Mephisto's user avatar
Mephisto's user avatar
Mephisto's user avatar
Mephisto
  • Member for 9 years, 9 months
  • Last seen more than a month ago
10 votes
1 answer
2k views

Lagrangian of 2D square lattice of point masses connected by springs

7 votes
2 answers
2k views

What is the result of a classical collision between THREE point particles at the same precise instant?

3 votes
4 answers
1k views

What is the mathematical justification for the quadratic approximation to the energy of a spring in a one-dimensional lattice?

2 votes
1 answer
628 views

Which is this formula Feynman talks about in the QED book?

2 votes
1 answer
129 views

Please provide the simplest example you can think of, of generators of time evolution and generalized coordinates

1 vote
2 answers
216 views

$\langle B|A \rangle$ expressed in terms of the Partition Function

1 vote
0 answers
221 views

Electron matrix element in a most simple QFT problem, the e+ e- annihilation

1 vote
1 answer
584 views

What is the meaning of "closure is lost" for a set of kets (or any members of a vector space)?