Featured Research

from universities, journals, and other organizations

Viewing macro behaviors of ultra-cold quantum gases through the micro-world

Date:
January 13, 2014
Source:
ICFO-The Institute of Photonic Sciences
Summary:
Scientists have been able to observed, for the first time, the collective spin dynamics of ultra-cold fermions with large spins.

Understanding collective behavior of ultra-cold quantum gases is of great interest since it is intimately related to many encountered systems in nature such as human behavior, swarms of birds, traffic jam, sand dunes, neutron stars, fundamental magnetic properties of solids, or even super-fluidity or super-conductivity. In all of these everyday life examples, collective behavior plays a crucial role since all participating objects move, voluntarily or not, synchronously.

Related Articles


In a recent study coordinated by the Institute of Laser Physics, University of Hamburg -- Germany, in collaboration with ICFO -- the Institute of Photonic Sciences, researchers have observed, for the first time, the collective spin dynamics of ultra-cold fermions by analyzing the microscopic properties of the particles through their local collisions. The researchers were able to observe that at very low temperatures, close to absolute zero, the individual properties of each particle team up and behave coherently as a single identity in spin space. The results obtained from this study have recently been published in Science.

The "super" behavior of matter is actually a macro manifestation of the micro-laws of quantum mechanics. In the quantum micro-world, particles are divided into two main groups: bosons (e.g. photons) and fermions (e.g. constituents of matter such as electrons, protons, neutrons). The difference between these particles is basically their spin: bosons have integer spins and fermions have half-integer spins. Bosons behave collectively in spin rotation since they like to bundle up as friends and go with the flow. In the case of fermions, scientists did not know, up to now, whether these particles could behave the same way since they apparently are loners in this world.

Even more, if an atomic gas is cooled down to extremely low temperatures, bosons present the characteristics that many of them can occupy the same quantum state -- they constitute a Bose condensate. In contrast, fermions have the particular characteristic of having only one particle per single state occupied, according to Pauli's exclusion principle.

To obtain ultra-cold fermions, the researchers trapped, via the use of a laser light, a quantum degenerate gas containing potassium atoms, cooled it down to very low temperatures and prepared different spin mixtures at very low magnetic fields to induce spin-changing dynamics. They were able to observe that when particles with very high spins collide between each other in local interactions, the resulting individual spins change. However, as a whole, they behave in a collective manner stabilizing the gas through long-lived, large-amplitude spin oscillations.

Hence, the research group led by ICREA Professor at ICFO Dr. Maciej Lewenstein came up with a novel effective theory that could explain correctly the experiment and discovered that the collective behavior is a quantum phenomenon which is very sensitive to perturbations (e.g. the effect completely disappears with a very slight change in the temperature). As Maciej Lewenstein states, "Fermions, due to Pauli's principle, are "individualists" -- they do not like to behave in a same way. Nevertheless, here they team up to exhibit amazingly robust collective behavior. "

Through the controlled interplay of different fundamental processes that either stimulate or suppress the collective behavior, scientists are being able to have an in-depth understanding of the model system at work and therefore seek new pathways to study yet inaccessible exotic phenomena such as the creation of topological structures and textures in degenerate quantum gases with high spin or future applications such as quantum sensors for the smallest magnetic fields possible.


Story Source:

The above story is based on materials provided by ICFO-The Institute of Photonic Sciences. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. S. Krauser, U. Ebling, N. Flaschner, J. Heinze, K. Sengstock, M. Lewenstein, A. Eckardt, C. Becker. Giant Spin Oscillations in an Ultracold Fermi Sea. Science, 2014; 343 (6167): 157 DOI: 10.1126/science.1244059

Cite This Page:

ICFO-The Institute of Photonic Sciences. "Viewing macro behaviors of ultra-cold quantum gases through the micro-world." ScienceDaily. ScienceDaily, 13 January 2014. <www.sciencedaily.com/releases/2014/01/140113100909.htm>.
ICFO-The Institute of Photonic Sciences. (2014, January 13). Viewing macro behaviors of ultra-cold quantum gases through the micro-world. ScienceDaily. Retrieved December 18, 2014 from www.sciencedaily.com/releases/2014/01/140113100909.htm
ICFO-The Institute of Photonic Sciences. "Viewing macro behaviors of ultra-cold quantum gases through the micro-world." ScienceDaily. www.sciencedaily.com/releases/2014/01/140113100909.htm (accessed December 18, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Thursday, December 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
3D Printed Cookies Just in Time for Christmas

3D Printed Cookies Just in Time for Christmas

Reuters - Innovations Video Online (Dec. 18, 2014) A tech company in Spain have combined technology with cuisine to develop the 'Foodini', a 3D printer designed to print the perfect cookie for Santa. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
First Etihad Superjumbo Flight in December

First Etihad Superjumbo Flight in December

AFP (Dec. 18, 2014) The first flight of Etihad Airways' long-awaited Airbus A380 superjumbo will take place later in December, the Abu Dhabi carrier said Thursday, also announcing its first Boeing 787 Dreamliner route. Duration: 01:09 Video provided by AFP
Powered by NewsLook.com
Ford Expands Air Bag Recall Nationwide

Ford Expands Air Bag Recall Nationwide

Newsy (Dec. 18, 2014) The automaker added 447,000 vehicles to its recall list, bringing the total to more than 502,000. Video provided by Newsy
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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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