Measuring the quadrature coherence scale on a cloud quantum computer

Coherence underlies quantum phenomena, yet it is manifest in classical theories; delineating coherence's role is a fickle business. The quadrature coherence scale (QCS) was invented to remove such ambiguity, quantifying quantum features of any single-mode bosonic system without choosing a prefe...

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Bibliographic Details
Published in:arXiv.org 2023-04
Main Authors: Goldberg, Aaron Z, Thekkadath, Guillaume S, Heshami, Khabat
Format: Article
Language:English
Subjects:
Beam splitters
Coherence
Photon beams
Photons
Preferred orientation
Quadratures
Quantum computers
Quantum phenomena
Online Access:Get full text
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Summary:Coherence underlies quantum phenomena, yet it is manifest in classical theories; delineating coherence's role is a fickle business. The quadrature coherence scale (QCS) was invented to remove such ambiguity, quantifying quantum features of any single-mode bosonic system without choosing a preferred orientation of phase space. The QCS is defined for any state, reducing to well-known quantities in appropriate limits, including Gaussian and pure states, and perhaps most importantly for a coherence measure, it is highly sensitive to decoherence. Until recently, it was unknown how to measure the QCS; we here report on an initial measurement of the QCS for squeezed light and thermal states of light. This is performed using Xanadu's machine Borealis, accessed through the cloud, which offers the configurable beam splitters and photon-number-resolving detectors essential for measuring the QCS. The data and theory match well, certifying the usefulness of interferometers and photon-counting devices in certifying quantumness.
ISSN:2331-8422
DOI:10.48550/arxiv.2302.01343