Pulse Design of Baseband Flux Control for Adiabatic Controlled-Phase Gates in Superconducting Circuits

TL;DR

This paper presents a systematic approach to designing high-fidelity adiabatic controlled-phase gates in superconducting circuits by optimizing pulse trajectories, significantly reducing gate infidelity compared to traditional methods.

Contribution

It introduces a Chebyshev-based pulse design framework for adiabatic CPHASE gates, improving fidelity over existing Slepian-based trajectories in simulations.

Findings

Chebyshev-based trajectories reduce infidelity by 23.3% on average.

Simulation results demonstrate improved gate performance.

The framework offers a systematic method for pulse optimization in superconducting qubits.

Abstract

Despite progress towards achieving low error rates with superconducting qubits, error-prone two-qubit gates remain a bottleneck for realizing large-scale quantum computers. Therefore, a systematic framework to design high-fidelity gates becomes imperative. One type of two-qubit gate in superconducting qubits is the controlled-phase (CPHASE) gate, which utilizes a conditional interaction between higher energy levels of the qubits controlled by a baseband flux pulse on one of the qubits or a tunable coupler. In this work, we study an adiabatic implementation of CPHASE gates and formulate the design of the control trajectory for the gate as a pulse-design problem. We show in simulation that the Chebyshev-based trajectory can, in certain cases, enable gates with gate infidelity lower by an average of 23.3% when compared to the widely used Slepian-based trajectory.