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Were Galileo, Newton and Einstein mistaken? At least just a little? Thanks to them, today we know that heavy mass and inertial mass are different approaches to describe the same physical effect: mass. Thus in vacuum, all objects fall to the ground with equal acceleration, no matter how heavy they are. This 400-year-old discovery has thus far withstood every test. Scientists confirm the so-called equivalence principle with an accuracy of 10-13, thus accurate to one ten billionth. However, modern physical theories, such as the string theory, assume that far behind the decimal point the proof could be waiting that heavy mass and inertial mass differ from one another. French scientists now want to put the principle to the test again – with the active support of the "Wissenschaftlicher Gerätebau" (Scientific Instrumentation Department) of the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig. It was there that two pairs of hollow...

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In principle, helium doesn’t like combining with its ilk at all. Yet, occasionally, it does exactly this, albeit with extremely slight binding energies. Scientists at Goethe University Frankfurt have successfully measured these energies for the first time. For this metrological sensation, they are to be honored with this year’s Helmholtz Prize together with their fellow researchers in Cambridge. The Cambridge researchers have enhanced the single-molecule measurement technique, which is already established in DNA analysis, in a revolutionary way using nanopores, thereby creating the conditions to, in theory, be able to detect any number of different protein molecules within the same measurement. The Helmholtz Prize’s categories of “fundamentals” and “applications” are each endowed with 20,000 euros; the prize is considered to be one of the world’s most prominent distinctions in the field of metrology, the science of precise measurement.

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Nanotechnologie umfasst ein breites Spektrum zukunftsweisender Querschnitts­technologien. Ein Schlüssel zu ihrer Weiterentwicklung ist eine präzise Messtechnik, um Nanosysteme zu beschreiben, zu verstehen und herzustellen. Zur Stärkung des Forschungsschwerpunkts Nanometrologie baut das Land Niedersachsen für die TU Braunschweig ein neues Gebäude für das Forschungszentrum LENA. Bund und Land investieren gemeinsam über 33 Millionen Euro in den Forschungsbau. Er wird über eine hervorragende Ausstattung an Großgeräten für die Nanoanalytik verfügen.

Das Laboratory for Emerging Nanometrology (LENA) ist ein Forschungszentrum der Technischen Universität Braunschweig, das in enger Kooperation mit der Physikalisch Technischen Bundesanstalt Braunschweig gegründet wurde und in Kooperation der beteiligten Institute bereits betrieben wird. 

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At the first groundbreaking (from left to right): Dr. Harald Müller (PTB), Dr. Rolf Kumme (PTB), Dr. Karin Kniel (PTB), Dr. Frank Härtig (PTB, project coordinator), Prof. Dr. Joachim Ullrich (PTB, President), Renate Müller-Steinweg (public building construction management), Juliane and Peter von Klitzing (architects), Hendrik Welp (architect), Dr. Christian Schlegel (PTB)

As the first national metrology institute in the world to do so, PTB is planning to provide reliable and comprehensive quality assurance to the wind energy industry. To this end, a new building is being built on the premises of PTB in Braunschweig: The Wind Energy Competence Center. This building will house a large coordinate measuring machine which can be used to measure very large components of wind turbines. The building will also contain measurement and calibration facilities for very large torques, as well as wind speed measurement instruments by means of which the yield forecasts of high wind turbines can be improved.

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Frank Härtig

In January, the head of Division 1 (Mechanics and Acoustics) was made an honorary professor by the Institute of Ultra-precision Optoelectronic Instrument Engineering of the Harbin Institute of Technology (HIT), a university in Harbin, China, based on his work in the field of metrology and his pioneering developments in the field of traceability of metrological algorithms.

Harald Schnatz

The head of Department 4.3 (Quantum Optics and Unit of Length), was presented with the European Frequency and Time Award 2016 at the European Frequency and Time Forum (EFTF), which took place from 4-7 April 2016 in York.


