Scientists have found a way to "program" atoms with light without magnetic fields — a breakthrough for quantum computing.
A group of researchers from the Faculty of Physics at Vilnius University has presented a theoretical model that allows "programming" atoms using light, completely eliminating the need for external magnetic fields. This could fundamentally change the approach to creating quantum processors and communication systems.
The development is based on the use of optical vortices—laser beams with a spiral wavefront structure. In such beams, the intensity at the center drops to zero, forming a dark region. The size of this region is determined by the topological charge, which can take any integer value—both positive and negative. In practice, this means the ability to generate up to 10,000 different states. Instead of conventional qubits, which operate with two states, the researchers propose using qudits—multidimensional units of quantum information.
The mechanism of the model works as follows: light first "programs" the atomic medium, and then this prepared medium alters the shape and polarization of complex laser beams. The interaction occurs in an atomic gas, where atoms have three energy levels. The prepared medium inherits the spatial pattern of the light: in some regions, atoms actively absorb radiation, while in others, they become nearly transparent. A feedback loop then emerges—the atomic response reshapes the beam itself.
The result is impressive: instead of a simple ring structure, a lobed pattern forms with several bright regions around the center. The polarization structure also changes. Previously, achieving this level of control required powerful magnetic fields and bulky equipment.
Theoretically, this approach paves the way for creating faster quantum processors, highly secure quantum communication networks, and ultra-precise optical sensors. Eliminating magnetic fields significantly simplifies device design and reduces energy consumption.
My comment: This is not just an elegant theoretical solution—it addresses one of the key engineering challenges in quantum physics. Controlling atoms without magnetic fields could be the "accelerator" that brings quantum computing out of laboratories and into the real sector. If the model is confirmed experimentally, we may witness a paradigm shift in quantum design.