L10.3 Integrating over the continuum to find Fermi's Golden Rule

MIT 8.06 Quantum Physics III, Spring 2018
Instructor: Barton Zwiebach
View the complete course: ocw.mit.edu/8-...
RUclips Playlist: • MIT 8.06 Quantum Physi...
L10.3 Integrating over the continuum to find Fermi's Golden Rule
License: Creative Commons BY-NC-SA
More information at ocw.mit.edu/terms
More courses at ocw.mit.edu

[@xTheUnknownAnimator]

Cleared up many of my doubts regarding the assumptions made in this derivation.

[@AMANKUMAR-sf3fd]

At 3:41 why sir put the density of states as 'i' i.e energy density of initial state. Can anyone explain it.

[@Kathie-ov8lv]

Because we're evaluating the case of Ef=Ei, so only energy contribution to density of states comes from Ei;
and we consider "t0" to be large enough to make the limit Ef--> Ei (so that we can treat Vfi and ro(Ei) as constant/energy-independent and take them out of the integral) but small enough to "not override" the probability sum and keep it much smaller than 1.

[@michaelalbergo8893]

At 17:23 he says "transition amplitude...at the initial and final state with the same energy," but that should be in the limit that E_f converges to E_i for sufficiently large time t_0, no?

[@luqmansaleem894]

dyummmm... it's a very good lecture to attend during coronavirus lockdown days. Thank you professor.

[@luqmansaleem894]

@Micah Dennis that that's that's an ad

[@yogadivayana509]

One of the most difficult concept to explain, due to the many assumptions needed.