 mag from the local power-law fit, consistent
with photometric errors. After t~4 days, the decay slows considerably, and the
light curve remains approximately flat at R~24 mag for a month before decaying
by another magnitude to reach R~25 mag two months after the burst. This
``bump'' is well-fitted by a k-corrected light curve of SN1998bw, but only if
stretched by a factor of 1.38 in time. In comparison with the other GRB-related
SNe bumps, GRB 041006 stakes out new parameter space for GRB/SNe, with a very
bright and significantly stretched late-time SN light curve. Within a small
sample of fairly well observed GRB/SN bumps, we see a hint of a possible
correlation between their peak luminosity and their ``stretch factor'', broadly
similar to the well-studied Phillips relation for the type Ia supernovae.Comment: ApJ Letters, accepted. Additional material available at
ftp://cfa-ftp.harvard.edu/pub/kstanek/GRB041006
Two 'b's in the Beehive: The Discovery of the First Hot Jupiters in an Open Cluster
We present the discovery of two giant planets orbiting stars in Praesepe
(also known as the Beehive Cluster). These are the first known hot Jupiters in
an open cluster and the only planets known to orbit Sun-like, main-sequence
stars in a cluster. The planets are detected from Doppler shifted radial
velocities; line bisector spans and activity indices show no correlation with
orbital phase, confirming the variations are caused by planetary companions.
Pr0201b orbits a V=10.52 late F dwarf with a period of 4.4264 +/- 0.0070 days
and has a minimum mass of 0.540 +/- 0.039 Mjup, and Pr0211b orbits a V=12.06
late G dwarf with a period of 2.1451 +/- 0.0012 days and has a minimum mass of
1.844 +/- 0.064 Mjup. The detection of 2 planets among 53 single members
surveyed establishes a lower limit on the hot Jupiter frequency of 3.8
(+5.0)(-2.4) % in this metal-rich open cluster. Given the precisely known age
of the cluster, this discovery also demonstrates that, in at least 2 cases,
giant planet migration occurred within 600 Myr after formation. As we endeavor
to learn more about the frequency and formation history of planets,
environments with well-determined properties -- such as open clusters like
Praesepe -- may provide essential clues to this end.Comment: 5 pages, 3 tables, 2 figures. Published in ApJ Letter
Generation of degenerate, factorizable, pulsed squeezed light at telecom wavelengths
We characterize a periodically poled KTP crystal that produces an entangled,
two-mode, squeezed state with orthogonal polarizations, nearly identical,
factorizable frequency modes, and few photons in unwanted frequency modes. We
focus the pump beam to create a nearly circular joint spectral probability
distribution between the two modes. After disentangling the two modes, we
observe Hong-Ou-Mandel interference with a raw (background corrected)
visibility of 86 % (95 %) when an 8.6 nm bandwidth spectral filter is applied.
We measure second order photon correlations of the entangled and disentangled
squeezed states with both superconducting nanowire single-photon detectors and
photon-number-resolving transition-edge sensors. Both methods agree and verify
that the detected modes contain the desired photon number distributions
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