Dynamics and transport in random quantum systems governed by strong-randomness fixed points

Physics – Condensed Matter – Disordered Systems and Neural Networks

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

Long version (with many additional results) of Phys. Rev. Lett. {\bf 84}, 3434 (2000) (available as cond-mat/9904290); two-col

Scientific paper

10.1103/PhysRevB.63.134424

We present results on the low-frequency dynamical and transport properties of random quantum systems whose low temperature ($T$), low-energy behavior is controlled by strong disorder fixed points. We obtain the momentum and frequency dependent dynamic structure factor in the Random Singlet (RS) phases of both spin-1/2 and spin-1 random antiferromagnetic chains, as well as in the Random Dimer (RD) and Ising Antiferromagnetic (IAF) phases of spin-1/2 random antiferromagnetic chains. We show that the RS phases are unusual `spin metals' with divergent low-frequency spin conductivity at T=0, and we also follow the conductivity through novel `metal-insulator' transitions tuned by the strength of dimerization or Ising anisotropy in the spin-1/2 case, and by the strength of disorder in the spin-1 case. We work out the average spin and energy autocorrelations in the one-dimensional random transverse field Ising model in the vicinity of its quantum critical point. All of the above calculations are valid in the frequency dominated regime $\omega \agt T$, and rely on previously available renormalization group schemes that describe these systems in terms of the properties of certain strong-disorder fixed point theories. In addition, we obtain some information about the behavior of the dynamic structure factor and dynamical conductivity in the opposite `hydrodynamic' regime $\omega < T$ for the special case of spin-1/2 chains close to the planar limit (the quantum x-y model) by analyzing the corresponding quantities in an equivalent model of spinless fermions with weak repulsive interactions and particle-hole symmetric disorder.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Dynamics and transport in random quantum systems governed by strong-randomness fixed points does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Dynamics and transport in random quantum systems governed by strong-randomness fixed points, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamics and transport in random quantum systems governed by strong-randomness fixed points will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-362107

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.