Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR

Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (mu_B > 500 MeV), effects of chiral symmetry, and the equation-of-state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2022, in the context of the worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal

Entwicklung und Validierung eines laenderuebergreifenden Handlungsrasters bei der Altlastensanierung auf der Grundlage abgeschlossener Sanierungsmassnahmen. Handlungsraster Altlastensanierung. Bd. 2

Based on an analysis of completed projects for the cleanup of contaminated sites, working aids in the form of flow schemes have been developed for the work stages investigation, planning, performance of remedial action, aftercare and long-term monitoring. Consolidating the experience gained so far in Germany in cleanup projects, they set out general procedures for decision-making and action in the course of contaminated sites treatment. The flow schemes are uniform in structure and each include an introduction to the respective area concerned. In cases in which the technical scope of the work and the detail of the task so demand, sub-schemes have been allocated to individual stages. These provide a sufficiently sound technical basis for the respective tasks at hand, reflecting in condensed form the available experience. The flow schemes developed for remediation planning and aftercare relate to relatively new fields of contaminated sites remediation and hence document the current status of the discussion or present practices in these fields. The flow schemes presented are to serve as guidance for those responsible for remediation, for planners as well as for the competent authorities. They also contain useful suggestions and hints for affected parties, remediation firms and local authorities. Numerous cross-references permit users to explore relevant issues in greater depth at a given stage while simultaneously taking on checking and memory functions. An aspect to be highlighted is the numerous links with urban land use planning. (orig.)SIGLEAvailable from TIB Hannover: RN 8422(1998,11,2) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Umwelt, Naturschutz und Reaktorsicherheit, Bonn (Germany)DEGerman

Orthogonal frequency division multiplexing (OFDM) in photonic communications

OFDM has emerged as a promising modulation technique in long-haul and access optical networks because of a number of advantages: Scalable spectrum partitioning, good spectral efficiency, dispersion tolerance, and a natural suitability for software-defined transmission. However, there are also issues inherent in OFDM: High peak-to-average power ratio making the system more susceptible to nonlinearity, sensitivity to frequency offset and phase noise, and the required computational complexity. With the advent of powerful digital signal processors and by exploiting all-optical signal processing, some of these obstacles can be overcome

Analyse durchgefuehrter Altlastensanierungen im Hinblick auf Sanierungserfolge (Monitoring sanierter Altlasten)

In the project strategies were elaborated, through evaluation of practical cases, for a standardised decision-making process applicabel to all Laender with regard to the sanitation of hazordous waste sites in the task areas of remedial investigations, project planning, implementation of remedial measures and monitoring of success. 25 remedial measures conducted in 8 Laender were investigated in this respect. It became clear that the experience gained and the approach chosen in these cases of remedial action were only generalisable or transferable to a limited degree. The analysis of the particular circumstances and of the feasibility of a remedial measure has proved itself as an essential precondition for the application of ecologically and economically appropriate procedures and techniques. This preliminary step to a sanitation measure, the remedial investigation, permits a flexible and dynamic approach to the optimal harmonisation of remedial action with the location-specific circumstances of a hazardous waste site. (orig.)Available from TIB Hannover: RN 8422(1996,67) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Umwelt, Naturschutz und Reaktorsicherheit, Bonn (Germany)DEGerman

Flexible WDM-PON with Nyquist-FDM and 31.25 Gbit/s per wavelength channel using colorless, low-speed ONUs

A remotely seeded flexible WDM network solution with 31.25 Gbit/s based on Nyquist sinc-pulses is demonstrated. The low-speed, colorless ONUs use remote heterodyne detection with electrical up- and down-conversion and SOAs for potential cost reduction.Peer ReviewedPostprint (published version