Featured Research

from universities, journals, and other organizations

Pancake Shape Prevents Collapse Of Quantum Gases

Date:
February 28, 2008
Source:
University of Stuttgart
Summary:
Instabilities in clouds of attracting matter are a well known phenomenon. In astrophysics, they lead to spectacular effects such as supernovae. But also in a gas, when it is made up of tiny atomic magnets, the magnetic forces lead to instabilities. Such a gas cloud implodes due to the attractive interaction between the magnetic atoms. The finding that attracting matter is unstable is known to everybody who has ever played with a bunch of magnets: they simply clump together.

Chromium atoms are cooled down to below one MicroKelvin by blue lasers. At such low temperatures a quantum gas of magnets is formed.
Credit: University of Stuttgart

Instabilities in clouds of attracting matter are a well known phenomenon. In astrophysics, they lead to spectacular effects such as supernovae. But also in a gas, when it is made up of tiny atomic magnets, the magnetic forces lead to instabilities. Such a gas cloud implodes due to the attractive interaction between the magnetic atoms. The research group of Professor Tilman Pfau of the 5th Institute of Physics at the University of Stuttgart have recently measured the complete stability diagram of such a gas of magnets which maps exactly the border between stable and unstable states of the gas.

The finding that attracting matter is unstable is known to everybody who has ever played with a bunch of magnets: they simply clump together. Even when they are aligned in parallel the same happens - unless the magnets are, at the same time, forced to stay in a plane. Such an arrangement in a pancake-like shape – in contrast to a spherical or cigar-like geometry – is stable. In the case of these spheres or cigars, only an additional repulsive interaction between the atoms that keeps them apart could prevent the whole system from collapsing (clumping together).

Tilman Pfau’s group are investigating the properties of so called “quantum gases” in the framework of their trans-regional collaborative research centre (SFB/TRR21 “Control of quantum correlations in tailored matter –Co.Co.Mat.” ). The gas in which the above experiments were performed consists of chromium atoms that are forced to undergo a phase transition to a so called Bose-Einstein condensate at extremely low temperatures.

In this special state of quantum matter, the interactions as well as the shape of the trap that holds the atomic cloud and squeezes it into the desired shape can be controlled very precisely. Ten years ago Tilman Pfau, together with a group of polish scientists,  had predicted theoretically the border between stable and unstable conditions. Only now could his group show experimentally that the gas behaves as had been predicted and that it is indeed stabilized by forcing it into a plain pancake shape.

In their ongoing research project, the group are having a closer look at the dynamics of the collapse itself. Due to its similarity to a supernova, this collapse is sometimes called “Bose Nova”. During the collapse the researchers expect for certain parameters the occurrence of new states of quantum matter caused by the magnetic interaction. An exactly controlled and triggered collapse could – on the other hand – also be used to deposit precisely focused chromium atoms on a surface.

Journal reference: Tobias Koch, Thierry Lahaye, Jonas Metz, Bernd Frφhlich, Axel Griesmaier, Tilman Pfau: „Stabilizing a purely dipolar quantum gas against collapse", Nature Physics (2008), DOI number 10.1038/nphys887 [arXiv:cond-mat 0710.3643]


Story Source:

The above story is based on materials provided by University of Stuttgart. Note: Materials may be edited for content and length.


Cite This Page:

University of Stuttgart. "Pancake Shape Prevents Collapse Of Quantum Gases." ScienceDaily. ScienceDaily, 28 February 2008. <www.sciencedaily.com/releases/2008/02/080226170616.htm>.
University of Stuttgart. (2008, February 28). Pancake Shape Prevents Collapse Of Quantum Gases. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2008/02/080226170616.htm
University of Stuttgart. "Pancake Shape Prevents Collapse Of Quantum Gases." ScienceDaily. www.sciencedaily.com/releases/2008/02/080226170616.htm (accessed July 28, 2014).

Share This




More Matter & Energy News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) — AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Shipping Crates Get New 'lease' On Life

Shipping Crates Get New 'lease' On Life

Reuters - Business Video Online (July 25, 2014) — Shipping containers have been piling up as America imports more than it exports. Some university students in Washington D.C. are set to get a first-hand lesson in recycling. Their housing is being built using refashioned shipping containers. Lily Jamali reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) — Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) — TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins