New Anomalous LiebRobinson Bounds in Quasiperiodic XY Chains
Abstract
We announce and sketch the rigorous proof of a new kind of anomalous (or subballistic) LiebRobinson (LR) bound for an isotropic XY chain in a quasiperiodic transversal magnetic field. Instead of the usual effective light cone x≤vt, we obtain x≤vt^{α} for some 0<α <1. We can characterize the allowed values of α exactly as those exceeding the upper transport exponent αu+ of a onebody Schrödinger operator. To our knowledge, this is the first rigorous derivation of anomalous quantum manybody transport. We also discuss anomalous LR bounds with powerlaw tails for a random dimer field.
 Publication:

Physical Review Letters
 Pub Date:
 September 2014
 DOI:
 10.1103/PhysRevLett.113.127202
 arXiv:
 arXiv:1408.1796
 Bibcode:
 2014PhRvL.113l7202D
 Keywords:

 75.10.Pq;
 03.65.Ud;
 05.50.+q;
 05.60.Gg;
 Spin chain models;
 Entanglement and quantum nonlocality;
 Lattice theory and statistics;
 Quantum transport;
 Mathematical Physics;
 Condensed Matter  Statistical Mechanics;
 Quantum Physics
 EPrint:
 5 pages, to appear in Phys. Rev. Lett