Universal quantum control of two-electron spin quantum bits using dynamic nuclear polarization

Abstract

One fundamental requirement for quantum computation is to perform universal manipulations of quantum bits at rates much faster than the qubit's rate of decoherence. Recently, fast gate operations have been demonstrated in logical spin qubits composed of two electron spins where the rapid exchange of the two electrons permits electrically controllable rotations around one axis of the qubit. However, universal control of the qubit requires arbitrary rotations around at least two axes. Here we show that by subjecting each electron spin to a magnetic field of different magnitude we achieve full quantum control of the two-electron logical spin qubit with nanosecond operation times. Using a single device, a magnetic field gradient of several hundred milliTesla is generated and sustained using dynamic nuclear polarization of the underlying Ga and As nuclei. Universal control of the two-electron qubit is then demonstrated using quantum state tomography. The presented technique provides the basis for single and potentially multiple qubit operations with gate times that approach the threshold required for quantum error correction.

11 pages, 4 figures. Supplementary Material included as ancillary file

References in corpus (12)

• Coupling Superconducting Qubits via a Cavity Bus
• Driven coherent oscillations of a single electron spin in a quantum dot
• Coherent control of a single electron spin with electric fields
• Electrically driven single electron spin resonance in a slanting Zeeman field
• Theory of electron spin decoherence by interacting nuclear spins in a quantum dot
• Electron Spin Dephasing due to Hyperfine Interactions with a Nuclear Spin Bath
• Dynamic Nuclear Polarization with Single Electron Spins
• Dynamics of Quantum Dot Nuclear Spin Polarization Controlled by a Single Electron
• Universal set of quantum gates for double-dot spin qubits with fixed interdot coupling
• Hyperfine interaction induced decoherence of electron spins in quantum dots
• Exponential decay in a spin bath
• Exchange-controlled single-electron-spin rotations in quantum dots

Cited by in corpus (14)

• Enhancing the Coherence of a Spin Qubit by Operating it as a Feedback Loop That Controls its Nuclear Spin Bath
• Coherent spin manipulation in an exchange-only qubit
• Ultrafast optical control of entanglement between two quantum dot spins
• Conditional operation of a spin qubit
• Hubbard model description of silicon spin qubits: charge stability diagram and tunnel coupling in Si double quantum dots
• Phase Transitions in Dissipative Quantum Transport and Mesoscopic Nuclear Spin Pumping
• Quantum-to-Classical Correspondence and Hubbard-Stratonovich Dynamical Systems, a Lie-Algebraic Approach
• Electron-nuclear dynamics in a quantum dot under non-unitary electron control
• Greenberger-Horne-Zeilinger States in Quantum Dot Molecule
• Long coherence of electron spins coupled to a nuclear spin bath
• Spin dynamics at the singlet-triplet crossings in double quantum dot
• Coherent spin-current oscillations in transverse magnetic fields
• Chiral spin currents and spectroscopically accessible single merons in quantum dots
• Chiral Spin Textures of Strongly Interacting Particles in Quantum Dots