Characterizing Gaussian quantum processes with Gaussian resources

Abstract

Characterizing quantum processes is indispensable for the implementation of any task in quantum information processing. In this paper, we develop an efficient method to fully characterize arbitrary Gaussian processes in continuous-variable quantum systems. This is done by directly obtaining all elements of the symplectic matrix that describes the process. Only Gaussian resources such as coherent probes and quadrature measurements are needed for this task. The method is efficient, involving only $O(N^2)$ steps to characterize an $N$-mode system. Further, the method is resilient to uniform loss. We simulate this procedure using the Python package Strawberry Fields. We observe that heterodyne measurements outperform homodyne measurements for reconstructing Gaussian processes.

10 pages including appendices, 7 figures, v2: published version

References in corpus (22)

• Quantum information with continuous variables
• Gaussian Quantum Information
• Encoding a qubit in an oscillator
• Continuous variable quantum information: Gaussian states and beyond
• Squeezing as an irreducible resource
• A Quantum Rosetta Stone for Interferometry
• Quantum information with Gaussian states
• Strawberry Fields: A Software Platform for Photonic Quantum Computing
• Multimode quantum interference of photons in multiport integrated devices
• An On-chip Homodyne Detector for Measuring Quantum States and Generating Random Numbers
• Triggered single-photon generation and resonance fluorescence in ultra-low loss integrated photonic circuits
• Applications of Near-Term Photonic Quantum Computers: Software and Algorithms
• Direct characterization of linear-optical networks
• Classical simulation of photonic linear optics with lost particles
• Quantum-enhanced tomography of unitary processes
• Accurate and precise characterization of linear optical interferometers
• All-optical quantum computing using cubic phase gates
• Quantum process tomography of linear and quadratically nonlinear optical systems
• When heterodyning beats homodyning: an assessment with quadrature moments
• Efficient tomography of quantum-optical Gaussian processes probed with a few coherent states
• Characterization of multi-mode linear optical networks
• Optimal characterization of Gaussian channels using photon-number-resolving detectors