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New study of shot noise with the nonequilibrium Kubo formula in mesoscopic systems, application to the Kondo effect at a quantum dot
- Publication Year :
- 2008
-
Abstract
- Recently we have developed a theory of Keldysh formalism for mesoscopic systems. The resulting nonequilibrium Kubo formula for differential conductance makes it possible to propose the new formula of shot noise $S_h$, and thus to study shot noise in correlated systems at any temperature and any bias voltage. Employing this new approach, we analyze shot noise in the Kondo regime through a quantum dot for the symmetric case at zero temperature. Using the renormalized perturbation theory, we prove that in the leading order of bias voltage $S_h$ equal to noise power at zero temperature conventionally used as shot noise. With $S_h$, we calculate the Fano factor for a backscattering current $I_b$: $F_b=S_h/2eI_b$. It is shown that the Fano factor takes the universal form of $F_b=1+4(R-1)^2/(1+5(R-1)^2)$ determined by the Wilson ratio $R$ for arbitrary strength of the Coulomb interaction. Using the Wilson ratio R=2, our result coincides with the fractional value of $F_b=5/3$ already derived in the Kondo regime.<br />Comment: 12 pages, 1 figure, submitted to Phys. Rev. B
Details
- Database :
- arXiv
- Publication Type :
- Report
- Accession number :
- edsarx.0807.4869
- Document Type :
- Working Paper