# Is force quantised?

Things like charge, distance, energy, etc are quantised , Are all the phenomenon around us also quantised ?? Like time or say Force !?

I was reading this question which goes about seeing the effect of individual human being on the Pluto. I wanted to ask, is there limit of for how small a force can be like if I have two particles, is there a limit after which the force that they exert is so so small , that it is less than a theoretical limit.

Is there a limit to everything ??

Like I read about smallest unit that is possible for length ( planks length ) and since the fastest possible speed is that of the light that I'm ultimately is quantised, is everything else too ?? I'm still in highschool, and read some of these things just for fun, so I don't know a lot about these actually...:P

• Distance is not quantized. Commented Jun 21, 2019 at 23:04
• @my2cts Then what's plank length ??
– user232243
Commented Jun 22, 2019 at 3:11
• For info about the significance of the Planck length, please see the answers here. Commented Jun 22, 2019 at 14:36

There are a few things to clarify:

1. EM charge is quantized, and we do have a elementary charge (electron), and you would think that all elementary particles have multiples of this charge. In reality, quarks (though they do not exist freely) do carry one third (or multiples of that) of the elementary EM charge. So EM charge is quantized, but not just multiples of the elementary charge exist in objects (QM).

2. energy is quantized and photons are the elementary quanta of EM energy

3. W and Z particles are the quanta of the electroweak field

4. distance is not quantized (yet), we think of the fabric of spacetime as a continuous manifold

Now there seems to be a misunderstanding about the forces. Forces are mediated by virtual particles (not real particles, but a mathematical model), that is:

1. EM force is mediated by virtual photons (QED quantized)

2. strong force by virtual gluons (pions for nuclear) (QCD quantized)

3. weak force is mediated by w and z bozons

4. gravity by virtual gravitons (hypothetical)

The energy of a wave in a field (for example, electromagnetic waves in the electromagnetic field) is quantized, and the quantum excitations of the field can be interpreted as particles. The Standard Model contains the following particles, each of which is an excitation of a particular field

Thus, forces themselves are quantized, meaning that according to QFT, every force field is quantized and there is a vector boson associated with it.

There is a misunderstanding with the Planck length too. The Planck length does not mean that distance is quantized. It is a scale at which the classical ideas about space and time cease to be valid and QM dominates. You become confused because they call it the quantum of length, but in reality it is just the smallest measurement of length with any meaning.

• Ohhhhhh..... Thanks a lot, this clarifies a lot
– user232243
Commented Jun 22, 2019 at 13:19
• “Forces are mediated by virtual particles (not real particles, but a mathematical model)”. This sounds like an absurdity. How can a force something that is real in reality be mediated by something that is “virtual” not in reality ? Commented Dec 17, 2022 at 1:59
• @Blue5000 we are using mathematical models to model the interaction between particles (or objects) when we model how forces create these interactions. We know from experiments that these forces are real, but we need to model them. These so called near fields (where a near field for example is a magnetic field, and a far field is an EM radiation) are what this is mainly about. These near fields do not involve real photons for example, there is no EM radiation involved in the effect of a magnet. The effect of the magnet is still verifiable. Commented Dec 17, 2022 at 5:45
• @Blue5000 we model the effect of the magnet (the magnetic field or near field) with these virtual photons. These are not real photons, but a mathematical model. Commented Dec 17, 2022 at 5:46

Any macroscopic interaccion that we understand as 'applying force' is produced by electromagnetic interaction. Any action that you can make, like when you push or pull any object, is the product of interactions between microscopic charged particles (protons and electrons). Aside from gravity, any force in our daily lives comes, in the very basic level, from charged particles. And charge is quantized: the charge of a particle, or of any object, can only be a multiple of that of the electron.

So, yes. Forces are quantized in the sense that charge is quantized.

• This does not answer the question, which can be phrased as: are there situations in which force can only take discrete values. Commented Jun 21, 2019 at 22:56