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Quenching through Dirac and semi-Dirac points in optical lattices: Kibble-Zurek scaling for anisotropic quantum critical systems
A. Dutta, R.R.P. Singh,
Published in IOP PUBLISHING LTD
2010
Volume: 89
   
Issue: 6
Abstract
We propose that Kibble-Zurek scaling can be studied in optical lattices by creating geometries that support Dirac, semi-Dirac and quadratic band crossings. On a honeycomb lattice with fermions, as a staggered on-site potential is varied through zero, the system crosses the gapless Dirac points, and we show that the density of defects created scales as 1/τ, where τ is the inverse rate of change of the potential, in agreement with the Kibble-Zurek relation. We generalize the result for a passage through a semi-Dirac point in d dimensions, in which spectrum is linear in m parallel directions and quadratic in the rest of the perpendicular (d-m) directions. We find that the defect density is given by 1/τ mν||z||+(d-m) ν⊥z⊥ where ν||, z|| and ν⊥, z⊥ are the dynamical exponents and the correlation length exponents along the parallel and perpendicular directions, respectively. The scaling relations are also generalized to the case of non-linear quenching. Copyright © 2010 EPLA.
About the journal
JournalEPL
PublisherIOP PUBLISHING LTD
ISSN02955075
Open AccessNo