We develop a theory of spin-noise spectroscopy of itinerant, noninteracting, and spin-carrying fermions in different regimes of temperature and disorder. We use kinetic equations for the density matrix in spin variables. We find a general result with a clear physical interpretation, and discuss its dependence on temperature, the size of the system, and applied magnetic field. We consider two classes of experimental probes: (1) electron-spin-resonance-type measurements, in which the probe response to a uniform magnetization increases linearly with the volume sampled and (2) optical Kerr/Faraday rotation-type measurements, in which the probe response to a uniform magnetization increases linearly with the length of the light propagation in the sample but is independent of the cross section of the light beam. Our theory provides a framework for interpreting recent experiments on atomic gases and conduction electrons in semiconductors and provides a baseline for identifying the effects of interactions on spin-noise spectroscopy.

This article reports on the formation of strongly overstoichiometric ZrN _x>1 and Ti(Al, V)N _x>1 coatings by reactive magnetron sputtering. Problems in the formation of overstoichiometric coatings and possible ways to form strongly overstoichiometric TMN _x>1 nitride coatings up to TMN _x=2 dinitride coatings are discussed; here, TM are transition metals such as Ti, Zr, Mo, Ta, Nb, W, etc. The coating stoichiometry x = N/TM strongly influences its electrical and mechanical properties. The creation and properties of reactively sputtered ZrN _x coatings were investigated. It was found that (1) the electrical resistivity of the ZrN _x coating varies with increasing x from well electrically conducting films with x ≤ 1 through semi-conducting films with x ranging from 1 to ≤ 1.26 to non-conductive with x ≥ 1.3, showing that the stoichiometry x is a strong parameter which enables to control an electric conductivity of the coating in a wide range, (2) electrically conductive coatings with x ≤ 1 are harder than the semiconducting and electrically insulating coatings, and (3) the ZrN ₂ dinitride film cannot be created due to the formation of a Zr ₃ N ₄ phase whose formation enthalpy is greater than that of a ZrN ₂ phase. Further, it is shown that the main problem in the formation of strongly overstoichiometric TMN _x>1 and dinitride TMN ₂ coatings is a strong increase of ionization of the nitrogen sputtering gas to achieve a necessary high ratio N/TM > 1. Trends enabling the mastery of formation of the TMN ₂ dinitride coatings are briefly outlined.

As we approach the centennial anniversary of modern quantum mechanics, this paper revisits the foundational debates through a new poll within the research community. Inspired by the survey by Schlosshauer, Kofler, and Zeilinger at the specialized 2011 Quantum Physics and the Nature of Reality conference, we expanded our recruitment to include a more representative sample of the broader community of physicists with the aim of revealing potential shifts in scientists’ views and to compare our findings with those from several previous polls. While quantum foundations still lack a consensus interpretation, our results indicate a persistent preference for the Copenhagen interpretation. This enduring support likely reflects both the educational emphasis on the Copenhagen interpretation and its pragmatic appeal in avoiding complex metaphysical questions and introducing new notions (e.g., other worlds or the pilot wave). Our findings thus underscore the relative stability of interpretational preferences over the past decades.