Quantum Dots Quantum Computing Gates

Daniel Loss, David Peter Divincenzo

We propose an implementation of a universal set of one- and two-quantum-bit gates for quantum computation using the spin states of coupled single-electron quantum dots. Desired operations are effected by the gating of the tunneling barrier between neighboring dots. Several measures of the gate quality are computed within a recently derived spin master equation incorporating decoherence caused by a prototypical magnetic environment. Dot-array experiments that would provide an initial demonstration of the desired nonequilibrium spin dynamics are proposed.

Tetsufumi Tanamoto

Coupled quantum-dot system in semiconductor is considered to be one of the promising candidates of quantum computer. It will be most desirable that the quantum computing devices are implemented into the same substrate as the widely used LSI circuits. From this viewpoint, the quantum computer of coupled quantum dots of semiconductors is presented concentrating on the controlled-NOT-gate operation. The decoherence time of the quantum computation and the measurement procedure by field-effect-transistor structure are discussed.

Amin Mobasher, Saeed Fathololoumi, Somayyeh Rahimi

Jiesen Li, Zhibing Li, Dao‐Xin Yao

We study an array of graphene nano sheets that form a two-dimensional S = 1/2 Kagome spin lattice used for quantum computation. The edge states of the graphene nano sheets are used to form quantum dots to confine electrons and perform the computation. We propose two schemes of bang-bang control to combat decoherence and realize gate operations on this array of quantum dots. It is shown that both schemes contain a great amount of information for quantum computation. The corresponding gate operations are also proposed.

Daniel Loss