Quantum control of bosonic modes with superconducting circuits

TL;DR

This paper reviews recent advances in controlling bosonic modes using superconducting circuits, focusing on universal control methods beyond Gaussian operations for quantum computing applications.

Contribution

It summarizes new techniques for nonlinear control of bosonic modes in circuit QED, enabling universal quantum computation and entanglement.

Findings

Development of unitary and feedback control methods

Implementation of driven-dissipative and holonomic control

Progress in entangling bosonic modes

Abstract

Bosonic modes have wide applications in various quantum technologies, such as optical photons for quantum communication, magnons in spin ensembles for quantum information storage and mechanical modes for reversible microwave-to-optical quantum transduction. There is emerging interest in utilizing bosonic modes for quantum information processing, with circuit quantum electrodynamics (circuit QED) as one of the leading architectures. Quantum information can be encoded into subspaces of a bosonic superconducting cavity mode with long coherence time. However, standard Gaussian operations (e.g., beam splitting and two-mode squeezing) are insufficient for universal quantum computing. The major challenge is to introduce additional nonlinear control beyond Gaussian operations without adding significant bosonic loss or decoherence. Here we review recent advances in universal control of a single bosonic code with superconducting circuits, including unitary control, quantum feedback control, driven-dissipative control and holonomic dissipative control. Various approaches to entangling different bosonic modes are also discussed.