https://phys.org/news/2020-12-technique-sift-universe-gravitational.html A technique to sift out the universe's first gravitational waves: In the moments immediately following the Big Bang, the very first gravitational waves rang out. The product of quantum fluctuations in the new soup of primordial matter, these earliest ripples through the fabric of space-time were quickly amplified by inflationary processes that drove the universe to explosively expand. Primordial gravitational waves, produced nearly 13.8 billion years ago, still echo through the universe today. But they are drowned out by the crackle of gravitational waves produced by more recent events, such as colliding black holes and neutron stars. Now a team led by an MIT graduate student has developed a method to tease out the very faint signals of primordial ripples from gravitational-wave data. Their results are published today in Physical Review Letters. Gravitational waves are being detected on an almost daily basis by LIGO and other gravitational-wave detectors, but primordial gravitational signals are several orders of magnitude fainter than what these detectors can register. It's expected that the next generation of detectors will be sensitive enough to pick up these earliest ripples. In the next decade, as more sensitive instruments come online, the new method could be applied to dig up hidden signals of the universe's first gravitational waves. The pattern and properties of these primordial waves could then reveal clues about the early universe, such as the conditions that drove inflation. more at link................... the paper: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.125.241101 Measuring the Primordial Gravitational-Wave Background in the Presence of Astrophysical Foregrounds: ABSTRACT: Primordial gravitational waves are expected to create a stochastic background encoding information about the early Universe that may not be accessible by other means. However, the primordial background is obscured by an astrophysical foreground consisting of gravitational waves from compact binaries. We demonstrate a Bayesian method for estimating the primordial background in the presence of an astrophysical foreground. Since the background and foreground signal parameters are estimated simultaneously, there is no subtraction step, and therefore we avoid astrophysical contamination of the primordial measurement, sometimes referred to as “residuals.” Additionally, since we include the non-Gaussianity of the astrophysical foreground in our model, this method represents the statistically optimal approach to the simultaneous detection of a multicomponent stochastic background.
A comment and a question on the two red highlighted parts. The first "explosively expand" ...the BB was not an explosion in the familiar sense. It was simply an evolution of space and time [spacetime] Blame journalism. The second phrase, " It's expected that the next generation of detectors will be sensitive enough to pick up these earliest ripples." is a question. Does this actually refer to modification [which they are continually doing] of existing apparatus like aLIGO and VIRGO and the Japanese detector, or are there plans afoot for new detectors? I say the first.
No. Only incremental further gains for aLIGO/Virgo detectors are expected. They are close to being stretched to their limits. Next gen detectors will be radically different: https://en.wikipedia.org/wiki/Gravitational-wave_observatory#Novel_detector_designs
I completely forgot the LISA project!!![Laser Interferometer Space Antenna] https://en.wikipedia.org/wiki/Laser_Interferometer_Space_Antenna
