Seminar on Thurs. 9 December

[ivanisse]

JOINT ICTP/SISSA CONDENSED MATTER SEMINAR

Thursday, 9 December    -    11:30 a.m.

Luigi Stasi Seminar Room ICTP Leonardo Building (1st floor)


Lara FAORO (Paris Jussieu)

" Dissipationless dynamics of randomly coupled spins at high temperatures "

Abstract

We develop a technique to compute high-frequency  asymptotics of spin 
correlators in weakly interacting disordered spin systems.  We show that 
the high frequency spin correlators decreases exponentially at high 
frequencies, <S S>  ~ exp(-omega t*) and compute the characteristic 
time, t*, of this dependence.

In a typical disordered system a significant number of spins have a 
strongly coupled neighbor.  We show that this, together with the 
exponential decrease of the spin correlator at high frequencies 
translates into a low-frequency 1/f noise in all physical quantities 
sensitive to the spin state of the strongly coupled pairs.  We discuss 
the application of these results to the problem of susceptibility and 
flux noise in superconducting circuits.

Work in collaboration with Lev Ioffe and Alexei Kitaev.