Jennifer’s enumeration of the PARTICLE BILL OF RIGHTS reminds me of a neat effect. I hope the second amendment

The right of unstable Particles to decay shall not be infringed.

only applies to militias fundamental particles, because people have been messing with that “right” for a while in atoms. These are demonstrated by some fascinating experiments in cavity QED I read about while I was in grad school. Probably the most familiar cavity QED phenomenon is the Casimir force, which arises from modifying the electromagnetic modes that are allowed to exist. In free space, waves of any and all frequencies and polarizations can exist, but when conducting surfaces are present, these alter the boundary conditions. Two flat conductors, closely spaced, will exclude many mode of electromagnetic oscillation, and because each mode carries 1/2 hf of energy even when there are no photons in that mode, this exclusion gives rise to the attractive force.

But there’s more fun to be had with this.

Imagine placing an atom inside a cavity under circumstances similar to where the Casimir force could be observed. You can prepare the atom in a state so that it can only decay by one mode — one transition, with a particular polarization of photon (either linear or circular), and you can also orient the atom so that the photon’s direction of emission (perpendicular pr parallel to the surface) will correspond to a photon mode that isn’t supported by the cavity configuration. When you do this, what is an atom to do? There is no vacuum fluctuation to induce it to decay, nor would a photon from that decay be able to exist. The atom is forced to sit there, grudgingly (or perhaps happily, I don’t think anyone’s asked) not decaying.

You can also choose your system so that there is a higher mode density, and get atoms to decay more quickly than they would in free space. (You can also repeatedly measure an atom’s state and keep it from decaying, in a phenomenon called the quantum Zeno effect, but I’m not going to go there. Or even halfway there)

So I must conclude that since this action is routinely taken on atoms and molecules, without writ or warrant, and we have declared that we do not torture inhibit decay, that this right does not apply to composite systems.

——

Some references
Heinzen, et.al, Phys Rev Lett. 58 1320 (1987)
Jhe, et. al, Phys Rev. Lett. 58, 666 (1987)
Haroche and Kleppner, Physics Today Jan 1989 24-30