Faoro, Lara and Ioffe, Lev and Kitaev, Alexei (2011) Dissipationless dynamics of randomly coupled spins at high temperatures. . (Submitted) http://resolver.caltech.edu/CaltechAUTHORS:20120713-092458311
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We develop a technique to compute the high-frequency asymptotics of spin correlators in weakly interacting disordered spin systems. We show that the dynamical spin correlator decreases exponentially at high frequencies, <SS>ω ~ exp(-τ*w) and compute the characteristic time τ_w of this dependence. In a typical random configuration, some fraction of spins form strongly coupled pairs, which behave as two-level systems. Their switching dynamics is driven by the high-frequency noise from the surrounding spins, resulting in low-frequency 1/f noise in the magnetic susceptibility and other physical quantities. We discuss application of these results to the problem of susceptibility and flux noise in superconducting circuits at mK temperatures.
|Item Type:||Report or Paper (Discussion Paper)|
|Additional Information:||We are grateful to R. McDermott for the discussion of the experimental situation. This work was supported, in part, by Triangle de la physique 2007-36, ANR-06-BLAN-0218, ECS- 0608842, ARO W911-09-1-0395, DARPA HR0011-09-1-0009. A.K. acknowledges funding by the Institute of Quantum Information under NSF grant no. PHY-0803371.|
|Group:||IQIM, Institute for Quantum Information and Matter|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||19 Jul 2012 22:23|
|Last Modified:||26 Dec 2012 15:31|
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