Factorization and criticality in spin sytems

R. ROSSIGNOLI; M. CEREZO; N. CANOSA

Natal

Workshop; EXACTLY SOLVABLE QUANTUM CHAINS; 2018

The ground state of interacting spin systems in the presence of magnetic fields is tipically an entangled state. However, under certain conditions these systems may possesses a factorized completely separable ground state. In this work we show that in spins systems with XXZ interactions, in non uniform transverse fields, there are sets of separable ground states exceptionally degenerate that arise in multicritical factorized points where all the magnetization collapse. Such points exist for systems of any size, spin s and dimension, and for a wide range of nono uniform field configurations. We also shown the possibility of field induced frustration for particular field configurations. The entanglement in the vicinity of such points is also analized.