Suppose there are two similar particle-like objects attempting to "bump" against each other to create friction, they are prevented from colliding against one another due to either electrostatic repulsion or Pauli exclusion principle. My question is how friction (heat) is produced in the above stated scenario. Am I mistaken as in classical physics, when two rough surfaces slide against each other, heat is generated and what does quantum physics say about it?
Electrostatics – How Does Friction Produce Heat?
electrostaticsfrictionpauli-exclusion-principle
Related Solutions
The problem with this question is that static friction and kinetic friction are not fundamental forces in any way-- they're purely phenomenological names used to explain observed behavior. "Static friction" is a term we use to describe the observed fact that it usually takes more force to set an object into motion than it takes to keep it moving once you've got it started.
So, with that in mind, ask yourself how you could measure the relative sizes of static and kinetic friction. If the coefficient of static friction is greater than the coefficient of kinetic friction, this is an easy thing to do: once you overcome the static friction, the frictional force drops. So, you pull on an object with a force sensor, and measure the maximum force required before it gets moving, then once it's in motion, the frictional force decreases, and you measure how much force you need to apply to maintain a constant velocity.
What would it mean to have kinetic friction be greater than static friction? Well, it would mean that the force required to keep an object in motion would be greater than the force required to start it in motion. Which would require the force to go up at the instant the object started moving. But that doesn't make any sense, experimentally-- what you would see in that case is just that the force would increase up to the level required to keep the object in motion, as if the coefficients of static and kinetic friction were exactly equal.
So, common sense tells us that the coefficient of static friction can never be less than the coefficient of kinetic friction. Having greater kinetic than static friction just doesn't make any sense in terms of the phenomena being described.
(As an aside, the static/kinetic coefficient model is actually pretty lousy. It works as a way to set up problems forcing students to deal with the vector nature of forces, and allows some simple qualitative explanations of observed phenomena, but if you have ever tried to devise a lab doing quantitative measurements of friction, it's a mess.)
Friction acts on objects at rest too . The definition meant that if there is relative motion between two objects then friction will act as a resistance between them . If you find two objects at rest even when an external force is applied on it then it means friction is acting on them . Had there been no friction there would have been relative motion and the definition means that this motion will be opposed by friction ( if it happens to exist ) .
In the static case, the frictional force is exactly what it must be in order to prevent motion between the surfaces; it balances the net force tending to cause such motion.
This was on Wikipedia
Best Answer
You've stumbled on an interesting idea: how do classical systems that dissipate heat or energy via friction arise from quantum systems that perfectly conserve energy in their interactions? Particles in the collision kind of scenario you described don't really exhibit friction.
One convenient point is that temperature and heat transfer in quantum physics is very similar to the classical physics case. To give something of an idea within the regime of classical physics, let's imagine our surfaces as having small bumps and crevices, but still large enough as to be governed by classical mechanics. As the two surfaces slide along each other, the bumps on either surface collide against each other. These collisions cause shock waves, which will disperse and travel through the material in a chaotic fashion, resulting in what's effectively a random vibrational movement. Temperature is to an extent a measure of this random movement.
Looking back to your scenario of two quantum particles colliding, you could consider this as the collision step in the above explanation, except at the quantum level. An important point to note is that temperature is related to both the energy of the particles, as well as how chaotic or randomly they're behaving. In this way, two particles undergoing a simple collision can't really be described in terms of temperature. The motion has to have a degree of randomness or chaoticness for there to be temperature. Quantum particles are usually described in terms of probabilities anyways, so they're well-suited to temperature descriptions.