Getting atoms to do what you want is not easy, but it is at the heart of much important research in physics.
Creating and controlling the behavior of new forms of matter is an active area of special interest and research.
Our new research, published in Physical Review Letters, has discovered an entirely new way to sculpt ultracold atoms into different shapes using laser light.
Ultracold atoms, which have been cooled to temperatures close to absolute zero (-273°C), are of great interest to researchers because they allow them to observe and discover physical phenomena that would otherwise be impossible.
At these temperatures, cooler than outer space, clusters of atoms form a new state of matter (not solid, liquid, or gas) called Bose-Einstein condensates (BECs). In 2001, physicists received the Nobel Prize for creating such condensates.
A defining characteristic of BEC is that its atoms behave very differently from what we normally expect. Instead of acting as independent particles, they all have the same (very low) energy and are coherent with each other.
This is similar to the difference between photons (particles of light) from the sun, which can have many different wavelengths (energies) and are transmitted independently, and those from a laser beam, which have the same wavelength.
In this new state of matter, the atoms behave more like a single wave structure than a group of individual particles.
Researchers have been able to demonstrate wave-like interference patterns between two different BECs and even create moving “BEC blobs.” The latter can be considered as the atomic equivalent of a laser beam.
Moving drops.
In our latest study, conducted with our colleagues Gordon Robb and Gianluca Oppo, we investigated how to use a specially shaped laser beam to manipulate the ultracold atoms of a BEC.
The idea of using light to make objects move is not new: when light hits an object, it can exert a (very small) force. This radiation pressure is the principle behind the idea of the solar cell, where the power of sunlight in large mirrors can be used to propel a spacecraft through a spacecraft.
However, in this study, we used a special type of light that is capable of not only “pushing” atoms, but also turning them, a bit like an “optical wrench.”
These laser beams look like glowing circles (or donuts) rather than dots and have a twisted (helical) wavefront, under the right conditions, when such twisted light shines into a moving BEC. The atoms are first attracted by the light. Ring before it spins.
As the atoms rotate, both the light and the atoms begin to form droplets that rotate in the original direction of the laser beam before being ejected from the ring.
The number of droplets is equal to twice the number of spins of light. By changing the number of turns, or direction, in the initial laser beam, we had complete control over the number of droplets formed and the speed and direction of their subsequent rotation, we could even prevent atomic droplets from leaving the ring. To keep them spinning longer, the ultracold atoms form a current.
ultracold atomic currents
This approach of glowing twisted light through ultracold atoms opens up a new, simpler way to control and sculpt matter into more complex and unconventional shapes.
One of the most interesting potential applications of BECs is the generation of “atomic circuits,” in which matter waves from ultracold atoms are guided and manipulated by optical and/or magnetic fields to create electronic circuits and devices such as transistors and can become high power. diode level equivalents.
Reliable manipulation of the BEC shape will ultimately help create atomtronic circuits.
Our ultracold atoms, here acting as an “atomic superconducting quantum interface device”, have the potential to provide devices far superior to conventional electronics.
This is because neutral atoms result in less information loss than electrons that normally make up the current.
However, what is most interesting is that our method allows us to produce complex atomtronic circuits that would be impossible to design with ordinary materials.
This could help design highly controllable and easily reconfigurable quantum sensors capable of measuring small magnetic fields that are otherwise impossible to measure.
Such sensors will be useful in fields ranging from research
