179 research outputs found
Patterns of Contagious Yawning and Itching Differ Amongst Adults With Autistic Traits vs. Psychopathic Traits
Both individuals with diagnosed with Autism Spectrum Disorder (ASD) and individuals high in psychopathic traits show reduced susceptibility to contagious yawning; that is, yawning after seeing or hearing another person yawn. Yet it is unclear whether the same underlying processes (e.g., reduced eye gaze) are responsible for the relationship between reduced contagion and these very different types of clinical traits. College Students (n = 97) watched videos of individuals yawning or scratching (a form of contagion not reliant on eye gaze for transmission) while their eye movements were tracked. They completed the Interpersonal Reactivity Index (IRI), the Autism-Spectrum Quotient (AQ), the Psychopathy Personality Inventory-Revised (PPI-R), and the Adolescent and Adult Sensory Processing Disorder Checklist. Both psychopathic traits and autistic traits showed an inverse relationship to contagious yawning, consistent with previous research. However, the relationship between autistic (but not psychopathic) traits and contagious yawning was moderated by eye gaze. Furthermore, participants high in autistic traits showed typical levels of contagious itching whereas adults high in psychopathic traits showed diminished itch contagion. Finally, only psychopathic traits were associated with lower overall levels of empathy. The findings imply that the underlying processes contributing to the disruptions in contagious yawning amongst individuals high in autistic vs. psychopathic traits are distinct. In contrast to adults high in psychopathic traits, diminished contagion may appear amongst people with high levels of autistic traits secondary to diminished attention to the faces of others, and in the absence of a background deficit in emotional empathy
Broadband quadrature-squeezed vacuum and nonclassical photon number correlations from a nanophotonic device
We report the first demonstrations of both quadrature squeezed vacuum and
photon number difference squeezing generated in an integrated nanophotonic
device. Squeezed light is generated via strongly driven spontaneous four-wave
mixing below threshold in silicon nitride microring resonators. The generated
light is characterized with both homodyne detection and direct measurements of
photon statistics using photon number-resolving transition edge sensors. We
measure ~dB of broadband quadrature squeezing (~dB inferred
on-chip) and ~dB of photon number difference squeezing (~dB
inferred on-chip). Nearly-single temporal mode operation is achieved, with raw
unheralded second-order correlations as high as measured
(~when corrected for noise). Multi-photon events of over 10 photons
are directly detected with rates exceeding any previous quantum optical
demonstration using integrated nanophotonics. These results will have an
enabling impact on scaling continuous variable quantum technology.Comment: Significant improvements and updates to photon number squeezing
results and discussions, including results on single temporal mode operatio
The CORALIE survey for southern extra-solar planets. X. A Hot Jupiter orbiting HD73256
Recent radial-velocity measurements obtained with the CORALIE spectrograph on
the 1.2-m Euler Swiss telescope at La Silla unveil the presence of a new
Jovian-mass Hot Jupiter around HD 73256. The 1.85-M_Jup planet moves on an
extremely short-period (P=2.5486 d), quasi-circular orbit. The best Keplerian
orbital solution is presented together with an unsuccessful photometric
planetary-transit search performed with the SAT Danish telescope at La Silla.
Over the time span of the observations, the photometric follow-up of the
candidate has nevertheless revealed a P=14-d photometric periodicity
corresponding to the rotational period of the star. This variation as well as
the radial-velocity jitter around the Keplerian solution are shown to be
related to the fair activity level known for HD 73256.Comment: 7 pages, 7 figures. Accepted in A&
Photon Pair Generation in Silicon Micro-Ring Resonator with Reverse Bias Enhancement
Photon sources are fundamental components for any quantum photonic
technology. The ability to generate high count-rate and low-noise correlated
photon pairs via spontaneous parametric down-conversion using bulk crystals has
been the cornerstone of modern quantum optics. However, future practical
quantum technologies will require a scalable integration approach, and
waveguide-based photon sources with high-count rate and low-noise
characteristics will be an essential part of chip-based quantum technologies.
