An icy gaze into the Big Bang

An icy gaze into the Big Bang
The research group led by Rudolf Grimm reports on a first experimental step into the strongly interacting regime of an ultracold Fermi-Fermi mixture. Graphics: Ritsch

( -- Scientists of the Institute for Quantum Optics and Quantum Information (IQOQI) in Innsbruck, Austria, have reached a milestone in the exploration of quantum gas mixtures. In an international first, the research group led by Rudolf Grimm and Florian Schreck has succeeded in producing controlled strong interactions between two fermionic elements - lithium-6 and potassium-40. This model system not only promises to provide new insights into solid-state physics but also shows intriguing analogies to the primordial substance right after the Big Bang.

According to theory, the whole universe consisted of quark-gluon plasma in the first split seconds after the Big Bang. On the earth this cosmic primordial "soup" can be observed in big particle accelerators when, for example, the nuclei of lead atoms are accelerated to nearly the speed of light and smashed into each other, which results in particle showers that are investigated with detectors. Now the group of quantum physicists led by Prof. Rudolf Grimm and PhD Florian Schreck from the Institute for and (IQOQI) of the Austrian Academy of Sciences together with Italian and Australian researchers has for the first time achieved strong controlled interactions between clouds of lithium-6 and potassium-40 atoms. Hence, they have established a model system that behaves in a similar way as the quark-gluon plasma, whose energy scale has a twenty times higher order of magnitude.

Explanations by Rudolf Grimm and Florian Schreck. Credit: IQOQI.

Hydrodynamic expansion

In 2008 already, the Innsbruck physicists found Feshbach resonances in an ultracold gas mixture consisting of lithium and potassium atoms, which they have used to modify quantum mechanical interactions between particles in a controlled way by applying a magnetic field. In the meantime, they have overcome all technical challenges and are now the first to also produce strong interactions between those particles. “The magnetic fields have to be adjusted precisely to one in 100000 and controlled accurately to achieve this result,“ explains Florian Schreck.

In the experiment the physicists prepare the ultracold gases of lithium-6 (Li) and potassium-40 (K) atoms in an optical trap and overlap them, with the smaller cloud of heavier K atoms residing in the centre of the Li cloud. After turning off the trap, the researchers observe the expansion of the quantum gases at different magnetic fields. “When the particles show a strong interaction, the gas clouds behave hydrodynamically,“ says Schreck. “An elliptical nucleus is formed in the centre of the particle cloud, where the potassium and lithium atoms interact. Moreover, the expansion velocity of the particles, which are different initially, become equal.“ According to theory, both phenomena suggest hydrodynamic behavior of the mixture. “This behavior is the most striking phenomenon observed in quantum gases, when particles strongly interact,“ says Rudolf Grimm. “Therefore, this experiment opens up new research areas in the field of many-body physics.“

New possibilities for exciting experiments

High energy physicists have made these two observations as well when producing quark-gluon plasmas in particle accelerators. The Innsbruck quantum gas experiment can be regarded as a model system to investigate cosmic phenomena that occurred immediately after the Big Bang. “In addition and above all, we can also use this system to address many questions of solid-state physics,“ says Rudolf Grimm, who is going to further explore the quantum gas mixture with his research group. “The big goal is to produce quantum condensates, such as Bose-Einstein condensates consisting of molecules made up of lithium and . This will tremendously increase our capabilities to realize novel states of matter.“

The physicists have published their findings in the scientific journal Physical Review Letters.

Explore further

Ultracold chemistry: First direct observation of exchange process in quantum gas

More information: Hydrodynamic Expansion of a Strongly Interacting Fermi-Fermi Mixture. A. Trenkwalder, C. Kohstall, M. Zaccanti, D. Naik, A. I. Sidorov, F. Schreck, R. Grimm. Physical Review Letters 106, 115304 (2011), DOI: 10.1103/PhysRevLett.106.115304
Provided by Austrian Academy of Sciences
Citation: An icy gaze into the Big Bang (2011, March 18) retrieved 21 August 2019 from
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User comments

Mar 18, 2011
I dont believe in the big bang either, but this guy is a total idiot.

Mar 18, 2011
total idiot created the universe

i dont believe in god sorry. and you are not god either.

Mar 18, 2011
Please toddle down to your local clinic and pick up your prescription, you've obviously run out...

Mar 18, 2011
Who else thinks this malamucika just escaped from a mental institution?

edit: thank you mods

Mar 18, 2011
The Big Bang story is just a modern myth that once had some compelling correspondences with observation and theory but that now requires huge leaps of faith into inflation theory, non-existent GUTs, dark matter that is simply supposed to be there and dark energy conjured up from whole cloth to prop up a theory that weakens with every deep field observation.

I sometimes wonder if cosmologists observe, calculate or pray...bring on James Webb!!

BTW the lowest point in the history of Cosmology is Smoot's remark about the wrinkles in the CMBR "like looking into the face of God". In 'Wrinkles in Time' he refers to 'saving the Big Bang theory'. Scientists are supposed to be 'disinterested' or 'objective and aloof', not interested in defending favoured positions but discovering what is really there, hence smoot was more of a religio-philosopher than cosmologist ~ shame on him.

Mar 19, 2011
I wonder just how many scientists have commented above? I for one also doubt the Big Bang theory, but then just how does the science dictionary define the Big Band? I believe that since the universe is composed of Dark Matter and Dark Energy, it makes sense that perhaps Black Holes are the result of action of Dark Matter and the reaction with Dark Energy. I tend to believe that a Dark Hole was created and sucked more dark matter and created an output of all of the visible universe.

Mar 22, 2011
The Big Bang story is just a modern myth that once had some compelling correspondences with observation and theory but that now requires huge leaps of faith...

Since the universe is expanding, what happens if you push the rewind button?

Where did the microwave background radiation come from?

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