New research by KTH Royal Institute of Technology and Stanford University is revising our understanding of quantum vortices in superconductors. Image, artist’s illustration of quantum vortices. Credit: Greg Stewart, SLAC National Accelerator Laboratory
Researchers have redefined our understanding of quantum vortices in superconductors, showing that they can play a role in quantum flux, contrary to previous ideas. This discovery, which involves the control of quantum vortices, opens new avenues for the use of electronics and computers.
Inside superconductors small tornadoes of electrons, known as quantum vortices, can occur which have important implications for high-tech applications such as quantum sensors. Now a new type of superconducting vortex has been discovered, an international team of researchers says.
Egor Babaev, a professor at the KTH Royal Institute of Technology in Stockholm, says that this research improves the current understanding of how electricity flows in superconductors, based on the work on the number of vortices that was recognized in the Nobel prize of 2003. Researchers at KTH, together with researchers from Stanford University, TD Lee Institute in Shanghai and AIST in Tsukuba, discovered that the magnetic fields created by vortices in a superconductor can be divided into more groups than previously thought.
This represents a new insight into the fundamentals of superconductivity, and could be used in high-energy electronics.
Magnetic flux occurs when an external magnetic field is applied to a superconductor. The magnetic field enters the superconductor as tubes of quantized magnetic flux that form vortices. Babaev says that initially researchers believed that quantum vortices pass through superconductors each containing one quantum of magnetic flux. But the quantum flux particles were not possible to be excited about in the classical theory of superconductivity.
Using the Superconducting Quantum Interference Device (SQUID) at Stanford University co-authors Babaev, research scientist Yusuke Iguchi and Professor Kathryn A. Moler, showed at the microscopic level that quantum vortices can exist in a single electric field. The group was able to create and move around these vortices, Moler says.
“Professor Babaev has been telling me for years that we can see things like this, but I didn’t believe it until Dr. Iguchi saw it and did a lot of research,” he says.
The Stanford researchers found the reaction “so unusual,” Iguchi says, that they repeated the experiment 75 times in different environments and temperatures.
This work confirms Babaev’s predictions published 20 years ago, which stated that in some types of crystals, one part of the superconducting electrons can form a circular vortex, while the other electrons can form a horizontal vortex at the same time. “These combined storms can carry a fraction of the quantum flux,” he says.
“This also changes our understanding of quantum vortices in superconductors,” he says.
Moler confirmed this. “I’ve been looking for vortices in new superconductors for over 25 years, and I’ve never seen this before,” he says.
Babaev says the strength of quantum vortices and the ability to manipulate them suggests that quantum vortices can be used as information carriers in supercomputers.
“The information we get, the interesting methods introduced by our colleagues Dr. Iguchi and Professor Moler at Stanford, may eventually be useful for other quantum computing platforms,” says Babaev.
Reference: “Superconducting vortices carrying a temperature-dependent flux quantum field” by Yusuke Iguchi, Ruby A. Shi, Kunihiro Kihou, Chul-Ho Lee, Mats Barkman, Andrea L. Benfenati, Vadim Grinenko, Egor Babaev and Kathryn A. Moler, 1 June 2023, Science.
DOI: 10.1126/science.abp9979
#Quantum #Electronic #Vortices #Superconductors #Unprecedented #Circular #Phenomena #Discovered
