| Autor: |
Rodríguez-Laguna, Javier, Berganza, Miguel Ibáñez, Sierra, Germán |
| Rok vydání: |
2013 |
| Předmět: |
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| Zdroj: |
Phys. Rev. B 90, 041103 (2014) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1103/PhysRevB.90.041103 |
| Popis: |
Entanglement between blocks of energy-levels is analysed for systems exhibiting s-wave and p-wave superconductivity. We study the entanglement entropy and spectrum of a block of $\ell$ levels around the Fermi point, and also between particles and holes, in the ground state of Richardson-type Hamiltonians. The maximal entropy grows with the number of levels $L$ approximately as $1/2\log(L)$, as suggested by the permutational symmetry of the state at large coupling. The number of levels in the block around the Fermi surface with maximal entanglement is proposed as a measure of the number of {\em active Cooper pairs}, which correlates with standard estimates of this magnitude. The entanglement spectrum is always composed of a principal parabolic band plus {\em higher bands} whose disappearance signals a exact BCS state, e.g. in the Moore-Read line, while the Read-Green quantum phase transition is characterized by a maximum in their weight. |
| Databáze: |
arXiv |
| Externí odkaz: |
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