Injecting optical squeezed states of light, a technique known as squeezing, is now tool for gravitational wave detection. Its ability to reduce quantum noise helping reveal more transients, expanding the catalog observations in last observing run. This review introduces squeezing and its history context gravitational-wave detectors. It overviews benefits, limitations methods incorporating into ...

We study a cross-shaped cavity filled with superfluid $^4$He as prototype resonant-mass gravitational wave detector. Using membrane and re-entrant microwave sensitive optomechanical transducer, we were able to observe the thermally excited high-$Q$ acoustic modes of helium at 20 mK temperature achieved strain sensitivity $8 \times 10^{-19}$ Hz$^{-1/2}$ waves. To facilitate broadband detection c...

We use wave packet mode quantization to compute the creation of massless scalar quantum particles in a colliding plane wave spacetime. The background spacetime represents the collision of two gravitational shock waves followed by trailing gravitational radiation which focus into a Killing-Cauchy horizon. The use of wave packet modes simplifies the problem of mode propagation through the differe...