Naslov
Separability and ground-state factorization in quantum spin systems

Autori
Giampaolo, Salvatore M. ; Adesso, Gerardo ; Illuminati, Fabrizio

Izvornik
Physical review. B, Condensed matter and materials physics (1098-0121) 79 (2009), 22; 224434, 19

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

Ključne riječi
factorization

Sažetak
We investigate the existence and the properties of fully separable 共fully factorized兲 ground states in quantum spin systems. Exploiting techniques of quantum information and entanglement theory, we extend a recently introduced method and construct a general, self- contained theory of ground state factorization in frustration- free quantum spin models defined on lattices in any spatial dimension and for interactions of arbitrary range. We show that, quite generally, nonexactly solvable translationally invariant models in presence of an external uniform magnetic field can admit exact, fully factorized ground state solutions. Unentangled ground states occur at finite values of the Hamiltonian parameters satisfying well-defined balancing conditions between the applied field and the interaction strengths. These conditions are analytically determined together with the type of magnetic orderings compatible with factorization and the corresponding values of the fundamental observ- ables such as energy and magnetization. The method is applied to a series of examples of increasing complex- ity, including translationally invariant models with short, long, and infinite ranges of interaction, as well as systems with spatial anisotropies, in lower and higher dimensions. We also illustrate how the general method, besides yielding a large series of exact results for complex models in any dimension, recovers, as particular cases, the results previously achieved on simple models in low dimensions exploiting direct methods based on factorized mean-field ansatz.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA