Cerezo M, Rossignoli R, Canosa N, Ríos E
Instituto de Física de La Plata, CONICET, and Departamento de Física, Universidad Nacional de La Plata, C.C. 67, La Plata 1900, Argentina.
Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC), La Plata 1900, Argentina.
Phys Rev Lett. 2017 Dec 1;119(22):220605. doi: 10.1103/PhysRevLett.119.220605.
We analyze ground state (GS) factorization in general arrays of spins s_{i} with XXZ couplings immersed in nonuniform fields. It is shown that an exceptionally degenerate set of completely separable symmetry-breaking GSs can arise for a wide range of field configurations, at a quantum critical point where all GS magnetization plateaus merge. Such configurations include alternating fields as well as zero-bulk field solutions with edge fields only and intermediate solutions with zero field at specific sites, valid for d-dimensional arrays. The definite magnetization-projected GSs at factorization can be analytically determined and depend only on the exchange anisotropies, exhibiting critical entanglement properties. We also show that some factorization-compatible field configurations may result in field-induced frustration and nontrivial behavior at strong fields.
