Communication Complexity with Small Advantage

AbstractQuantum correlations, in particular those, which enable to violate a Bell inequality, open a way to advantage in certain communication tasks. However, the main difficulty in harnessing quantumness is its fragility to, e.g, noise or loss of particles. We study the persistency of Bell correlations of GHZ based mixtures and Dicke states. For the former, we consider quantum communication complexity reduction (QCCR) scheme, and propose new Bell inequalities (BIs), which can be used in that scheme for higher persistency in the limit of large number of particles N. In case of Dicke states, we show that persistency can reach 0.482N, significantly more than reported in previous studies.

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Efficient experimental quantum fingerprinting with channel multiplexing and simultaneous detection

Nature Communications ◽

10.1038/s41467-021-24745-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Xiaoqing Zhong ◽

Feihu Xu ◽

Hoi-Kwong Lo ◽

Li Qian

Keyword(s):

Communication Complexity ◽

Single Photon ◽

Simultaneous Detection ◽

Minimum Amount ◽

Photon Detectors ◽

Communication Time ◽

Quantum Communication Complexity ◽

Detection Of Signals ◽

Coherent Quantum ◽

Quantum Fingerprinting

AbstractQuantum communication complexity explores the minimum amount of communication required to achieve certain tasks using quantum states. One representative example is quantum fingerprinting, in which the minimum amount of communication could be exponentially smaller than the classical fingerprinting. Here, we propose a quantum fingerprinting protocol where coherent states and channel multiplexing are used, with simultaneous detection of signals carried by multiple channels. Compared with an existing coherent quantum fingerprinting protocol, our protocol could consistently reduce communication time and the amount of communication by orders of magnitude by increasing the number of channels. Our proposed protocol can even beat the classical limit without using superconducting-nanowire single photon detectors. We also report a proof-of-concept experimental demonstration with six wavelength channels to validate the advantage of our protocol in the amount of communication. The experimental results clearly prove that our protocol not only surpasses the best-known classical protocol, but also remarkably outperforms the existing coherent quantum fingerprinting protocol.

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Simple communication complexity separation from quantum state antidistinguishability

Physical Review Research ◽

10.1103/physrevresearch.2.013326 ◽

2020 ◽

Vol 2 (1) ◽

Cited By ~ 1

Author(s):

Vojtěch Havlíček ◽

Jonathan Barrett

Keyword(s):

Quantum State ◽

Communication Complexity

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Communication Complexity of Byzantine Agreement, Revisited

Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing - PODC '19 ◽

10.1145/3293611.3331629 ◽

2019 ◽

Cited By ~ 8

Author(s):

Ittai Abraham ◽

T-H. Hubert Chan ◽

Danny Dolev ◽

Kartik Nayak ◽

Rafael Pass ◽

...

Keyword(s):

Communication Complexity ◽

Byzantine Agreement

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External Validation of Surrogate Indices of Fatty Liver in the General Population: The Bagnacavallo Study

Journal of Clinical Medicine ◽

10.3390/jcm10030520 ◽

2021 ◽

Vol 10 (3) ◽

pp. 520

Author(s):

Francesco Foschi ◽

Fabio Conti ◽

Marco Domenicali ◽

Pierluigi Giacomoni ◽

Alberto Borghi ◽

...

Keyword(s):

General Population ◽

Fatty Liver ◽

External Validation ◽

Strongly Correlated ◽

Alcoholic Fatty Liver ◽

Fatty Liver Index ◽

C Statistic ◽

Hepatic Steatosis Index ◽

The Town ◽

Small Advantage

We externally validated the fatty liver index (FLI), the lipid accumulation product (LAP), the hepatic steatosis index (HSI), and the Zhejiang University index (ZJU) for the diagnosis of fatty liver (FL) and non-alcoholic fatty liver disease (NAFLD) in the general population. The validation was performed on 2159 citizens of the town of Bagnacavallo (Ravenna, Italy). Calibration was evaluated by calculating the calibration slope and intercept and by inspecting calibration plots; discrimination was evaluated using the c-statistic. The average calibration slope was 1 and the average intercept was 0 for all combinations of outcomes and indices. For the diagnosis of FL, the c-statistic was 0.85 for FLI, 0.83 for ZJU, 0.82 for HSI, and 0.80 for LAP; for the diagnosis of NAFLD, the c-statistic was 0.77 for FLI, 0.76 for ZJU, 0.75 for HSI, and 0.74 for LAP. All indices were strongly correlated with each other. In conclusion, FLI, LAP, HSI, and ZJU perform similarly well to diagnose FL and NAFLD in the Bagnacavallo population, even if FLI has a small advantage as discrimination is concerned.

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