Scientists from the LIGO collaboration have cooled one of the mirrors of the gravitational wave detector so that it becomes completely stationary: this is necessary to make observations of fluctuations in space-time more accurate.
LIGO is one of the two main instruments for recording gravitational waves. It is able to track the slightest displacement in the positions of the two mirrors, which are maximally isolated from the environment.
Gravitational waves are changes in the gravitational field that propagate like waves. They are emitted by moving masses, but after radiation, they break away from them and exist independently of these masses. Mathematically related to the perturbation of the space-time metric and can be described as “ripples of space-time”.
The LIGO project itself consists of several observatories located at a distance of thousands of kilometers, in each of which laser beams move along an L-shaped vacuum tube, reflected by mirrors. The interference of these rays allows you to notice the slightest change in the size of the shoulders caused by the passage of invisible gravity waves.
And recently, scientists from the LIGO collaboration were able to practically eliminate such a mirror from thermal noise, cooling it to almost absolute zero. According to them, this is the first time that a macroscopic body has been cooled to almost the ground energy state, at which the movement of particles stops.
In order to cool the object, the scientists tuned the installation so that it recorded the slightest shifts in one of the two mirrors and automatically tried to suppress them using electromagnets attached to the back of the reflecting surface. As a result, the mirror cooled down to –273.15 ° С and became almost completely motionless.
It is expected that this will increase the sensitivity of the gravitational-wave observatory, as well as improve the quality of experiments to study the manifestations of quantum physics in the macrocosm.