Impurities in materials are responsible for the colours of gemstones or the performance of modern semiconductors. The same applies to quantum systems, although it has hardly been researched in this field. For the first time, Kaiserslautern researchers were able to implant individual impurities formed by caesium atoms into an ultracold quantum gas of rubidium atoms in a controlled manner. They observed how the impurities exchange quantum mechanical angular momentum (spin) with the gas. They also demonstrated that caesium atoms can store quantum information. This has not been possible so far. The study was published in the renowned journal “Physical Review Letters.”
Individual atomic impurities are also present in other materials, for example in gemstones. They are responsible for various effects in quantum physics and are therefore interesting for experiments. At the TUK, physicists led by Professor Dr. Artur Widera and his doctoral student Felix Schmidt have now observed for the first time how such impurities behave in a Bose-Einstein condensate of rubidium atoms.
“In physics, this refers to a state of matter that is comparable with liquid and gaseous states. However, such a condensate is a perfect quantum mechanical state that behaves like a wave,” says Professor Widera, who heads the Individual Quantum Systems group.
For physicists, Bose-Einstein condensates are a popular model for investigating quantum effects - similar to the fruit fly Drosophila which is used in biology and medicine as a model organism to answer genetic questions.
In their current study, the Kaiserslautern physicists have investigated such a contamination in a quantum gas. They cool it down to temperatures close to the absolute zero point of -273.15° Celsius. “In this way, we can control a quantum mechanical system,” says first author Felix Schmidt. The researchers used caesium atoms as an impurity. Five to ten caesium atoms have been immersed in a Bose-Einstein condensate of around 10,000 rubidium atoms.
“The system can be examined under a microscope. The ultracold gas has a size of ten micrometres,” continues the doctoral student. The researchers have thus localized individual impurities and observed the change in their electronic structure, the so-called spin, through interaction with the quantum gas. “So far it has not been possible to observe individual atoms in such a gas. We are pleased that we succeeded in the experiment,” says Schmidt.
The researchers have also investigated whether caesium atoms can be used as information carriers and simultaneously cooled in quantum gas. “For atoms to store information, their electronic state must be preserved,” explains Widera.
“However, since the condensate interacts with the other atoms, there is a risk that they may lose sensitive information as a result of impact.” The researchers have now succeeded for the first time in cooling the impurity atoms in the quantum gas without losing quantum information.
“The model of individual impurities in an ultracold gas realizes a paradigm of quantum physics,” says Professor Widera. “It can serve as a starting point for a variety of other quantum experiments.” In particular, the findings of the Kaiserslautern scientists help to better understand what is happening at the quantum level.
This could play a role in the future, for example, in understanding superconductors and developing new materials. They could transport electricity over long distances without great energy loss at normal ambient temperatures. So far, this has only been possible at temperatures well below freezing point.
The study was published in the renowned journal Physical Review Letters: “Quantum spin dynamics of individual neutral impurities coupled to a Bose-Einstein condensate.” Felix Schmidt, Daniel Mayer, Quentin Bouton, Daniel Adam, Tobias Lausch, Nicolas Spethmann, and Artur Widera. Phys. Rev. Lett. 121, 130403
Widera and his doctoral student Felix Schmidt are researching quantum systems. The physicists at the State Research Centre for Optics and Materials Science (OPTIMAS) also work interdisciplinary with working groups from the area of chemistry, mechanical engineering and process engineering as well as electrical engineering and information technology in order to transfer basic research into applications.
Prof Dr Artur Widera
Department for Individual Quantum Systems
Phone: +49(0)631 205-4130
Phone: +49(0)631 205-5272
Quantum spin dynamics of individual neutral impurities coupled to a Bose-Einstein condensate. Felix Schmidt, Daniel Mayer, Quentin Bouton, Daniel Adam, Tobias Lausch, Nicolas Spethmann, and Artur Widera. Phys. Rev. Lett. 121, 130403
Melanie Löw | Technische Universität Kaiserslautern
Extremely close look at electron advances frontiers in particle physics
18.10.2018 | National Science Foundation
Blue phosphorus -- mapped and measured for the first time
16.10.2018 | Helmholtz-Zentrum Berlin für Materialien und Energie
Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz (Germany) together with scientists from Dresden, Leipzig, Sofia (Bulgaria) and Madrid (Spain) have now developed and characterized a novel, metal-organic material which displays electrical properties mimicking those of highly crystalline silicon. The material which can easily be fabricated at room temperature could serve as a replacement for expensive conventional inorganic materials used in optoelectronics.
Silicon, a so called semiconductor, is currently widely employed for the development of components such as solar cells, LEDs or computer chips. High purity...
Augsburg chemists present a new technology for compressing, storing and transporting highly volatile gases in porous frameworks/New prospects for gas-powered vehicles
Storage of highly volatile gases has always been a major technological challenge, not least for use in the automotive sector, for, for example, methane or...
When we put water in a freezer, water molecules crystallize and form ice. This change from one phase of matter to another is called a phase transition. While this transition, and countless others that occur in nature, typically takes place at the same fixed conditions, such as the freezing point, one can ask how it can be influenced in a controlled way.
We are all familiar with such control of the freezing transition, as it is an essential ingredient in the art of making a sorbet or a slushy. To make a cold...
Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed...
Das Zusammenspiel aus Struktur und Dynamik bestimmt die Funktion von Proteinen, den molekularen Werkzeugen der Zelle. Durch Fortschritte in der...
17.10.2018 | Event News
16.10.2018 | Event News
02.10.2018 | Event News
18.10.2018 | Life Sciences
18.10.2018 | Earth Sciences
18.10.2018 | Life Sciences