3k views

### Lagrangian mechanics vs Hamiltonian mechanics [duplicate]

First of all, what are the differences between these two: Lagrangian mechanics and Hamiltonian mechanics? And secondly, do I need to learn both in order to study quantum mechanics and quantum field ...
345 views

### What is the essence of Lagrangian/Hamiltonian mechanics? [duplicate]

I'm reading on the calculus of variations, and Hamiltonian mechanics is discussed there. However, I'm not a physicist, so I cannot very well place the concept of Hamiltonian Mechanics in perspective. ...
12k views

### Why not use the Lagrangian, instead of the Hamiltonian, in nonrelativistic QM?

Undergraduate classical mechanics introduces both Lagrangians and Hamiltonians, while undergrad quantum mechanics seems to only use the Hamiltonian. But particle physics, and more generally quantum ...
56k views

### What is the difference between Newtonian and Lagrangian mechanics in a nutshell?

What is Lagrangian mechanics, and what's the difference compared to Newtonian mechanics? I'm a mathematician/computer scientist, not a physicist, so I'm kind of looking for something like the ...
12k views

### Advantages of Lagrangian Mechanics over Newtonian Mechanics [closed]

Here, I'm going to pose a very serious list of doubts I have on Lagrangian Mechanics. Can we learn Lagrangian Mechanics without studying Newtonian Mechanics? Does Lagrangian help in solving problems ...
12k views

### What is the difference between configuration space and phase space?

What is the difference between configuration space and phase space? In particular, I notices that Lagrangians are defined over configuration space and Hamiltonians over phase space. Liouville's ...
8k views

### Differences between classical, analytical, rational and theoretical mechanics

Can you explain me what are the differences between the four following subjects? analytical mechanics rational mechanics classical mechanics theoretical mechanics
839 views

### Conceptual difference between Hamiltonian and Lagrangian formulation [duplicate]

What is the basic difference between Lagrangian formulation and Hamiltonian formulations of mechanics? Why do we have two formulations when we can work with Hamiltonian most of the times (in quantum ...
### $F = ma$ not applicable at atomic dimensions?
Is the following logic valid? $F = ma$ does not hold at atomic dimensions because it is a continuous function. But since we know from the Einstein-Plank relation $E = nh\nu$, energy is quantized and ...