Quantum breakthrough without magnets: scientists have learned to "program" atoms with light
A group of physicists from Vilnius University has presented a theoretical model that fundamentally changes the approach to controlling quantum systems. Instead of traditional external magnetic fields, the researchers propose using light to pre-"program" atoms. This discovery could serve as the foundation for a new generation of quantum devices—from processors to secure communication lines.
The essence of the method is as follows: a light beam first sets atoms to a specific state, after which this pre-prepared atomic medium begins to actively influence the shape and polarization of complex laser beams. The key element of the model is optical vortices—beams with a spiral wavefront structure. In their "core," the intensity drops to zero, and the size of the dark region is determined by the topological charge, which can take any integer value—both positive and negative.
From qubits to qudits: 10,000 states in a single beam
The practical potential of this technology is impressive. Using this approach, up to 10,000 different states can be achieved, allowing information to be encoded in qudits—multi-level units of quantum information that generalize the familiar qubits. This radically increases the amount of data that can be processed or transmitted in a single cycle.
To demonstrate control over vector vortices, the scientists simulated the interaction of a beam with an atomic gas, where each atom has three energy levels. In such a model, the prepared medium literally "inherits" the spatial pattern of light: in some areas, atoms begin to intensively absorb radiation, while 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 regions around the center, and the polarization structure is completely altered.
Expert opinion
Previously, such control required bulky and powerful external magnetic fields, making systems expensive and difficult to operate. Theoretically, this new development opens the path to faster quantum processors, highly secure quantum communication networks, and ultra-precise optical sensors. This is not just an evolution—it is a paradigm shift that could bring quantum technologies out of laboratories and into the real sector.