Room temperature superconductivity shown in graphite
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Researchers in Switzerland say they have observed room temperature superconductivity in graphite for the first time, opening up opportunities in quantum computing.
The research is published in Advanced Quantum Technologies and claims the first-ever observation of superconductivity at room temperature (300K) and normal pressure using bulk pyrolytic graphite.
The research was led by Prof. Valerii Vinokur, chief technology officer at Terra Quantum in Switzerland, with Professor Yakov Kopelevich and co-authors from the Universidade Estadual de Campinas, University of Perugia, and SwissScientific Technologies.
Terra Quantum has patented this approach, which Vinokur estimates could be 100 times more efficient than existing superconducting qubits. Before joining Terra Quantum in 2019, Vinokur was a senior scientist at U.S. Department of Energy’s Argonne National Laboratory for 30 years.
“Our work is an experimental discovery that humankind has been waiting for about a hundred years since the first observation of superconductivity in mercury,” said Vinokur.
Pyrolytic graphite is a manufactured form of graphite. Researchers at Universidade Estadual de Campinas, led by Kopelevich, used scotch tape to cleave this graphite into thin sheets. These sheets were covered by dense arrays of wrinkles in nearly parallel lines. The geometry of these wrinkles causes electrons to pair up into structures that allow superconducting currents to flow along the wrinkles.
“This discovery made by our scientific team with our academic and industry partners opens the door to spectacular advances in superconducting technology. Room-temperature superconductivity opens a gateway to transformative advancements across industries,” said Markus Pflitsch, Terra Quantum founder and CEO.
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“Imagine power grids almost free of energy loss, revolutionizing our approach to electricity transmission. In healthcare, enhanced MRI technologies will emerge, offering unprecedented diagnostic precision. Transportation will leap forward with energy-efficient, high-speed magnetically levitating trains. Electronics will enter a new era of miniaturization and power efficiency,” he said.
“The emerging field of quantum computing will benefit enormously since the qubits that now operate only at 10–20 mK can come to room temperature functioning,” added Vinokur.
However there have been several materials proposed that show room temperature superconductivity, but this has been difficult to reproduce.
The mechanism leading to superconductivity along the one-dimensional defects has been explained by C. A. Trugenberger, M. C. Diamantini, and V. M. Vinokur.
Strain fluctuations within these defects can be described by effective topological gauge fields, which mediate an attractive potential causing electrons within droplets in the defects to pair up and Bose condense.
The very thin dimension of these droplets leads to a very robust ground state for these pairs. The condensate droplets form an effective Josephson junction array on the surface of graphite, which freezes in its topological Bose metal state, with residual conduction on the edges formed by the defects.
On these defects, quantum phase slips typically cause dissipation. However, because of dimensional soldering with the two-dimensional surface and the three-dimensional bulk, quantum phase slips are just the tips of bulk vortices moving on the surface. Because of the very small resistance of the bulk, the motion of these vortices is suppressed, together with quantum-phase-slips-induced dissipation on the defects. These defects then turn superconducting.
The research was backed by Swiss startup Terra Quantum which offers “Quantum as a Service (QaaS)” in three core areas, from algorithms to quantum computing and quantum security.
The paper is at onlinelibrary.wiley.com/doi/10.1002/qute.202300230
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