Realization of a Quantum Error Detection Code with a Dynamically Reassigned Ancillary Qubit

TL;DR

This paper demonstrates a flexible quantum error detection method using a dynamically reassigned ancillary qubit on a linear chain of transmon qubits, addressing connectivity challenges in superconducting quantum processors.

Contribution

It introduces a novel dynamic ancilla scheme for quantum error detection that performs comparably to static methods and enhances state preparation efficiency.

Findings

Achieved quantum error detection with dynamic ancilla on three qubits

Demonstrated efficient quantum state preparation via tomography

Showed the method's scalability potential under connectivity constraints

Abstract

Quantum error correction (QEC) is essential for achieving fault-tolerant quantum computing. While superconducting qubits are among the most promising candidates for scalable QEC, their limited nearest-neighbor connectivity presents significant challenges for implementing a wide range of error correction codes. In this work, we experimentally demonstrate a quantum error detection scheme that employs a dynamically reassigned ancillary qubit on a chain of three linearly connected transmon qubits. We show that this scheme achieves performance comparable to conventional static-ancilla circuits. Additionally, the approach facilitates efficient quantum state preparation, which we demonstrate with tomography of arbitrary logical states. Our results provide a flexible method for implementing QEC codes under connectivity constraints and highlight a promising path toward scalable quantum architectures.