Velocity scanning tomography and its application in room-temperature quantum simulation

In room-temperature atomic systems, thermal motion induces Doppler broadening of energy levels, which has traditionally been regarded as classical noise hindering quantum control. Here we introduce the velocity scanning tomography technique that enables velocity-resolved spectroscopy of Doppler-broadened atoms, allowing quantum simulation under ambient conditions. We show that when atoms move in a spatially-periodic optical field, their dressed states acquire a geometric phase that appears as an anomalous Doppler shift. By selectively probing the shifts of atoms at different velocities, we establish the route from geometric-phase measurement to the extraction of topological invariants. Thus, thermal motion is no longer noise but becomes a controllable resource for quantum simulation in super-radiance lattices. This approach signifies a new avenue for investigating topological physics in room-temperature atomic systems, and provides a broad basis for the development of quantum sensing, quantum memory and quantum devices.