科研之友
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摘要
Using a functional renormalization group (RG) method, we reexamine the glass phase of the two-dimensional random-field sine Gordon model. It is described by a line of fixed points with a super-roughening amplitude [u(0)-u(r)](2)similar to A(T)ln(2)r as temperature T is varied. By speculating that this line is identical for all T to the one found in disordered free-fermion models via exact results from "nearly conformal" field theory, one would predict A(T=0)=0, contradicting numerics. We point out that this result may be related to failure of dimensional reduction, and that a functional RG method incorporating higher harmonics and nonanalytic operators predicts a nonzero A(T=0) which compares reasonably well with numerics.
- 出版日期2007-5
