Supercurrent parity-meter in a nanowire Cooper-pair transistor

Abstract

We study a Cooper-pair transistor realized by two Josephson weak links that enclose a superconducting island in an InSb-Al hybrid nanowire. When the nanowire is subject to a magnetic field, isolated subgap levels arise in the superconducting island and, due to the Coulomb blockade,mediate a supercurrent by coherent co-tunneling of Cooper pairs. We show that the supercurrent resulting from such co-tunneling events exhibits, for low to moderate magnetic fields, a phase offset that discriminates even and odd charge ground states on the superconducting island. Notably,this phase offset persists when a subgap state approaches zero energy and, based on theoretical considerations, permits parity measurements of subgap states by supercurrent interferometry. Such supercurrent parity measurements could, in a new series of experiments, provide an alternative approach for manipulating and protecting quantum information stored in the isolated subgap levels of superconducting islands.

References in corpus (8)

• Supercurrent reversal in quantum dots
• Majorana box qubits
• Charge detection enables free-electron quantum computation
• Demonstration of entanglement-by-measurement of solid state qubits
• Critical Current 0-$\pi$ Transition in Designed Josephson Quantum Dot Junctions
• Quantum-Dot Parity Effects in Trivial and Topological Josephson Junctions
• Entangling spins by measuring charge: a parity-gate toolbox
• Proximity Effect Transfer from NbTi into a Semiconductor Heterostructure via Epitaxial Aluminum

Cited by in corpus (7)

• Supercurrent reversal in ferromagnetic hybrid nanowire Josephson junctions
• Majorana modes in quantum dots coupled via a floating superconducting island
• Supercurrent transport through 1$e$-periodic full-shell Coulomb islands
• Impact of junction length on supercurrent resilience against magnetic field in InSb-Al nanowire Josephson junctions
• Flip-chip-based fast inductive parity readout of a planar superconducting island
• Superconducting bistability in floating Al islands of hybrid Al/InAs nanowires
• Supercurrent and multiple Andreev reflections in Ge hut nanowire Josephson Junctions