Are the elementary particles that make up everything rigid or elastic?

Answer

Dear sir,

Your question was already addressed around 1640.

Then people began to think seriously about the existence of atoms, ie “indivisible” entities, the smallest parts into which a substance could be divided. Were they elastic or not?

The common reasoning was as follows: an elastic piece of matter will deform under the influence of an applied force, eg upon collision with another piece of matter. But what is distortion? It means that part of the morsel of matter is approaching another part and/or yet another part is moving away. Elasticity therefore presupposes that one can distinguish parts in the relevant chunk. An atom is assumed to be indivisible, has no parts and therefore cannot be elastic. That condition was then defined as “hard”.

D’Alembert, the French encyclopedist, published his “Traité de Mécanique” in 1643 in which he attempts to present a fundamental theory of motion and interaction and all his argument is a comparative study of the interaction (collision) between hard particles and between elastic particles. . When elastic particles collide, the total kinetic energy is the same before and after the collision. According to that theory, when hard particles – atoms – collide, the energy is not conserved.

Can we extend that reasoning to our contemporary elements of matter, commonly referred to as “elementary particles”? The old concept of the atom relies – unconsciously – on the image of an atom as a small marble that occupies a specific volume of space: inside there is material substance, outside nothing. Quantum mechanics teaches us – from its inception – that we have to consider the phenomenon electron (the first discovered elementary particle, but this applies to all particles) under two aspects: particle and wave. We never perceive an electron the way we perceive a marble, we perceive the electron indirectly, through its effects: formation of a bubble in a superheated liquid, or a spark between two metal wires at different voltages (to name but two detection methods). mention). We can relate those effects by supposing that wave, in fact by supposing that there is something that is extended in time and space and that has no sharp boundary.

We divide the elementary particles into two types: particles that make up matter (quarks and leptons, including the electron) and particles that transfer the forces between the previous ones. But here too we have to speak of the waves (in mathematical language: fields) that we suppose to describe the whole world and that expand in space and time.

Your question is therefore not really applicable to our contemporary picture of the so-called elementary particles. A meaningful related question is: do elementary particles collide elastically? By which I mean: is the total energy of the particles (in fact: the total energy in the fields) before the collision equal to the energy after the collision? There the answer is unequivocally yes, even in those cases where particles have been destroyed and others have been created as a result of the collision.