To be honest, I'm quite skeptical regarding the mechanical perpetuum mobiles utilizing classical physics effects like the inertia or gravity (

Bhaskara wheel,

pendullum lever of Vejko Milkovic and similar toys), because I think, it's logically impossible to derive the violation of classical physics just from systems which are following classical physics. But

recent announcement of negative mass intrigued me by its connection to mechanical analogy of laser cooling.

The principle of laser cooling with Doppler effect can be simulated

even in classical way with system of mechanical resonators (like the pair of balls connected with spring) freely floating in microgravity conditions. Each such a resonator undulates at fixed frequency, whereas it's moving freely in space. If we would radiate sound waves at them, then these resonators will gain an energy and they will gradually become faster and "hotter". This effect will be particularly pronounced, if we would radiate sound at frequency, at which these resonators just oscillate by itself.

The trick here is, due to finite speed of sound spreading each oscillator "perceives" a bit different frequency, because of Doppler effect during its relative motion with respect to sound source. The faster the resonator is moving, the more it becomes untuned with sound field so it cannot absorb energy from it.

Therefore once the wavelength of sound will be precisely undertuned in such a way, that only resonators moving faster will absorb the sound most effectively, then these faster resonators will lose their kinetic energy into account of the energy of sound absorbed. In another words, the radiation of sound will slow down the faster resonators gradually. If we would shift the frequency of sound accordingly, then we can achieve the complete cooling and stopping of resonators - at least in principle. This is mechanical analogy of laser cooling with atoms (aka electron resonators) with carefully tuned laser light of variable frequency.

The intriguing aspect of this behavior is, from macroscopic perspective this system seemingly violates inertial law, because it cools and slows down itself with absorption of energy from outside. The system of spring dumbbells therefore behaves like the system of particles of negative inertia and it violates the Newton's inertia law macroscopically - despite its behavior can be derived just by application of Newton's inertia law to individual resonators.

Something here isn't right - or I'm doing some mistake in logic.