 Cold-atom Bloch oscillation experiment

In a 1996 experiment, ultracold cesium atoms were loaded into the lowest band of an optical standing wave made with $852\mathrm{nm}$ light. Chirping the frequency difference of its counterpropagating beams accelerated the lattice, producing a constant inertial force in its frame. Switching off the lattice after different evolution times allowed momentum-distribution measurements. The observed oscillations tested the periodic band velocity underlying a Bloch oscillation; the lattice period and imposed acceleration controlled the oscillation frequency.^[ref]