Quantum mechanics deals with the actions of the Universe in the super-small scale: atoms and subatomic particles which work in ways that classical physics cannot explain.
To explore the tension between the quantum and the classical, researchers are always attempting to get larger and larger objects to behave in a quantum-like way.
Back in 2021, a team succeeded by using a tiny glass nanosphere which was hundred nanometers in diameter – about a thousand times smaller than the thickness of a human hair.
To our minds that is very, very small, but in terminology of quantum physics, it’s really quite huge, made of as much as 10 million atoms.
Pushing such a nanosphere into the world of quantum mechanics was an enormous accomplishment. Using properly calibrated laser lights, the nanosphere was suspended in its lowest quantum mechanical state, 1 of extremely limited activity wherein quantum behavior is able to begin to happen.
“This is the first time that such a way is employed to manage the quantum state of a macroscopic object in complimentary space,” said Lukas Novotny, a professor of photonics from ETH Zurich in Switzerland, back in July 2021.
To achieve quantum states, movement and energy must be dialed right down. Novotny and the colleagues of his used a vacuum container cooled down to 269 degrees Celsius (452 degrees Fahrenheit) prior to utilizing a feedback process to make further adjustments.
Using the interference patterns produced by two laser beams, the researchers calculated the exact position of the nanosphere inside the chamber of its – and from there the accurate changes required to bring the motion of the object close to 0, utilizing the electric field produced by 2 electrodes.
It is not all that different from slowing down a playground swing by pushing and pulling it unless it involves a resting point. When that lowest quantum mechanical state is reached, further experiments could begin.
“To clearly see quantum effects the nanosphere needs to be slowed down… all the way to its motional ground state,” said electrical engineer Felix Tebbenjohanns, from ETH Zurich during the time.
“This means that we freeze the motional power of the sphere to a minimum that is near to the quantum mechanical zero-point motion.”
While results that are similar have been accomplished before, they used what is generally known as an optical resonator to balance objects using light.
The strategy used here much better protects the nanosphere against disturbances, and also indicates the item could be viewed in isolation after the laser is turned off – although that can require plenty of further research to see.
One of the ways the researchers hope the findings of theirs can be helpful is in studying just how quantum mechanics causes elementary particles to act like waves. It’s feasible that super sensitive setups this way nanosphere one may also help in the improvement of next-generation sensors beyond anything we have today.
Managing to levitate such a big sphere in a cryogenic environment represents a significant jump towards the macroscopic scale where the line between the classical and also the quantum can be studied.
“Together with the reality that the optical trapping potential is highly controllable, the experimental platform of ours offers a path to investigating quantum mechanics at macroscopic scales,” concluded the scientists in their published paper.
The research was published in Nature