Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 46: Transport: Nanomechanics (jointly with MM)

TT 46.6: Talk

Tuesday, March 17, 2015, 15:15–15:30, A 053

Mechanically induced iSWAP gate and maximally entangled states in a carbon nanotube — •Heng Wang and Guido Burkard — Department of Physics, University of Konstanz, D-78457 Konstanz, Germany

We study a nanomechanical system where two separated single-electron spins in two quantum dots in a suspended carbon nanotube (CNT) are driven by an ac electric field in a parallel magnetic field. An indirect coupling between two single-electron spins is induced based on the simultaneous interaction of the two spins with the mechanical mode of the CNT. We show how a two-qubit iSWAP gate and arbitrary single-qubit gate can be obtained by analyzing the effective Hamiltonian from the time dependent Schrieffer-Wolff transformation and the time evolution operator. Combining the iSWAP gate and single-qubit gates, maximally entangled states of two spins can be generated with a single step by varying the frequency and the strength of the external electric driving field. The iSWAP gate and single-qubit gates can be turned off when suppressing the spin-phonon coupling by electrostatically shifting the electron wave function on the nanotube.