Phase-Programmable Gaussian Boson Sampling Using Stimulated Squeezed Light.

Area of Science:

• Quantum Information Science
• Quantum Optics
• Photonic Quantum Computing

Background:

• Gaussian boson sampling (GBS) is a prominent quantum computational task.
• Previous GBS experiments faced limitations in scale and programmability.
• Developing scalable and programmable quantum light sources is crucial for advancing quantum computation.

Purpose of the Study:

• To report a phase-programmable GBS experiment with a 144-mode photonic circuit.
• To introduce a novel high-brightness, scalable quantum light source based on stimulated emission of squeezed photons.
• To validate the GBS samples and demonstrate quantum computational advantage.

Main Methods:

• Implementation of a phase-programmable GBS architecture.
• Development of a new quantum light source with high purity and efficiency.
• Validation of GBS output using computationally tractable subsystems.
• Application of nonclassicality tests and analysis of high-order correlations.

Main Results:

• Generation of up to 113 photon detection events in a 144-mode photonic circuit.
• Demonstration of phase programmability by tuning input squeezed states.
• Efficient validation ruling out distinguishable photons and thermal states.
• Evidence of nonclassicality and genuine high-order correlations in GBS samples.

Conclusions:

• The Jiuzhang 2.0 photonic quantum computer achieves a Hilbert space dimension of approximately 10^43.
• The experiment demonstrates a sampling rate approximately 10^24 times faster than classical supercomputers.
• The results showcase the robustness of the GBS experiment against classical simulation schemes.