Nils Huntemann,

a staff member of Department 4.4 (Time and Frequency), was presented with the European Frequency and Time Forum (EFTF) Young Scientist Award at the EFTF 2016.



Ingo Kröger

In December, the staff member of Department 4.1 (Photometry and Applied Radiometry) was named a Young Scientist of the...

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While scientists often explore the very smallest of dimensions, colossal objects weighing several tons are soon to play an important role as well: the Physikalisch-Technische Bundesanstalt (PTB) plans to measure large gears of up to four meters in diameter in its future excellence center for wind energy. Its goal in doing so is to develop and make available a form of measurement technology which enables the operation of increasingly large and efficient wind turbines. To conquer this uncharted technological territory, a new building specially conceived for this purpose is being built on the premises of PTB in Braunschweig, using 10 million euros in financing provided by the Federal Ministry for Economic Affairs and Energy (BMWi). The building will house a large coordinate measuring machine which can be used to measure huge wind turbine components, as well as measurement and calibration facilities for very large torques. In addition, the...

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Quantum logic spectroscopy of molecular ions

The interaction of thermal energy from the environment with motional degrees of freedom is well known and often referred to as Brownian motion (also thermal motion). But in the case of polar molecules, the internal degrees of freedom – in particular the rotational quantum state – are also influenced by the thermal radiation. So far, the detection of the rotational state was only possible by destroying the molecule. However, a German research group has now demonstrated the first implementation of a non-destructive state detection technique for molecular ions. Piet Schmidt and his colleagues from the QUEST-Institute at the Physikalisch-Technische Bundesanstalt (PTB) observed changes in the rotational state of a trapped and indirectly cooled molecular ion in real time and in situ. This technique enables novel spectroscopy methods with applications ranging from chemistry to tests of fundamental physics. The results are published in the...

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MetroSommer 2016 Titelseite Flyer

Vom 1. August bis zum 30. September 2016 können Studierende in aktuellen Forschungsprojekten der Physikalisch-Technischen Bundesanstalt (PTB) mitarbeiten. Das Motto lautet: „Dein genauester Sommer!“ Von der Grundlagenforschung bis zur technischen Zusammenarbeit – wer sich dafür begeistern kann, zwei Monate lang intensiv und gemeinsam mit hochqualifizierten Kolleginnen und Kollegen an interessanten Fragestellungen zu arbeiten, wird hier ein passendes Projekt finden. Die erstklassige technische Ausstattung der PTB und ihr breites Aufgabenspektrum bieten eine einmalige Basis für eigene Forschungserfolge. Die Bewerbungsfrist läuft bis zum 30. April 2016.

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Hirnaktivität bei der Wahrnehmung von tiefen Tönen

Are wind farms harmful to humans? Some believe so, others refute this; this controversial topic makes emotions run high. To give the debate more objectivity, an international team of experts dealt with the fundamentals of hearing in the lower limit range of the audible frequency range (i.e. infrasound), but also in the upper limit range (i.e. ultrasound). The project, which is part of the European Metrology Research Programme (EMRP), was coordinated by the Physikalisch-Technische Bundesanstalt (PTB). At PTB, not only acoustics experts, but also experts from the fields of biomagnetism (MEG) and functional magnetic resonance imaging (fMRI) were involved in the research activities. They have found out that humans can hear sounds lower than had previously been assumed. And the mechanisms of sound perception are much more complex than previously thought. Another vast field of research opens up here in which psychology also has to be taken...

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Exactly three years after the last leap second, it is that time again. In the night leading up to 1 July 2015 there will be an extra second once more. This will lengthen Coordinated Universal Time (UTC) and our legal time, currently Central European Summer Time (CEST) by one second. The Physikalisch-Technische Bundesanstalt (PTB) is following the specifications of the International Earth Rotation and Reference Systems Service (IERS) in Paris and will add the leap second to its time service signals: to the DCF77 time transmission for radio-controlled clocks, the telephone time service and the Internet time service via NTP. This action is necessary because the atomic clocks "tick" more regularly than the Earth rotates. 

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