Experimental Low-Latency Device-Independent Quantum Randomness

Zhang, Yanbao; Shalm, Lynden K.; Bienfang, Joshua C.; Stevens, Martin J.; Mazurek, Michael D.; Nam, Sae Woo; Abellán, Carlos; Amaya, Waldimar; Mitchell, Morgan W.; Fu, Honghao; Miller, Carl A.; Mink, Alan; Knill, Emanuel

doi:10.1103/physrevlett.124.010505

Cited by 51 publications

(46 citation statements)

References 43 publications

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“…Therefore the constructed QEF for the trial model C 222 (ABXY ) with uniformly random inputs is well-performing in the sense that it performs as well as the optimal PEF used for the classical trial model T (ABXY ). We emphasize that when the input distribution is close to uniform, the QEF derived from a PEF performs as well as the original PEF as demonstrated below and in our companion work [43]. However, when the input distribution is far away from uniform (for example, when the total-variation distance between the input and uniform distributions is larger than 0.7) and when the power β is small enough (for example, when β is smaller than 10 −7 ), we observed that the certified upper bound f max,ub could be larger than 1 by a non-negligible amount such that the QEF derived from a PEF does not perform as well as the original PEF.…”

Section: B Finite-data Performance Of Qefssupporting

confidence: 57%

“…In this work, we develop quantum probability estimation to yield DIRG protocols with unsurpassed finite-data efficiency and with respect to quantum side information. This enables a practical device-independent randomness beacon where a block of 512 device-independent random bits is generated with an average experiment time of less than 5 min and with certified error bounded by 2 −64 , see our companion experimental work [43]. Our work also enables the realization of device-independent randomness expansion in the near future.…”

Section: Discussionmentioning

confidence: 92%

“…. , K. In the experimental demonstration of DIRG reported in our companion work [43], K = 4. Let ρ ABXY E ∈ N (C 222 (ABXY )) be a normalized state.…”

Section: A Simple Characterization Of C 222 (Abxy )mentioning

confidence: 91%

“…Instead, we pad the trial outputs c k observed so far with zeros in order to run randomness extraction according to protocol 1, as the protocol requires a fixed number n of trials determined before the experiment. This ability of early stopping is exploited in our companion experimental work [43].…”

Section: B Qef Chainingmentioning

confidence: 99%

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Efficient randomness certification by quantum probability estimation

Zhang

Knill

2020

Phys. Rev. Research

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For practical applications of quantum randomness generation, it is important to certify and further produce a fixed block of fresh random bits with as few trials as possible. Consequently, protocols with high finite-data efficiency are preferred. To yield such protocols with respect to quantum side information, we develop quantum probability estimation. Our approach is applicable to device-independent as well as device-dependent scenarios, and it generalizes techniques from previous works [Miller and Shi, SIAM J. Comput. 46, 1304 (2017); Arnon-Friedman et al., Nat. Commun. 9, 459 (2018)]. Quantum probability estimation can adapt to changing experimental conditions, allows stopping the experiment as soon as the prespecified randomness goal is achieved, and can tolerate imperfect knowledge of the input distribution. Moreover, the randomness rate achieved at constant error is asymptotically optimal. For the device-independent scenario, our approach certifies the amount of randomness available in experimental results without first searching for relations between randomness and violations of fixed Bell inequalities. We implement quantum probability estimation for device-independent randomness generation in the CHSH Bell-test configuration, and we show significant improvements in finite-data efficiency, particularly at small Bell violations which are typical in current photonic loophole-free Bell tests.

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Section: B Finite-data Performance Of Qefssupporting

confidence: 57%

Section: Discussionmentioning

confidence: 92%

“…. , K. In the experimental demonstration of DIRG reported in our companion work [43], K = 4. Let ρ ABXY E ∈ N (C 222 (ABXY )) be a normalized state.…”

Section: A Simple Characterization Of C 222 (Abxy )mentioning

confidence: 91%

Section: B Qef Chainingmentioning

confidence: 99%

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Efficient randomness certification by quantum probability estimation

Zhang

Knill

2020

Phys. Rev. Research

Self Cite

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“…[ 48–50 ] So far, only a few experiments succeeded in realizing a loophole‐free violation of Bell inequalities and even further fully DI quantum information processing tasks. [ 51–60 ] Besides, not all entangled states can violate a Bell inequality. [ 61,62 ] Therefore, the entangled states that violate no Bell inequalities cannot be witnessed in a DI manner.…”

Section: Introductionmentioning

confidence: 99%

Estimating Coherence Measures with Untrusted Devices

2021

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The superposition of quantum states, quantified by coherence, is a fundamental feature to distinguish quantum mechanics from classical theories. Estimations of coherence with perfectly characterised devices have been well‐studied. However, imperfections or malfunctions of realistic measurement devices might nullify the characterization. Device‐independent (DI) tests allow to witness and quantify the quantum feature of a system, such as entanglement, without trusting the implementation devices. Although DI test is a powerful tool in many quantum information tasks, it generally requires nonlocal settings. Little is known if single party coherence can be witnessed and estimated via untrusted devices. In this work, coherence witnesses and estimations with untrusted devices are systematically studied. First, a no‐go theorem for detecting existences of single party coherence via a DI or semi DI means is proven. A general prepare‐and‐measure semi DI scheme for witnessing and estimating the amount of coherence is then proposed. How to estimate the relative entropy and the l1 norm of single party coherence with analytical and numerical approaches is shown. As coherence is an essential resource for tasks such as quantum random number generation and quantum key distribution, it is expected that this result may shed light on designing new quantum cryptographic schemes.

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Improved Real‐Time Post‐Processing for Quantum Random Number Generators

Li,

Sun,

Zhang

et al. 2024

Adv Quantum Tech

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Randomness extraction is a key problem in cryptography and theoretical computer science. With the recent rapid development of quantum cryptography, quantum‐proof randomness extraction has also been widely studied, addressing the security issues in the presence of a quantum adversary. In contrast with conventional quantum‐proof randomness extractors characterizing the input raw data as min‐entropy sources, it is found that the input raw data generated by a large class of trusted‐device quantum random number generators can be characterized as the so‐called reverse block source. This fact enables us to design improved extractors. Two novel quantum‐proof randomness extractors for reverse block sources that realize real‐time block‐wise extraction are proposed specifically. In comparison with the general min‐entropy randomness extractors, the designs achieve a significantly higher extraction speed and a longer output data length with the same seed length. In addition, they enjoy the property of online algorithms, which process the raw data on the fly without waiting for the entire input raw data to be available. These features make the design an adequate choice for the real‐time post‐processing of practical quantum random number generators. Applying the extractors to the raw data generated by a widely used quantum random number generator, a simulated extraction speed as high as 300 Gbps is achieved.

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Experimental Low-Latency Device-Independent Quantum Randomness

Cited by 51 publications

References 43 publications

Efficient randomness certification by quantum probability estimation

Efficient randomness certification by quantum probability estimation

Estimating Coherence Measures with Untrusted Devices

Improved Real‐Time Post‐Processing for Quantum Random Number Generators

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