Journal Club

Accompanying the lectures we will work on the original literature in the field that has been published in scientific journals such as Science, Nature, Physical Review Letters, etc. This will allow you to become acquainted not only with the original work, but also should help you in writing your own articles in the future.

1. The first article in the journal club is the first part of the Nobel lecture of William D. ("Bill") Philips, who received the Nobel Prize of 1997 for the demonstration of laser cooling. His lecture describes what he discovered -- and how. It is only partially a scientific paper and partially a story.The idea this time is that you get used to the vocabulary used in such papers and that you should try to understand "what" happened and the broad reason why -- not necessarily all the details on how exactly it works (that we will cover next month). We are interested, for now, in the beginning of the paper which describe the slowing of atoms by light (until page 210), and, if you get there, magnetic trapping (until page 215). At the beginning of page 211, by the way, you should have a look again at the Zeeman effect in figure 8.
2. The second article in the journal club is a Physical Review Letters (PRL) article from the group of Steven Chu and D.E. Pritchard PRL59,2631 (1987). It is one of the first papers on cooling and trapping of neutral atoms using a combination of optical and magnetic fields.
   Most journals impose a length limit on the article, which in the case of PRL is four pages. This leads to the use of a very concise language that may render initial understanding more difficult. In addition, you will find that this article does not only present the general principle of the experiment, but also some technical details, that are less relevant for our discussion. So, don't be scared if you don't understand parts of the article! You'll find most of the relevant physics already on the first page.
3. The third article is again by the group of Steven Chu and published in Physical Review Letters (PRL Vol 74, p3352 (1995)). It describes trapping and evaporative cooling in an optical dipole trap (instead of a magnetic trap).
4. This time (wednesday, Nov. 18th) we look at one of the early publications PRL 77, p4984 (1996) on Bose-Einstein condensation in dilute weakly interacting gases originating in the group of  Carl Wieman and Eric Cornell. It quantitatively looks at several basic parameters of the Bose-Einstein phase transition, especially the fraction of atoms occupying the ground state of the system as a function of temperature.
5. On Wednesday 25th we will again discuss a 4-page PRL, and again by one of the two first groups with BECs (this time the other one):
   "Collisionless and Hydrodynamic Excitations of a Bose-Einstein Condensate"
   D. M. Stamper-Kurn, H.-J. Miesner, S. Inouye, M. R. Andrews, and W. Ketterle
   Phys. Rev. Lett. 81, 500 - 503 (1998)
   The general type of experiment that they are doing is also explained in an earlier paper from the same group; to see what the raw data looks like from which they deduce their measurements, it can be instructive to look at the figures in that older paper, because the raw data is shown in more detail. The older measurements however cover only a small part of the regime that is covered in the newer paper from 1998, (figuring out the differences between the papers is of course also a way to understand the new and important aspects of the newer paper).
   This is the older paper:
   "Collective Excitations of a Bose-Einstein Condensate in a Magnetic Trap"
   M.-O. Mewes, M. R. Andrews, N. J. van Druten, D. M. Kurn, D. S. Durfee, C. G. Townsend, and W. Ketterle
   Phys. Rev. Lett. 77, 988 - 991 (1996)
6. On Wednesday, December 2nd we will look at a recent paper on solitons from the group of Klaus Sengstock in Hamburg:
   Oscillations and interactions of dark and dark–bright solitons in Bose–Einstein condensates
   Ch. Becker, S. Stellmer, P. Soltan-Panahi, S. Dörscher, M. Baumert, E. Richter, J. Kronjäger, K. Bongs & K. Sengstock
   Nature Physics 4, 496 - 501 (2008)
7. On December 9th, we will look at one of the first papers were a BEC is loaded into an optical lattice. It was published 2001 by the BEC group in munich. It is entitled "Exploring Phase Coherence in a 2D Lattice of Bose-Einstein Condensates" and can be found here Phys. Rev. Lett. 87, 160405 (2001).
8. On December 16th, the topic will again be Bosons in optical lattices, but this time the emphasis is on the interactions between them which drive a Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
   Nature 415,39-44 (2002)
9. On December 23th, we will have a closer look at the Mott insulator: Formation of Spatial Shell Structure in the Superfluid to Mott Insulator Transition
   PRL 97,060403 (2006)
10. On January 13th we will look at Repulsively bound atom pairs in an optical lattice, an at first sight counterintuitive result where -due to the presence of an optical lattice- atoms are bound together by a repulsive interaction Nature 441, 853 (2006)
11. On January 20th we will look at scattering experiments done with cold atoms. It is published by a group from new Zealand in PRL, 93, 173201 (2004). Related articles can be found here and here.
12. On January 27th the paper will be Observation of Feshbach resonances in a Bose–Einstein condensate, Nature 392 151 (1998), the first paper that demonstrated Feshbach resonances in BEC's (not the first observation of FR's in general, but this one is more relevant for us). The trap configuration is a bit unusual for technical reasons, but this has nothing to do with the detection scheme (what is it?). The paper is here.
13. On February, 3rd we will be talking about Creation of ultracold molecules from a Fermi gas of atoms, Nature 424, 47-50 (2003) written by the group of Deborah Jin at Jila, Boulder, Colorado, USA. The title essentially says what it is about. An we will find out, how they did it and what they discovered.
14. This is our last Journal Club paper for this course, which we will discuss on February, 10th. It is entitled Synthetic magnetic fields for ultracold neutral atoms, Nature 462, 628 (2009). A neutral ultracold gas is exposed to a pair of off resonant laser fields, which modify the effective system's hamiltonian such that it looks like one of charged particles in an external magnetic field, even though the atoms don't carry a real charge.

You also may browse yourself in the journals, which you can access here. For the journal club the most relevant journals will be Physical Review Letters (PRL), Physical Review A (PRA), Reviews of Modern Physics (Rev. Mod. Phys), Nature and Science.