Ketterle Research Articles

PLANCKS 2019

The sixth edition of the Physics League Across Numerous Countries for Kick-ass Students (PLANCKS) competition was held in the city of Odense, Denmark. The purpose of PLANCKS is to find the most prominent theoretical physics student team in the world. The competition was part of a three-day programme, featuring scientific as well as social events. The scientific programme featured three symposia all containing talks from prominent physicists, most notably the 2001 Nobel Prize laureate Wolfgang Ketterle of MIT. Both the competition and the symposia will enlighten the students about fields of physics which may not be present at their home university. The competition contained a total of 34 teams from 18 countries including the winning team ‘The Four Vectors’ from Germany, and the runners-ups ‘CV5 Irreducibles’ and ‘Komfur’ from Serbia and Denmark, respectively. This year’s problems featured 10 exciting exercises. Here we present two problems from PLANCKS 2019 and the line of reasoning behind making a PLANCKS problem, which is an opportunity for a scientist to highlight an interesting part of their field to young students.

Taming the world of atoms and photons

Taming the world of atoms and photons

Cover Picture: ChemPhysChem 9/2002

The cover picture shows quantum vortices in a rotating condensate of sodium atoms. A condensate 60 μm in diameter and 250 μm in length was set in rotation by rotating laser beams. It then formed a regular lattice of vortices. The condensate was allowed to ballistically expand, which resulted in a 20-fold magnification. The images here represent two-dimensional cuts through the density distribution and show the density minima due to the vortex cores. The examples shown contain 0, 16, 70, and 130 vortices. The diameter of the cloud is about 1 mm. Find out more in the Nobel Lecture by Wolfgang Ketterle on pages 736–753.

A Fermi gas of atoms

WHEN the 2001 Nobel Prize for Physics was awarded to Eric Cornell and Carl Wieman from JILA in Boulder, Colorado, and to Wolfgang Ketterle from the Massachusetts Institute of Technology, they were recognized for creating and studying Bose–Einstein condensates – dilute gases of atoms that are all in the same quantum state. Their remarkable achievement enabled “quantum gases” to be studied experimentally for the first time, and jump-started new sub-fields of research, including gaseous superfluidity, atom lasers and matter–wave optics.

The 2001 Nobel Prize in Physics

This year’s Nobel Prize in Physics has been jointly awarded to Eric A Cornell of the National Institute of Standards and Technology, Boulder (USA), Wolfgang Ketterle of the Massachusetts Institute of Technology, Cambridge (USA), and Carl E Wieman of the University of Colorado, Boulder (USA). They have been cited “for the achievement of Bose-Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates”. The scientists have been recognized for their pioneering work in a field that has grown explosively around the world in the past few years. Though the phenomenon of Bose-Einstein condensation (BEC) was predicted by Einstein in 1925 (based on the new statistics of Bose), it was observed only in 1995. In this article, we review the basic physics behind the phenomenon, the experimental techniques involved in achieving it, and high-light some of the potential applications of condensates.

Nobel population 1901–50: anatomy of a scientific elite

On 10 December this year the Nobel Foundation will celebrate the 100th anniversary of the award of the first Nobel prizes. As the winners of this year's physics prize – Eric Cornell, Wolfgang Ketterle and Carl Wieman – gather in Stockholm and Oslo, along with the rest of the 2001 prize winners and numerous laureates from previous years who are taking part in the celebrations, it is easy to forget that they represent only the most visible part of the Nobel institution. Since only a maximum of three people can share each prize, one can count scores of unlucky candidates who naturally will not have been invited.

The 2000 Benjamin Franklin Medal in Engineering presented to Carl Wieman , Eric Cornell and Wolfgang Ketterle

The Franklin Institute, Philadelphia, Pennsylvania, awarded the 2000 Benjamin Franklin Medal in Engineering to Carl Wieman, Eric Cornell, and Wolfgang Ketterle for their epoch-making experimental confirmation of the 1925 prediction by Satyendra Bose and Albert Einstein, who claimed on theoretical grounds that a dilute gas can condense into a large quantum–mechanical system and display properties that are usually found only on an atomic or molecular scale.

Researchers Can Now Vary the Atomic Interactions in a Bose–Einstein Condensate

Bose–Einstein condensates (BECs) were formed five years ago from rubidium-87 and sodium atoms, whose interactions are repulsive. BECs were also formed from lithium-7 atoms, which attract one another. (See the article by Wolfgang Ketterle in PHYSICS TODAY, December 1999, page 30.) Now researchers in Boulder, Colorado, have created a single condensate of rubidium-85 atoms, which can be taken continuously from the repulsive to the attractive regimes. The experimenters can vary the strength of the interaction between the atoms in their condensate by a factor of 100 or more—and even flip its sign—by changing the external magnetic field. The ability to tune the interactions of a condensate opens the door to systematic explorations of atomic behavior in new regimes.

New Atom Lasers Eject Atoms or Run CW

The experimental observation of Bose–Einstein condensation (BEC) in rubidium in 1995 demonstrated that a macroscopic number of bosons could be produced in a single quantum state of trapped atoms. The occupation of a single quantum state by a large number of identical bosons is the matter-wave analog of the storage of photons in a single mode of a laser cavity. In a conventional laser, one extracts a coherent beam of photons from a cavity by using a partially transmitting mirror as an output coupler. In 1997, Wolfgang Ketterle and his collaborators at MIT built a pulsed output coupler that extracted matter waves from a condensate, and they observed interference between atoms from two separate condensates, thereby demonstrating an atom laser for the first time (see PHYSICS TODAY, March 1997, page 17).

Optical Confinement of Bose-Einstein Condensates

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text Wolfgang Ketterle, "Optical Confinement of Bose-Einstein Condensates," Optics & Photonics News 9(12), 42-43 (1998) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

Laser Trap Gives Clearer View of Condensates

Since researchers created the first Bose-Einstein condensates (BECs) 3 years ago, they have been eagerly exploring this new state of matter and seeing what can be done with it—turning it into an atom laser, for example (see main text). But the magnetic traps used to confine the condensates put some kinds of studies off limits, because the magnetic fields freeze the spins of the trapped atoms in one orientation. Now Wolfgang Ketterle and his team at the Massachusetts Institute of Technology have removed the barrier with a new kind of trap.

Bose Condensates are Coherent Inside and Outside an Atom Trap

When Wolfgang Ketterle and his colleagues at MIT demonstrated an “atom laser” recently, the announcement excited the physics community and naturally grabbed the attention of the popular press. One essential property of a laser is, of course, its coherence, and the evidence provided by the MIT group is striking: Sharp interference fringes formed when two Bose–Einstein condensates from the same trap expanded and overlapped after being released from confinement. The fringes are reminiscent of the interference between coherent light waves emanating from a double slit. (See the figure below.)