Tuesday 30 April 2024

Th-229 isomer breakthrough

 A group in Germany has just published a paper showing a huge improvement in accuracy in measuring the energy and lifetime of the lowest-lying nuclear excited state that we know about - the 8.4 eV isomeric in Th-229.  While typical nuclear excitation energies are around one million electron-volts (1 MeV),  the relatively tiny energy of the thorium isomer puts it in the kind of energy range that can be manipulated by optical equipment.  In the case of the published work, the authors developed a bespoke ultraviolet laser that was able to sweep the right candidate frequencies to pin down the isomer energy to an accuracy of nearly 1000 times better then the previously best measurement.  

This isomer is not just a quirky curiosity:  A long-lived low-energy state in a nucleus, which is much better isolated from environmental effects than an electron in an atom or molecule, has the possibility of being used in applications such as a nuclear clock, potentially surpassing atomic clock timekeeping, as well as other possible quantum technology applications such as qubits for a quantum computer, or a quantum sensor to test fundamental physics. 

Plot from the (Creative Commons open access) paper below showing the resonant peak in the frequency scan:




Thursday 25 April 2024

16 year erratum

 There is an erratum published in Physical Review C this week which corrects paper from 16 years ago.  In their opening sentence they own up to adjusting the data in a way they shouldn't have:

In our original publication of level scheme of 104Nb, we determined level energies based on certain transitions and subsequently adjusted the raw data for other transitions to fit these energies. This is not correct scientific procedure as it alters original data, and it risks introducing incorrect transition and level energies into the literature. The main purpose of this erratum is to provide the original data.

and go on at the end to 

thank the Physical Review C editors and the data scientists at the National Nuclear Data Center at BNL for calling our attention to these corrections

To me, this shows that processes are working and that the data from their paper, which made its way into databases, was found to be erroneous, the error investigated, and corrected.  Too bad it happened in the first place, but the data remained available for scrutiny and the scrutiny worked.

 

Tuesday 16 April 2024

IoP conference at Liverpool

 It's my first day back at work since being at the IoP HEPP/AP/NP (that's High Energy & Particle Physics / Astroparticle Physics / Nuclear Physics) combined conference.  I was there, talking in the plenary session about quantum computing for nuclear structure, and a lot of Surrey postdocs and students also gave talks and posters.  

Here is a selection of photos from the conference:

My student Sam Sullivan presenting his poster

My student Grant Close presenting his poster

Me giving my talk

My postdoc Bharti giving her talk

My student Isaac giving his talk

The sky looked pretty as I walked to the conference dinner

Conference dinner!

As well as these photos, I had to take one video, as my postdoc Abhishek is a master of making animations, and so a static photo would not have done is presentation justice: