804 research outputs found
Propagation of Bose-Einstein condensates in a magnetic waveguide
Gaseous Bose-Einstein condensates of 2-3 million atoms were loaded into a
microfabricated magnetic trap using optical tweezers. Subsequently, the
condensates were released into a magnetic waveguide and propagated 12 mm.
Single-mode propagation was observed along homogeneous segments of the
waveguide. Inhomogeneities in the guiding potential arose from geometric
deformations of the microfabricated wires and caused strong transverse
excitations. Such deformations may restrict the waveguide physics that can be
explored with propagating condensates.Comment: 5 pages, 4 figure
Quantum-enhanced gyroscopy with rotating anisotropic Bose–Einstein condensates
High-precision gyroscopes are a key component of inertial navigation systems. By considering matter wave gyroscopes that make use of entanglement it should be possible to gain some advantages in terms of sensitivity, size, and resources used over unentangled optical systems. In this paper we consider the details of such a quantum-enhanced atom interferometry scheme based on atoms trapped in a carefully-chosen rotating trap. We consider all the steps: entanglement generation, phase imprinting, and read-out of the signal and show that quantum enhancement should be possible in principle. While the improvement in performance over equivalent unentangled schemes is small, our feasibility study opens the door to further developments and improvements
Transport of Bose-Einstein Condensates with Optical Tweezers
We have transported gaseous Bose-Einstein condensates over distances up to 44
cm. This was accomplished by trapping the condensate in the focus of an
infrared laser and translating the location of the laser focus with controlled
acceleration. Condensates of order 1 million atoms were moved into an auxiliary
chamber and loaded into a magnetic trap formed by a Z-shaped wire. This
transport technique avoids the optical and mechanical access constraints of
conventional condensate experiments and creates many new scientific
opportunities.Comment: 5 pages, 3 figure
Underdiagnosis of mild cognitive impairment: A consequence of ignoring practice effects
INTRODUCTION: Longitudinal testing is necessary to accurately measure cognitive change. However, repeated testing is susceptible to practice effects, which may obscure true cognitive decline and delay detection of mild cognitive impairment (MCI).
METHODS: We retested 995 late-middle-aged men in a ∼6-year follow-up of the Vietnam Era Twin Study of Aging. In addition, 170 age-matched replacements were tested for the first time at study wave 2. Group differences were used to calculate practice effects after controlling for attrition effects. MCI diagnoses were generated from practice-adjusted scores.
RESULTS: There were significant practice effects on most cognitive domains. Conversion to MCI doubled after correcting for practice effects, from 4.5% to 9%. Importantly, practice effects were present although there were declines in uncorrected scores.
DISCUSSION: Accounting for practice effects is critical to early detection of MCI. Declines, when lower than expected, can still indicate practice effects. Replacement participants are needed for accurately assessing disease progression.Published versio
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The Musical Abilities, Pleiotropy, Language, and Environment (MAPLE) framework for understanding musicality-language links across the lifespan
Using individual differences approaches, a growing body of literature finds positive associations between musicality and language-related abilities, complementing prior findings of links between musical training and language skills. Despite these associations, musicality has been often overlooked in mainstream models of individual differences in language acquisition and development. To better understand the biological basis of these individual differences, we propose the Musical Abilities, Pleiotropy, Language, and Environment (MAPLE) framework. This novel integrative framework posits that musical and language-related abilities likely share some common genetic architecture (i.e., genetic pleiotropy) in addition to some degree of overlapping neural endophenotypes, and genetic influences on musically and linguistically enriched environments. Drawing upon recent advances in genomic methodologies for unraveling pleiotropy, we outline testable predictions for future research on language development and how its underlying neurobiological substrates may be supported by genetic pleiotropy with musicality. In support of the MAPLE framework, we review and discuss findings from over seventy behavioral and neural studies, highlighting that musicality is robustly associated with individual differences in a range of speech-language skills required for communication and development. These include speech perception-in-noise, prosodic perception, morphosyntactic skills, phonological skills, reading skills, and aspects of second/foreign language learning. Overall, the current work provides a clear agenda and framework for studying musicality-language links using individual differences approaches, with an emphasis on leveraging advances in the genomics of complex musicality and language traits
First electron beam polarization measurements with a Compton polarimeter at Jefferson Laboratory
A Compton polarimeter has been installed in Hall A at Jefferson Laboratory.
This letter reports on the first electron beam polarization measurements
performed during the HAPPEX experiment at an electron energy of 3.3 GeV and an
average current of 40 A. The heart of this device is a Fabry-Perot cavity
which increased the luminosity for Compton scattering in the interaction region
so much that a 1.4% statistical accuracy could be obtained within one hour,
with a 3.3% total error
Multi Mode Interferometer for Guided Matter Waves
We describe the fundamental features of an interferometer for guided matter
waves based on Y-beam splitters and show that, in a quasi two-dimensional
regime, such a device exhibits high contrast fringes even in a multi mode
regime and fed from a thermal source.Comment: Final version (accepted to PRL
Novel Ferromagnetic Atom Waveguide with in situ loading
Magneto-optic and magnetostatic trapping is realized near a surface using
current carrying coils wrapped around magnetizable cores. A cloud of 10^7
Cesium atoms is created with currents less than 50 mA. Ramping up the current
while maintaining optical dissipation leads to tightly confined atom clouds
with an aspect ratio of 1:1000. We study the 3D character of the magnetic
potential and characterize atom number and density as a function of the applied
current. The field gradient in the transverse dimension has been varied from <
10 G/cm to > 1 kG/cm. By loading and cooling atoms in-situ, we have eliminated
the problem of coupling from a MOT into a smaller phase space.Comment: 4 pages, 4 figure
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