Fast elementary gates for universal quantum computation with Kerr parametric oscillator qubits

TL;DR

This paper introduces optimized control methods to significantly speed up elementary quantum gates for Kerr parametric oscillator qubits, achieving high fidelity and reducing errors from photon loss, advancing hardware-efficient quantum computing.

Contribution

It proposes experimentally feasible pulse-shaping techniques based on shortcuts to adiabaticity to accelerate quantum gates with KPO qubits, surpassing traditional adiabatic methods.

Findings

Achieves up to sixfold speedup over adiabatic gates

Maintains high gate fidelities of 99.9%

Demonstrates potential for more efficient KPO-based quantum computing

Abstract

Kerr parametric oscillators (KPOs) can stabilize the superpositions of coherent states, which can be utilized as qubits, and are promising candidates for realizing hardware-efficient quantum computers. Although elementary gates for universal quantum computation with KPO qubits have been proposed, these gates are usually based on adiabatic operations and thus need long gate times, which result in errors caused by photon loss in KPOs realized by, e.g., superconducting circuits. In this work, we accelerate the elementary gates by experimentally feasible control methods, which are based on numerical optimization of pulse shapes for shortcuts to adiabaticity. By numerical simulations, we show that the proposed methods can achieve speedups compared to adiabatic ones by up to six times with high gate fidelities of 99.9%. These methods are thus expected to be useful for quantum computers with KPOs.