Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Closing in on the Phenomenon of Superconductivity With a Two-dimensional Atomic Gas


Transition into superfluid phase: Heidelberg physicists characterise an exotic quantum superfluid

Using an exotic quantum superfluid that originates in a two-dimensional atomic gas, researchers from Heidelberg University are closing in on the phenomenon of superconductivity. The team headed by Prof. Dr. Selim Jochim of the Institute for Physics is using this special gas as a model system to more easily study the largely unknown mechanism of the superfluid phase transition in 2D structures.

Experimental setup to generate a two-dimensional ultracold quantum gas

In the background is the vacuum chamber in which the researchers prepared the quantum superfluid. The mirrors and lenses needed to create the laser trap are seen in the foreground. This apparatus allows the physicists to generate a two-dimensional ultracold gas every 15 seconds and then measure its properties. Photo: Martin Ries

Atomic gas in a magneto-optical trap

The luminous red cloud suspended in the centre of the vacuum chamber consists of approximately one billion lithium atoms. Their temperature is about 500 microkelvins, or about 500 millionths of a degree above absolute zero at negative 273.15 degrees Celsius. The atoms are captured by laser beams, cooled, and used as the foundation for all the experiments conducted by Prof. Dr. Selim Jochim’s team. Photo: Martin Ries

The researchers hope to gain new insight into the so-called room-temperature superconductor, a hypothetical material that does not require cooling to achieve lossless conduction of electricity. The research results were published in the journal “Physical Review Letters”.

Two of the most impressive phenomena that exhibit quantum mechanical behaviour in the “normal” world are superfluidity and its by-product, superconductivity. In physics, superfluidity is a state of matter in which a fluid loses all internal resistance.

Superconductivity results when the electrons in a material behave like a superfluid liquid. They flow without encountering any friction, and the electrical resistance drops to zero. This state occurs only below a certain critical temperature, which is different for every superconductor.

This behaviour is well understood in the conventional superconductor, in which the electrons move in three dimensions. But the problem is that the superconducting state can only be achieved at very cold temperatures well under negative 200 degrees Celsius. The necessary extensive cooling hampers a technological application, according to physicist Dr. Martin Ries.

“For several years, it has been possible to produce high-temperature superconductors. Their critical temperature is significantly higher, but unfortunately still just under negative 130 degrees Celsius. Additionally, we only have a partial understanding of the way they work, making it difficult to develop better superconductors of this kind,” says the scientist, who is a member of Prof. Jochim’s research team.

As Dr. Ries explains, science assumes that electrons can only move in two dimensions in high-temperature superconductors. So the Heidelberg physicists focused their research into superfluidity and superconductivity on two-dimensional structures. The superfluid transition is quite different between 2D and 3D structures, and the two-dimensional transition mechanism remains largely a mystery that is difficult to pin down theoretically.

Although the so-called BKT theory did address it in the 1970s, it is only valid if the forces between the electrons are weak. “But what exactly happens with stronger forces is not known, and that is precisely the scenario of major significance,” says Dr. Ries.

Jochim’s team of physicists has now succeeded in building a simple model system to perform a quantum simulation of the superfluid phase transition in 2D structures. They are using a two-dimensional ultracold gas captured in a laser trap. “We are able to create a ‘clean’ system that is easier to understand and in which the quantum mechanical behaviour of the particles resembles that of the electrons in two-dimensional structures,” reports Dr. Ries.

It actually allowed the researchers to observe the transition into the superfluid phase at low temperatures and measure the critical temperature for any strength of interparticle forces. “This gives us the ability to more easily test the various theories for 2D superfluidity in the future,” explains Prof. Jochim, whose team is currently investigating the correlations in the superfluid phase. “Over the long term, we hope to gain a better understanding of high-temperature superconductivity that could lead to the development of a room-temperature superconductor at some point in the future.”

This research was conducted by a cooperation of experimental and theoretical physicists at Heidelberg University's Center for Quantum Dynamics. For their article published in the “Physical Review Letters”, the authors received the coveted “Editors’ Suggestion” distinction.

Original publication:
M.G. Ries, A.N. Wenz, G. Zürn, L. Bayha, I. Boettcher, D. Kedar, P.A. Murthy, M. Neidig, T. Lompe and S. Jochim: Observation of Pair Condensation in the Quasi-2D BEC-BCS Crossover. Physical Review Letters 114, 230401 (8 June 2015), doi: 10.1103/PhysRevLett.114.230401

Dr. Martin Ries
Institute for Physics
Phone: +49 6221 54-19484

Communications and Marketing
Press Office, phone: +49 6221 54-2311

Weitere Informationen:


Marietta Fuhrmann-Koch | idw - Informationsdienst Wissenschaft

More articles from Physics and Astronomy:

nachricht 'Frequency combs' ID chemicals within the mid-infrared spectral region
16.03.2018 | American Institute of Physics

nachricht Fraunhofer HHI have developed a novel single-polarization Kramers-Kronig receiver scheme
16.03.2018 | Fraunhofer-Institut für Nachrichtentechnik, Heinrich-Hertz-Institut, HHI

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

Im Focus: Radar for navigation support from autonomous flying drones

At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.

Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

International Virtual Reality Conference “IEEE VR 2018” comes to Reutlingen, Germany

08.03.2018 | Event News

Latest News

Development and Fast Analysis of 3D Printed HF Components

19.03.2018 | Trade Fair News

In monogamous species, a compatible partner is more important than an ornamented one

19.03.2018 | Life Sciences

Signaling Pathways to the Nucleus

19.03.2018 | Life Sciences

Science & Research
Overview of more VideoLinks >>>