Entangled electronic state via an interacting quantum dot
arXiv:cond-mat/0402603 · doi:10.1209/epl/i2003-10257-1
Abstract
We study a device for entangling electrons as cotunneling occurs through a quantum dot where on-site electron-electron interactions are in place. The main advantage of this device is that single particle processes are forbidden by energy conservation as proposed by Oliver et al\cite{oli02}. Within this model we calculated two electron transition amplitude, in terms of the T-matrix, to all orders in the coupling to the dot, and consider a finite lead bandwidth. The model filters singlet entangled pairs with the sole requirement of Pauli principle. Feynman paths involving consecutive and doubly occupied dot interfere destructively and produce a transition amplitude minimum at a critical value of the onsite repulsion . Singlet filtering is demonstrated as a function of a gate voltage applied to the dot with a special resonance condition when the dot levels are symmetrically placed about the input lead energy.
5 pages, 5 figures
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