Ancilla-assisted measurement of photonic spatial correlations and entanglement

Abstract

We report an experiment in which the moments of spatial coordinates of down-converted photons are measured directly, without having to reconstruct any marginal probability distributions. We use a spatial light modulator to couple the spatial degrees of freedom and the polarization of the fields, which act as ancilla systems. Information about the spatial correlations is obtained via measurements on the ancilla qubits. Among other applications, this new method provides a more efficient technique to identify continuous variable entanglement.

6 pages (4+Supplementary Information), 3 figures

References in corpus (5)

• Entanglement in continuous variable systems: Recent advances and current perspectives
• Imaging high-dimensional spatial entanglement with a camera
• Anisotropically high entanglement of biphotons generated in spontaneous parametric down conversion
• Experimental Violation of Bell's Inequality in Spatial-Parity Space
• Detection of transverse entanglement in phase space

Cited by in corpus (12)

• Quantifying the Momentum Correlation between Two Light Beams by Detecting One
• Quantum information processing in phase space: A modular variables approach
• Twin Photon Correlations in Single-Photon Interference
• Toolbox for continuous variable entanglement production and measurement using spontaneous parametric down conversion
• Deterministic Quantum Computation With One Photonic Qubit
• Thermodynamics of N-dimensional quantum walks
• Characterization of a spatial light modulator as a polarization quantum channel
• Testing the Clauser-Horne-Shimony-Holt inequality using observables with arbitrary spectrum
• Experimental ancilla-assisted phase-estimation in a noisy channel
• Uncertainty relations for characteristic functions
• Unified framework to determine Gaussian states in continuous variable systems
• Negative Wigner function by decaying interaction from equilibrium