B Quantum Mechanics: Origin of the Term & Why Mechanics?

Quotidian
Messages
98
Reaction score
14
Why is 'quantum physics' often referred to as 'mechanics'? I'm interested in the specific origin of the term - when it came into vogue, and why 'mechanics' was thought suitable as a term, when it doesn't seem at all obvious that the subject matter involves mechanical principles.
 
Physics news on Phys.org
Have you learned any QM? If so, were you not struck by the parallels between QM and Classical mechanics? The same kinds of problems using similar techniques (Lagrangian and Hamiltonian) as Classical?
 
  • Like
Likes bhobba and berkeman
I've read popular science books, like Brian Greene and Paul Davies, but have never studied physics after high school. But the term has entered popular discourse, so I'm just interested in the etymology. 'Quantum Physics' seems fairly self-evident but I associate 'mechanics' with mechanical (perhaps incorrectly!)
 
Quotidian said:
but I associate 'mechanics' with mechanical (perhaps incorrectly!)
The term ''mechanics'' is used in physics in a much more general way than in everyday life. For example, classical electrodynamics and fluid flow (''fluid mechanics'') are also treated according to the principles of classical mechanics.

Mechanics is a particular, systematic and general way to approach arbitrary problems in physics by means of forces acting upon objects, whether the objects are particles, solids, fluids, or fields. Its modern form exists in two closely related approaches - Lagrangian mechanics and Hamiltonian mechanics. For the history see https://en.wikipedia.org/wiki/Mechanics.

Thus quantum physics treated by the quantum version of the same principles is called quantum mechanics.
 
Last edited:
  • Like
Likes Imager, atyy and berkeman
That's interesting! That is actually just the explanation I was looking for. (I hadn't thought to look up the Wikipedia entry on mechanics.) But I think the incongruity I'm feeling is the application of mechanics to 'fields'.
 
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!
Back
Top