Frequency-Dependent Squeezing for Advanced LIGO

The first detection of gravitational waves by the Laser Interferometer Gravitational-wave Observatory (LIGO) in 2015 launched the era of gravitational wave astronomy. The quest for gravitational wave signals from objects that are fainter or farther away impels technological advances to realize ever more sensitive detectors. Since 2019, one advanced technique, the injection of squeezed states of light is being used to improve the shot noise limit to the sensitivity of the Advanced LIGO detectors, at frequencies above $\sim 50$ Hz. Below this frequency, quantum back action, in the form of radiation pressure induced motion of the mirrors, degrades the sensitivity. To simultaneously reduce shot noise at high frequencies and quantum radiation pressure noise at low frequencies requires a quantum noise filter cavity with low optical losses to rotate the squeezed quadrature as a function of frequency. We report on the observation of frequency-dependent squeezed quadrature rotation with rotation frequency of 30Hz, using a 16m long filter cavity. A novel control scheme is developed for this frequency-dependent squeezed vacuum source, and the results presented here demonstrate that a low-loss filter cavity can achieve the squeezed quadrature rotation necessary for the next planned upgrade to Advanced LIGO, known as "A+."Comment: 6 pages, 2 figures, to be published in Phys. Rev. Let

Effect of fish meal extract spray on the yield of Co-47 rice variety

A field experiment was conducted with Co-47 rice variety at Annamalai University experimental farm from July to September 2018 with 12 treatments to evolve a suitable organic and inorganic preparations foliar spray along with the application of 75 and 100% recommended NPK + humic acid granules. The results revealed that the treatment T6 - 100% NPK + humic acid granules @12.5 kg/ha+ Panchagavya + fish meal extract + Auxin Gold seaweed extract spray on 20, 35, and 50 DAT ranked first in terms of tiller number/m2 (385), number of filled grains/panicle (105.42), panicle length (23.99), and grain yield (5660). Among the individual organic preparations foliar spray, fish meal extract spray was found to be better and improved the grain yield to the tune of 439 and 387 kg/ha over respective 100 and 75% NPK + humic acid granules @12.5 kg/ha application

Effect of fish meal extract spray on the yield of Co-47 rice variety

116-121A field experiment was conducted with Co-47 rice variety at Annamalai University experimental farm from July to September 2018 with 12 treatments to evolve a suitable organic and inorganic preparations foliar spray along with the application of 75 and 100% recommended NPK + humic acid granules. The results revealed that the treatment T6 - 100% NPK + humic acid granules @12.5 kg/ha+ Panchagavya + fish meal extract + Auxin Gold seaweed extract spray on 20, 35, and 50 DAT ranked first in terms of tiller number/m2 (385), number of filled grains/panicle (105.42), panicle length (23.99), and grain yield (5660). Among the individual organic preparations foliar spray, fish meal extract spray was found to be better and improved the grain yield to the tune of 439 and 387 kg/ha over respective 100 and 75% NPK + humic acid granules @12.5 kg/ha application

Perceptions of gender and tuberculosis in a south Indian urban community

Background: The Revised National Tuberculosis Control Programme (RNTCP) in India advocating Directly Observed Treatment-Short course (DOTS) detects nearly three times more male than female TB patients. The reasons for this difference are unclear. An understanding of the community’s health beliefs, perceptions on the disease and behaviour towards TB patients may throw some light on this issue. Material and Methods: A qualitative study using focus group discussions was conducted among men and women of younger and older age groups from lower income neighbourhoods. The information obtained was grouped into themes which included, understanding of TB, vulnerability, access to health care and social responses. Gender differences in community perceptions on TB seem to be critical in issues related to marriage. Results: The stigma of TB is more visible in women than men when it comes to marriage. Men and children were perceived to get preferential attention by their families during illness. While the younger age group, irrespective of gender, accessed care from private providers, the older group preferred a government facility. Awareness of TB was acceptable but it seemed more associated as a respiratory disease and the common symptom associated with TB was cough. Conclusion: This study highlights the need for gender specific intervention strategies to enhance better access of TB services

Broadband Quantum Enhancement of the LIGO Detectors with Frequency-Dependent Squeezing

Quantum noise imposes a fundamental limitation on the sensitivity of interferometric gravitational-wave detectors like LIGO, manifesting as shot noise and quantum radiation pressure noise. Here, we present the first realization of frequency-dependent squeezing in full-scale gravitational-wave detectors, resulting in the reduction of both shot noise and quantum radiation pressure noise, with broadband detector enhancement from tens of hertz to several kilohertz. In the LIGO Hanford detector, squeezing reduced the detector noise amplitude by a factor of 1.6 (4.0 dB) near 1 kHz; in the Livingston detector, the noise reduction was a factor of 1.9 (5.8 dB). These improvements directly impact LIGO’s scientific output for high-frequency sources (e.g., binary neutron star postmerger physics). The improved low-frequency sensitivity, which boosted the detector range by 15%–18% with respect to no squeezing, corresponds to an increase in the astrophysical detection rate of up to 65%. Frequency-dependent squeezing was enabled by the addition of a 300-meter-long filter cavity to each detector as part of the LIGO A+ upgrade