Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Physicists: Quantum Dance Draws Unexpected Guests

31.07.2007
It was always thought to be restricted to everyday types, with no magnetic sorts allowed in the door.

But the quantum dance party’s guest list just got bigger.

In a paper that appeared Friday in the online edition of Physical Review Letters, University of Florida physicists report that — contrary to expectations — electrons in magnetic metals exhibit the same quantum tendencies as their counterparts in ordinary metals at extremely low temperatures. Rather than acting like particles that move independently of each other, they behave as waves, influencing each other’s paths and trajectories.

The effect is a bit like a roomful of dancers performing, arm-in-arm, a frenetic set piece.

The electrons push and pull each other around, then return to the spot where they started off, as though completing a choreographed finale.

Call it “the wave.”

“They move around and have these elastic collisions, and then they remember they are waves, and they end up back in the same place they started,” said Art Hebard, a UF professor of physics and one of four co-authors of the paper.

It is an accepted fact in condensed matter physics, the branch of physics that studies the physical properties of matter, that electrons in ordinary metals can act as waves. This behavior is seen at extremely low temperatures of hundreds of degrees below zero, when random collisions are reduced to a minimum. “Quantum” refers to the electrons’ schizophrenic ability to behave both as the independent particles they are, and as waves, with each electron’s “ripple” affecting those of neighboring electrons and vice versa.

Physicists had long suspected that electrons in magnetic metals would not share this trait, since magnetic fields would interfere or, in Hebard’s words, “scramble up” the peaks and troughs in the waves.

Add the magnetic field, they thought, and it would be like Judas Priest crashing a waltz. All the dancers would scatter.

But Hebard and the other scientists found to their surprise that the dancing electrons in magnetic iron kept up their routines, seemingly oblivious to the change in atmospherics.

With the aid of a one-of-a-kind apparatus called Sample Handling in Vacuum, or SHIVA, they grew extremely thin films of iron — films thousands of times thinner than a human hair. The stainless steel apparatus maintains an ultra high vacuum to guard against humid air, which would cause them to rust immediately and become useless. The physicists relied on such thin films because they could observe the quantum effects much more easily in near two-dimensional samples, rather than the three dimensions that would come with thicker samples.

The scientists then wielded multiple mechanical arms within the $180,000 machine — the SHIVA name is intentionally reminiscent of the many-armed Indian god — to transfer the films to a test chamber. There, at a temperature of minus 452 degrees Fahrenheit, they submitted the films to tests, including applying magnetic fields as strong as 140,000 times the earth’s magnetic field.

The end result: The physicists observed a “signature response” as electrical currents flowed through the films, giving away the fact that the electrons were doing the quantum dance.

“What I find most remarkable about this work is that it shows that electrons do not really have one-to-one encounters,” said Dmitrii Maslov, a UF professor of physics. “The ‘collective’ versus ‘one-to-one’ interactions are now being seen in many materials of practical interest, and Prof. Hebard’s study gives an important contribution to this emerging field.”

Hebard said physicists believe the electrons in the magnetic iron continue to act like waves because of the presence of magnetic interactions that previously were not considered relevant.

The findings have no immediate practical application. But with computer chips and other modern electronics based on thin metals and how they interact, that could change in the future. “We’re asking fundamental questions about magnets,” Hebard said. “And magnetic materials are used in many applications.”

The lead author of the Physical Review Letters paper is Partha Mitra, who performed the experimental research as a doctoral student at UF and who is now a postdoctoral associate at The Pennsylvania State University. The other authors are UF doctoral student Rajiv Misra, Khandker Muttalib, a UF faculty member in theoretical physics, and Peter Wolfle, also a theoretical physicist, of the Universitat Karlsruhe in Germany.

| newswise
Further information:
http://www.ufl.edu

More articles from Physics and Astronomy:

nachricht When fluid flows almost as fast as light -- with quantum rotation
22.06.2018 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

nachricht Thermal Radiation from Tiny Particles
22.06.2018 | Universität Greifswald

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: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>