Scientists demonstrate the controlled transfer of atoms through coherent tunneling between optical tweezers

An experimental setup built at the Technion Faculty of Physics demonstrates the transfer of atoms from one place to another through quantum tunneling between optical tweezers. Led by Prof. Yoav Sagi and graduate student Yanay Florshaim from the Solid State Institute, the research was published in Scientific advances.

The experiment relies on optical tweezers – an experimental tool for trapping atoms, molecules and even living cells using an optical potential created by laser beams focused on a micron-sized spot.

How is that possible? The interaction of light with matter creates a force proportional to the intensity of the light. This force is too weak to affect our daily lives, but when it comes to tiny particles like atoms, it can be strong enough to hold them in place or move them from one place to another.

The invention of optical tweezers, which has become an important tool in physics, earned physicist Arthur Ashkin the Nobel Prize in Physics in 2018.

The Technion researchers used a linear array of three optical tweezers in their experiment. By changing the distances between each pair of adjacent tweezers, they dynamically controlled the tunneling speed of the atoms between them.

Tunneling is a phenomenon unique to the quantum world in which particles have the chance to overcome a potential barrier that they cannot classically overcome. By controlling the speed of the tunnel, the researchers were able to transfer atoms smoothly and efficiently between the two outer tweezers.

In addition, the researchers showed that although the atoms move between both sides of the chain, the probability of finding them in the middle tweezers is very low. This fascinating feature of the transmission scheme can be understood by remembering that in quantum theory a particle is described by a wave packet.

In the scheme shown in the experiment, the waves interfere destructively in the middle trap, making it impossible to find the atoms there. This is the first demonstration of this transmission method and the researchers believe it could represent a significant milestone in the development of new quantum platforms.