Featured Research

from universities, journals, and other organizations

First direct evidence of 'spin symmetry' in atoms

Date:
August 21, 2014
Source:
National Institute of Standards and Technology (NIST)
Summary:
Physicists have observed the first direct evidence of symmetry in the magnetic properties -- or nuclear 'spins' -- of atoms. The advance could spin off practical benefits such as the ability to simulate and better understand exotic materials such as superconductors.

This is an illustration of symmetry in the magnetic properties -- or nuclear 'spins' -- of strontium atoms. JILA researchers observed that if two atoms have the same nuclear spin state (top), they interact weakly, and the interaction strength does not depend on which of the 10 possible nuclear spin states are involved. If the atoms have different nuclear spin states (bottom), they interact much more strongly, and, again, always with the same strength.
Credit: Ye and Rey groups and Steve Burrows/JILA

Just as diamonds with perfect symmetry may be unusually brilliant jewels, the quantum world has a symmetrical splendor of high scientific value.

Confirming this exotic quantum physics theory, JILA physicists led by theorist Ana Maria Rey and experimentalist Jun Ye have observed the first direct evidence of symmetry in the magnetic properties -- or nuclear "spins" -- of atoms. The advance could spin off practical benefits such as the ability to simulate and better understand exotic materials exhibiting phenomena such as superconductivity (electrical flow without resistance) and colossal magneto-resistance (drastic change in electrical flow in the presence of a magnetic field).

The JILA discovery, described in Science Express, was made possible by the ultra-stable laser used to measure properties of the world's most precise and stable atomic clock. JILA is jointly operated by the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder.

"Spin symmetry has a very strong impact on materials science, as it can give rise to unexpected behaviors in quantum matter," JILA/NIST Fellow Jun Ye says. "Because our clock is this good -- really it's the laser that's this good -- we can probe this interaction and its underlying symmetry, which is at a very small energy scale."

The global quest to document quantum symmetry looks at whether key properties remain the same despite various exchanges, rotations or reflections. For example, matter and antimatter demonstrate fundamental symmetry: Antimatter behaves in many respects like normal matter despite having the charges of positrons and electrons reversed.

To detect spin symmetry, JILA researchers used an atomic clock made of 600 to 3,000 strontium atoms trapped by laser light. Strontium atoms have 10 possible nuclear spin configurations (also referred to as angular momentum), which influences magnetic behavior. In a collection of clock atoms there is a random distribution of all 10 states.

The researchers analyzed how atom interactions -- their collisions -- at the two electronic energy levels used as the clock "ticks" were affected by the spin state of the atoms' nuclei. In most atoms, the electronic and nuclear spin states are coupled, so atom collisions depend on both electronic and nuclear states. But in strontium, the JILA team predicted and confirmed that this coupling vanishes, giving rise to collisions that are independent of nuclear spin states.

In the clock, all the atoms tend to be in identical electronic states. Using lasers and magnetic fields to manipulate the nuclear spins, the JILA researchers observed that, when two atoms have different nuclear spin states, no matter which of the 10 states they have, they will interact (collide) with the same strength. However, when two atoms have the same nuclear spin state, regardless of what that state is, they will interact much more weakly.

"Spin symmetry here means atom interactions, at their most basic level, are independent of their nuclear spin states," Ye explains. "However, the intriguing part is that while the nuclear spin does not participate directly in the electronic-mediated interaction process, it still controls how atoms approach each other physically. This means that, by controlling the nuclear spins of two atoms to be the same or different, we can control interactions, or collisions."

The new research adds to understanding of atom collisions in atomic clocks documented in previous JILA studies. Further research is planned to engineer specific spin conditions to explore novel quantum dynamics of a large collection of atoms.

JILA theorist Ana Maria Rey made key predictions and calculations for the study. Theorists at the University of Innsbruck in Austria and the University of Delaware also contributed. Funding was provided by NIST, the National Science Foundation, the Air Force Office of Scientific Research, and the Defense Advanced Research Projects Agency.


Story Source:

The above story is based on materials provided by National Institute of Standards and Technology (NIST). Note: Materials may be edited for content and length.


Journal Reference:

  1. X. Zhang, M. Bishof, S. L. Bromley, C.V. Kraus, M. S. Safronova, P. Zoller, A. M. Rey, and J. Ye. Spectroscopic observation of SU(N)-symmetric interactions in Sr orbital magnetism. Science, Published online 21 August 2014 DOI: 10.1126/science.1254978

Cite This Page:

National Institute of Standards and Technology (NIST). "First direct evidence of 'spin symmetry' in atoms." ScienceDaily. ScienceDaily, 21 August 2014. <www.sciencedaily.com/releases/2014/08/140821141436.htm>.
National Institute of Standards and Technology (NIST). (2014, August 21). First direct evidence of 'spin symmetry' in atoms. ScienceDaily. Retrieved September 14, 2014 from www.sciencedaily.com/releases/2014/08/140821141436.htm
National Institute of Standards and Technology (NIST). "First direct evidence of 'spin symmetry' in atoms." ScienceDaily. www.sciencedaily.com/releases/2014/08/140821141436.htm (accessed September 14, 2014).

Share This



More Matter & Energy News

Sunday, September 14, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Scientists Have Captured The Sound Of An Atom

Scientists Have Captured The Sound Of An Atom

Newsy (Sep. 12, 2014) Scientists have captured the sound of a single atom by measuring its vibrations. We can't hear it, but it's reportedly the faintest sound possible. Video provided by Newsy
Powered by NewsLook.com
Solar Flare Surges Off Sun

Solar Flare Surges Off Sun

Reuters - US Online Video (Sep. 11, 2014) NASA captures video of a significant flare surging off the sun. Jillian Kitchener reports. Video provided by Reuters
Powered by NewsLook.com
Soccer Players' Feet to Generate Electricity

Soccer Players' Feet to Generate Electricity

AP (Sep. 11, 2014) A new energy-generating soccer field was inaugurated in Brazil. The field is built on energy-capturing tiles, allowing players to generate electricity as they run and compete. (Sept. 11) Video provided by AP
Powered by NewsLook.com
Doctor: Poor Protective Gear Hurts Ebola Fight

Doctor: Poor Protective Gear Hurts Ebola Fight

AP (Sep. 11, 2014) Infectious disease specialist Dr. Dan Lucey is just back from Sierra Leone, where he treated Ebola patients and experienced firsthand the extensive challenges facing health care workers. (Sept. 11) Video provided by AP
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:
from the past week

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