On the existence of impurity bound excitons in one-dimensional systems with zero range interactions

We consider a three-body one-dimensional Schr\"odinger operator with zero range potentials, which models a positive impurity with charge $\kappa > 0$ interacting with an exciton. We study the existence of discrete eigenvalues as $\kappa$ is varied. On one hand, we show that for sufficiently small $\kappa$ there exists a unique bound state whose binding energy behaves like $\kappa^4$, and we explicitly compute its leading coefficient. On the other hand, if $\kappa$ is larger than some critical value then the system has no bound states

Computational thinking i matematik, naturfag og samfundsfag: - hvorfor, hvad og hvordan?

I et projekt der strakte sig over fire år, udviklede og afprøvede vi sammen med lærere fra gymnasiet undervisningsforløb der integrerer modelbaserede computationelle metoder i undervisningen i STEM-fagene. Der er publiceret og udviklet en didaktik for den integrerede undervisning, skrevet forskningsartikler herom samt udviklet ca. 100 nye undervisningsforløb der udnytter didaktikken. Samtidig er der udviklet et efteruddannelseskoncept som sætter lærerne i stand til selv at fortsætte arbejdet på egen skole. Projektet har vist at det er muligt at forny fagenes metoder og samtidig udvikle elevernes computationelle modelleringskompetencer ved at inddrage computationel tænkning og kodning i den faglige undervisning

Optical orientation with linearly polarized light in transition metal dichalcogenides

We study the optical properties of semiconducting transition metal dichalcogenide monolayers under the influence of strong out-of-plane magnetic fields, using the effective massive Dirac model. We pay attention to the role of spin-orbit-coupling effects, doping level, and electron-electron interactions, treated at the Hartree-Fock level. We find that optically induced valley and spin imbalance, commonly attained with circularly polarized light, can also be obtained with linearly polarized light in the doped regime. Additionally, we explore an exchange-driven mechanism to enhance the spin-orbit splitting of the conduction band, in n-doped systems, controlling both the carrier density and the intensity of the applied magnetic field.G.C. and J.F.-R. acknowledge financial support from Fundação para a Ciência e a Tecnologia (FCT) for the Grant No. P2020-PTDC/FIS-NAN/4662/2014. J.H. acknowledges financial support by the QUSCOPE Center, sponsored by the Villum foundation. J.F.-R. acknowledges financial support from FCT for the Grants No. P2020-PTDC/FISNAN/3668/2014 and No. UTAP-EXPL/NTec/0046/2017, as well as Generalitat Valenciana funding Prometeo2017/139 and MINECO-Spain (Grant No. MAT2016-78625-C2). N.M.R.P. acknowledges financial support from the European Commission through the project “Graphene-Driven Revolutions in ICT and Beyond” (Ref. No. 785219) and the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Financing Grant No. UID/FIS/04650/2013. Additionally, N.M.R.P. acknowledges COMPETE2020, PORTUGAL2020, FEDER and the Portuguese Foundation for Science and Technology (FCT) for the Grants No. PTDC/FIS-NAN/3668/2013 and No. POCI-01-0145-FEDER-028114

Sequencing and de novo assembly of 150 genomes from Denmark as a population reference

Hundreds of thousands of human genomes are now being sequenced to characterize genetic variation and use this information to augment association mapping studies of complex disorders and other phenotypic traits. Genetic variation is identified mainly by mapping short reads to the reference genome or by performing local assembly. However, these approaches are biased against discovery of structural variants and variation in the more complex parts of the genome. Hence, large-scale de novo assembly is needed. Here we show that it is possible to construct excellent de novo assemblies from high-coverage sequencing with mate-pair libraries extending up to 20 kilobases. We report de novo assemblies of 150 individuals (50 trios) from the GenomeDenmark project. The quality of these assemblies is similar to those obtained using the more expensive long-read technology. We use the assemblies to identify a rich set of structural variants including many novel insertions and demonstrate how this variant catalogue enables further deciphering of known association mapping signals. We leverage the assemblies to provide 100 completely resolved major histocompatibility complex haplotypes and to resolve major parts of the Y chromosome. Our study provides a regional reference genome that we expect will improve the power of future association mapping studies and hence pave the way for precision medicine initiatives, which now are being launched in many countries including Denmark