Nav: Home

Non-adiabatic dynamics of strongly driven diffusive Josephson junctions

December 04, 2019

Understanding how microwave absorption changes the transport properties of diffusive Josephson junctions is at the forefront of interest in the quantum transport community. It is especially relevant for the current efforts to address the current-phase relation in topological Josephson junctions and more generally the microwave transport in quantum devices. Researchers from the University of Paris-Saclay, the University of Regensburg (Germany) and the University of Jyvaskyla; (Finland) have delivered a combined experimental and theoretical work which reveal the profound nature of quantum transport in strongly driven diffusive Josephson junctions. Results are published in Physical Review Research in October.

At sufficiently low temperatures, superconductors cannot absorb microwave radiation of energy smaller than the superconducting energy gap D. In Josephson weak links instead, where two superconductors (S) are weakly coupled through a long diffusive metallic wire (N), radiation can be absorbed in N because the induced gap in the density of states or minigap is considerably smaller than D.

In a recent article the researchers' team have studied the out-of-equilibrium dynamical state induced by the absorption of high frequency microwave photons in diffusive Superconductor-Normal metal-Superconductor (SNS) junction. To characterize this state, the researchers pioneered a harmonic-resolved ac-Josephson spectroscopy technique which allows to access the harmonic content of the current-phase relation under microwave radiation.

With this approach, which does not require a specialized on-chip circuitry, they could see that a strong anharmonicity of the current-phase relation arises under illumination, especially at high frequency when inelastic transitions across the induced minigap are favored. This novel regime goes well beyond the standard Eliashberg theory and is understood because of the modifications of the supercurrent-carrying Andreev spectrum induced by non-adiabatic transitions.

These findings shed light on the complex mechanisms involved in irradiated mesoscopic superconductors and has important implications in Andreev-based quantum computing prospects.
-end-
Link to the article in Physical Review Research 1, 032009 (2019): https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.1.032009

For further information:

Professor Tero Heikkilä, University of Jyvaskyla;, Finland, tero.t.heikkila@jyu.fi, tel. +358408054804

University researcher Pauli Virtanen, University of Jyvaskyla, Finland, pauli.t.virtanen@jyu.fi

Communications officer Tanja Heikkinen, tanja.s.heikkinen@jyu.fi, tel +35850 581 8351

University of Jyväskylä - Jyväskylän yliopisto

Related Superconductors Articles:

Study probes relationship between strange metals and high-temperature superconductors
SLAC theorists have observed strange metallicity in a well-known model for simulating the behavior of materials with strongly correlated electrons, which join forces to produce unexpected phenomena rather than acting independently.
Uncovering a new aspect of charge density modulations in high temperature superconductors
Researchers from Chalmers University of Technology and Politecnico di Milano have identified a crucial new aspect of charge density modulations in cuprate high critical temperature superconductors.
Charge fluctuations, a new property in superconductors
An experiment conducted jointly at the ESRF European Synchrotron Radiation Facility by the Politecnico di Milano, National Research Council, the Università La Sapienza di Roma and the Chalmers University of Technology in Gothenburg has revealed a new property of cuprates, so-called high critical temperature superconductors.
Physicists make graphene discovery that could help develop superconductors
When two mesh screens are overlaid, beautiful patterns appear when one screen is offset.
Experiments explore the mysteries of 'magic' angle superconductors
A team led by Princeton physicist Ali Yazdani conducted experiments to explore superconductivity in a groundbreaking new material known as magic-angle twisted graphene.
AI and high-performance computing extend evolution to superconductors
In a new study from the US Department of Energy's Argonne National Laboratory, researchers used the power of artificial intelligence and high-performance supercomputers to introduce and assess the impact of different configurations of defects on the performance of a superconductor.
Superconductors: Resistance is futile
New experimental results change the way we think about high-temperature superconductors.
Revealing hidden spin: Unlocking new paths toward high-temperature superconductors
Researchers from the Department of Energy's Lawrence Berkeley National Laboratory have discovered that electron spin is key to understanding how cuprate superconductors can conduct electricity without loss at high temperature.
Abrikosov vortices help scientists explain inconsistencies in 'dirty' superconductors theory
International team of physicists explained anomalous low temperature behavior of 'dirty' superconductors.
Making new layered superconductors using high entropy alloys
Researchers from Tokyo Metropolitan University have created new superconductors made of layers of bismuth sulfide (BiS2) and a high entropy rare earth alloy oxyfluoride, containing five different rare earth elements at the same crystallographic site.
More Superconductors News and Superconductors Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

In & Out Of Love
We think of love as a mysterious, unknowable force. Something that happens to us. But what if we could control it? This hour, TED speakers on whether we can decide to fall in — and out of — love. Guests include writer Mandy Len Catron, biological anthropologist Helen Fisher, musician Dessa, One Love CEO Katie Hood, and psychologist Guy Winch.
Now Playing: Science for the People

#543 Give a Nerd a Gift
Yup, you guessed it... it's Science for the People's annual holiday episode that helps you figure out what sciency books and gifts to get that special nerd on your list. Or maybe you're looking to build up your reading list for the holiday break and a geeky Christmas sweater to wear to an upcoming party. Returning are pop-science power-readers John Dupuis and Joanne Manaster to dish on the best science books they read this past year. And Rachelle Saunders and Bethany Brookshire squee in delight over some truly delightful science-themed non-book objects for those whose bookshelves are already full. Since...
Now Playing: Radiolab

An Announcement from Radiolab