Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cooling With the Coldest Matter in the World

25.11.2014

Physicists at the University of Basel have developed a new cooling technique for mechanical quantum systems. Using an ultracold atomic gas, the vibrations of a membrane were cooled down to less than 1 degree above absolute zero. This technique may enable novel studies of quantum physics and precision measurement devices, as the researchers report in the journal Nature Nanotechnology.

Ultracold atomic gases are among the coldest objects in existence. Laser beams can be used to trap atoms inside a vacuum chamber and slow down their motion to a crawl, reaching temperatures of less than 1 millionth of a degree above absolute zero – the temperature at which all motion stops.


A cloud of ultracold atoms (red) is used to cool the mechanical vibrations of a millimeter-sized membrane (brown, in black frame). Tobias Kampschulte, University of Basel

At such low temperatures, atoms obey the laws of quantum physics: they move around like small wave packets and can be in a superposition of being in several places at once. These features are harnessed in technologies such as atomic clocks and other precision measurement devices.

An ultracold atomic fridge

Can these ultracold gases also be used as refrigerants, to cool other objects to very low temperatures? This would open up many possibilities for the investigation of quantum physics in new and potentially larger systems.

The problem is that the atoms are microscopically small and even the largest clouds produced thus far, which consist of several billion ultracold atoms, still contain far fewer particles than something as small as a grain of sand. As a result, the cooling power of the atoms is limited.

A team of University of Basel researchers led by Professor Philipp Treutlein has now succeeded in using ultracold atoms to cool the vibrations of a millimeter-sized membrane. The membrane, a silicon nitride film of 50 nm thickness, oscillates up and down like a small square drumhead.

Such mechanical oscillators are never fully at rest but show thermal vibrations that depend on their temperature. Although the membrane contains about a billion times more particles than the atomic cloud, a strong cooling effect was observed, which cooled the membrane vibrations to less than 1 degree above absolute zero.

“The trick here is to concentrate the entire cooling power of the atoms on the desired vibrational mode of the membrane,” explains Dr. Andreas Jöckel, a member of the project team. The interaction between atoms and membrane is generated by a laser beam.

As the physicist explains: “The laser light exerts forces on the membrane and atoms. Vibration of the membrane changes the light force on the atoms and vice versa.” The laser transmits the cooling effect over distances of several meters, so the atomic cloud does not have to be in direct contact with the membrane. The coupling is amplified by an optical resonator consisting of two mirrors, between which the membrane is sandwiched.

The first experiment of its kind worldwide

Systems that use light to couple ultracold atoms and mechanical oscillators have already been proposed theoretically. The experiment at the University of Basel is the first worldwide to realize such a system and use it to cool the oscillator. Further technical improvements should make it possible to cool the membrane vibrations to the quantum-mechanical ground state.

For the researchers, cooling the membrane with the atoms is only the first step: “The well-controlled quantum nature of the atoms combined with the light-induced interaction is opening up new possibilities for quantum control of the membrane,” says Treutlein.

This may enable fundamental quantum physics experiments with a relatively macroscopic mechanical system, visible to the naked eye. It may also be possible to generate what are known as entangled states between atoms and membrane. These would allow measurement of membrane vibrations with unprecedented precision, which in turn could enable the development of new kinds of sensors for small forces and masses.

The experiments at the University of Basel were co-funded by the European Union and are part of the National Center of Competence in Research in Quantum Science and Technology (NCCR QSIT) and the Swiss Nanoscience Institute (SNI).

Original source
Andreas Jöckel, Aline Faber, Tobias Kampschulte, Maria Korppi, Matthew T. Rakher, and Philipp Treutlein
Sympathetic cooling of a membrane oscillator in a hybrid mechanical-atomic system
Nature Nanotechnology, advance online publication (2014).
http://dx.doi.org/10.1038/nnano.2014.278
Publication date: 24 November 2014

Further information
Prof. Dr. Philipp Treutlein, University of Basel, Department of Physics, Tel: +41 (0)61 267 37 66, Email: philipp.treutlein@unibas.ch

www.unibas.ch

Olivia Poisson | Universität Basel

More articles from Physics and Astronomy:

nachricht Heating quantum matter: A novel view on topology
22.08.2017 | Université libre de Bruxelles

nachricht Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>