Valley-based noise-resistant quantum computation using Si quantum dots

TL;DR

This paper proposes a valley-based quantum computing platform using silicon quantum dots that offers enhanced noise resistance through valley degree of freedom, controllable tunneling, and echo techniques.

Contribution

It introduces a novel valley-based qubit encoding in silicon quantum dots with mechanisms for initialization, control, and readout, improving noise resilience over traditional qubits.

Findings

Reduced sensitivity to charge and spin fluctuations.

Demonstration of valley echo for noise suppression.

Feasibility of one- and two-qubit operations using valley states.

Abstract

We devise a platform for noise-resistant quantum computing using the valley degree of freedom of Si quantum dots. The qubit is encoded in two polarized (1,1) spin-triplet states with different valley compositions in a double quantum dot, with a Zeeman field enabling unambiguous initialization. A top gate gives a difference in the valley splitting between the dots, allowing controllable interdot tunneling between opposite valley eigenstates, which enables one-qubit rotations. Two-qubit operations rely on a stripline resonator, and readout on charge sensing. Sensitivity to charge and spin fluctuations is determined by intervalley processes and is greatly reduced as compared to conventional spin and charge qubits. We describe a valley echo for further noise suppression.