<< What happens now when you add or subtract a single phonon? At first thought, you may expect this would simply change the average to n + 1 or n - 1, respectively, however the actual outcome defies this intuition. Indeed, quite counterintuitively, when you subtract a single phonon, the average number of phonons actually goes up to 2n. This surprising result where the mean number of quanta doubles has been observed for all-optical photon-subtraction experiments and is observed for the first time outside of optics here. >>
<< One way to think of the experiment is to imagine a claw machine that you often see in video arcades, except that you can't see how many toys there are inside the machine. Before you agree to play, you've been told that on average there are n toys inside but the exact number changes randomly each time you play. Then, immediately after a successful grab with the claw, the average number of toys actually goes up to 2n, >> Michael Vanner.
Adding or subtracting single quanta of sound. Imperial College London. Jan 25, 2021.
G. Enzian, J. J. Price, et al. Single-Phonon Addition and Subtraction to a Mechanical Thermal State. Phys. Rev. Lett. 126, 033601. Jan 21, 2021.
