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Scientists from the Physikalisch-Technische Bundesanstalt (PTB) have implemented a novel pressure measurement method, quasi as a byproduct of the work on the "new" kelvin. In addition to being new, this procedure is a primary method, i.e. it only depends on natural constants. As an independent method, it can be used to check the most accurate pressure gauges, for which PTB is known as the world...

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Ein Wissenschaftler-Team der Physikalisch-Technische Bundesanstalt (PTB) erhält am 8. November 2019 den Technologietransferpreis der Industrie- und Handelskammer Braunschweig für die gelungene Weitergabe einer mess- und fertigungstechnischen Meisterleistung aus der Forschung in die Industrie. Die Rede ist von hochreinen, extrem runden Siliziumkugeln, die die neue Definition des Kilogramms...

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In the new MPG-PTB-RIKEN Centre for Time, Constants and Fundamental Symmetries, experimental physicists with a passion for precision will jointly tackle forefront topics in fundamental physics such as the question for the constancy in time of natural constants or the subtle differences between matter and antimatter. This new initiative started on January 1, 2019; the official opening ceremony will...

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The nucleus of thorium-229 possesses a property that is unique among all known nuclides: It should be possible to excite it with ultraviolet light. To date, little has been known about the low-energy state of the Th-229 nucleus that is responsible for this property. Together with their colleagues from Munich and Mainz, researchers at the Physikalisch-Technische Bundesanstalt (PTB) have now...

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The Physikalisch-Technische Bundesanstalt (PTB) is known for providing time e.g. for radio-controlled clocks. For this purpose, it operates some of the best cesium atomic clocks in the world. At the same time, PTB is already developing various atomic clocks of the next generation. These clocks are no longer based on a microwave transition in cesium, but they rather operate with other atoms that...

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This revolution has been a long time in the making. Behind it are metrologists working in their scientific laboratories, and scientific managers in their decision-making committees. Now the moment is approaching when many of the old quantities (specifically, the definitions behind them) will have to step down to make way for their successors, who are waiting in the wings. The quantities concerned...

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The "atomic second" was the beginning of a revolutionary era: it was born as early as 1955, when the first cesium atomic clock was put into operation. In the fall of 1967, it was included in the International System of Units. This was the beginning of a development which will, in all likelihood, come to an end in the fall of 2018 when the 20th General Conference on Weights and Measures (CGPM)...

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No one had ever come so close to the ideal laser before: theoretically, laser light has only one single color (also frequency or wavelength). In reality, however, there is always a certain linewidth. With a linewidth of only 10 mHz, the laser that researchers from the Physikalisch-Technische Bundesanstalt (PTB) have now developed together with US researchers from JILA, a joint institute of the...

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At present, the kelvin is literally based on no more than water – on the triple point of water, to be more precise. The base unit of temperature is therefore dependent on a material whose properties may vary. But this is about to change: In the fall of 2018, the kelvin, as well as all the other units of the International System of Units (SI), will be redefined to rest on a solid and invariable...

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