55 research outputs found
The Quest for Understanding in Relativistic Quantum Physics
We discuss the status and some perspectives of relativistic quantum physics.Comment: Invited contribution to the Special Issue 2000 of the Journal of
Mathematical Physics, 38 pages, typos corrected and references added, as to
appear in JM
Bell's local causality is a d-separation criterion
This paper aims to motivate Bell's notion of local causality by means of
Bayesian networks. In a locally causal theory any superluminal correlation
should be screened off by atomic events localized in any so-called
\textit{shielder-off region} in the past of one of the correlating events. In a
Bayesian network any correlation between non-descendant random variables are
screened off by any so-called \textit{d-separating set} of variables. We will
argue that the shielder-off regions in the definition of local causality
conform in a well defined sense to the d-separating sets in Bayesian networks.Comment: 13 pages, 8 figure
Bell's local causality is a d-separation criterion
This paper aims to motivate Bell’s notion of local causality by means of Bayesian networks. In a locally causal theory any superluminal correlation should be screened off by atomic events localized in any so-called shielder-off region in the past of one of the correlating events. In a Bayesian network any correlation between non-descendant random variables are screened off by any so-called d-separating
set of variables. We will argue that the shielder-off regions in the definition of local causality conform in a well defined sense to the d-separating sets in Bayesian
networks
Comparing quantitative image parameters between animal and clinical CT-scanners: a translational phantom study analysis
PurposeThis study compares phantom-based variability of extracted radiomics features from scans on a photon counting CT (PCCT) and an experimental animal PET/CT-scanner (Albira II) to investigate the potential of radiomics for translation from animal models to human scans. While oncological basic research in animal PET/CT has allowed an intrinsic comparison between PET and CT, but no 1:1 translation to a human CT scanner due to resolution and noise limitations, Radiomics as a statistical and thus scale-independent method can potentially close the critical gap.MethodsTwo phantoms were scanned on a PCCT and animal PET/CT-scanner with different scan parameters and then the radiomics parameters were extracted. A Principal Component Analysis (PCA) was conducted. To overcome the limitation of a small dataset, a data augmentation technique was applied. A Ridge Classifier was trained and a Feature Importance- and Cluster analysis was performed.ResultsPCA and Cluster Analysis shows a clear differentiation between phantom types while emphasizing the comparability of both scanners. The Ridge Classifier exhibited a strong training performance with 93% accuracy, but faced challenges in generalization with a test accuracy of 62%.ConclusionThese results show that radiomics has great potential as a translational tool between animal models and human routine diagnostics, especially using the novel photon counting technique. This is another crucial step towards integration of radiomics analysis into clinical practice
THE SUPERSELECTION STRUCTURE OF PARTICLE PHYSICS
I want to report on some joint work with Sergio Doolicher and E. Roberts which extended over the past 5 years. It concerns the origin of charge quatum numbers and particle statistics in relativistic, local quantum theory with short range forces and the classification of the possibilities allowed by the basic principles . A bibliography of this and earlier work on the same lines is attached (ref . (1) to (7)). In the available time I can, of course, only gives a very incomplete accomt but hope to be able to sketch the physical backgromd, the theoretical framework used and the main resulte in an understandable way suppressing all detailed arguments and proofs
Some people and some problems met in half a century of commitment to mathematical physics
Personnal recollection of half a century of Mathematical Physics
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