Vortex spin qubits: Andreev spin qubits bound to Josephson vortices in spin-orbit coupled planar Josephson junctions
ORAL
Abstract
We introduce the Vortex Spin Qubit (VSQ), a novel Andreev Spin Qubit (ASQ) architecture realized in a planar superconductor-normal-superconductor (SNS) junction featuring a spin-orbit coupled 2DEG. A weak out-of-plane magnetic field induces a linear phase gradient and nucleates Josephson vortices hosting Andreev Bound States (ABSs). We show that the combination of the magnetic field and spin-orbit coupling stabilizes an odd-fermion parity ground state. This mechanism binds a single, isolated spinful low-energy degree of freedom to the vortex, which defines the VSQ. We detail operational protocols, including single-qubit gates via dynamic flux driving, the adaptation of established resonator-based readout strategies from conventional ASQs, and a framework for entangling two-qubit gates. By avoiding Zeeman fields and normal confinement, the VSQ offers reduced hardware overhead compared to standard ASQ implementations alongside new approaches for interconnectivity.
*This work is also supported by the Laboratory for Physical Sciences through its continuous support of the Condensed Matter Theory Center at the University of Maryland. J.S. acknowledges support from the Joint Quantum Institute at the Unviersity of Maryland.
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Presenters
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Jay Deep Sau
- University of Maryland College Park