A chain of quantum spins can act as a perfect energy converter that changes frequencies with mathematical precision.
Moving energy between different frequencies usually involves significant heat loss and messy fluctuations. Topological protection ensures that energy transfers happen at a quantized, fixed ratio that cannot be disrupted by noise. Theoretical limits previously suggested that large conversion ratios would be too unstable for practical use in quantum systems. A chain of interacting quantum spins now provides a way to build power converters that work with an arbitrarily large number of steps. Such components could serve as the power grid for future quantum computers, ensuring that information flows between different hardware parts without degrading.
Universal Topological Power Transfer with Arbitrarily Large Chern Number in Driven Quantum Spin Chains
arXiv · 2604.24851
Topological frequency converters exploit a quantized transfer of power between two driving fields in a quantum system, a phenomenon topologically protected by the Chern number of the associated fiber bundle. While realizations with few-spin systems have theoretically demonstrated this effect, the conversion factors have typically been restricted to small integer values. Here, we investigate an interacting $XXZ$ Heisenberg spin-$1/2$ chain driven adiabatically by two magnetic drives with incommen