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Simulation of electronic collision circuit: Two electron sources (S1, S2) simultaneously send indistinguishable electrons down counter-propagating paths. The electrons’ movement within the potential of an electronic beam splitter can be controlled precisely due to their mutual interaction. The outcome is detected by two detectors (D1, D2) that can determine the arrival of an individual electron.

Targeted collision of single photons or electrons enables a sensitive measurement method that can be used to investigate and control the way in which they influence each other. This reduction to single sharp signal impulses allows the measurement resolution to be improved and new components to be created for quantum information processing. In nanostructured semiconductor circuits, two separate electrons can be guided ballistically on intersecting signal paths; in this way, the electrons’ interaction can be used to control or probe electrical signals. The basic function of a non-linear circuit component of this type has been demonstrated in distinct, complementary realizations by three independent research teams led by NEEL (F), NPL (UK) and PTB.

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As part of the search for dark matter, three atomic clocks were compared, two of which use different transitions in the same Yb<sup>+</sup> ion stored in a single-ion trap (left). The third optical clock uses approx. 1000 neutral strontium ions in an optical lattice (right).

Can dark matter interact with photons and influence atomic structure? A comparison of two different kinds of optical atomic clocks at PTB has improved existing experimental detection limits for a possible coupling by more than an order of magnitude and over a wide range of dark matter particle mass. While no evidence of a dark matter coupling has been found, the work brings us closer to understanding the nature and potential interactions of dark matter.

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Schematic representation of the measuring room with a few sensors. By means of this new method, temperatures and their uncertainties can be estimated at any desired location based on local sensor data.

In principle, sensor networks and appropriate interpolation methods can be used to determine the temperature at any desired location in a room. The reliability of such interpolated data was tested at PTB.

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Brain pacemakers are very helpful for diseases such as Parkinson’s. But an implant can cause dangerous
tissue heating during an MRI scan. (X-ray image; source: Wikimedia Commons)

With well over 100 million examinations per year worldwide, magnetic resonance imaging (MRI) is the second most important medical imaging method. However, patients with implants often have to refrain from this life-saving diagnostic option or accept a lower image quality. Especially with active implants, such as cardiac pacemakers and neurostimulators, MRI scanning can lead to dangerous tissue heating in the body if not applied in a cautious way. PTB has shown that wireless communication between the implant and the magnetic resonance scanner can solve this problem.

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Windräder und Flugzeug

Es machte Schlagzeilen: Das PTB-Projekt WERAN hat auf einen Schlag sehr viele neue potenzielle Flächen für Windenergieanlagen freigemacht. In dem Projekt wurde gezeigt, dass Windenergieanlagen weniger Einfluss auf Funksignale haben als davor angenommen. Daher hat die DFS Deutsche Flugsicherung GmbH Anfang 2023 die Schutzbereiche rund um einige ihrer Flugsicherungsanlagen verkleinert: Der Anlagenschutzbereich von Drehfunkfeuern (innerhalb dessen zu prüfen ist, ob Windenergieanlagen die Funknavigation beeinflussen) beträgt jetzt nicht mehr 15 km, sondern nur noch 7 km. Das ergab mehr als 21 000 Quadratkilometer neue Flächen für Windenergieanlagen. Jetzt geht die Forschung noch weiter, ist aber nicht mehr primäre Aufgabe eines nationalen Metrologieinstitutes: Ein neues An-Institut an der Jade-Hochschule Wilhelmshaven übernimmt den Staffelstab.  

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BASE-Experiment

They have done a good job, and their cooperation will be continued: After a successful review by an international commission of high-ranking scientists, the German-Japanese Center for Time, Constants and Fundamental Symmetries (TCFS) can start its second term. It will continue to strengthen the collaboration among German and Japanese institutes to advance most sensitive instruments for fundamental measurements in atomic and nuclear physics, antimatter and dark matter research, quantum optics and metrology. Three partners – the Max Planck Institutes for nuclear physics (MPIK) and for quantum optics (MPQ), the National Metrology Institute of Germany (PTB) and the Japanese flagship research institution RIKEN – will fund the centre in equal amounts with a total of around €7.5 million for an additional five years, starting in January 2024.

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“Think Metrology” is the motto from 26-29 August 2024 at the World Congress of the International Measurement Confederation (IMEKO). It will be a summit meeting for the world’s leading metrologists. More than 700 researchers and users will report on innovations and current topics stemming from the expansive field of metrology. You can already register and submit your paper.

Further information: Opens external link in new windowhttps://www.imeko2024.org 
(Contact: Opens local program for sending emailimeko2024(at)ptb.de)

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ELMEC Guide 7.2, “Software”, is the most widely used WELMEC manual. It is now available in an updated and revised 2023 version. This guide offers European notified bodies, manufacturers of measuring instruments and supervisory authorities harmonized technical interpretations of the fundamental demands of the European Measuring Instruments Directive (MID and of NAWID;31/2014/EU and 32/2014/EU). It is available here: Opens external link in new windowwww.welmec.org (Contact: Florian Thiel, +49 30 3481-7529, Opens local program for sending emailflorian.thiel(at)ptb.de)

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In the recently launched project “TruePA” (Truly Resilient Quantum Limited Traveling Wave Parametric Amplifiers), researchers from PTB and seven European partner institutions are jointly developing the next generation of parametric amplifiers, or TWPAs for short. Due to their extremely low noise, they are significant for the detection of weak electromagnetic signals at microwave frequencies of several gigahertz. The EU is providing three million euros in funding for the project which will run for three years. The project’s website: Opens external link in new windowwww.truepa.eu. (Contact: Lukas Grünhaupt, +49 531 592-9453, Opens local program for sending emaillukas.gruenhaupt(at)ptb.de)

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