In quantum circuits involving many qubits, we usually need to perform gates such as CNOT between qubits that are not proximal. For spin qubits, this requires intermediate gate operations because the exchange interaction is very short ranged. Here, we consider three quantum dots in a linear array. We explore the effective coupling between the two outer spins mediated by the central spin. By using the central spin as a ``bus", we show how to efficiently perform gates such as CNOT between the outer spins. We find that arbitrary two-qubit gates can be achieved by applying the bus operations repetitively, with additional single-qubit rotations.
*Work supported by DARPA-QuEST
–
Authors
Jianjia Fei
University of Wisconsin-Madison
Yun-Pil Shim
Department of Physics, University of Wisconsin-Madison
University of Wisconsin-Madison
Sangchul Oh
Department of Physics, University at Buffalo, State University of New York
Department of Physics, University at Buffalo, The State University of New York
University at Buffalo, SUNY
Xuedong Hu
Department of Physics, University at Buffalo, SUNY
University at Buffalo, The State University of New York
Department of Physics, University at Buffalo, State University of New York
Department of Physics, University at Buffalo, The State University of New York
University at Buffalo, SUNY
SUNY at Buffalo
Mark Friesen
Department of Physics, University of Wisconsin-Madison
