ORCID Profile
0000-0003-0391-2390
Current Organisations
University of Manchester
,
University of Oxford
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Publisher: American Physical Society (APS)
Date: 19-02-2016
Publisher: MDPI AG
Date: 02-09-2015
DOI: 10.3390/ATOMS3030392
Publisher: Springer Science and Business Media LLC
Date: 03-2018
DOI: 10.1038/S41534-018-0064-4
Abstract: Continuous-time stochastic processes pervade everyday experience, and the simulation of models of these processes is of great utility. Classical models of systems operating in continuous-time must typically track an unbounded amount of information about past behaviour, even for relatively simple models, enforcing limits on precision due to the finite memory of the machine. However, quantum machines can require less information about the past than even their optimal classical counterparts to simulate the future of discrete-time processes, and we demonstrate that this advantage extends to the continuous-time regime. Moreover, we show that this reduction in the memory requirement can be unboundedly large, allowing for arbitrary precision even with a finite quantum memory. We provide a systematic method for finding superior quantum constructions, and a protocol for analogue simulation of continuous-time renewal processes with a quantum machine.
Publisher: Springer Science and Business Media LLC
Date: 06-05-2023
DOI: 10.1038/S41467-023-37555-0
Abstract: Complex systems are embedded in our everyday experience. Stochastic modelling enables us to understand and predict the behaviour of such systems, cementing its utility across the quantitative sciences. Accurate models of highly non-Markovian processes – where the future behaviour depends on events that happened far in the past – must track copious amounts of information about past observations, requiring high-dimensional memories. Quantum technologies can ameliorate this cost, allowing models of the same processes with lower memory dimension than corresponding classical models. Here we implement such memory-efficient quantum models for a family of non-Markovian processes using a photonic setup. We show that with a single qubit of memory our implemented quantum models can attain higher precision than possible with any classical model of the same memory dimension. This heralds a key step towards applying quantum technologies in complex systems modelling.
Publisher: American Physical Society (APS)
Date: 18-06-2019
Publisher: American Physical Society (APS)
Date: 11-01-2022
Publisher: American Physical Society (APS)
Date: 19-03-2020
Publisher: IOP Publishing
Date: 28-01-2019
Publisher: American Vacuum Society
Date: 09-2023
DOI: 10.1116/5.0139099
Publisher: Frontiers Media SA
Date: 22-06-2022
Abstract: While there have been various studies on global vegetation dynamics, limited studies have been conducted to understand vegetation changes in arid areas. Vegetation distribution patterns can be affected by multiple factors, so understanding their interactions can help improve the capability of predicting future vegetation dynamics. This study, therefore, analyzed the dynamic vegetation changes in Alxa League, China, using the Normalized Difference Vegetation Index (NDVI) dataset (2000–2019), with the consideration of land cover types, digital elevation model, air temperature, precipitation, soil moisture, total evaporation, and air quality. The results show that the NDVI in Alxa League is small. Before 2012, the NDVI value fluctuated, while after 2012, the NDVI value dropped sharply and then slowly recovered after 2015. High NDVI values were found in areas with high and frequent human activities (city centers). The NDVI in the northwest region showed a slight degradation trend, and the southeast showed a slight improvement trend. According to the land cover type analysis, the NDVI value was the largest when the land cover type was tree cover, and the NDVI value was the smallest when the land cover type was bare/sparse vegetation. Alxa League was dominated by a bare/sparse vegetation distribution. The terrain analysis indicates that when the height was between 1800 and 3492 m, the NDVI value was the highest, and high NDVI values were mainly distributed in the area with a slope & 25°. When the slope was flat, the NDVI value was the smallest. Considering climate factors, the NDVI was negatively correlated with air temperature, precipitation, soil moisture, and total evaporation in space, and only precipitation and soil moisture were positively correlated in time. Moreover, the population size has a strong positive correlation with the NDVI in this area. The monthly variation of the NDVI and absorbable particulate matter (PM 10 ) was negatively correlated, i.e., strongly negatively correlated in spring, summer, and autumn, but only weakly positively correlated in winter. The seasonal variation of the NDVI was as follows: summer & autumn & spring & winter, and the seasonal variation of PM 10 was spring & winter & summer & autumn. The interannual variation of the NDVI and PM 10 was positively correlated. This suggests that the absorbable particulate matter (PM 10 ) may be an essential factor for the normalized vegetation index to underestimate the dynamic changes of vegetation in arid regions. This study provides a theoretical basis for the dynamic changes of vegetation in the dry Alxa League.
Publisher: Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften
Date: 27-04-2023
DOI: 10.22331/Q-2023-04-27-991
Abstract: In classical physics, memoryless dynamics and Markovian statistics are one and the same. This is not true for quantum dynamics, first and foremost because quantum measurements are invasive. Going beyond measurement invasiveness, here we derive a novel distinction between classical and quantum processes, namely the possibility of hidden quantum memory . While Markovian statistics of classical processes can always be reproduced by a memoryless dynamical model, our main result shows that this is not true in quantum mechanics: We first provide an ex le of quantum non-Markovianity whose manifestation depends on whether or not a previous measurement is performed – an impossible phenomenon for memoryless dynamics we then strengthen this result by demonstrating statistics that are Markovian independent of how they are probed, but are nonetheless s t i l l incompatible with memoryless quantum dynamics. Thus, we establish the existence of Markovian statistics gathered by probing a quantum process that nevertheless f u n d a m e n t a l l y require memory for their creation.
Publisher: American Physical Society (APS)
Date: 19-03-2015
Publisher: American Physical Society (APS)
Date: 23-06-2020
Publisher: American Physical Society (APS)
Date: 22-12-2020
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Peng Zhou.