The latest from the coal face, including the lab, theory and fun! Hopefully, we can keep this up-to-date...
QEII
Dr. Nick Robins became a QEII Fellow in the ARC Discovery grants just announced.
News
Eureka Prize night
John, Cristina and Nick had attended the recent Eureka prize night. Being one of three finalists in the 'Scientific Research' category meant that the evening was full of anticipation. In the end we didn't win, but we had an excellent dinner and enjoyed the company of nearly 1000 eminent scientists from around Australia. We heartily thank the organisers for a fantastic evening and send our congratulations and best wishes to all the winners.
Farewell to Justin
Fullbright Scholar, Justin Schultz is heading back to the US on Friday. We will miss you for many reasons, not the least because of the great physics you did while here. Thanks also for fueling the entire team with chocolate. We will all become significantly thinner in your absence!
Julien Dugué
Congratulations to Julien for successfully defending his thesis. Best of luck in all your future endeavors.
BEC in 85Rb
We now have a BEC of 85Rb, thanks to the efforts of Paul Altin. Paul had a lot of support and help from the whole experimental atom laser team including in particular Rachel Poldy, Johnny Debs and Daniel Doering.
The phase transition is reached with about 50,000 atoms at around 15-30nK via sympathetic cooling in our hybrid optical/magnetic trap. 85Rb has a broad Feshbach resonance at 155G, with quite interesting inelastic scattering properties, as well as the tunability of the s-wave cross-section, from large positive to large negative values. We have had a week to explore and examine this new playground, making RF spectroscopy of the resonance itself, as well as getting all the usual data to prove the presence of a condensate: thermal, through bimodal, to pure condensate, aspect ratio changes, and varying the scattering length of the condensate after formation.
Ramsey fringes with an atom laser
We recently observed Ramsey fringes on the atomic clock transition of 87Rb using a pulsed atom laser. The visibility of the fringes is close to 100%.
Media coverage
Our nature physics paper about the pumped atom laser has received quite a bit of media attention. See media comments in the Publications section.
BEC in the new apparatus
Paul Altin achieved a BEC of 87Rb atoms in our new machine at about 11:30pm on the 8/8/08. The machine features a 2DMOT loaded, air cooled QUIC magnetic trap (24*260*260@0.3G). Evaporation in 10s yields a BEC of about 100,000 atoms.
Shown in the sidebar is a pulsed atom laser imaged through the QUIC trap ioffe coil.
Welcome to Fulbright Scholar Justin Schultz
Justin arrived from NIST on Wednesday this week. Welcome from all of us in the group.
Continuous 6.8GHz Raman atomlaser
JD and Daniel realised a new type of atomlaser based on coherent two-photon coupling. To quote the victory email:
"These are the first pictures of an atom laser produced using a raman transition between the two hyperfine ground states of Rb87. Daniel, Nick and I have been working on this for the last few months, and achieved out coupling today. We have imaged only the F=2 [mF=0] atoms, and thus the condensate [F=1,mF=-1] is not visible in the picture." -JD
You can see a small 'bound state' in the image.
Really fast switching of our high inductance coils.
We finally go fast switching of magnetic coils working using an LC resonance to charge the coils
Welcome back to Matt Jeppesen
Matt's been in Paris for six months working in the lab of David Guery-Odelin. Matt also attended the YAO conference.
New machine up and running
Our new machine is up and running. It consists of a 2DMOT to 3DMOT system, with a combined magnetic/dipole trap for evaporative cooling. We'll try and condense 85Rb in the next bit. Putting the vacuum system together was a fantastic group effort: flat out from 4pm in the afternoon to 4am!
Physics World Article
We recently received some attention from Physics World regarding our archive paper on using an atom laser to measure a scattering length. You have to register with Physics World to read the article (which takes a bit of time). The Physics World article is here. Our preprint is here.