Abstract
We use representation theory to write a formula for the magnetisation of the quantum Heisenberg ferromagnet. The core new result is a spectral decomposition of the function αk2α1+···+αn where αk is the number of cycles of length k of a permutation. In the mean-field case, we simplify the formula further, arriving at a closed-form expression for the magnetisation, which allows to analyse the phase transition.
Original language | English |
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Pages (from-to) | 1203-1228 |
Number of pages | 26 |
Journal | Annales de l'institut Henri Poincare (B) Probability and Statistics |
Volume | 57 |
Issue number | 3 |
DOIs | |
State | Published - Aug 2021 |
Bibliographical note
Publisher Copyright:© Association des Publications de l’Institut Henri Poincaré, 2021.
Keywords
- Interchange process
- Magnetisation
- Phase transition
- Quantum heizenberg ferromagnet
- Random walk
- Symmetric group