Speaker's Brief Introduction： Ingo Nosske studied physics in Munich and Heidelberg and China Studies at Zhejiang University. He gained first ultracold atom experiences in the lab of Zhen-Sheng Yuan at USTC in Hefei (2012-2013), after which he worked on the ultracold strontium Rydberg atom setup of Matthias Weidemüller at USTC in Shanghai for his PhD (2014-2018). After a short research stay at IIT Delhi, in 2019 he joined PTB in Braunschweig, where he is working on a transportable strontium lattice clock.
Abstract: Transportable high-performance optical atomic clocks are currently being developed worldwide. Due to the gravitational redshift – a general relativistic effect – they serve as quantum sensors of the local gravity potential. It is anticipated that they will allow to determine the Earth’s gravity potential with even greater accuracy than is currently possible by state-of-the-art satellite geodesy. They also enable frequency comparisons between institutes, for example between those which are currently not yet connected by an accurate frequency comparison link.
Here I describe the second-generation transportable 87Sr optical lattice clock of PTB, which is operational since 2023. The fractional frequency uncertainty of the clock’s blackbody
radiation shift – often the leading systematic in strontium lattice clocks – is reduced to 4E-19, as the atoms are interrogated inside a well-characterized thermal shield at −100 °C. Taking all frequency shifts into account, the total systematic clock uncertainty is evaluated to be 2.1E-18.
The atomic clock is installed in an air-conditioned car trailer and operated after several transportations. I briefly review its recent off-campus measurement campaigns in Europe.