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arXiv · 1005.4809

Phase Transitions in Dissipative Quantum Transport and Mesoscopic Nuclear Spin Pumping

M. S. Rudner·L. S. Levitov
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Abstract

Topological phase transitions can occur in the dissipative dynamics of a quantum system when the ratio of matrix elements for competing transport channels is varied. Here we establish a relation between such behavior in a class of non-Hermitian quantum walk problems [M. S. Rudner and L. S. Levitov, Phys. Rev. Lett. 102, 065703 (2009)] and nuclear spin pumping in double quantum dots, which is mediated by the decay of a spin-blockaded electron triplet state in the presence of spin-orbit and hyperfine interactions. The transition occurs when the strength of spin-orbit coupling exceeds the strength of the net hyperfine coupling, and results in the complete suppression of nuclear spin pumping. Below the transition point, nuclear pumping is accompanied by a strong reduction in current due to the presence of non-decaying "dark states" in this regime. Due to its topological character, the transition is expected to be robust against dephasing of the electronic degrees of freedom.

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M. S. Rudner, L. S. Levitov. 2010-05-26. Phase Transitions in Dissipative Quantum Transport and Mesoscopic Nuclear Spin Pumping. https://doi.org/10.1103/physrevb.82.155418

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