Title: Researchers at Universität Hamburg Observe Elusive Quantum State Predicted 50 Years Ago
Subtitle: Artificial atoms and superconductivity pave the way for nanoscale electronic devices.
Hamburg, Germany – A team of researchers from the Department of Physics at Universität Hamburg has successfully observed a quantum state that was theorized over half a century ago by Japanese scientists. By manipulating an artificial atom on a superconductor’s surface, the scientists achieved electron pairing in the smallest possible version of a superconductor. The groundbreaking research, published in the journal Nature, carries significant implications for the development of nanostructured electronic devices.
Electrons typically repel each other due to their negative charge, impacting material properties such as electrical resistance. However, when electrons are paired and form bosonic pairs, their behavior changes drastically. Bosonic pairs do not avoid each other like individual electrons but can reside in the same location or perform the same motion. This unique characteristic gives rise to superconductivity, where electrical current can flow through a material without encountering any resistance.
Superconductivity has long been utilized in various technological applications, including magnetic resonance imaging and highly sensitive magnetic field detectors. However, as electronic devices continue to shrink in size, researchers are focused on inducing superconductivity in much smaller structures at the nanoscale.
The team at Universität Hamburg achieved electron pairing in an artificial atom called a quantum dot, which serves as the smallest building block for nanostructured electronic devices. Led by PD Dr. Jens Wiebe, the researchers constructed tiny cages from silver atoms, locking the electrons inside. By coupling these locked electrons with an elemental superconductor, the electrons inherited the tendency towards pairing from the superconductor.
Working in collaboration with theoretical physicists from the Cluster of Excellence “CUI: Advanced Imaging of Matter,” led by Dr. Thore Posske, the researchers were able to identify the experimental signature of the quantum state predicted by Kazushige Machida and Fumiaki Shibata in the early 1970s. While the state had remained elusive to experimental detection, recent work by researchers from the Netherlands and Denmark revealed its usefulness in suppressing unwanted noise in transmon qubits, an essential component of modern quantum computers.
Expressing his appreciation, Kazushige Machida reached out to the first author of the publication, Dr. Lucas Schneider, stating, “I thank you for ‘discovering’ my old paper a half century ago. But by your ingenious method, you have finally checked it to be true experimentally.”
The successful observation of this elusive quantum state not only confirms long-standing theoretical predictions but also opens up new possibilities for harnessing superconductivity at the nanoscale. As scientists continue to unravel the mysteries of quantum phenomena, these findings offer hope for advancements in nanotechnology and quantum computing.
For further information, please refer to the research paper titled “Proximity superconductivity in atom-by-atom crafted quantum dots” published in Nature.
Journal Reference:
Lucas Schneider et al, Proximity superconductivity in atom-by-atom crafted quantum dots, Nature (2023). DOI: 10.1038/s41586-023-06312-0
About Nature:
Nature is a renowned scientific journal recognized for publishing cutting-edge research across various scientific disciplines.
Source: University of Hamburg