Onsager asymmetries and nonequilibrium fluctuation-dissipation relations in mesoscopic conductors

David Sanchez

University of the Balearic Islands, Spain

Monday, October 19, 2009, 3:15 PM
Matfys library

In the nonlinear regime of electron transport, screening effects can lead to a breakdown of microreversibility in mesoscopic systems. The nonequilibrium response of the potential landscape along the system is, quite generally, an uneven function of the magnetic field, implying a magnetoasymmetry of the differential conductance [1]. This effect has been observed in many different phase-coherent conductors. Recent theoretical developments relate the asymmetry of the noise to the asymmetry of the differential conductance in the leading order of a voltage expansion [2,3]. As a consequence, a higher-order fluctuation dissipation relation (FDR) is established between the two magnetoasymmetries even when fluctuation theorems are not obeyed. Here, we discuss the magnetoasymmetries arising in the current fluctuations of quantum dots with strong Coulomb correlations and explicitly demonstrate the validity of nonequilibrium FDRs when interactions are treated beyond the mean field approximation [4].

[1] D. Sanchez and M. Buttiker, Phys. Rev. Lett. 93, 106802 (2004).
[2] H. Forster and M. Buttiker, Phys. Rev. Lett. 101, 136805 (2008).
[3] D. Sanchez, Phys. Rev. B 79, 045305 (2009).
[4] J.S. Lim, D. Sanchez, and R. Lopez (unpublished, 2009).