Revealing quantum effects at the level of atoms and elementary particles is a difficult and difficult task. It is always better to comprehend what can be observed and measured accurately. Ideally, it is necessary to make quantum effects occur at the macro level – at the level of classical physics. Researchers at the ETH Zurich have tackled this problem and have succeeded.

Recently, in an article published in the journal Nature, a group of authors led by ETH Zurich photonics professor Lukas Novotny (Lukas Novotny) reported on a quantum experiment with a glass nanosphere with a diameter of 100 nm. It is an object of our native macroscopic world, although it is hundreds of times thinner than human hair. At the same time, a tiny ball of glass contains ten million atoms and cannot (and should not) exhibit quantum effects. But scientists have created a glass ball conditions under which it can behave like an electron or a single atom. In particular, a ball can behave like a wave, and not just like a particle, and this phenomenon can be observed almost with one’s own eyes.

The challenge for the researchers was to slow the glass ball as a collection of all atoms down to the quantum state with the lowest energy. In this state, the particles remain stable and allow the observation of wave properties. For this, the ball was placed in a vacuum chamber and cooled to a temperature of 269 ° C below zero. The thermal motion of the atoms of the sphere has significantly decreased, but for the ball to manifest quantum effects, stronger cooling is required, which the researchers have not yet coped with.

In the meantime, scientists have tested the possibility of slowing down on the nanosphere using electromagnetic waves. In a suspended state in a vacuum, the nanosphere is held in an optical trap created by a laser beam. Another beam allows you to accurately measure the oscillations of the nanosphere, and the feedback from the electrodes allows you to turn on the electromagnetic fields at specified times to damp the oscillatory movements of the sphere. Something like this in ordinary life we ​​swing or slow down a swing – we create an accelerating or braking impulse at the moments of time necessary for solving the problem.

If scientists can slow down the nanosphere to the quantum state with the lowest energy, which will give the ball quantum-mechanical properties, then it will be small. There are physics-tested double-slit experiments that exhibit particle wave functions. In such experiments, electrons or atoms seem to be in two places at the same time, exhibiting wave properties. In fact, we are talking about the phenomenon of interference, when different parts of the wave pass through two spaced slots and create a characteristic picture at the exit. Scientists expect to see a similar picture in an experiment with a glass nanosphere, which will be evidence of a quantum phenomenon at the macrolevel.

We add that even today such experiments, which have not been completed to the end, have enormous potential. Based on such nanospheres and near-quantum phenomena, it is possible to create acceleration and displacement sensors that will more accurately track the movement of objects than all GPS combined. The military is especially fond of this, but that’s another story.