Speed Quanta: Is There a Lower Limit?

  • Thread starter Thread starter Physonic
  • Start date Start date
  • Tags Tags
    Limit Speed
Physonic
Messages
5
Reaction score
0
we all know that there is upper limit for speed that is speed of light, but is there a lower limit, I mean is there quanta for speed.
 
Physics news on Phys.org
There is no quanta for speed.
The effective "lower limit" for speed will be the uncertainty principle, because of the wave-particle duality. The speed of a particle can be arbitrarily close to zero as long as the uncertainty in the position is sufficiently large (i.e. the particle is delocalized).

If a particle is confined to any discrete region of space, there will be a lower limit on its velocity. Hope this helps.
 
lzkelley said:
There is no quanta for speed.
The effective "lower limit" for speed will be the uncertainty principle, because of the wave-particle duality. The speed of a particle can be arbitrarily close to zero as long as the uncertainty in the position is sufficiently large (i.e. the particle is delocalized).

If a particle is confined to any discrete region of space, there will be a lower limit on its velocity. Hope this helps.

Thank you that helped.
 
No, not at all.

The uncertainty principle applies for dXdP, not dXd(mv) which is a slight difference; in the case of light the uncertainty applies to its wavelength, frequency and energy via the relation P = hf/c where f is the frequency or alternatively, P = h/w where w is the wavelength.

Correct me if I'm wrong but that's how it seems.
 
Last edited:
In the case of light, the lower limit is quite well defined... its still just c. but even in the not photon case, by the deBroglie equation the same relation applies (p=h/L).
dst : your point, thought true, is trivial and semantical. In quantum mechanics there is no way to define an instantaneous (accurate) velocity; however, the concept of spatial motion does apply very closely to momentum --> hence it is the term that we should be looking at, in the "lower limit of velocity."
 
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. Towards the end of the first lecture for the Qiskit Global Summer School 2025, Foundations of Quantum Mechanics, Olivia Lanes (Global Lead, Content and Education IBM) stated... Source: https://www.physicsforums.com/insights/quantum-entanglement-is-a-kinematic-fact-not-a-dynamical-effect/ by @RUTA
If we release an electron around a positively charged sphere, the initial state of electron is a linear combination of Hydrogen-like states. According to quantum mechanics, evolution of time would not change this initial state because the potential is time independent. However, classically we expect the electron to collide with the sphere. So, it seems that the quantum and classics predict different behaviours!

Similar threads

Replies
4
Views
1K
Replies
5
Views
1K
Replies
1
Views
1K
Replies
1
Views
1K
Replies
3
Views
2K
Back
Top