Six-electron semiconductor double quantum dot qubits

TL;DR

This paper explores a six-electron double quantum dot qubit, demonstrating that quantum operations are feasible and robust, with potential advantages over traditional two-electron qubits, based on realistic experimental parameters.

Contribution

It introduces a six-electron DQD qubit encoding and shows that initialization, manipulation, and readout are comparable to two-electron systems with robust energy gaps.

Findings

Quantum operations are feasible with six-electron DQD qubits.

Energy gaps remain large enough for robust quantum control.

Results are supported by two complementary computational methods.

Abstract

We consider a double-quantum-dot (DQD) qubit which contains six electrons instead of the usual one or two. In this spin qubit, quantum information is encoded in a low-lying singlet-triplet space much as in the case of a two-electron DQD qubit. We find that initialization, manipulation, and read- out can be performed similarly to the two-electron case, and that energy gaps remain large enough that these operations can be performed robustly. We consider DQD potentials with parameters chosen to be representative of current experimental capabilities. Results are obtained using two complementary full configuration interaction methods.