Quantum breakthrough without magnets: physicists have learned to 'program' atoms with light
A group of researchers from the Faculty of Physics at Vilnius University has presented a theoretical model that fundamentally changes the approach to controlling quantum systems. Instead of traditional bulky external magnetic fields, the scientists propose using light to pre-"program" atoms. This is not just a laboratory curiosity—it holds real potential for accelerating quantum computing and creating secure communication networks.
The essence of the model is that light first sets atoms into a specific state, and then this pre-prepared medium begins to actively influence the laser beams passing through it. The key element is optical vortices: laser beams with a spiral wavefront structure. At their center, intensity drops to zero, forming a dark region. The size of this region is determined by the topological charge, which, as the authors note, can take any integer value—both positive and negative.
The practical significance of this feature is immense. Theoretically, up to 10,000 different states can be achieved. This marks a transition from conventional qubits, which operate with only two states, to qudits—multi-level units of quantum information. Such capacity paves the way for exponentially more powerful computations.
How "Programming" with Light Works
To control vector vortices, the researchers simulated the interaction of a laser beam with an atomic gas, where each atom has three energy levels. In this model, the prepared medium literally "inherits" the spatial pattern of light. In some areas, atoms begin to actively absorb radiation; in others, they become almost transparent. A feedback loop emerges: the atomic response reshapes the beam itself.
Instead of a simple ring structure, a complex petal-like pattern appears with several bright zones around the center. The polarization structure of the beam also changes. Previously, achieving this level of control required powerful magnetic fields and complex equipment. Now, everything is solved with light.
My Expert Opinion
This work is an elegant example of how fundamental physics solves engineering problems. Abandoning magnetic fields not only simplifies the design of quantum devices but also potentially enhances their stability. If the model is confirmed experimentally, we could see a new class of compact, high-speed quantum processors, as well as sensors with unprecedented precision. The market should take note of this development—it could become one of the key drivers of the next generation of quantum technologies.