Quantum non-Gaussianity certification of photon number-resolving detectors

Area of Science:

• Quantum optics
• Quantum information science
• Experimental physics

Background:

• Characterizing quantum detectors is crucial for quantum technologies.
• Existing quantum non-Gaussianity criteria are for quantum states, not measurements.
• Photon number-resolving detectors are key components in quantum systems.

Purpose of the Study:

• To develop and experimentally demonstrate a protocol for direct certification of a photon number-resolving detector's quantum non-Gaussian character.
• To adapt existing quantum non-Gaussianity criteria from quantum states to quantum measurements.
• To provide a method for benchmarking complex optical quantum detectors.

Main Methods:

• Adapted quantum non-Gaussianity criteria for quantum measurements.
• Probed a photon number-resolving detector (spatially multiplexed array of single-photon avalanche photodiodes) with vacuum and two different thermal states.
• Confirmed quantum non-Gaussianity of POVM elements associated with m-fold coincidence counts (up to m=7).

Main Results:

• Successfully demonstrated direct experimental certification of quantum non-Gaussianity for a photon number-resolving detector.
• Found that injecting Gaussian background noise can reduce measurement time for certification.
• Modified the protocol using a third thermal state instead of vacuum to accelerate measurements.

Conclusions:

• Developed efficient tools for practical characterization of fundamental non-classical properties in quantum detectors.
• The experimental certification of quantum non-Gaussianity is feasible, with potential improvements using background noise or modified state probes.
• The findings contribute to the reliable benchmarking of advanced optical quantum detectors.