In his Special Theory of Relativity, Einstein formulated the hypothesis according to which the speed of light is always the same, no matter what the conditions are. It may, however, be possible that – according to theoretical models of quantum gravitation – this uniformity of space-time does not apply to particles. Physicists have now tested […]
About Thorsten Schumm
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Entries by Thorsten Schumm
Optical clocks with trapped ions and the Th-229 nuclear clock will be a topic at several summer schools this year, featuring nuClock partner E. Peik as lecturer: European Frequency and Time Seminar EFTS 2019 1-5 July 2019, Besancon, France International School of Physics “Enrico Fermi” COURSE 206 – NEW FRONTIERS FOR METROLOGY: FROM BIOLOGY AND […]
Using 2-photon resonant laser spectroscopy, the PTB team identifies 166 previously uncharted electronic states of the Th1+ ion in the energy range between 7.8 and 9.8 eV. The observed levels can be relevant for the excitation or decay of the 229mTh isomeric nuclear state which lies in this energy range. The high density of electronic […]
A VUV frequency comb seems to be a promising candidate for performing high-resolution spectroscopy on the Th-229 nucleus. Such a device up-converts the frequency of a stabilized femtosecond laser from the infrared to the ultraviolet using a process called “high-harmonic generation” (HHG). This process is usually performed in noble gas jets. It requires extreme optical […]
While several groups make progress on determining the exact energy of the Th-229 isomer, the uncertainty is still too large for a direct optical excitation with a narrow-band source to be successful. Most approaches use the U-233 alpha-decay as a means of populating the isomer with a 2% probability. This alpha decay is however a […]
Brenden, Wen-Te, and Adriana of MPIK in Heidelberg have released a new paper investigating collective effects that could occur in Thorium doped crystals when excited by narrow-band coherent pulses. Here’s the link to the paper. A variety of schemes are discussed with the goal of creating unique signatures of excitation which can be used to determine the detuning of the exciting laser pulses from 229Th nuclear transition energy. Other details such as multi pulsed excitation, pulse shape, phase shifting…
Marianna Safronova and colleagues from the Univ. of Delaware and from the Kurchatov Institute in St. Petersburg have performed new atomic structure calculations for Th+and Th2+that are used to relate measured spectroscopic isotope shifts to differences of the nuclear charge radii. Such calculations are notoriously difficult for these thorium ions because of strong configuration mixing […]
Starting with October 22., Tomas Sikorsky is enforcing the TU Wien Thorium team. Tomas has worked on NMR during his masters and on ion collisions with ultra cold gasses during his PhD in the team of Roee Ozeri at Weizmann. In Vienna, he will establish detection of the Thorium isomer via nuclear quadrupole resonance spectroscopy […]