|
1 Introduction
A qubit, the basic element of a quantum computer, is
a two-level system for which many physical realizations
have been proposed, such as silicon-based nuclear spins
[1], excitons in quantum dots [2], etc. To construct
quantum circuits, some qubits should be coupled as a quantum gate. A control NOT (CNOT) is a typical quantum gate operating on two qubits, a control
bit and a target bit [3] It is important to find efficient ways to implement it physically. We propose a
design of the CNOT gate with coupled quantum dot
molecules in 3-dimensional structure. The gate employs dual-rail encoding to represent its input and output qubits, which corresponds with four input and four
output lines. It is driven by oherent transports (or resonant tunnelings) through the dots and by Coulomb
interaction between them.
|