Feynman's Thesis: video series #1, pt 2/3

Next part: http://www.youtube.com/watch?v=dfo8W-QJS3w
Last part: http://www.youtube.com/watch?v=Ju_ywvXoq6E

Summary: I discuss Hamilton's principle and the sexy physics that is the least-action calculus in Feynman's Thesis: A New Approach to Quantum Theory. This is my first video set on this topic, part 2 of 3.

Equations: http://community.livejournal.com/physics_reading/802.html#cutid1
LJ Community: http://community.livejournal.com/physics_reading/

Category:

Science & Technology

Tags:

• Feynman
• quantum
• electrodynamics
• feynman's
• thesis
• sexy
• physics

[QUARKyNERD]

When he says "In which case THIS can only be nonzero" WHAT is "this"? What is it that he is reffering to that can "only be nonzero"?

[Drostie]

@QUARKyNERD I meant the leftmost term. To be totally explicit, this term is:

m v (dot) delta r, evaluated at the boundary points of C.

If I make the restriction that the path perturbation doesn't perturb the endpoints, then delta r = 0 at those boundary points. The only way you could get the term as a whole to be nonzero is if v went off to infinity somehow at the same time, so that the two limited towards some nonzero limit.

[AllahinakadarAdanali]

@Drostie Hi,

(at 1:40)

When you dot dr into ma= - gradU + F, Are you not suppose to be getting ma.dr= -gradU.dr + F.dr ? Instead of ma.dr= -gradU + F.dr

I dont understand that part

[QUARKyNERD]

Wonderful. You're wonderful! And thanks for the super-speedy response!!!

[NiteAngel]

you need a bigger black broad

[gubbins1987]

These are great, sexy math indeed.