Coherent rotations of a single spin-based qubit in a single quantum dot at fixed Zeeman energy

Abstract

Coherent rotations of single spin-based qubits may be accomplished electrically at fixed Zeeman energy with a qubit defined solely within a single electrostatically-defined quantum dot; the $g$-factor and the external magnetic field are kept constant. All that is required to be varied are the voltages on metallic gates which effectively change the shape of the elliptic quantum dot. The pseudospin-1/2 qubit is constructed from the two-dimensional $S=1/2$, $S_z=-1/2$ subspace of three interacting electrons in a two-dimensional potential well. Rotations are created by altering the direction of the pseudomagnetic field through changes in the shape of the confinement potential. By deriving an exact analytic solution to the long-range Coulomb interaction matrix elements, we calculate explicitly the range of magnitudes and directions the pseudomagnetic field can take. Numerical estimates are given for {GaAs}.

Restructured manuscript, more details shown (results unchanged); Six pages, revtex4; More info at http://soliton.phys.dal.ca

References in corpus (6)

• Quantum Computation with Quantum Dots
• Coupled quantum dots as quantum gates
• Universal Quantum Computation with the Exchange Interaction
• Theory of Decoherence-Free Fault-Tolerant Universal Quantum Computation
• Universal Fault-Tolerant Computation on Decoherence-Free Subspaces
• Voltage-tunable singlet-triplet transition in lateral quantum dots

Cited by in corpus (10)

• Spins in few-electron quantum dots
• Universal set of quantum gates for double-dot spin qubits with fixed interdot coupling
• Three-electron spin qubits
• Three-electron anisotropic quantum dots in variable magnetic fields: exact results for excitation spectra, spin structures, and entanglement
• Spin filling of a quantum dot derived from excited-state spectroscopy
• Universal quantum computing with correlated spin-charge states
• Validity of the single-particle description and charge noise resilience for multielectron quantum dots
• Theory of solid state quantum information processing
• Modeling shallow confinement in tuneable quantum dots
• Spin precession caused by spin-spin interaction between bounded electrons in quantum dots