Quantum correlations measured with multi-pixel detectors

This thesis investigates the measurement of spatial correlations of photon pairs generated through spontaneous parametric down-conversion with single-photon sensitive multi-pixel detectors. A custom designed and fabricated 8£1 fibre array detector for time to position multiplexing was characterised. This detector was then commissioned in an experiment measuring the spatial correlations of photon pairs in position, momentum and intermediate bases. The fibre array measured eight positions simultaneously with one Single-Photon Avalanche Diode, which led to an eight-fold increase in the data acquisition rate compared to traditional experiments, where a single SPAD was scanned across the detection plane. To capture all of the emitted light, an electron-multiplying CCD (EMCCD) camera was used. The spatial correlations were measured for the first time in momentumand position bases with a single-photon sensitive camera. Additionally, over 2500 spatial states were accessed,which, to date, is the highest number of accessed states, using the transverse positions of correlated photon pairs. The detected photon pairs were tested, if they fulfil the requirements of entanglement. The calculated variance product was 1 order of magnitude and almost three orders of magnitude below the classical limit of separability for the fibre array and the EMCCD camera respectively. Finally the image enhancement of using a correlated light source with a noise rejection algorithm was investigated experimentally and theoretically

Climate history of Byzantium at the crossroads

This chapter is meant as a basic introduction to the field of climate history of Byzantium as of AD 2022. After explaining what climate history is, it discusses the source base and the big questions of the field, as well as it outlooks for the future

What stories should historians be telling at the dawn of the Anthropocene?

This chapter discusses the ways in which history can contribute to coping with the current planetary crisis. It argues that historians should engage more in interdisciplinary exchange across the humanities-natural sciences divide. Thus they will be able to create historical narratives fitting for the Anthropocene—both in terms of explaining it and shaping our responses to it, in particular to the acute planetary crisis that marks its advent. At the same time, history should not give up its drive to critically dissect and analyse socio-political, economic, cultural and ecological change, contributing to developing balanced and resilient public policy

Attitude of People in Their Emerging Adulthood Towards Selected Moral Norms Related to Sexual Activity

Nowadays, we witness a principal change in the normative order referring to human sexuality, and a change of the role of individual factors of sexual socialisation. This paper presents selected findings of the research on sexual morals of people at their emerging adulthood, aged 18–25, carried out in Poland on a representative sample in 2017. The research focused on the respondents’ attitude to the social norms related to sexual activity. Two thirds of the respondents had established sexual relations. There is a clear trend among women to stabilize the intimate relations, and the respondents tend to postpone their matrimonial and procreative plans. The respondents support the norms which may be defined as components of the “golden mean” sexual ethics. Greater liberalism of young men shows in their attitude to the norms related with risky sexual behaviour, widening the repertoire of the forms of sexual intercourse, and sexual activity on the internet. Women significantly more often support the norms which refer to functioning in a relationship. The views of the people who had their sexual initiation are the expression of support for permissive ethics. Religious people and those who regularly practice religion more often present views characteristic of restrictive ethics. It was not proved that the respondents who had attended school family planning classes more often supported restrictive norms referring to sexual activity, which might be expected taking into consideration the abstinence model of the classes

Some aspects of the approach to modelling assignments of the means for the tasks in municipal services companies

In this article the assignment problem of vehicles to tasks in municipal services companies in the context of designating the minimum routes of vehicles was presented. The mathematical model of the assignment problem was developed, and proposed a method for solving the assignment problem in municipal services companies. The method consists of two stages i.e. the stage of designating the minimum route consisting of all tasks and the stage of designating individual routes for each vehicle. In the light of considerations indicating individual routes we designate the tasks to the implementation, which is the equivalent of solving the assignment problem. The genetic algorithm for solving the optimization problem presented in the first stage of the method was proposed. Verification of this algorithm confirmed its effectiveness.W artykule przedstawiono zagadnienie przydziału pojazdów do zadań w przedsiębiorstwach komunalnych w kontekście wyznaczania minimalnych tras jazdy pojazdów. Opracowano model matematyczny zagadnienia przydziału oraz zaproponowano metodę rozwiązującą zagadnienie przydziału w przedsiębiorstwach komunalnych. Metoda składa się z dwóch etapów, tj. etapu wyznaczającego minimalną trasę składającą się ze wszystkich zadań oraz etapu wyznaczania tras indywidualnych dla poszczególnych pojazdów. W świetle przeprowadzonych rozważań wskazując trasy indywidualne wyznaczymy zadania do realizacji, co jest tożsame z rozwiązaniem problemu przydzia- łu. Zaproponowano algorytm genetyczny do rozwiązania problemu optymalizacyjnego przedstawionego w pierwszym etapie metody. Weryfikacja algorytmu potwierdziła jego skuteczność

Optimizing the use of detector arrays for measuring intensity correlations of photon pairs

Intensity correlation measurements form the basis of many experiments based on spontaneous parametric down-conversion. In the most common situation, two single-photon avalanche diodes and coincidence electronics are used in the detection of the photon pairs, and the coincidence count distributions are measured by making use of some scanning procedure. Here we analyze the measurement of intensity correlations using multielement detector arrays. By considering the detector parameters such as the detection and noise probabilities, we found that the mean number of detected photons that maximizes the visibility of the two-photon correlations is approximately equal to the mean number of noise events in the detector array. We provide expressions predicting the strength of the measured intensity correlations as a function of the detector parameters and on the mean number of detected photons. We experimentally test our predictions by measuring far-field intensity correlations of spontaneous parametric down-conversion with an electron multiplying charge-coupled device camera, finding excellent agreement with the theoretical analysis

Managing the Roman Empire for the long term: risk assessment and management policy in the fifth to seventh centuries

This chapter analyses the reasons for the survival of the eastern Roman state from three different but complementary angles: imperial administration, the environmental conditions impacting land-use for the period, and the ability of the state to leverage resources. We conclude that a major contributory factor in survival was the effective use of natural resources and a self-reinforcing social-ecological system through which the state and its elites and infrastructure facilitated the survival of landscapes, generating the resources necessary for the state’s continued existence. In areas where this broke down—as in the western part of the empire—the Roman state in the long term disappeared