In the quantum world, uncertainty prevails, and this uncertainty is broken at the last moment by the fact of observation (measurement). This is achieved through complex installations. It might be expected that there would be room for quantum uncertainty in our ordinary world of large and heavy objects, but this is very, very difficult to prove by direct observation. But scientists do not give up.

The principle of quantum uncertainty is often illustrated with the help of an imaginary experiment with Schrödinger’s cat (in the original it is a cat, not a cat); Before opening the box with the animal, it is neither alive nor dead. This allows us to understand the counterintuitive laws of quantum mechanics, but does not get us any closer to detecting quantum events at the macro level.

Scientists from University College London (UCL), the University of Southampton in Great Britain, and the Bose Institute in India have proposed their own versions of natural experiments to capture quantum uncertainty in massive objects. Scientists suggested using the system of the LIGO gravimetric observatory in the United States for the research. These are two tunnels of 4 km each, connected at a right angle (letter G). A laser beam passes through the tunnels repeatedly with reflection, which can record the distortion of space-time as it passes through the gravitational wave detector. Scientists believe the same system could be used to detect quantum uncertainty with macro objects without strict constraints on mass and energy.

In each of the tunnels, you can hang mirrors at the ends of the pendulums (or targets covering the sensor’s main mirrors) and send a pair of laser flashes at them at regular intervals. If there is quantum uncertainty in our big world, the first blow will disrupt the motion of the pendulum; this will introduce the so-called observer effect, and the second pulse will record deviations from the calculated orbit.

From a mathematical perspective, the experiment must prove or disprove that the two conditions of the Leggett-Garg inequality are satisfied. It must meet all the conditions of the classical world. If one of these conditions is not met when interacting with 10 kg mirrors, the object will exhibit quantum uncertainty properties.

In mathematical terms, this means that there is a high probability that you are currently sitting in a chair in front of a monitor, but there is also an extremely small (but by no means zero) probability that you are on the Moon, on Mars, etc. or Andromeda galaxy. The main thing is that proving such a possibility will not have to risk the life of a cat, but the experiment itself with mirrors in the LIGO installation will require non-trivial equipment and conditions. An article about the research was published in the magazine Physical Examination Letters. Also available on the website arxiv.org.