Optical Trapping of High-Aspect-Ratio NaYF Hexagonal Prisms for kHz-MHz Gravitational Wave Detectors.

We present experimental results on optical trapping of Yb-doped ß-NaYF subwavelength-thickness high-aspect-ratio hexagonal prisms with a micron-scale radius. The prisms are trapped in vacuum using an optical standing wave, with the normal vector to their face oriented along the beam propagation direction, yielding much higher trapping frequencies than those typically achieved with microspheres of similar mass. This platelike geometry simultaneously enables trapping with low photon-recoil-heating, high mass, and high trap frequency, potentially leading to advances in high frequency gravitational wave searches in the Levitated Sensor Detector, currently under construction. The material used here has previously been shown to exhibit internal cooling via laser refrigeration when optically trapped and illuminated with light of suitable wavelength. Employing such laser refrigeration methods in the context of our work may enable higher trapping intensity and thus higher trap frequencies for gravitational wave searches approaching the several hundred kilohertz range.

Searching for New Physics with a Levitated-Sensor-Based Gravitational-Wave Detector.

The levitated sensor detector (LSD) is a compact resonant gravitational-wave (GW) detector based on optically trapped dielectric particles that is under construction. The LSD sensitivity has more favorable frequency scaling at high frequencies compared to laser interferometer detectors such as LIGO and VIRGO. We propose a method to substantially improve the sensitivity by optically levitating a multilayered stack of dielectric discs. These stacks allow the use of a more massive levitated object while exhibiting minimal photon recoil heating due to light scattering. Over an order of magnitude of unexplored frequency space for GWs above 10 kHz is accessible with an instrument 10 to 100 meters in size. Particularly motivated sources in this frequency range are gravitationally bound states of the axion from quantum chromodynamics with decay constant near the grand unified theory scale that form through black hole superradiance and annihilate to GWs. The LSD is also sensitive to GWs from binary coalescence of sub-solar-mass primordial black holes and as-yet unexplored new physics in the high-frequency GW window.

LISA Sources in Milky Way Globular Clusters.

We explore the formation of double-compact-object binaries in Milky Way (MW) globular clusters (GCs) that may be detectable by the Laser Interferometer Space Antenna (LISA). We use a set of 137 fully evolved GC models that, overall, effectively match the properties of the observed GCs in the MW. We estimate that, in total, the MW GCs contain ∼21 sources that will be detectable by LISA. These detectable sources contain all combinations of black hole (BH), neutron star, and white dwarf components. We predict ∼7 of these sources will be BH-BH binaries. Furthermore, we show that some of these BH-BH binaries can have signal-to-noise ratios large enough to be detectable at the distance of the Andromeda galaxy or even the Virgo cluster.

Exertional rhabdomyolysis: a case series of 30 hospitalized patients.

INTRODUCTION: Exertional rhabdomyolysis is a clinical entity of significant muscle breakdown in the setting of exercise. However, clinical course and discharge criteria, once hospitalized, are poorly described. We describe 30 cases of exertional rhabdomyolysis and their hospital course. METHODS: Thirty hospitalized cases with ICD-9 code of 722.88 (rhabdomyolysis) as the primary diagnosis were reviewed from 2010 to 2012. We excluded those with associated trauma, toxin, and heat illnesses. RESULTS: The average length of stay was 3.6 days (range: 1-8 days). Length of stay correlated significantly with peak creatine kinase (CK) levels. The mean admission CK was 61,391 U/L (range 697-233,180 U/L). The mean discharge CK was 23,865 U/L with a wide range (1,410-94,665 U/L). Six cases (20%) had evidence of acute kidney injury, but most had serum creatinine (Cr) <1.7 mg/dL. One had a peak Cr of 4.8 mg/dL. Higher serum Cr levels correlated significantly with lower CK levels. Twenty-nine out of 30 patients were discharged when CKs downtrended. CONCLUSION: Higher peak CK levels predicted longer length of stay. Higher serum Cr significantly correlated with lower CK levels. There did not appear to be any threshold CK for admission or discharge, however, all but one patient were discharged after CK downtrended.

Testing General Relativity with Low-Frequency, Space-Based Gravitational-Wave Detectors.

We review the tests of general relativity that will become possible with space-based gravitational-wave detectors operating in the ∼ 10-5 - 1 Hz low-frequency band. The fundamental aspects of gravitation that can be tested include the presence of additional gravitational fields other than the metric; the number and tensorial nature of gravitational-wave polarization states; the velocity of propagation of gravitational waves; the binding energy and gravitational-wave radiation of binaries, and therefore the time evolution of binary inspirals; the strength and shape of the waves emitted from binary mergers and ringdowns; the true nature of astrophysical black holes; and much more. The strength of this science alone calls for the swift implementation of a space-based detector; the remarkable richness of astrophysics, astronomy, and cosmology in the low-frequency gravitational-wave band make the case even stronger.