Device-independent quantum random-number generation.

Area of Science:

• Quantum Information Science
• Quantum Cryptography
• Experimental Physics

Background:

• Randomness is crucial for numerical modeling and cryptography.
• Device-independent quantum random-number generation (DIQRNG) offers ultimate security by not requiring assumptions about device workings.
• Previous DIQRNG experiments had security limitations or did not close all loopholes.

Purpose of the Study:

• To present a DIQRNG system secure against both quantum and classical adversaries.
• To achieve a loophole-free violation of a Bell inequality for provably secure randomness.
• To demonstrate the practical feasibility of DIQRNG for high-security applications.

Main Methods:

• Utilized advanced quantum optical technology to generate, modulate, and detect entangled photon pairs.
• Achieved high detection efficiency (>78%) over 200 meters, surpassing the threshold for the detection loophole.
• Ensured space-like separation of measurements and random base settings to close the locality loophole and satisfy the no-signalling condition.

Main Results:

• Demonstrated DIQRNG secure against the most general adversaries.
• Obtained over 6.24 x 10^7 quantum-certified random bits in 96 hours using a Toeplitz-matrix hashing technique.
• Achieved a failure probability of less than 10^-5 for producing insecure random numbers.

Conclusions:

• This work represents a significant advancement in realizing provably secure DIQRNG.
• The demonstration paves the way for practical applications requiring genuine, unpredictable randomness.
• The findings contribute to a fundamental understanding of quantum randomness.