Quantum Science goes public

Once again, researchers of all areas of science have united for a „Long Night of Science“ („Lange Nacht der Forschung“) to present their work to the general public. More than 25.000 people visited over 260 stations all over Vienna on Friday, April 27. Of course the Thorium team was taking part, presenting the beautiful „ion trap“ by Wolfgang (actually trapping ionized dust particles – but the principle is the same) and helping out presenting other stations concerned with quantum physics. As the Technical University could not officially participate in the event due to financial difficulties, the team from the Atominstitut was generously hosted by our CoQuS friends at the Vienna University. You can find some press info about the event here: Krone.at, tv.derstandard.at, and of course, on the CoQuS homepage, thanks to Christiane.

A BIG THANKS to Kathrin Buczak, Dominik Fischer, Maximilian Kuhnert, Wolfgang Rohringer, Wolfgang Schlichtner, Florian Steiner, Matthias Schreitl, and Michael Trupke from ATI, TU Vienna.

MORE THANKS to Stefanie Barz, Garrett Cole, Uros Delic, Nadine Dörre, David Grass, Hans Hepach, Michael Keller, Nikolai Kiesel, Christiane Losert-Valiente Kroon, Philipp Schmid, Max Tillmann, Mathias Tomandl. and Witlef Wieczorek from Vienna University.

For them, the “Long Night” is the one BEFORE the actual event, to get everything ready in time.

First Thorium paper submitted

Finally, the hard work of the Thorium team (in this case to a great extend Georgy) pays off in publishable (hopefully!) results. This one is about the idea of constructing a “Solid-state nuclear clock” by doping Thorium into transparent crystals and performing precision spectroscopy. We find that of course, doing spectroscopy within a material leads to all sorts of line shifts and broadenings. In particular, the magnetic moment of the Thorium nucleus interacts with neighboring nuclear spins, leading to a decoherence rate of the order 1 kilohertz. This renders the usual “coherent” clock interrogation schemes like Ramsey or Rabi useless. However, we show that doing the kind of naive direct fluorescence laser spectroscopy, we gain from the fact that we have a huge number of oscillators in the sample and that they are kind of “frozen” in the crystal, so that we can interrogate them continuously. If everything works ideally (especially the interrogation laser) we show that one can reach a fractional inaccuracy of 10^-19 with this clock is almost surprisingly good. Good news for us, let’s hope the referee’s like it too!

You can find the ArXive version here.

P.S. The figure comes from Philipp Dessovic, with whom we are working on the next publication on the electronic structure of the Thorium within a crystal.

Bianka Ullman joins the Thorium team

From Italy to Space

This October 24.-27. the European Space Agency (ESA) organized the „4th International Workshop on Optical Atomic Frequency Standards and Clocks“ in the beautiful city of Trani in southern Italy. The meeting resumed the current status of projects and efforts in bringing optical clocks into space. The organizer Eamonn Murphy did a great job in mixing talks on already very technologically advanced approaches (like neutral atoms lattice clocks and laser stabilization using ULE cavities) with fundemantally new approaches like spectral hole-burning stabilization or (of course) the Thorium project. It was nice to experience, how much interest the clock community takes in our research, there where many questions and discussions AND a lot offers for help and collaboration. The incredible scenery of Trani’s old town (picture shows the view from my hotel room!) and the above 20 °C temperatures (not to mention the seafood) did the rest to make this meeting a memorable experience. You can find the program here.

To ESA people: YES, I’d be happy to come again any time;-)

A rainbow out of the box

This week, the brave Marc Fischer from Menlo Systems drove all the way from Munich to Vienna to bring us the long-expected frequency comb system. All parts arrived in good shape (thanks again to the unknown soldiers of science who helped in unloading) and since Tuesday May 17 and after an intense crash course by Marc, we have all the colors of the rainbow in our lab. Everybody is invited to have a look, no special weather conditions required. Now we ONLY have to create the fifth harmonic in a build-up cavity filament to get to the VUV range – piece of cake! (Here and here are some papers on how this has been done by other groups) Thanks again to Marc for all your patience and help! To the rest of you: buy MENLO products, officially  selected (by the Thorium team) the nicest and most helpful laser company on this planet (also check out their cool frequency comb community page).

Georgy Kazakov joins the Thorium team

Good news for those of us who are more afraid of integrals and tensors than femtolasers and vacuum (e.g. the author): The Thorium project now has its own theorist. Georgy Kazakov, long standing collaborator from St. Petersburg has won a prestigious Lise Meitner fellowship from the Austrian Science Fund (FWF) and joined the team in April. Welcome! With a background in atomic clocks, he will guide the experimentalists to sensible measurements. As an extra bonus, he can read the original nuclear physics papers (published in Russian, obviously).

A message to our beloved spammers

It’s quite short: F..CK YOU!

(this message is exclusively by Thorsten and does by no means represent the opinions and views of the Thorium team, no animals were harmed). I really love the idea of a science blog (thanks Julia from Datenwerk for talking me into it) and your comments always make my day. Unfortunately, I have to filter them out of hundreds of fake messages, promoting pills in all shapes of colors, various enlargements or reductions of extremities and generous offerings to write my thesis for me (?). I don’t know how you guys get around the spam blocker but you really should meditate your aims in life. Dr. T. pities you!

To the rest of you: sorry for loosing my temper, breathe, 10, 9, 8, 7, … ok, back to science now…

The first Thorium-doped crystal

Coming in fresh from our collaborator Reinhard Uecker from the IKZ Berlin: The first Thorium-doped Calziumfluoride crystal. The little fellow weighs 75 g, is about 6 cm tall and in good health, at least from an outside look. Its grown using the Czochralski method, the total time it needs for one sample is 1 week! As it’s a first test, it contains the “stable” Th-232 isotope. The doping concentration is 6 * 10¹⁸ per cm³. Now, we have to learn to cut the crystal into pieces and optically polish some surfaces. Please apologize the totally non-scientific green lighting – my UV laser pointer is still being shipped.

UV spectrometer arrived

Finally, after 18 (in words eighteen!) months of planing, fighting with order procedures, waiting, more fighting with budget accounting, more waiting, some final delay due to terrible weather conditions around Boston, and some last-minute customs document delivery by Georg, the McPherson UV Spectrometer (tata!) arrived in Vienna. Probably the biggest box we ever got. Inside, everything nicely packaged by McPherson, even a small table for the computer – thanks, over and over again! Vacuum is already working fine, Matthias is working his way through the meters of documentation. A modified sample holder is in the workshop, so soon we can start characterizing first UV transparent material…

We want YOU for Projektarbeit!

Did you ever wanted to experience the weirdness of quantum mechanics first hand? Feel like turning the world of classical physics upside down in only one afternoon? Then this your chance! You might also grab a few ECTS points on the way. This semester we are looking for students who feel like doing some good for their younger fellows. In the framework of a “Projektarbeit” (that’s about 4 weeks of full-time labwork) we will set up an experiment to demonstrate quantum non-locality by violating Bell’s inequality. The Project contains setting up the experiment (it’s a commercial “entanglement demonstrator” from QuTools), testing out the do’s and don’ts and preparing a nice pedagogical manual for your mates. This device will be the first element of a new “Quantum Practikum” for younger students, others will follow (NMR, laser spectroscopy, neutron interferometry, optical resonators…). This Projektabeit gives the full 8 ECTS points, it would be ideal for a student wanting to become a physics teacher or as a bachelor project. Contact Thorsten for further info. By the way: more teaching opportunities can be found here.