Double-Occupancy Errors, Adiabaticity, and Entanglement of Spin-Qubits in Quantum Dots
Abstract
Quantum gates that temporarily increase singlet-triplet splitting in order to swap electronic spins in coupled quantum dots, lead inevitably to a finite double-occupancy probability for both dots. By solving the time-dependent Schr\"odinger equation for a coupled dot model, we demonstrate that this does not necessarily lead to quantum computation errors. Instead, the coupled dot ground state evolves quasi-adiabatically for typical system parameters so that the double-occupancy probability at the completion of swapping is negligibly small. We introduce a measure of entanglement which explicitly takes into account the possibilty of double occupancies and provides a necessary and sufficient criterion for entangled states.
Cite
@article{arxiv.cond-mat/0009083,
title = {Double-Occupancy Errors, Adiabaticity, and Entanglement of Spin-Qubits in Quantum Dots},
author = {John Schliemann and Daniel Loss and A. H. MacDonald},
journal= {arXiv preprint arXiv:cond-mat/0009083},
year = {2009}
}
Comments
9 pages, 4 figures included