Exchange-interaction of two spin qubits mediated by a superconductor

Abstract

Entangling two quantum bits by letting them interact is the crucial requirements for building a quantum processor. For qubits based on the spin of the electron, these two-qubit gates are typically performed by exchange interaction of the electrons captured in two nearby quantum dots. Since the exchange interaction relies on tunneling of the electrons, the range of interaction for conventional approaches is severely limited as the tunneling amplitude decays exponentially with the length of the tunneling barrier. Here, we present a novel approach to couple two spin qubits via a superconducting coupler. In essence, the superconducting coupler provides a tunneling barrier for the electrons which can be tuned with exquisite precision. We show that as a result exchange couplings over a distance of several microns become realistic, thus enabling flexible designs of multi-qubit systems.

6 pages, 2 figures

References in corpus (10)

• Surface codes: Towards practical large-scale quantum computation
• An addressable quantum dot qubit with fault-tolerant control fidelity
• Demonstration of Entanglement of Electrostatically Coupled Singlet-Triplet Qubits
• Hard gap in epitaxial semiconductor-superconductor nanowires
• Electrometry Using Coherent Exchange Oscillations in a Singlet-Triplet-Qubit
• Fluctuation Superconductivity in Mesoscopic Aluminum Rings
• Robust micro-magnet design for fast electrical manipulations of single spins in quantum dots
• Second Harmonic Coherent Driving of a Spin Qubit in a Si/SiGe Quantum Dot
• Fermi-liquid effects in the gapless state of marginally thin superconducting films
• Thouless energy of a superconductor from non local conductance fluctuations

Cited by in corpus (17)

• Interfacing spin qubits in quantum dots and donors - hot, dense and coherent
• The germanium quantum information route
• Coherent shuttle of electron-spin states
• Three-electron spin qubits
• Coherent spin-exchange via a quantum mediator
• Controlled crossed Andreev reflection and elastic co-tunneling mediated by Andreev bound states
• Lightly-strained germanium quantum wells with hole mobility exceeding one million
• Transport signatures of an Andreev molecule in a quantum dot -- superconductor -- quantum dot setup
• Coupled superconducting spin qubits with spin-orbit interaction
• Generation of Schrödinger's cat states in a planar semiconductor heterostructure
• Long-range exchange interaction between spin qubits mediated by a superconducting link at finite magnetic field
• A flux-controlled two-site Kitaev chain
• Weak localization corrections to the thermal conductivity in $s$-wave superconductors
• Spin-resolved nonlocal transport in proximitized Rashba nanowires
• Methodology for bus layout for topological quantum error correcting codes
• Measurement enhances long-distance Entanglement generation in spin chains with dissipative processes
• All-electric single electron spin-to-charge conversion