Microwave quantum illumination using a digital receiver

Area of Science:

• Quantum optics and microwave engineering
• Exploration of quantum phenomena at microwave frequencies

Background:

• Quantum illumination leverages entangled photon pairs to improve detection sensitivity in noisy conditions.
• This technique shows promise for low-power applications like biomedical imaging and radar.

Purpose of the Study:

• To experimentally investigate quantum illumination at microwave frequencies.
• To assess the performance of a quantum illumination system against classical benchmarks in a free-space setup.

Main Methods:

• Generation of entangled microwave fields.
• Illumination of a room-temperature object at 1-meter distance.
• Implementation of a digital phase-conjugate receiver with linear quadrature measurements.

Main Results:

• The quantum illumination receiver demonstrated superior performance compared to a classical noise radar.
• Even with entanglement breaking in the signal path, the quantum approach showed advantages.
• Simulations with perfect idler photon detection confirmed a quantum advantage over classical methods.

Conclusions:

• Quantum illumination is feasible and advantageous at microwave frequencies, even at room temperature.
• The study highlights practical opportunities and challenges for implementing microwave quantum circuits in real-world applications.
• Experimental validation paves the way for future room-temperature quantum technologies.