Maximizing the nondemolition nature of a quantum measurement via an adaptive readout protocol

Abstract

Quantum error correction (QEC) requires non-invasive measurements for fault tolerant quantum computing. Deviations from ideal quantum non-demolition (QND) measurements can disturb the encoded information. To address this challenge, we develop a readout protocol for a $D-$dimensional system that, after a single positive outcome, switches to probing only the $D-1$ remaining subspace. This adaptive switching strategy minimizes measurement-induced errors by relying on negative-result measurement results that do not perturb the Hamiltonian. We apply the protocol on an 8-dimensional ${}^{123}\mathrm{Sb}$ nuclear qudit in silicon, and achieve an increase in the readout fidelity from $(98.93\pm 0.07)\%$ to $(99.61\pm 0.04)\%$, while reducing threefold the overall readout time. To highlight the broader relevance of measurement-induced errors, we study a 10-dimensional ${}^{73}\mathrm{Ge}$ nuclear spin read out through Pauli spin blockade, revealing nuclear spin flips arising from hyperfine and quadrupole interactions. These results unveil the effect of non-ideal QND readout across diverse platforms, and introduce an efficient readout protocol that can be implemented with minimal FPGA logic on existing hardware.

arXiv commentMain text: 10 pages, 5 figures. Supplementary Material: 7 pages, 5 figures

References in corpus (37)

• Single-shot read-out of an individual electron spin in a quantum dot
• State preservation by repetitive error detection in a superconducting quantum circuit
• Single-shot readout of an electron spin in silicon
• Quantum Error Correction for Beginners
• High-fidelity projective readout of a solid-state spin quantum register
• Quantum Mechanical Interaction-Free Measurements
• High-fidelity readout and control of a nuclear spin qubit in silicon
• Detecting bit-flip errors in a logical qubit using stabilizer measurements
• Precision tomography of a three-qubit donor quantum processor in silicon
• Fault-tolerant operation of a logical qubit in a diamond quantum processor
• Non-Poissonian Quantum Jumps of a Fluxonium Qubit due to Quasiparticle Excitations
• Repeated multi-qubit readout and feedback with a mixed-species trapped-ion register
• Coherent electrical control of a single high-spin nucleus in silicon
• Fault-tolerant thresholds for quantum error correction with the surface code
• High-fidelity operation and algorithmic initialisation of spin qubits above one kelvin
• Pauli Blockade in Silicon Quantum Dots with Spin-Orbit Control
• Architecture for high-sensitivity single-shot readout and control of the electron spin of individual donors in silicon
• A dual-species Rydberg array
• Repetitive single electron spin readout in silicon
• Encoding a qubit in a spin
• Charge-noise-insensitive gate operations for always-on, exchange-only qubits
• Repetitive quantum non-demolition measurement and soft decoding of a silicon spin qubit
• Navigating the 16-dimensional Hilbert space of a high-spin donor qudit with electric and magnetic fields
• Addressable electron spin resonance using donors and donor molecules in silicon
• Schrödinger cat states of a nuclear spin qudit in silicon
• Interaction of Strain and Nuclear Spins in Silicon: Quadrupolar Effects on Ionized Donors
• High-fidelity adiabatic inversion of a ${}^{31}\mathrm{P}$ electron spin qubit in natural silicon
• Qudit Dynamical Decoupling on a Superconducting Quantum Processor
• Coherent control via weak measurements in ${}^{31}$P single-atom electron and nuclear spin qubits
• Beating the thermal limit of qubit initialization with a Bayesian Maxwell's demon
• Single-Step Parity Check Gate Set for Quantum Error Correction
• Robust Macroscopic Schrödinger's Cat on a Nucleus
• Analysis and mitigation of residual exchange coupling in linear spin qubit arrays
• Error channels in quantum nondemolition measurements on spin systems
• Engineering local strain for single-atom nuclear acoustic resonance in silicon
• Certifying the quantumness of a nuclear spin qudit through its uniform precession
• Single-shot readout of the nuclear spin of an on-surface atom