This site uses cookies. By continuing to use this site you agree to our use of cookies. To find out more, see our Privacy and Cookies policy.
Skip to the content

Share this

Free weekly newswire

Sign up to receive all our latest news direct to your inbox.

Physics on film

100 Second Science Your scientific questions answered simply by specialists in less than 100 seconds.

Watch now

Bright Recruits

At all stages of your career – whether you're an undergraduate, graduate, researcher or industry professional – can help find the job for you.

Find your perfect job

Physics connect

Are you looking for a supplier? Physics Connect lists thousands of scientific companies, businesses, non-profit organizations, institutions and experts worldwide.

Start your search today


A triplet of rovibrational ground states

The weakly bound rubidium molecules (upper image) are transferred into the rovibrational ground state with a STIRAP laser pulse. (Courtesy: Austrian Academy of Sciences).

By Hamish Johnston

Rovibrational ground states are a bit like buses — you wait a long time for nothing and then three come along one after another.

A few weeks ago, we reported on the first realization of a quantum gas of ultracold polar molecules by Deborah Jin, Jun Ye and colleagues at JILA in Boulder, Colorado.

The big challenge in creating the 350-nK gas was to put the potassium-rubidium molecules into their “rovibrational” ground state, where they have the smallest amount of rotational and vibrational energy allowed by quantum mechanics.

Normally, the molecules heat up the gas when they give up their excess rovibrational energy. Jin and Ye avoided this by using lasers to get the molecules to give up their energy as light that exits the gas without heating it — a technique called “stimulated Raman adiabatic passage” (STIRAP).

Now, Rudi Grimm and Johannes Hecker Denschlag at the Austrian Academy of Sciences have used the same technique to create an ultracold gas of rubidium-rubidium molecules in the “triplet” rovibrational ground state (Phys. Rev. Lett. 101 133305). Such a triplet state is interesting because the molecules have large magnetic moments, and therefore the gas could be useful as a “quantum simulator” of solid magnetic materials.

In the same issue of Physical Review Letters, Matthias Weidemueller and colleagues at Germany’s University of Freiburg explained how they created an ultracold gas of lithium-caesium molecules in the rovibrational ground state (Phys. Rev. Lett. 101 133304).

Like the potasium-rubidium, lithium-caesium molecules have electric dipole moments — which means that they could someday be used as quantum bits that are controlled by the simple application of an electric field.

This entry was posted in General. Bookmark the permalink.
View all posts by this author  | View this author's profile

One comment to A triplet of rovibrational ground states

  1. this is still far from equilibrium


  • Comments should be relevant to the article and not be used to promote your own work, products or services.
  • Please keep your comments brief (we recommend a maximum of 250 words).
  • We reserve the right to remove excessively long, inappropriate or offensive entries.

Show/hide formatting guidelines

Tag Description Example Output
<a> Hyperlink <a href="">google</a> google
<abbr> Abbreviation <abbr title="World Health Organisation" >WHO</abbr> WHO
<acronym> Acronym <acronym title="as soon as possible">ASAP</acronym> ASAP
<b> Bold <b>Some text</b> Some text
<blockquote> Quoted from another source <blockquote cite="">IOP</blockquote>
<cite> Cite <cite>Diagram 1</cite> Diagram 1
<del> Deleted text From this line<del datetime="2012-12-17"> this text was deleted</del> From this line this text was deleted
<em> Emphasized text In this line<em> this text was emphasised</em> In this line this text was emphasised
<i> Italic <i>Some text</i> Some text
<q> Quotation WWF goal is to build a future <q cite="">
where people live in harmony with nature and animals</q>
WWF goal is to build a future
where people live in harmony with nature and animals
<strike> Strike text <strike>Some text</strike> Some text
<strong> Stronger emphasis of text <strong>Some text</strong> Some text