Is this a Stirling number of the second kind?

In summary, the conversation discusses a paper on phonon sidebands, multiphonon relaxation, and phonon-assisted energy transfer. The person has trouble understanding Equation (3.17) which involves the Stirling numbers of the second kind. They question the fact that the lower number is larger than the top number, but it is explained that this corresponds to the plus or minus sign. The person apologizes for their previous question and thanks the other person for the clarification.
  • #1
HAYAO
Science Advisor
Gold Member
376
236
I saw this paper that talks about phonon sidebands, multiphonon relaxation, and phonon-assisted energy transfer.

I was skimming through each of the equations, but I have problem understanding the formulation of some of them, for example Equation (3.17):
[tex]g_{\pm }(t) = \int d\omega \begin{Bmatrix} n_{\omega }\\ n_{\omega } +1 \end{Bmatrix}exp\left ( \pm i\omega t \right )[/tex]

If I understand correctly, the part in the braces is the Stirling numbers of the second kind. However, it doesn't make sense to me that the bottom number is larger than the top number, because that should only give zero. So is this something else?

EDIT: dear the moderators. I wasn't really sure where this thread belongs. Purely from mathematics, this thread could belong in the math section, but considering that the discussion centers around the physical aspect of a quantum mechanical phenomena, I decided to put this in this section.
 
  • Like
Likes Iliody
Physics news on Phys.org
  • #2
I haven't seen the paper, but would it make sense that upper (lower) case corresponds to the plus (minus) sign?
 
  • Like
Likes HAYAO
  • #3
Demystifier said:
I haven't seen the paper, but would it make sense that upper (lower) case corresponds to the plus (minus) sign?
Oh, now it makes great sense. Sorry for the bum question. Thank you very much!
 
  • Like
Likes Demystifier

1. What is a Stirling number of the second kind?

A Stirling number of the second kind is a mathematical concept used in combinatorics to represent the number of ways to partition a set of n objects into k non-empty subsets.

2. How is a Stirling number of the second kind denoted?

A Stirling number of the second kind is denoted by S(n,k) or {n,k}.

3. What is the formula for calculating a Stirling number of the second kind?

The formula for calculating a Stirling number of the second kind is S(n,k) = 1/k! * Σ((-1)^j * (k choose j) * (k-j)^n) where j ranges from 0 to k.

4. What is the significance of Stirling numbers of the second kind?

Stirling numbers of the second kind are used in many areas of mathematics, including combinatorics, number theory, and graph theory. They also have applications in physics, computer science, and economics.

5. How are Stirling numbers of the second kind related to Stirling numbers of the first kind?

Stirling numbers of the second kind represent the number of ways to partition a set, while Stirling numbers of the first kind represent the number of ways to arrange a set into cycles. They are related by the formula S(n,k) = k! * {n,k}.

Similar threads

  • Atomic and Condensed Matter
Replies
7
Views
2K
Replies
1
Views
783
  • Advanced Physics Homework Help
Replies
7
Views
2K
  • Calculus and Beyond Homework Help
Replies
1
Views
1K
  • Set Theory, Logic, Probability, Statistics
Replies
4
Views
3K
  • Calculus and Beyond Homework Help
Replies
6
Views
1K
  • Math Proof Training and Practice
2
Replies
40
Views
14K
  • Quantum Interpretations and Foundations
Replies
1
Views
500
  • Math Proof Training and Practice
3
Replies
98
Views
11K
  • Introductory Physics Homework Help
Replies
4
Views
2K
Back
Top