Featured Research

from universities, journals, and other organizations

Hunt for an unidentified electron object

Date:
March 24, 2014
Source:
University of Cambridge
Summary:
New research sheds light on the nature of 'unidentified electron objects' -- a mysterious class of objects that exists in superfluid helium at low temperature. Researchers have developed a new mathematical framework capable of describing motions in superfluids -- low temperature fluids that exhibit classical as well as quantum behavior.

Vortex rings as the result of vortex multiplication in a quantum fluid; some electrons are free, and some got trapped by one or more vortices.
Credit: Gleb and Sofia Berloff, ISM

New research sheds light on the nature of 'unidentified electron objects' -- a mysterious class of objects that exists in superfluid helium at low temperature.

The mystery of an unidentified electron object is just a teaser problem; we are ready for other challenges.

Researchers have developed a new mathematical framework capable of describing motions in superfluids -- low temperature fluids that exhibit classical as well as quantum behavior. The framework was used to lift the veil of mystery surrounding strange objects in superfluid helium (detected ten years ago at Brown University). The study, conducted by an international collaboration of researchers from the UK, Russia and France is published today in the journal Proceedings of National Academy of Sciences (PNAS).

The quantum nature of superfluids manifests itself in the form of quantized vortices, tiny twisters, with the core sizes of the order of an Angstrom (0.1nm -- approximately the diameter of an atom) that move through fluid severing and coalescing, forming bundles and tangles. To make these processes even more intricate and distinct from motions in usual classical fluids, these tiny twisters live on the background consisting of a mixture of viscous and inviscid fluid components that constitute superfluid. The mathematical modelling of such complex systems that involve a range of scales is a notoriously difficult problem.

The international team of researchers -- Natalia Berloff of the University of Cambridge and Skolkovo Institute of Science and Technology, Marc Brachet of Universitι Pierre-et-Marie-Curie and Nick Proukakis of Joint Quantum Centre Durham-Newcastle -- came up with a novel framework for achieving this task. The team applied their method to elucidate an intriguing phenomenon in liquid helium research.

Electrons immersed in superfluid helium are useful experimental probes. As they move through superfluid they form soft bubbles of about 2 nm in diameter that get trapped by quantized vortices quite similar to how houses and cars become trapped and transported by a tornado.

A research team from Brown University led by Professor Humphrey Maris has studied the effect of oscillating pressures on electron bubbles. As pressure decreases below the criticality, the bubble expands and explodes, reaching micron sizes, with the bubble trapped by a vortex exploding at a pressure larger than that for the free bubble. Maris' team also discovered another class of object that existed at very low temperatures only and exploded at even larger pressures. They termed these "unidentified electron objects."

The new approach published in PNAS today allowed the researchers to look at the processes as oscillating pressure was applied to a quantum fluid containing a vortex ring at a range of temperatures. The researchers discovered a novel mechanism of vortex multiplication: the vortex core expands and then contracts, forming a dense array of new vortex rings during the contraction stage. They conjectured that it becomes quite likely that the electron bubble becomes trapped by more than one vortex line, furthermore reducing the pressure change needed for consequent explosions. They have also shown that the mechanism of vortex multiplication is suppressed at higher temperatures, explaining why such objects were found experimentally only at lower temperatures.

Professor Berloff who led the team commented: "It is fascinating to have a tool to look at the dynamics of processes that occur on the Angstrom lengthscales and at ultra-low temperatures in quantum fluids. The mystery of an unidentified electron object is just a teaser problem; we are ready for other challenges."

"Understanding the intricate features of behavior of quantized vortices is one of the grand unsolved problems that can be tackled with this framework," added Professor Proukakis.

The research was funded by the Engineering and Physical Sciences Research Council, the EU and the Skolkovo Foundation.


Story Source:

The above story is based on materials provided by University of Cambridge. The original story is licensed under a Creative Commons Licence. Note: Materials may be edited for content and length.


Journal Reference:

  1. N. G. Berloff, M. Brachet, N. P. Proukakis. Modeling quantum fluid dynamics at nonzero temperatures. Proceedings of the National Academy of Sciences, 2014; 111 (Supplement_1): 4675 DOI: 10.1073/pnas.1312549111

Cite This Page:

University of Cambridge. "Hunt for an unidentified electron object." ScienceDaily. ScienceDaily, 24 March 2014. <www.sciencedaily.com/releases/2014/03/140324154011.htm>.
University of Cambridge. (2014, March 24). Hunt for an unidentified electron object. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2014/03/140324154011.htm
University of Cambridge. "Hunt for an unidentified electron object." ScienceDaily. www.sciencedaily.com/releases/2014/03/140324154011.htm (accessed October 1, 2014).

Share This



More Matter & Energy News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

US Police Put Body Cameras to the Test

US Police Put Body Cameras to the Test

AFP (Oct. 1, 2014) — Police body cameras are gradually being rolled out across the US, with interest surging after the fatal police shooting in August of an unarmed black teenager. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com
Argentina's Tax Evaders Detected, Hunted Down by Drones

Argentina's Tax Evaders Detected, Hunted Down by Drones

AFP (Sep. 30, 2014) — Argentina doesn't only have Lionel Messi the footballer, it has now also acquired "Mesi" the drone system which monitors undeclared mansions, swimming pools and soy fields to curb tax evasion in the country. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Do Video Games Trump Brain Training For Cognitive Boosts?

Do Video Games Trump Brain Training For Cognitive Boosts?

Newsy (Sep. 29, 2014) — More and more studies are showing positive benefits to playing video games, but the jury is still out on brain training programs. Video provided by Newsy
Powered by NewsLook.com
CERN Celebrates 60 Years of Science

CERN Celebrates 60 Years of Science

Reuters - Business Video Online (Sep. 29, 2014) — CERN, the European Organisation for Nuclear Research, celebrates 60 years of bringing nations together through science. As Joanna Partridge reports from inside the famous science centre it's also planning to turn the Large Hadron Collider particle accelerator back on after an upgrade. Video provided by Reuters
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