Berlin 2018 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 80: Brownian Motion and Transport

DY 80.2: Vortrag

Freitag, 16. März 2018, 10:15–10:30, BH-N 128

Quantum motion of ions in a molecular junction during current flow — •Lev Kantorovich — Physics, King's College London, London, WC2R 2LS

We consider a combined system of electrons and nuclei of a molecular junction. Initially the whole system is in thermal equilibrium at some temperature, no partitioning approximation is made. Then, a bias is applied causing a current to flow. Using path integrals and non-equilibrium Green*s Functions formalisms, an expression for the density matrix of ions (reduced with respect to electrons) is derived and hence the corresponding effective Liouville equation. It is assumed that atomic displacements with respect to average (and time dependent) atomic positions are small (the harmonisation approximation). Then a hierarchy of equations of motion for average ionic positions is obtained without any additional approximations. This work generalises the method of Ref. [Jing-Tao Lü et al, PRB 85, 245444 (2012)] in two main aspects: (i) going beyond the partitioned approximation and (ii) the stochastic equations of motion for quantum ions are rigorously derived.