Raman cooling and heating of two trapped Ba+ ions

We study cooling of the collective vibrational motion of two 138Ba+ ions confined in an electrodynamic trap and irradiated with laser light close to the resonances S_1/2-P_1/2 (493 nm) and P_1/2-D_3/2 (650 nm). The motional state of the ions is monitored by a spatially resolving photo multiplier. Depending on detuning and intensity of the cooling lasers, macroscopically different motional states corresponding to different ion temperatures are observed. We also derive the ions' temperature from detailed analytical calculations of laser cooling taking into account the Zeeman structure of the energy levels involved. The observed motional states perfectly match the calculated temperatures. Significant heating is observed in the vicinity of the dark resonances of the Zeeman-split S_1/2-D_3/2 Raman transitions. Here two-photon processes dominate the interaction between lasers and ions. Parameter regimes of laser light are identified that imply most efficient laser cooling.Comment: 8 pages, 5 figure

Synthetic biology - the next phase of biotechnology and genetic engineering. TAB-Fokus

Scientific and technological progress allows to genetically redesign natural organisms in ever more profound ways (synbio in the broader sense). In the long term, the aim is to create artificial biological systems (synbio in the narrow sense). Application areas are chemical and energy production, environmental protection as well as the medical sector. Considering the current, early state of research and development, it is impossible to forecast reliably which approaches of synbio will prevail against procedures that make use of the available biological diversity or that are limited to more subtle interventions. Risk assessment and the evaluation of substantially modified organisms will require the development and exploration of new methods and procedures. Opportunities for different societal groups to participate in the responsible development of synbio are ranging from stakeholder involvement in setting research agendas to DIY biology. Dealing with intellectual property within the framework of an increasingly digital economy will also represent a major challenge for the future use of synbio

A relaxationless demonstration of the Quantum Zeno Paradox on an individual atom

The driven evolution of the spin of an individual atomic ion on the ground-state hyperfine resonance is impeded by the observation of the ion in one of the pertaining eigenstates. Detection of resonantly scattered light identifies the ion in its upper ``bright'' state. The lower ``dark'' ion state is free of relaxation and correlated with the detector by a null signal. Null events represent the straightforward demonstration of the quantum Zeno paradox. Also, high probability of survival was demonstrated when the ion, driven by a fractionated $\pi$ pulse, was probed {\em and monitored} during the intermissions of the drive, such that the ion's evolution is completely documented.Comment: 7 page

Simultaneous cooling of axial vibrational modes in a linear ion trap

In order to use a collection of trapped ions for experiments where a well-defined preparation of vibrational states is necessary, all vibrational modes have to be cooled to ensure precise and repeatable manipulation of the ions quantum states. A method for simultaneous sideband cooling of all axial vibrational modes is proposed. By application of a magnetic field gradient the absorption spectrum of each ion is modified such that sideband resonances of different vibrational modes coincide. The ion string is then irradiated with monochromatic electromagnetic radiation, in the optical or microwave regime, for sideband excitation. This cooling scheme is investigated in detailed numerical studies. Its application for initializing ion strings for quantum information processing is extensively discussed

Degradation Kinetics of Lignocellulolytic Enzymes in a Biogas Reactor Using Quantitative Mass Spectrometry

The supplementation of lignocellulose-degrading enzymes can be used to enhance the performance of biogas production in industrial biogas plants. Since the structural stability of these enzyme preparations is essential for efficient application, reliable methods for the assessment of enzyme stability are crucial. Here, a mass-spectrometric-based assay was established to monitor the structural stability of enzymes, i.e., the structural integrity of these proteins, in anaerobic digestion (AD). The analysis of extracts of Lentinula edodes revealed the rapid degradation of lignocellulose-degrading enzymes, with an approximate half-life of 1.5 h. The observed low structural stability of lignocellulose-degrading enzymes in AD corresponded with previous results obtained for biogas content. The established workflow can be easily adapted for the monitoring of other enzyme formulations and provides a platform for evaluating the effects of enzyme additions in AD, together with a characterization of the biochemical methane potential used in order to determine the biodegradability of organic substrates

Synthetische Biologie - die nächste Stufe der Bio- und Gentechnologie. TAB-Fokus

Wissenschaftliche und technologische Fortschritte ermöglichen einen zunehmend tiefer greifenden genetischen Umbau natürlicher Organismen (Synbio i. w. S.), perspektivisch wird die Schaffung künstlicher biologischer Systeme (Synbio i. e. S.) anvisiert. Anwendungsbereiche liegen in der Chemie- und Energieproduktion, in der Medizin und im Umweltschutz. Welche Ansätze der Synbio sich durchsetzen werden gegenüber Verfahren, die die vorhandene biologische Vielfalt nutzen oder sich auf subtile Eingriffe beschränken, ist beim heutigen Stand von Forschung und Entwicklung nicht verlässlich prognostizierbar. Für die Risikoabschätzung und -bewertung substanziell veränderter Organismen müssen neue Methoden und Verfahren entwickelt und erprobt werden. Die Partizipationsmöglichkeiten der Gesellschaft an einer verantwortungsvollen Weiterentwicklung der Synbio reichen von einer Stakeholderbeteiligung an der Forschungsprogrammatik bis zur DIY-Biologie. Der Umgang mit geistigem Eigentum unter den Bedingungen einer zunehmend digitalen Ökonomie stellt eine der zentralen Zukunftsherausforderungen auch für die Nutzung der Synbio dar