5 research outputs found
Topology induced anomalous defect production by crossing a quantum critical point
We study the influence of topology on the quench dynamics of a system driven
across a quantum critical point. We show how the appearance of certain edge
states, which fully characterise the topology of the system, dramatically
modifies the process of defect production during the crossing of the critical
point. Interestingly enough, the density of defects is no longer described by
the Kibble-Zurek scaling, but determined instead by the non-universal
topological features of the system. Edge states are shown to be robust against
defect production, which highlights their topological nature.Comment: Phys. Rev. Lett. (to be published
Topology induced anomalous defect production by crossing a quantum critical point
We study the influence of topology on the quench dynamics of a system driven
across a quantum critical point. We show how the appearance of certain edge
states, which fully characterise the topology of the system, dramatically
modifies the process of defect production during the crossing of the critical
point. Interestingly enough, the density of defects is no longer described by
the Kibble-Zurek scaling, but determined instead by the non-universal
topological features of the system. Edge states are shown to be robust against
defect production, which highlights their topological nature.Comment: Phys. Rev. Lett. (to be published
Entanglement crossover close to a quantum critical point
We discuss the thermal entanglement close to a quantum phase transition by
analyzing the concurrence for one dimensional models in the quantum Ising
universality class. We demonstrate that the entanglement sensitivity to thermal
and to quantum fluctuations obeys universal --scaling behaviour. We
show that the entanglement, together with its criticality, exhibits a peculiar
universal crossover behaviour.Comment: 12 pages; 5 figures (eps). References added; to be published in
Europhysics Letter
Bose-Einstein condensation and entanglement in magnetic systems
We present a study of magnetic field induced quantum phase transitions in
insulating systems. A generalized scaling theory is used to obtain the
temperature dependence of several physical quantities along the quantum
critical trajectory (, ) where is a longitudinal external
magnetic field and the critical value at which the transition occurs.
We consider transitions from a spin liquid at a critical field and
from a fully polarized paramagnet, at , into phases with long range
order in the transverse components. The transitions at and
can be viewed as Bose-Einstein condensations of magnons which however belong to
different universality classes since they have different values of the dynamic
critical exponent . Finally, we use that the magnetic susceptibility is an
entanglement witness to discuss how this type of correlation sets in as the
system approaches the quantum critical point along the critical trajectory,
, .Comment: 7 pages, 1 Table; accepted version; changes in text and new
reference