Scalar Spin Chirality from Dissipative Pumping and Lamb Shift Precession
Abstract
Circulating currents in triangular triple quantum dots reverse repeatedly with bias even at zero magnetic flux and for a real Hamiltonian, a phenomenon whose origin has remained unclear. We show that dissipative tunneling prepares an orbital pseudospin, while virtual charge fluctuations generate a noncollinear Lamb field that rotates it toward the chiral direction. Bias changes their relative orientation and thereby reverses the current. This reservoir-induced orbital Hanle effect converts a nonchiral orbital polarization into scalar spin chirality, which an exact ground-multiplet identity links to the circulating current. Hierarchical-equations-of-motion calculations show that the low-bias reversal survives beyond the second-order weak-coupling description, while the quadratic growth of chirality after a sudden voltage switch identifies precession. More broadly, time-reversal-odd responses can emerge in open quantum systems from the interplay between dissipative state preparation and coherent precession.
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BibTeX
@misc{wang2026scalar,
title = {{Scalar Spin Chirality from Dissipative Pumping and Lamb Shift Precession}},
author = {YuanDong Wang and JianHua Wei},
howpublished = {arXiv},
year = {2026},
month = aug,
doi = {10.48550/arxiv.2608.30324},
eprint = {2608.30324},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2608.30324},
}
RIS
TY - UNPB
TI - Scalar Spin Chirality from Dissipative Pumping and Lamb Shift Precession
AU - YuanDong Wang
AU - JianHua Wei
PY - 2026
DA - 2026/08/31
PB - arXiv
DO - 10.48550/arxiv.2608.30324
UR - https://arxiv.org/abs/2608.30324
AB - Circulating currents in triangular triple quantum dots reverse repeatedly with bias even at zero magnetic flux and for a real Hamiltonian, a phenomenon whose origin has remained unclear. We show that dissipative tunneling prepares an orbital pseudospin, while virtual charge fluctuations generate a noncollinear Lamb field that rotates it toward the chiral direction. Bias changes their relative orientation and thereby reverses the current. This reservoir-induced orbital Hanle effect converts a nonchiral orbital polarization into scalar spin chirality, which an exact ground-multiplet identity links to the circulating current. Hierarchical-equations-of-motion calculations show that the low-bias reversal survives beyond the second-order weak-coupling description, while the quadratic growth of chirality after a sudden voltage switch identifies precession. More broadly, time-reversal-odd responses can emerge in open quantum systems from the interplay between dissipative state preparation and coherent precession.
ER -