ELECTRON PROPERTIES IN DIRECTED SELF-ASSEMBLY GE/SIC/SI QUANTUM DOTS

Artificially ordered semiconductor quantum dot (QD) patterns may be used to implement functionalities such as spintronic bandgap systems, quantum simulation and quantum computing, by manipulating the interaction between confined carriers via direct exchange coupling. In this dissertation, magnetotransport measurements have been conducted to investigate the electronic orbital and spin states of directed self-assembly single- and few-Ge/SiC/Si QD devices, fabricated by a directed self-assembly QD growth technique developed by our group. Diamagnetic and Zeeman energy shifts of electrons confined around the QD have been observed from the magnetotransport experiments. A triple-barrier resonant tunneling model has been proposed to describe the electron and spin transport. The strength of the Coulomb interaction between electrons confined at neighboring QDs has been observed dependent on the dot separation, and represents an important parameter for fabricating QD-based molecules and artificial arrays, which may be implemented as building blocks for future quantum simulation and quantum computing architectures

Binary sampling ghost imaging: add random noise to fight quantization caused image quality decline

When the sampling data of ghost imaging is recorded with less bits, i.e., experiencing quantization, decline of image quality is observed. The less bits used, the worse image one gets. Dithering, which adds suitable random noise to the raw data before quantization, is proved to be capable of compensating image quality decline effectively, even for the extreme binary sampling case. A brief explanation and parameter optimization of dithering are given.Comment: 8 pages, 7 figure

Negative exponential behavior of image mutual information for pseudo-thermal light ghost imaging: Observation, modeling, and verification

When use the image mutual information to assess the quality of reconstructed image in pseudo-thermal light ghost imaging, a negative exponential behavior with respect to the measurement number is observed. Based on information theory and a few simple and verifiable assumptions, semi-quantitative model of image mutual information under varying measurement numbers is established. It is the Gaussian characteristics of the bucket detector output probability distribution that leads to this negative exponential behavior. Designed experiments verify the model.Comment: 13 pages, 6 figure

Public preferences for vaccination campaigns in the COVID-19 endemic phase: insights from the VaxPref database

Objective Despite widespread perceptions that SARS-CoV-2 (COVID-19) is no longer a significant threat, the virus continues to loom, and new variants may require renewed efforts to control its spread. Understanding how individual preferences and attitudes influence vaccination behaviour and policy compliance in light of the endemic phase is crucial in preparation for this scenario. Method This paper presents descriptive data from a global stated choice survey conducted in 22 countries across 6 different continents between July 2022 and August 2023, and reports the methodological work developed to address the need for comparable data. Results This study included 50,242 respondents. Findings indicated significant heterogeneity across countries in terms of vaccination status and willingness to accept boosters. Vaccine hesitancy and refusal were driven by lower trust in public health bodies, younger age, and lower educational levels. Refusers and hesitant people reported lower willingness to take risks compared to those fully vaccinated (p<0.05). Lower mental health levels were found for the hesitant cohort (p<0.05). Conclusions Insights from this database can help public health authorities to gain a new understanding of the vaccine hesitancy phenomenon, support them in managing the transition from the pandemic to the endemic phase, and favour a new stream of research to maximise behavioural response to vaccination programs in preparation of future pandemics