Electron cascade for spin readout

Abstract

Electrons confined in semiconductor quantum dot arrays have both charge and spin degrees of freedom. The spin provides a well-controllable and long-lived qubit implementation. The charge configuration in the dot array is influenced by Coulomb repulsion, and the same interaction enables charge sensors to probe this configuration. Here we show that the Coulomb repulsion allows an initial charge transition to induce subsequent charge transitions, inducing a cascade of electron hops, like toppling dominoes. A cascade can transmit information along a quantum dot array over a distance that extends by far the effect of the direct Coulomb repulsion. We demonstrate that a cascade of electrons can be combined with Pauli spin blockade to read out spins using a remote charge sensor. We achieve > 99.9% spin readout fidelity in 1.7 $\mu$s. The cascade-based readout enables operation of a densely-packed two-dimensional quantum dot array with charge sensors placed at the periphery. The high connectivity of such arrays greatly improves the capabilities of quantum dot systems for quantum computation and simulation.

13 pages, 6 figures

References in corpus (5)

• Single-shot read-out of an individual electron spin in a quantum dot
• Universal quantum logic in hot silicon qubits
• Rapid high-fidelity gate-based spin read-out in silicon
• Loading a quantum-dot based "Qubyte" register
• Efficient orthogonal control of tunnel couplings in a quantum dot array

Cited by in corpus (12)

• Review of performance metrics of spin qubits in gated semiconducting nanostructures
• Noisy intermediate-scale quantum computers
• Fast and high-fidelity state preparation and measurement in triple-quantum-dot spin qubits
• Quantum simulation of antiferromagnetic Heisenberg chain with gate-defined quantum dots
• Interplay of charge noise and coupling to phonons in adiabatic electron transfer between quantum dots
• Enhanced quantum state transfer: Circumventing quantum chaotic behavior
• Extended Hubbard model describing small multi-dot arrays in bilayer graphene
• Operating two exchange-only qubits in parallel
• Resonator-mediated quantum gate between distant charge qubits
• Radiofrequency cascade readout of coupled spin qubits
• Electrical Interconnects for Silicon Spin Qubits
• High-fidelity spin readout via the double latching mechanism