Researchers at ETH Zurich have uncovered a surprising reversal in quantum systems, shedding new light on the behavior of topological effects in artificial solids. The researchers constructed an artificial solid using extremely cold atoms (fermionic potassium atoms) trapped in spatially periodic lattices using laser beams. By employing additional laser beams, they caused the energy levels of adjacent lattice sites to move up and down periodically, out of sync with each other. This setup allowed them to observe the doughnut topology of the energy states, which caused the particles to be transported by one lattice site consistently in the same direction at each repetition of the cycle, a phenomenon known as topological pumping.
Topological Pumping and the Doughnut Topology
The researchers were able to observe the doughnut topology of the energy states, which caused the particles to be transported by one lattice site consistently in the same direction at each repetition of the cycle, a phenomenon known as topological pumping. This setup allowed them to study the behavior of topological effects in artificial solids.