We introduce an always-on, exchange-only qubit made up of three localized semiconductor spins that offers a true “sweet spot” to fluctuations of the quantum dot energy levels. Both single- and two-qubit gate operations can be performed using only exchange pulses while maintaining this sweet spot. We show how to interconvert this qubit to other three-spin encoded qubits as a new resource for quantum computation and communication.
Talks: coming soon
Notable benefits include:
- Full sweet spot to both detuning parameters that affect dot energy levels offering immunity to charge noise.
- Ability to maintain this double sweet spot while tunnel gates change, allowing for all-DC, exchange-based control for charge-noise-insensitive (to first order) single and two qubit gates.
- A two-encoded qubit entangling gate with a single exchange pulse (versus approximately 18 pulses for a traditional exchange only qubit).
- Ability to smoothly convert the qubit to a 3-spin decoherence free subspace (3-DFS) qubit or an RX qubit while maintaining the encoded quantum information, again while staying on the full sweet spot.
- Zero dipole moment.