Interferometers for Displacement-Noise-Free Gravitational-Wave Detection

We propose a class of displacement- and laser-noise free gravitational-wave-interferometer configurations, which does not sense non-geodesic mirror motions and laser noises, but provides non-vanishing gravitational-wave signal. Our interferometer consists of 4 mirrors and 2 beamsplitters, which form 4 Mach-Zehnder interferometers. By contrast to previous works, no composite mirrors are required. Each mirror in our configuration is sensed redundantly, by at least two pairs of incident and reflected beams. Displacement- and laser-noise free detection is achieved when output signals from these 4 interferometers are combined appropriately. Our 3-dimensional interferometer configuration has a low-frequency response proportional to f^2, which is better than the f^3 achievable by previous 2-dimensional configurations.Comment: 5 pages, 4 figure

A NEW METHOD OF SURGICAL TREATMENT OF LUMBAR SPINAL STENOSIS

As the treatment of lumbar or lumbosacral stenosis, laminectomy with the preservation of tissues supporting the spine and the embracement of the exposed dura mater with thin silicone rubber to prevent the occurrence of restenosis due to exuberant fibrous tissue formation at the operative site have been performed over a period of seven years. Before the prevention of restenosis with silicone rubber, we had to reoperate in cases which developed recurrent symptoms resulting from restenosis of the lumbosacral canal. This operation that we describe is technically feasible and with practical benefit can be done routinely for spinal decompression not only in the lumbosaral, but also in cervical spinal region without requiring an extensive laminectomy

Diphenhydramine against cisplatin nephrotoxicity

Cisplatin is widely used as an anti-tumor drug for the treatment of solid tumors. Unfortunately, it causes nephrotoxicity as a critical side effect, limiting its use, given that no preventive drug against cisplatin-induced nephrotoxicity is currently available. This study identified that a previously developed drug, diphenhydramine, may provide a novel treatment for cisplatin-induced nephrotoxicity based on the results of the analysis of medical big data. We evaluated the actual efficacy of diphenhydramine via in vitro and in vivo experiments in a mouse model. Diphenhydramine inhibited cisplatin-induced cell death in renal proximal tubular cells. Mice administered cisplatin developed kidney injury with renal dysfunction (plasma creatinine: 0.43 ± 0.04 mg/dl vs 0.15 ± 0.01 mg/dl, p<0.01) and showed augmented oxidative stress, increased apoptosis, elevated inflammatory cytokines, and mitogen-activated protein kinases activation; however, most of these symptoms were suppressed by treatment with diphenhydramine. Further, the renal concentration of cisplatin was attenuated in diphenhydramine-treated mice (platinum content: 70.0 ± 3.3 µg/g dry kidney weight vs 53.4 ± 3.6 µg/g dry kidney weight, p<0.05). Importantly, diphenhydramine did not influence or interfere with the anti-tumor effect of cisplatin in any of the in vitro or in vivo experiments. Moreover, a retrospective clinical study of 1467 cancer patients treated with cisplatin showed that patients who had used diphenhydramine exhibited less acute kidney injury than patients who had not used diphenhydramine (6.1 % vs 22.4 %, p<0.05). Thus, diphenhydramine demonstrated efficacy as a novel preventive medicine against cisplatin-induced nephrotoxicity

Upper limits on the strength of periodic gravitational waves from PSR J1939+2134

The first science run of the LIGO and GEO gravitational wave detectors presented the opportunity to test methods of searching for gravitational waves from known pulsars. Here we present new direct upper limits on the strength of waves from the pulsar PSR J1939+2134 using two independent analysis methods, one in the frequency domain using frequentist statistics and one in the time domain using Bayesian inference. Both methods show that the strain amplitude at Earth from this pulsar is less than a few times $10^{-22}$.Comment: 7 pages, 1 figure, to appear in the Proceedings of the 5th Edoardo Amaldi Conference on Gravitational Waves, Tirrenia, Pisa, Italy, 6-11 July 200

Improving the sensitivity to gravitational-wave sources by modifying the input-output optics of advanced interferometers

We study frequency dependent (FD) input-output schemes for signal-recycling interferometers, the baseline design of Advanced LIGO and the current configuration of GEO 600. Complementary to a recent proposal by Harms et al. to use FD input squeezing and ordinary homodyne detection, we explore a scheme which uses ordinary squeezed vacuum, but FD readout. Both schemes, which are sub-optimal among all possible input-output schemes, provide a global noise suppression by the power squeeze factor, while being realizable by using detuned Fabry-Perot cavities as input/output filters. At high frequencies, the two schemes are shown to be equivalent, while at low frequencies our scheme gives better performance than that of Harms et al., and is nearly fully optimal. We then study the sensitivity improvement achievable by these schemes in Advanced LIGO era (with 30-m filter cavities and current estimates of filter-mirror losses and thermal noise), for neutron star binary inspirals, and for narrowband GW sources such as low-mass X-ray binaries and known radio pulsars. Optical losses are shown to be a major obstacle for the actual implementation of these techniques in Advanced LIGO. On time scales of third-generation interferometers, like EURO/LIGO-III (~2012), with kilometer-scale filter cavities, a signal-recycling interferometer with the FD readout scheme explored in this paper can have performances comparable to existing proposals. [abridged]Comment: Figs. 9 and 12 corrected; Appendix added for narrowband data analysi

Search for gravitational wave bursts in LIGO's third science run

We report on a search for gravitational wave bursts in data from the three LIGO interferometric detectors during their third science run. The search targets subsecond bursts in the frequency range 100-1100 Hz for which no waveform model is assumed, and has a sensitivity in terms of the root-sum-square (rss) strain amplitude of hrss ~ 10^{-20} / sqrt(Hz). No gravitational wave signals were detected in the 8 days of analyzed data.Comment: 12 pages, 6 figures. Amaldi-6 conference proceedings to be published in Classical and Quantum Gravit

Quantum state preparation and macroscopic entanglement in gravitational-wave detectors

Long-baseline laser-interferometer gravitational-wave detectors are operating at a factor of 10 (in amplitude) above the standard quantum limit (SQL) within a broad frequency band. Such a low classical noise budget has already allowed the creation of a controlled 2.7 kg macroscopic oscillator with an effective eigenfrequency of 150 Hz and an occupation number of 200. This result, along with the prospect for further improvements, heralds the new possibility of experimentally probing macroscopic quantum mechanics (MQM) - quantum mechanical behavior of objects in the realm of everyday experience - using gravitational-wave detectors. In this paper, we provide the mathematical foundation for the first step of a MQM experiment: the preparation of a macroscopic test mass into a nearly minimum-Heisenberg-limited Gaussian quantum state, which is possible if the interferometer's classical noise beats the SQL in a broad frequency band. Our formalism, based on Wiener filtering, allows a straightforward conversion from the classical noise budget of a laser interferometer, in terms of noise spectra, into the strategy for quantum state preparation, and the quality of the prepared state. Using this formalism, we consider how Gaussian entanglement can be built among two macroscopic test masses, and the performance of the planned Advanced LIGO interferometers in quantum-state preparation

Searching for a Stochastic Background of Gravitational Waves with LIGO

The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new limit is $\Omega_{\rm GW} < 6.5 \times 10^{-5}$. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background.Comment: 37 pages, 16 figure