Hidden quantum resistance of a superconductor nanowire, Science Advances

Superconductors are known for zero electrical resistance, which is one of the consequences of superconductivity as a macroscopic quantum phenomenon.
However, in an unusual experiment on extremely narrow superconducting nanowires performed by Ivan Madan and Jože Buh under the leadership of Dragan Mihailovic, the superconductor is switched by ultrashort laser pulses to a hidden metastable resistive quantum state with the introduction of quantum phase slip centers. While the work demonstrates a new fundamental quantum phenomenon of nonequilibrium superconducting states related to quantum chaos, it is also of interest for designing new single photon detectors for use in quantum encrypted communications.
The nanowires were synthesised by Aleš Mrzel, while the theory calculations were performed by Viktor Kabanov and his student Vladimir Baranov, so everything from nanomaterial synthesis, nanocircuit technology to electrical and optical measurements, including theory is proprietary knowledge developed at the Jozef Stefan Institute and the CENN Nanocenter. The work was published on March 30 in Science Advances.

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Skrita kvantna upornost superprevodne nanožice

Superprevodniki so znani po tem, da nimajo električnega upora, kar je ena izmed posledic makroskopske kvantne narave tega pojava. Vendar pa se izkaže, da v to ne velja vedno. V eksperimentu, ki sta ga izvedla Ivan Madan in Jože Buh pod vodstvom Dragana Mihailovića s kratkimi laserskimi sunki so raziskovalci pokazali, da je možno superprevodne nanožice z majhnimi premeri spraviti v metastabilno kvantno stanje v katerih je upor končen. Poleg tega, da delo odkriva nov temeljni kvantni pojav neravnovesnih superprevodnih stanj povezan s kvantnim kaosom, je odkritje zanimivo tudi iz vidika razvoja novih detektorjev posameznih fotonov v kvantnih šifriranih komunikacijah. Nanožice je sintentiziral Aleš Mrzel, teoretične izračune pa opravil Viktor Kabanov s svojim študentom Vladimirom Baranovim. Celotno delo, ki vključuje sintezo nanožic po novi poti, priprave vezij nanometrskih dimenzij, električnih in optičnih meritev ter teoretičnimi izračuni, je rezultat lastnega znanja z Inštituta »Jožef Stefan« in CO Nanocentra. Delo je objavljeno 30. marca v ugledni reviji Science Advances.