Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Quantized heat conduction by photons observed

09.11.2006
Physicists at the Low Temperature Laboratory of Helsinki University of Technology publish pathbreaking results in Nature

In a recent experiment, to be published in Nature on November 9, Dr Matthias Meschke and professor Jukka Pekola, together with Dr Wiebke Guichard, a coworker from French CNRS, investigated heat exchange between two small pieces of normal metal, connected to each other only via superconducting leads. The results demonstrate that at very low temperatures heat is transferred by electromagnetic radiation.

The PICO research group is a part of the Low Temperature Laboratory at Helsinki University of Technology - TKK, Finland. The domain of interest of the PICO research group is how heat is transported in nano- and micrometer sized devices on an ordinary silicon chip at only 0.1 degrees above absolute zero.

The project is part of the Future Electronics (TULE) Research Programme of the Academy of Finland.

Generally, even experts consider that superconductors are ideal insulators as regards to usual heat conduction. These new experimental results demonstrate that at very low temperatures heat is transferred by electromagnetic radiation, much in analogy to how light is propagated, along the superconductors, and furthermore these observations show that the heat transfer rate cannot have an arbitrary value: it is limited by what is called a quantum of thermal conductance. As is often the case, this observation contradicts our experiences in daily life. Certainly, one would not see this effect for instance while cooking an egg; it is just another example of how physical laws are changing when quantum mechanics comes into play.

These experiments are quite demanding, as they have to measure the temperature of an extremely tiny piece of a metal. Any usual thermometer would not do it, as it is simply far too big. Again, only the quantum mechanics can provide a solution: nano-sized (about 100 nm in cross-section) probes make use of the quantum mechanical effect of tunneling, that is penetration of particles through a classically forbidden area. Electrical current due to tunneling probes the energy distribution, and thus temperature, of the electrons in the metal. The experiment may have seemed too easy, unless, in order to distinguish the signal from the background, the researchers had to install an “in-situ” switch into the superconducting line: this allowed them to alternatively either pass or reject the heat by electromagnetic radiation through it.

The observation demonstrates a very basic phenomenon, which has no immediate consequences for new products or applications. Yet the observation helps us to understand the fundamental transport mechanisms in nanoscale devices. This effect has implications for, e.g., performance and design of ultra-sensitive radiation detectors in astronomy, whose operation at very low temperature is largely dependent on weak thermal coupling between the device and its environment.

Niko Rinta | alfa
Further information:
http://www.aka.fi

More articles from Physics and Astronomy:

nachricht From the cosmos to fusion plasmas, PPPL presents findings at global APS gathering
13.11.2018 | DOE/Princeton Plasma Physics Laboratory

nachricht A two-atom quantum duet
12.11.2018 | Institute for Basic Science

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: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

The dawn of a new era for genebanks - molecular characterisation of an entire genebank collection

13.11.2018 | Life Sciences

Fish recognize their prey by electric colors

13.11.2018 | Life Sciences

Ultrasound Connects

13.11.2018 | Awards Funding

VideoLinks
Science & Research
Overview of more VideoLinks >>>