Fast Bosonic Control via Multiphoton Qubit-Oscillator Interactions

TL;DR

This paper introduces a fast, robust protocol for preparing and controlling bosonic oscillator states with rotational symmetry using multiphoton interactions, enhancing quantum error correction capabilities.

Contribution

It presents a novel multiphoton interaction-based protocol for efficient state preparation and control of bosonic oscillators, improving over linear interaction methods.

Findings

Reduces state preparation time significantly.

Demonstrates robustness against realistic noise in superconducting circuits.

Enables arbitrary control over oscillator Hilbert space.

Abstract

We present a protocol for preparing oscillator states with $n$-fold rotational symmetry, which include many logical codewords for bosonic quantum error correction codes. The protocol relies on a multiphoton interaction between the oscillator and an auxiliary qubit. Further, we achieve arbitrary control over the oscillator's Hilbert space by using a combination of different multiphoton interaction orders. We also discuss the preparation of rotationally symmetric multi-oscillator states using a generalized variant of the protocol. We show that the use of multiphoton qubit-oscillator interactions can substantially reduce the state preparation time, in comparison to the linear qubit-oscillator interactions that are usually employed. Furthermore, we perform numerical simulations that take into account qubit and oscillator relaxation and dephasing using realistic planar superconducting circuit parameters that validate the robustness of our protocol. Our findings can significantly improve the performance of bosonic codes on planar superconducting hardware, which are an almost inevitable necessity for scalable bosonic fault-tolerant superconducting quantum computers.