Naslov
Ellipses of constant entropy in theXYspin chain

Autori
Franchini, F ; Its, A R ; Jin, B-Q ; Korepin, V E

Izvornik
Journal of Physics A: Mathematical and Theoretical (1751-8113) 40 (2007), 29; 8467-8478

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, ostalo

Ključne riječi
Entanglement, Von Neumann Entropy, XY Chain

Sažetak
Entanglement in the ground state of the XY model on the infinite chain can be measured by the von Neumann entropy of a block of neighboring spins. We study a double scaling limit: the size of the block is much larger then 1 but much smaller then the length of the whole chain. The entropy of the block has an asymptotic limit. We study this limiting entropy as a function of the anisotropy and of the magnetic field. We identify its minima at product states and its divergencies at the quantum phase transitions. We find that the curves of constant entropy are ellipses and hyperbolas and that they all meet at one point (essential critical point). Depending on the approach to the essential critical point the entropy can take any value between 0 and infinity. In the vicinity of this point small changes in the parameters cause large change of the entropy.

Izvorni jezik
Engleski

POVEZANOST RADA