Here, we demonstrate photon pair generation through spontaneous four-wave
mixing in a silicon micro-ring resonator, reporting a maximum
coincidence-to-accidental (CAR) ratio of 602 (+-) 37, and a maximum photon pair
generation rate of 123 MHz (+-) 11 KHz. To overcome free-carrier related
performance degradations we have investigated reverse biased p-i-n structures,
demonstrating an improvement in the pair generation rate by a factor of up to
2, with negligible impact on CAR.Comment: 5 pages, 3 figure
Cross-polarized photon-pair generation and bi-chromatically pumped optical parametric oscillation on a chip
Nonlinear optical processes are one of the most important tools in modern optics with a broad spectrum of applications in, for example, frequency conversion, spectroscopy, signal processing and quantum optics. For practical and ultimately widespread implementation, on-chip devices compatible with electronic integrated circuit technology offer great advantages in terms of low cost, small footprint, high performance and low energy consumption. While many on-chip key components have been realized, to date polarization has not been fully exploited as a degree of freedom for integrated nonlinear devices. In particular, frequency conversion based on orthogonally polarized beams has not yet been demonstrated on chip. Here we show frequency mixing between orthogonal polarization modes in a compact integrated microring resonator and demonstrate a bi-chromatically pumped optical parametric oscillator. Operating the device above and below threshold, we directly generate orthogonally polarized beams, as well as photon pairs, respectively, that can find applications, for example, in optical communication and quantum optics
The CORALIE survey for southern extra-solar planets IX. A 1.3-day period brown dwarf disguised as a planet
In this article we present the case of HD 41004 AB, a system composed of a
K0V star and a 3.7-magnitude fainter M-dwarf companion separated by only 0.5
arcsec. An analysis of CORALIE radial-velocity measurements has revealed a
variation with an amplitude of about 50m/s and a periodicity of 1.3days. This
radial-velocity signal is consistent with the expected variation induced by the
presence a very low mass giant planetary companion to HD 41004 A, whose light
dominates the spectra. The radial-velocity measurements were then complemented
with a photometric campaign and with the analysis of the bisector of the
CORALIE Cross-Correlation Function (CCF). While the former revealed no
significant variations within the observational precision of 0.003-0.004 mag
(except for an observed flare event), the bisector analysis showed that the
line profiles are varying in phase with the radial-velocity. This latter
result, complemented with a series of simulations, has shown that we can
explain the observations by considering that HD 41004 B has a brown-dwarf
companion orbiting with the observed 1.3-day period. If confirmed, this
detection represents the first discovery of a brown dwarf in a very short
period (1.3-day) orbit around an M dwarf. Finally, this case should be taken as
a serious warning about the importance of analyzing the bisector when looking
for planets using radial-velocity techniques.Comment: 16 pages, 17 eps figures, A&A in press (Figure 11 not as in original
version due to size
A Blue Straggler Binary System with at least Three Progenitors in the Core of a Globular Cluster?
We show that the X-ray source W31 in the core of the globular cluster 47
Tucanae is physically associated with the bright blue straggler BSS-7. The two
sources are astrometrically matched to 0.061\arcsec, with a chance coincidence
probability of less than 1%. We then analyse optical time-series photometry
obtained with the {\em Hubble Space Telescope} (HST) and find that BSS-7
displays a 1.56 day periodic signal in the I band. We also construct a
broad-band (far-ultraviolet through far-red) spectral energy distribution for
BSS-7 and fit this with single and binary models. The binary model is a better
fit to the data, and we derive the corresponding stellar parameters.
All of our findings are consistent with BSS-7 being a detached binary
consisting of a blue straggler primary with an X-ray-active,
upper-main-sequence companion. The formation of such a system would necessarily
involve at least three stars, which is consistent with recent N-body models in
which blue stragglers often form via multiple encounters that can involve both
single and binary stars. However, we cannot yet entirely rule out the
possibility that BSS-7 descended directly from a binary system via mass
transfer. The system parameters needed to distinguish definitively between
these scenarios may be obtainable from time-resolved spectroscopy.Comment: 19 pages, 3 figures, accepted for publication in ApJ; revised version
includes a discussion of an alternative 2-progenitor binary evolution
scenario, and an appendix discussing other probable/possible BSS/X-ray
matches in globular clusters and related source
Transcriptional landscape of the human and fly genomes: Nonlinear and multifunctional modular model of transcriptomes
Regions of the genome not coding for proteins or not involved in cis-acting regulatory activities are frequently viewed as lacking in functional value. However, a number of recent large-scale studies have revealed significant regulated transcription of unannotated portions of a variety of plant and animal genomes, allowing a new appreciation of the widespread transcription of large portions of the genome. High-resolution mapping of the sites of transcription of the human and fly genomes has provided an alternative picture of the extent and organization of transcription and has offered insights for biological functions of some of the newly identified unannotated transcripts. Considerable portions of the unannotated transcription observed are developmental or cell-type-specific parts of protein-coding transcripts, often serving as novel, alternative 5′ transcriptional start sites. These distal 5′ portions are often situated at significant distances from the annotated gene and alternatively join with or ignore portions of other intervening genes to comprise novel unannotated protein-coding transcripts. These data support an interlaced model of the genome in which many regions serve multifunctional purposes and are highly modular in their utilization. This model illustrates the underappreciated organizational complexity of the genome and one of the functional roles of transcription from unannotated portions of the genome. Copyright 2006, Cold Spring Harbor Laboratory Press © 2006 Cold Spring Harbor Laboratory Press
Quantum circuits with many photons on a programmable nanophotonic chip
Growing interest in quantum computing for practical applications has led to a
surge in the availability of programmable machines for executing quantum
algorithms. Present day photonic quantum computers have been limited either to
non-deterministic operation, low photon numbers and rates, or fixed random gate
sequences. Here we introduce a full-stack hardware-software system for
executing many-photon quantum circuits using integrated nanophotonics: a
programmable chip, operating at room temperature and interfaced with a fully
automated control system. It enables remote users to execute quantum algorithms
requiring up to eight modes of strongly squeezed vacuum initialized as two-mode
squeezed states in single temporal modes, a fully general and programmable
four-mode interferometer, and genuine photon number-resolving readout on all
outputs. Multi-photon detection events with photon numbers and rates exceeding
any previous quantum optical demonstration on a programmable device are made
possible by strong squeezing and high sampling rates. We verify the
non-classicality of the device output, and use the platform to carry out
proof-of-principle demonstrations of three quantum algorithms: Gaussian boson
sampling, molecular vibronic spectra, and graph similarity
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