# An efficient protocol of quantum walk in circuit QED

## TL;DR

This paper proposes a fast and resource-efficient protocol for implementing discrete-time quantum walks in circuit QED, enabling larger-step quantum simulations with current technology.

## Contribution

The authors introduce a novel protocol requiring fewer components and faster operations for quantum walks in circuit QED, facilitating experimental studies of large-step quantum walks.

## Key findings

- High-similarity quantum walks up to 20 steps are feasible with current circuit QED technology.
- The protocol reduces the number of required qubits and cavities for N-step quantum walks.
- Operations are rapid due to the exclusive use of resonant processes.

## Abstract

Implementation of discrete-time quantum walk (DTQW) with superconducting qubits is difficult since on-chip superconducting qubits cannot hop between lattice sites. We propose an efficient protocol for the implementation of DTQW in circuit quantum electrodynamics (QED), in which only $N+1$ qutrits and $N$ assistant cavities are needed for an $N$-step DTQW. The operation of each DTQW step is very quick because only resonant processes are adopted. The numerical simulations show that high-similarity DTQW with the number of step up to $20$ is feasible with present-day circuit QED technique. This protocol can help to study properties and applications of large-step DTQW in experiments, which is important for the development of quantum computation and quantum simulation in circuit QED.