Giant atom eats quantum gas

October 31, 2013
Giant atom eats quantum gas
Illustration of the system investigated: A highly excited Rydberg-atom, consisting of a single electron (blue), traveling on a large orbit far from the positively charged core (red). The Rydberg atom has the same spatial extent as the ultracold atomic cloud. The single electron is exciting oscillations, so called phonons, in the surrounding quantum gas.

A team of experimental and theoretical physicists from the University of Stuttgart studied a single micrometer sized atom. This atom contains tens of thousands of normal atoms in its electron orbital. These results have been published in the journal Nature.

The interaction of electrons and matter is fundamental to material properties such as electrical conductivity. Electrons are scattering from of the surrounding matter and can excite lattice oscillations, so called phonons, thereby transferring energy to the environment. The electron is therefore slowed which causes electrical resistance. However, in certain materials phonons can surprisingly cause the opposite effect, so called superconductivity, where the drops to zero. Understanding the interaction of electrons and matter is therefore important goal in order to both answer fundamental questions as well as to solve technical problems.

A single electron is best suited for systematic investigations of such processes. For the first time, physicists from Stuttgart have now realized a model system in the laboratory, where the interaction of a single electron with many atoms inside its orbital can be studied. These atoms are from an ultracold cloud near absolute zero, a so called Bose-Einstein condensate.

The basic idea now is simple: Instead of using a technically challenging electron trap, the scientists are using the fact that in nature are bound to a positively charged atomic core. In a classical picture, they are travelling on ellipsoidal orbits around the core. These orbits are usually very small, typically in the range below one nanometer. In order to achieve an interaction between an electron and many atoms, an atom is excited from a cloud consisting of 100.000 atoms using laser light. The orbit of a single electron then expands to several micrometers and a Rydberg atom is formed. On atomic length scales, this atom is huge, larger than most bacteria, which are consisting each of several billions to trillions of atoms. The Rydberg atom is then containing tens of thousands of atoms from the cold cloud. Thus, a situation is realized where the electron is trapped in a defined volume and at the same time interacts with a large number of atoms. This interaction is so strong that the whole atomic cloud, consisting of 100,000 atoms is considerably influenced by the single electron. Depending on its quantum state the electron excites phonons in the atomic cloud, which can be measured as collective oscillations of the whole cloud culminating in a loss of atoms from the trap.

The experimental observations in the group of Prof. Tilman Pfau could so far largely be explained by collaborative work with the theory group of Prof. Hans Peter Büchler. However, this work is only the basis for a series of further exciting experiments. According to the previous studies an electron is leaving a clear trace in the surrounding atomic cloud. Therefore imaging a single electron in a well defined quantum state seems to be feasible. Due to the impact on various fields, including quantum optics, these results were published in the highly respected journal Nature.

Explore further: Physicists find charge separation in a molecule consisting of two identical atoms

More information: Balewski, J. et al. Coupling a single electron to a Bose-Einstein condensate, Nature. DOI: 10.1038/nature12592

Related Stories

Researchers propose a new system for quantum simulation

September 3, 2013

Researchers from the universities in Mainz, Frankfurt, Hamburg and Ulm have proposed a new platform for quantum simulation. In a theoretical paper recently published in Physical Review Letters, they show that a combined system ...

New technique traces ejected electrons back to atomic shells

October 2, 2013

(Phys.org) —In a detailed study of how intense light strips electrons from atoms, researchers used an X-ray laser, SLAC's Linac Coherent Light Source (LCLS), to measure and sort the ejected electrons and discover how this ...

Recommended for you

New blow for 'supersymmetry' physics theory

July 27, 2015

In a new blow for the futuristic "supersymmetry" theory of the universe's basic anatomy, experts reported fresh evidence Monday of subatomic activity consistent with the mainstream Standard Model of particle physics.

Rogue wave theory to save ships

July 29, 2015

Physicists have found an explanation for rogue waves in the ocean and hope their theory will lead to devices to warn ships and save lives.

Researchers build bacteria's photosynthetic engine

July 29, 2015

Nearly all life on Earth depends on photosynthesis, the conversion of light energy into chemical energy. Oxygen-producing plants and cyanobacteria perfected this process 2.7 billion years ago. But the first photosynthetic ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

beleg
1 / 5 (1) Nov 03, 2013
Is this applicable to a leviton?
http://phys.org/n...ton.html

Is a electron Bose-Einstein condensate a permissible or possible?
beleg
1 / 5 (1) Nov 03, 2013
Typo:
Is a electron Bose-Einstein condensate... [ ]... permissible or possible?
"a" is deleted.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.