Multi-mode architectures for noise-resilient superconducting qubits

TL;DR

This paper reviews multi-mode superconducting circuits, especially the $0- extpi$ circuit, highlighting their design, implementation, and experimental progress towards noise-resilient quantum information processing.

Contribution

It provides a comprehensive survey of multi-mode superconducting circuits with intrinsic decoherence protection, including recent experimental advances and fabrication techniques.

Findings

Demonstrated physical implementations of $0- extpi$ circuits

Discussed fabrication and characterization methods

Reviewed noise-resilience mechanisms in superconducting qubits

Abstract

Great interest revolves around the development of new strategies to efficiently store and manipulate quantum information in a robust and decoherence-free fashion. Several proposals have been put forward to encode information into qubits that are simultaneously insensitive to relaxation and to dephasing processes. Among all, given their versatility and high degree of control, superconducting qubits have been largely investigated in this direction. Here, we present a survey on the basic concepts and ideas behind the implementation of novel superconducting circuits with intrinsic protection against decoherence at a hardware level. In particular, the main focus is on multi-mode superconducting circuits, the paradigmatic example being the so-called $0-\pi$ circuit. We report on their working principle and possible physical implementations based on conventional Josephson elements, presenting recent experimental realizations, discussing both fabrication methods and characterizations.