Posted in | Quantum Physics

New Technique to Control Quantum States of Individual Atoms

A team of researchers at the Center for Quantum Nanoscience (QNS) has made a significant discovery in controlling the quantum properties of individual atoms.

QNS researchers, in an international collaboration with IBM Research in San Jose, USA, used novel and sophisticated methods to identify the type of mechanisms that destroy the quantum properties of single atoms. They achieved this by exploiting the magnetic state of an individual iron atom on a thin insulator. Using a Scanning Tunneling Microscope, which uses an atomically sharp metal tip, the researchers precisely measured single iron atoms and also measured and controlled the time taken by the iron atom to sustain its quantum behavior.

Illustration: The metallic tip of a scanning tunneling microscope is used to drive the magnetic quantum state of an iron atom into a different direction. (Credit: IBS)

The results of the study were reported in the journal Science Advances which demonstrate that the loss in quantum state superposition is primary caused by nearby electrons that were injected by the researchers with extreme control into the iron atom.                                                    

We found that almost every electron destroys the quantum state. In addition, we found that nearby fluctuating magnets had a similar negative impact. While our experiments decreased the state of superposition on purpose, it also gave us valuable clues on how to improve atoms' quantum states.

Dr. Philip Willke, First Author of the study

Andreas Heinrich, Director of the IBS Center for Quantum Nanoscience added, "Understanding these destructive interactions allows us to avoid them in future experiments and improve the performance of magnetic quantum sensors that, in this case, only consist of a single atom."

Quantum nanoscience depends on leveraging the properties of molecules and atoms for potential developments in quantum sensing, possibly enhancing the devices using such technology, including hospital MRI machines.

The research could also benefit quantum computers. While quantum computation is still in early development, it promises to considerably surpass traditional computers in tasks such as search, database management, and optimization. At its core lies the fact that it is possible for a quantum system to be in two quantum states simultaneously – an effect known as the superposition of quantum states. Yet, this superposition of states is easily destroyed when such a quantum system interacts in specific environments - either through desired or undesired contact. For quantum nanoscientists, this principle makes it very important to comprehend and control these processes.

Located on the campus of Ewha University in Seoul, the IBS Center for Quantum Nanoscience is a pioneering research center that merges nanoscience and Quantum to push the boundaries of human knowledge in basic study. Driven by Korea’s Institute for Basic Science, which was established in 2011, the Center for Quantum Nanoscience explores the behavior of molecules and atoms on surfaces, surpassing the potential of the tiniest building blocks humans can use to produce engineered Quantum. Headed by Andreas Heinrich (A Boy and His Atom, IBM, 2013), a world-renowned physicist, QNS is dedicated to bringing leading researchers from around the globe to its sophisticated facility to perform  research that will unlock the mysteries of the quantum universe.

Philip Willke,William Paul, Fabian D. Natterer, Kai Yang, Yujeong Bae,Taeyoung Choi,Joaquin ernández-Rossier,Andreas J. Heinrich,Christoper P. Lutz. Probing quantum coherence in single-atom Science Advances (2018). DOI: 10.1126/sciadv.aaq1543

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