Entanglement and local extremes at an infinite-order quantum phase transition

Journal Article · Mon Mar 15 00:00:00 EDT 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.81.032334· OSTI ID:21408403

Rulli, C C; Sarandy, M S ^[1]

---

1. Instituto de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Gragoata, 24210-346, Niteroi, RJ (Brazil)

The characterization of an infinite-order quantum phase transition (QPT) by entanglement measures is analyzed. To this aim, we consider two closely related solvable spin-1/2 chains, namely, the Ashkin-Teller and the staggered XXZ models. These systems display a distinct pattern of eigenstates but exhibit the same thermodynamics, that is, the same energy spectrum. By performing exact diagonalization, we investigate the behavior of pairwise and block entanglement in the ground state of both models. In contrast with the XXZ chain, we show that pairwise entanglement fails in the characterization of the infinite-order QPT in the Ashkin-Teller model, although it can be achieved by analyzing the distance of the pair state from the separability boundary. Concerning block entanglement, we show that both XXZ and Ashkin-Teller models exhibit identical von Neumann entropies as long as a suitable choice of blocks is performed. Entanglement entropy is then shown to be able to identify the quantum phase diagram, even though its local extremes (either maximum or minimum) may also appear in the absence of any infinite-order QPT.

• OSTI ID: 21408403
• Journal Information: Physical Review. A, Vol. 81, Issue 3; Other Information: DOI: 10.1103/PhysRevA.81.032334; (c) 2010 The American Physical Society; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
36 MATERIALS SCIENCE
74 ATOMIC AND MOLECULAR PHYSICS
EIGENSTATES
ENERGY SPECTRA
ENTROPY
GROUND STATES
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
QUANTUM ENTANGLEMENT
SPIN
THERMODYNAMICS
ANGULAR MOMENTUM
DIAGRAMS
ENERGY LEVELS
INFORMATION
PARTICLE PROPERTIES
PHYSICAL PROPERTIES
SPECTRA
THERMODYNAMIC PROPERTIES