Localization and tensorization properties of the curvature-dimension condition for metric measure spaces

This paper is devoted to the analysis of metric measure spaces satisfying locally the curvature-dimension condition CD(K,N) introduced by the second author and also studied by Lott & Villani. We prove that the local version of CD(K,N) is equivalent to a global condition CD^∗(K,N), slightly weaker than the (usual, global) curvature-dimension condition. This so-called reduced curvature-dimension condition CD^∗(K,N) has the local-to-global property. We also prove the tensorization property for CD^∗(K,N). As an application we conclude that the fundamental group π₁(M,x₀) of a metric measure space (M,d,m) is finite whenever it satisfies locally the curvature-dimension condition CD(K,N) with positive K and finite N.     

On the reactivity of ascomycin at the binding domain. Part 2: Hydroxide mediated rearrangement reactions

The natural product ascomycin represents a highly functionalised 23-membered macrocycle with a polyketide backbone. Within the binding domain, ascomycin features the unusual pattern of a masked tricarbonyl moiety, which potentially allows for high structural diversity via simple isomerisation events. Herein, highly stereoselective, hydroxide mediated rearrangement reactions at the binding domain are reported.     

Exciton states in strongly coupled asymmetric semimagnetic double quantum dots

Exciton states in a pair of strongly coupled artificial asymmetric quantum dots (QDs) have been studied in magnetic fields up to B = 8T by means of photoluminescence spectroscopy. The QD molecules have been fabricated using a selective interdiffusion technique applied to asymmetric CdTe/(Cd,Mg,Mn)Te double quantum wells. The lateral confinement potential within the plane induced by the diffusion gives rise to effective zero-dimensional exciton localization. Incorporation of the Mn ions in only one dot results in a pair of QDs with a markedly different spin splitting. In contrast to a positive value of the exciton Lande g factor in nonmagnetic (Cd,Mg)Te-based single QDs, the ground exciton transition in the nonmagnetic QD demonstrates nearly zero g factor, thus, indicating a strong electron coupling between the dots. A new low-energy band with a strong red shift appears at high B signifying formation of the indirect exciton in accordance with our calculations. The text was submitted by the authors in English.     

Photoluminescence study of magnesium doped movpe indium phosphide

The incorporation of magnesium in indium phosphide grown by metalorganic vapor phase epitaxy is interpreted using photoluminescence data. Magnesium is seen to form deep level complexes with other flaws in indium phosphide, in addition to isolated substitutional shallow acceptors. Growth parameters which produce doping in the range 10¹⁶-10¹⁹ cm^-3 are reported.