Phys.org  May 14, 2024 Periodic temporal modulation of Hamiltonians can induce geometrical and topological phenomena in the dynamics of quantum states. Using the interference between two lasers an international team of researchers (Japan, USA – industry, Singapore, Australia, Germany) demonstrated an off-resonant optical lattice for a polariton condensate with controllable potential depths and nearest-neighbour coupling strength. Temporal modulation was introduced via a gigahertz frequency detuning between pump lasers, creating a polariton ‘conveyor belt’. The breaking of time-reversal symmetry caused band structures to become non-reciprocal and acquired a universal tilt. The non-reciprocal tilting was connected to the non-trivial topology of the […]