New Technique Enables Non-Local Detection of Fragile Quantum States in magnet-Superconductor Hybrids
Hamburg, Germany – November 26, 2025 – Researchers at the University of Hamburg and the University of Illinois Chicago have developed a new measurement technology for fragile quantum states in hybrid materials composed of magnets and superconductors. Their findings, published in Nature Physics, could have important implications for the progress of topological quantum computers.
Why did this research happen? The need to observe and manipulate fragile quantum states without disrupting them is a major hurdle in quantum computing. Existing measurement techniques frequently enough interfere with the very states thay aim to study. This research aimed to overcome that limitation.
Who was involved? The research was a collaborative effort led by Dr. Jens Wiebe of the University of Hamburg, and involved researchers from both the University of hamburg and the University of Illinois Chicago. Key researchers included KT Ton, C. Xu, I. Ioannidis, L. Schneider, T. Posske, R. Wiesendanger,and DK Morr.
These materials exhibit sensitive quantum phenomena that require measurement with minimal interference. The team, led by Dr. Jens Wiebe, successfully measured a quantum state – specifically yu-Shiba-Ruzinov quasiparticles created when a magnetic atom is placed in a superconductor – over distances more than twenty times its original size, significantly reducing interference from the measuring probe.
What was the breakthrough? The team achieved non-local detection of Yu-Shiba-Ruzinov quasiparticles. This means they could measure the quantum state of a magnetic atom within a superconductor at a distance,minimizing the disturbance caused by the measurement process itself. They extended the measurable range of these states by over twenty times.
Key to the breakthrough: The researchers created a “quantum enclosure” for the magnetic atom, constructed from 91 silver atoms on a superconducting silver crystal using a scanning tunneling microscope. By precisely controlling the enclosure’s dimensions, they positioned the magnetic atom to exploit a specific quantum state of the silver electrons.
“Surprisingly,the Yu-Shiba-Rusinov quasi-particle can even be measured at the right-hand “belly” of the quantum enclosure state,which is furthest away from the magnetic atom,without its probability of presence decreasing noticeably with the distance to the atom,” explains Dr. Wiebe. simulations confirmed the creation of a spatially coherent quantum state involving Cooper pairs both within and on the surface of the silver crystal.The researchers also demonstrated the ability to control the particle-hole composition of the quantum state by adjusting the enclosure’s size and shape.
How did they achieve this? Researchers used a scanning tunneling microscope to build a precise “quantum enclosure” of 91 silver atoms around a magnetic atom placed on a superconducting silver crystal. This enclosure manipulated the quantum state of the surrounding electrons, allowing for remote measurement of the magnetic atom’s quantum properties.
This technique minimizes the disruptive influence of the measuring probe while allowing for the observation of fragile quantum states.The researchers believe this method can be applied to study Majorana quasiparticles, crucial for building topological quantum computers, and potentially used to control interactions between quasiparticles in multiple magnet-superconductor hybrids.
How did it end? The research concluded with a successful demonstration of non-local detection and control of Yu-Shiba-Ruzinov quasiparticles. The team validated their findings through simulations and believe the technique is applicable to other quantum phenomena, particularly those related to Majorana quasiparticles, paving the way for advancements in topological quantum computing.
Scientific Contact:
dr.jens Wiebe
University of Hamburg
Institute for nanostructure and Solid state Physics
Email: [email protected]
Related reading
- Latest Advances in Alzheimer’s Disease Treatment and Diagnosis (news-usa.today)
