Quantum Breakthrough: Physicists Learn to 'Program' Atoms with Light Without Magnetic Fields
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. The core of the development lies in the ability to "program" atoms using light, completely eliminating the need for external magnetic fields.
The essence of the method involves a two-step process. First, a light beam sets the initial state of the atomic medium, effectively writing a "program" onto it. Then, this pre-prepared medium actively interacts with laser beams, altering their shape and polarization. A key element of the model is optical vortices—beams with a spiral wavefront structure. At the center of such a vortex, the light intensity drops to zero, forming a dark core. The size of this core is determined by the topological charge, which can take any integer value—both positive and negative.
The practical significance of this discovery is immense. Using optical vortices, up to 10,000 different states can be achieved. This allows information to be encoded not in conventional qubits (with two states), but in qudits—multilevel quantum units—which exponentially increases computational power.
How it works: feedback between light and atoms
To control vector vortices, the scientists modeled the interaction of a beam with an atomic gas, where each atom has three energy levels. The prepared medium "inherits" the spatial pattern of the light: in some zones, atoms strongly absorb radiation, while in others they become almost transparent. A feedback effect occurs—the atomic response restructures the beam itself. A simple ring-shaped structure transforms into a complex petal-like pattern with several bright regions around the center, and the polarization structure also undergoes changes.
Previously, such control required powerful external magnetic fields and bulky equipment. The new model offers an elegant and compact solution.
Theoretically, this development paves the way for creating faster quantum processors, highly secure quantum communication networks, and ultra-precise optical sensors.
Expert opinion. This research is an important step toward practical quantum technologies. Eliminating magnetic fields not only simplifies device architecture but also reduces noise levels, which is critical for the stable operation of qudits. If the model is successfully implemented experimentally, we could see commercial next-generation quantum systems within the next 5–7 years.