Light instead of magnets: a new model of "programming" atoms paves the way for a new generation of quantum computing
Physicists from the Faculty of Physics at Vilnius University have presented a theoretical model that could radically change the approach to controlling atoms in quantum systems. Instead of traditional external magnetic fields, which require bulky and expensive equipment, the researchers propose using light to pre-"program" the atomic environment.
The essence of the concept lies in a two-step process. First, laser radiation sets a specific state of the atoms, after which this pre-prepared environment begins to actively influence the shape and polarization of complex light beams. The key element of the model is optical vortices—beams with a spiral wavefront structure. In their "core," intensity drops to zero, and the size of this dark region is determined by the topological charge. Importantly, this charge has no limitations and can take any positive or negative integer value.
In practice, this opens access to a vast state space: up to 10,000 different configurations. This allows information to be encoded not in the familiar qubits (two-level systems), but in qudits—multi-level units of quantum information—significantly increasing computational capacity and efficiency.
How Feedback Works
To control vector vortices, the scientists modeled the interaction of a beam with an atomic gas, where each atom has three energy levels. In the model, the prepared environment "inherits" the spatial pattern of light: in some regions, atoms strongly absorb radiation, while in others, they become nearly transparent. Then, a feedback effect occurs—the atomic response begins to reshape the beam itself. Instead of a simple ring structure, a petal-like pattern forms with several bright areas around the center, and the polarization structure of the radiation also changes.
Previously, such control required powerful external magnetic fields and complex setups. Now, as calculations show, all of this can be achieved using light.
Practical Prospects
Theoretically, this development paves the way for creating faster quantum processors, highly secure quantum communication networks, and ultra-precise optical sensors. Eliminating magnetic fields not only simplifies device architecture but also reduces requirements for shielding and stabilization.
My expert comment: This model is an elegant example of how fundamental physics can bypass technological barriers. If experiments confirm the theory, we will gain not just a new way to control atoms, but a fundamentally different approach to designing quantum systems. The ability to work with 10,000 states instead of two is not an evolution but a leap that could significantly accelerate the emergence of practical quantum computers.