The Mermin-Wagner Theorem - Condensed Matter Theory Group

How symmetry breaking occurs in principle
Actors
Proof of the Mermin-Wagner Theorem
Discussion
We can now estimate the scalar product:
(A, A) < β
2
≤ β
2
= β
2
This finally leads to
The Bogoliubov inequality
The Mermin-Wagner Theorem
n
A †
m 〈m| A |n〉 (Wn + Wm)
n=m
n
A †
m 〈m| A |n〉 (Wn + Wm)
n,m
n
Wn
n
A †
A n + n
AA †
n
(A, A) ≤ β
A, A
2
†
+
Andreas Werner The Mermin-Wagner Theorem