Universal adaptive Gaussian quantum operations

Gaussian operation on hybrid bosonic modes is a critical technology for quantum information processing and communication. For example, SWAP of two hybrid bosonic modes enables quantum transduction, which is a fundamental building block for scalable quantum computing; and two-mode squeezing operations are widely applied to quantum signal amplification, crucial to bettering quantum measurement. However, different Gaussian operations are usually achieved with setups and procedures with distinct physical configurations, limiting the flexibility and feasibility of these protocols. Here, we propose a scheme based on a randomly given immutable hybrid Gaussian unitary operation and single-mode quantum operations and classical controls. More specifically, our scheme utilizes single-mode squeezing, single-mode homodyne measurements and adaptive displacement operations to transform the given hybrid Gaussian operation to one of a different form. Moreover, we also demonstrate that the generated Gaussian operation can be of an arbitrary desired form by composing <!-- ?? -->the given hybrid operation with carefully designed single-mode phase-shifters. Our scheme only requires minimal modification of the experimental setup—tuning the phase-shifters—to yield universal hybrid Gaussian operations and hence can be hardware-efficient in experimental settings.