Universal Dephasing Control During Quantum Computation

TL;DR

This paper introduces a universal dynamical control method to mitigate dephasing effects throughout quantum computation, enhancing fidelity and robustness of quantum operations.

Contribution

It proposes a comprehensive control strategy that addresses dephasing during all quantum computation stages, including novel insights on gate duration and cross-dephasing elimination.

Findings

Tailoring multi-frequency gate pulses improves fidelity.

Cross-dephasing caused by entanglement can be eliminated.

Increasing gate duration can enhance overall fidelity.

Abstract

Dephasing is a ubiquitous phenomenon that leads to the loss of coherence in quantum systems and the corruption of quantum information. We present a universal dynamical control approach to combat dephasing during all stages of quantum computation, namely, storage, single- and two-qubit operators. We show that (a) tailoring multi-frequency gate pulses to the dephasing dynamics can increase fidelity; (b) cross-dephasing, introduced by entanglement, can be eliminated by appropriate control fields; (c) counter-intuitively and contrary to previous schemes, one can increase the gate duration, while simultaneously increasing the total gate fidelity.