Implications of Simultaneous Requirements for Low Noise Exchange Gates in Double Quantum Dots

TL;DR

This paper investigates the conditions under which exchange interactions in double quantum dots can be optimized for low-error quantum computing, using a more accurate computational method to identify regimes compatible with error correction and robust gate operation.

Contribution

It introduces a full configuration interaction approach to analyze exchange energy behavior, revealing multiple regimes suitable for low-error quantum gate implementation.

Findings

Multiple regimes found where exchange energy supports quantum error correction

Full configuration interaction provides more accurate insights than traditional methods

Identifies conditions for robust, low-error quantum gates in quantum dots

Abstract

Achieving low-error, exchange-interaction operations in quantum dots for quantum computing imposes simultaneous requirements on the exchange energy's dependence on applied voltages. A double quantum dot (DQD) qubit, approximated with a quadratic potential, is solved using a full configuration interaction method. This method is more accurate than Heitler-London and Hund-Mulliken approaches and captures new and significant qualitative behavior. We show that multiple regimes can be found in which the exchange energy's dependence on the bias voltage between the dots is compatible with current quantum error correction codes and state-of-the-art electronics. Identifying such regimes may prove valuable for the construction and operation of quantum gates that are robust to charge fluctuations, particularly in the case of dynamically corrected gates.