Quantum breakthrough without magnets: a new model for controlling atoms with light
Researchers from the Faculty of Physics at Vilnius University have presented a theoretical model that allows "programming" atoms using light without external magnetic fields. This discovery could fundamentally change the approach to quantum computing and communications.
The model is based on the concept of optical vortices — laser beams with a spiral wavefront structure. At the center of such a beam, the intensity drops to zero, forming a dark region. The size of this region is determined by the topological charge, which can take any positive or negative integer value. This is a key parameter, as it allows encoding information in qudits — multi-level units of quantum information that significantly surpass standard qubits in capacity.
In practice, calculations show that up to 10,000 different states can be achieved. This means that instead of the traditional binary system (0 and 1), we obtain a multidimensional space for data encoding. To control vector vortices, the team considered the interaction of the beam with an atomic gas, where atoms have three energy levels. In this system, light first "programs" the atoms, and then the prepared medium changes the shape and polarization of complex laser beams.
During the interaction, feedback occurs: in some regions, atoms absorb radiation more strongly, while in others they become almost transparent. As a result, instead of a simple ring structure, a petal-like pattern with several bright regions around the center appears. This changes the polarization structure of the beam, which previously required powerful external magnetic fields and complex equipment.
Expert analysis: This work demonstrates that we are on the verge of a new generation of quantum systems, where control is achieved not by magnetic fields but by light. If the model is implemented in practice, it could lead to the creation of faster quantum processors, highly secure quantum communication networks, and ultra-precise optical sensors. However, it is worth remembering that this is a theoretical work — the path from model to laboratory prototype may take years. Nevertheless, the direction is extremely promising and promises a revolution in quantum engineering.