More randomness from a prepare-and-measure scenario with independent devices

Abstract

How to generate genuine quantum randomness from untrusted devices is an important problem in quantum information processing. Inspired by the previous work on self-testing quantum random number generator [Phys. Rev. Lett. 114, 150501], we present a new method to generate quantum randomness from a prepare-and-measure scenario with independent devices. In existing protocols, the quantum randomness only depends on a witness value (e.g., CHSH value ), which is calculated with the observed probabilities. Differently, here all the observed probabilities are directly used to calculate the min-entropy in our method. Through numerical simulation, we find that the minentropy of our proposed scheme is higher than the previous work, when a typical untrusted BB84 setup is used. Consequently, thanks to the proposed method, more genuine quantum random numbers may be obtained than before.

Quantum Contextuality Provides Communication Complexity Advantage

“…In addition to the QKD protocol, these communication tasks can also be used to generate quantum randomness in the prepare-and-measure scenario [53][54][55]. We have discussed this in Appendix D of [37].…”

Quantum contextuality provides communication complexity advantage

“…Randomness certification.-Schemes for quantum randomness generation have been proposed based on quantum advantages in communication tasks [27][28][29]. We can also use the communication complexity task introduced in ( 5)-( 6) to generate secure random bits from the untrusted preparation and measurement devices under the assumptions (i)-(ii) mentioned in the preceding section.…”

“…Next, we present a semi-device independent (SDI) protocol for quantum key distribution (QKD) [23] based on the quantum advantage in our communication complexity tasks, in which security is proven by using the monogamy relation (MR) [24][25][26] of contextuality. Additionally, these communication tasks can also be used to generate quantum randomness in the prepare-and-measure scenario [27][28][29].…”

Tighter bound of quantum randomness certification for independent-devices scenario

“…Based on the aforementioned witness, Lunghi et al . 35 proposed a self-testing QRNG protocol (BQB14 for short) 36 with a bounded dimension constraint, in which devices had no need to be characterized. The BQB14 derived a lower bound of the min-entropy as a function of dimension witness, and was capable of monitoring the randomness in real time.…”