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Superconducting Qubit Based on Twisted Cuprate Van der Waals Heterostructures
Valentina Brosco1,2, Giuseppe Serpico3,4, Valerii Vinokur5,6
1Institute for Complex Systems (ISC) Consiglio Nazionale delle Ricerche and Physics Department University of Rome, "La Sapienza," Piazzale Aldo Moro, 2, 00185 Roma, Italy.
Physical Review Letters
|January 19, 2024
Summary
Researchers developed a novel Josephson junction using twisted Bi2Sr2CaCu2Ox (Bi2212) flakes. This junction enables a new qubit, the flowermon, offering inherent protection against noise for advanced quantum devices.
Area of Science:
- Quantum Computing
- Superconductivity
- Materials Science
Background:
- Van-der-Waals assembly allows for precise fabrication of interfaces.
- Bi2Sr2CaCu2Ox (Bi2212) is an unconventional superconductor with a d-wave order parameter.
Purpose of the Study:
- To propose a novel qubit design, the flowermon, utilizing a unique Josephson junction.
- To leverage the properties of Bi2212 for enhanced qubit coherence.
Main Methods:
- Fabrication of Josephson junctions via Van-der-Waals assembly of twisted Bi2212 flakes.
- Analysis of current-phase relation dominated by two-Cooper pair tunneling at specific twist angles (~45°).
Main Results:
- Demonstration of an atomically sharp interface in Bi2212 Josephson junctions.
- Identification of a regime where interlayer two-Cooper pair tunneling is dominant.
Conclusions:
- The proposed flowermon qubit offers inherent protection against charge noise and quasiparticle dissipation due to the d-wave nature of Bi2212.
- This work paves the way for high-coherence quantum devices based on unconventional superconductors.
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