Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Physicists investigate the formation of defects during phase transitions in crystals of ions

12.08.2013
Recent research findings are relevant to a model of matter structure formation tiny fractions of a second after the Big Bang

Research groups at Johannes Gutenberg University Mainz (JGU) and the Physical-Technical Federal Institute (PTB) in Braunschweig, working in collaboration with scientists at the University of Ulm and The Hebrew University of Jerusalem, have been investigating the formation of defects occurring when a Coulomb crystal of ions is driven through a second-order phase transition.

For this purpose, they compressed one-dimensional linear chains of ions at high speeds to form a two-dimensional zigzag structure with a form similar to that of an accordion. This process can lead to the generation of defects in the resultant crystal structure. The probability of such defects forming is determined by the speed of the phase transition. The Kibble-Zurek mechanism, which describes the formation of such defects, is universal as it plays an important role in many physical systems. Among other things, this mechanism is the basis of one theory of how matter was created 10 to the power of minus 30 seconds after the Big Bang. The experiments undertaken in Mainz investigated and analyzed this effect with a hitherto unrivalled precision.

The Mainz research team from the Quantum, Atomic, and Neutron Physics (QUANTUM) work group of the Institute of Physics at Mainz University trapped 16 ions in a Paul trap. In this form of trap, ions are confined to a very small space with the aid of electric fields where they arrange themselves in a sequence like pearls in a necklace. The next step is to drastically reduce the space in which the ions are confined so that the ion chain is compressed and becomes folded to form a zigzag structure. However, the ions can assume a particular zigzag pattern or its mirror-inverted version. If one half of the ion chain takes on a different structure to that of the other half of the ion chain, the two patterns that are the opposite of each other will meet in the middle. Since the two different patterns cannot join perfectly, there will be a defect in the crystal structure right at this point.

Due to the form of the trapping potential, the phase transition first occurs in the center of the ion chain and is then transmitted from the center to the ends of the crystal. If the rate of this transmission is faster than the speed of the exchange of information between two neighboring ions, one of these ions will not be able to orientate itself on the basis of its neighbor's structure and will arrange itself randomly. This is why the probability of such defects occurring is significantly determined by the rate at which the phase transition occurs. The speed can be precisely controlled and varied in ion traps, which allowed the Mainz and Braunschweig researchers to determine the rate at which defects occurred relative to phase transition speed. The experimental findings confirm the hypothetical assumptions on which the Kibble-Zurek mechanism is based at a 2 percent level of significance.

Publications:
S. Ulm, J. Roßnagel, G. Jacob, C. Degünther, S.T. Dawkins, U.G. Poschinger, R. Nigmatullin, A. Retzker, M.B. Plenio, F. Schmidt-Kaler, K. Singer¬¬¬
Observation of the Kibble–Zurek scaling law for defect formation in ion crystals
Nature Communications 4, 2290 (2013)
http://www.nature.com/ncomms/2013/130807/ncomms3290/full/ncomms3290.html
[arXiv:1302.5343]
K. Pyka, J. Keller, H. L. Partner, R. Nigmatullin, T. Burgermeister, D.-M. Meier, K. Kuhlmann, A. Retzker, M.B. Plenio, W.H. Zurek, A. del Campo, T.E. Mehlstäubler
Topological defect formation and spontaneous symmetry breaking in ion Coulomb crystals
Nature Communications 4, 2291 (2013)
http://www.nature.com/ncomms/2013/130807/ncomms3291/full/ncomms3291.html
[arXiv:1211.7005]
Image:
www.uni-mainz.de/bilder_presse/08_physik_kibble-zurek-mechanismus.jpg
Diagram of the ion trap employed. The ions are held in place by the electrical fields between the gold-plated electrodes. The image of the ionic crystal with defect has been massively enlarged.

image/©: QUANTUM, JGU

Related links:
http://www.quantenbit.de – "Cold Ions and Experimental Quantum Information" work group
http://www.quantum.physik.uni-mainz.de/index_ENG.php – QUANTUM work group
http://www.quantummetrology.de – Center for Quantum Engineering and Space-Time Research
Further information:
Dipl.-Phys. Stefan Ulm
QUANTUM work group
Institute of Physics
Johannes Gutenberg University Mainz (JGU)
D 55099 Mainz, GERMANY
phone +49 6131 39-23671
fax +49 6131 39-25179
e-mail: ulmst@uni-mainz.de

Petra Giegerich | idw
Further information:
http://www.quantenbit.de/
http://www.uni-mainz.de/presse/16629_ENG_HTML.php

More articles from Physics and Astronomy:

nachricht Researchers discover link between magnetic field strength and temperature
21.08.2018 | American Institute of Physics

nachricht Smallest transistor worldwide switches current with a single atom in solid electrolyte
17.08.2018 | Karlsruher Institut für Technologie (KIT)

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: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Air pollution leads to cardiovascular diseases

21.08.2018 | Ecology, The Environment and Conservation

Researchers target protein that protects bacteria's DNA 'recipes'

21.08.2018 | Life Sciences

A paper battery powered by bacteria

21.08.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>