Chronological feed of everything captured from Michelle Simmons.
youtube / michellesimmons / Jul 16
Michelle Simmons, founding director of Australia's ARC Centre of Excellence for Quantum Computation and Communication Technology, built a globally competitive quantum research program around a single contrarian thesis: that atomic-level precision in silicon—not superconducting circuits or trapped ions—offers the most scalable path to practical quantum computing. Her team used scanning tunneling microscopy (STM) to place individual phosphorus atoms within silicon substrates with sub-nanometer accuracy, producing the world's first single-atom transistor and demonstrating stable, readable qubit spin states. This approach treats decoherence as an engineering problem to be eliminated at fabrication rather than corrected at runtime, and leverages silicon's mature semiconductor manufacturing infrastructure for future scalability. Her work repositioned Australia as a serious contender in the global quantum race and established a model for interdisciplinary, talent-pipeline-driven research ecosystems.
quantum-computingsilicon-qubitsatomic-precisionmichelle-simmonswomen-in-stemscientific-leadershipquantum-hardware
“Simmons's team used STM to place single phosphorus atoms in a silicon substrate and demonstrated they could function as stable, readable qubits—producing the world's first single-atom transistor.”
paper / michellesimmons / Jun 4
Researchers demonstrate a fully controlled 11-qubit quantum processor built from two phosphorus-atom nuclear spin registers in silicon, linked via electron exchange interaction. Nuclear spins in silicon offer coherence times exceeding seconds, and by clustering multiple phosphorus atoms within nanometer-scale proximity, a shared electron mediates multi-qubit control through hyperfine coupling. The system achieves gate fidelities between 99.5% and 99.99%, non-local Bell state fidelities beyond 99%, and GHZ state generation across all data qubits — collectively representing a key hardware milestone toward fault-tolerant quantum computation.
quantum-computingsilicon-qubitsnuclear-spinfault-tolerant-quantumquantum-error-correctionqubit-architectureentanglement
“All single- and multi-qubit gate fidelities in the 11-qubit processor range from 99.5% to 99.99%, exceeding the fault-tolerant threshold.”
youtube / michellesimmons / Apr 21
Silicon Quantum Computing (SQC) leverages phosphorus atoms in isotopically pure silicon-28 to create highly stable, low-noise qubits with industry-leading fidelities. Their unique atomic precision manufacturing allows for high-quality, reproducible qubits and proprietary control circuitry. SQC offers three products: quantum machine learning, analog simulation, and aims for a full-scale error-corrected quantum computer by 2033, building on a full-stack in-house development and rapid chip cycle times.
quantum-computingsilicon-quantum-computingquantum-machine-learninganalog-simulationquantum-error-correctionquantum-hardwarestartup-strategy
“Silicon Quantum Computing (SQC) uses phosphorus atoms in isotopically pure silicon-28 to create high-fidelity, low-noise qubits.”
paper / michellesimmons / Jan 8
This roadmap details the significant advancements and future directions in atomic-scale semiconductor device fabrication and quantum computing since Kane's 1998 proposal. It emphasizes using donor atom spins in silicon for highly stable qubits, exploring diverse materials and techniques beyond silicon, and integrating experimental, technological, and theoretical approaches to overcome current scalability challenges. The document provides a comprehensive overview of the field's progress and potential for advanced semiconductor quantum technologies.
quantum-computingsemiconductor-devicesatomic-scale-fabricationquantum-technologiessilicon-quantum-computersspin-qubitsnanofabrication
“Spin states in semiconductors offer highly stable and noise-resistant environments for qubits, making them ideal for reliable quantum computing.”
paper / michellesimmons / May 6
Correlated noise poses a significant challenge to quantum error correction in multi-qubit architectures. This study investigates the spatial and frequency dependence of noise correlations in silicon spin qubits, a previously uncharacterized area. The findings indicate that correlated charge noise in silicon spin qubits significantly decreases with increasing inter-dot distance, unlike superconducting qubits where cosmic radiation induces spatially dependent noise. The primary source of this noise is attributed to low-frequency charge fluctuations from two-level fluctuators at the silicon-silicon dioxide interface.
quantum-computingsilicon-spin-qubitsnoise-reductionquantum-error-correctionmesoscale-physics
“Correlated noise in silicon quantum dot pairs is significantly suppressed as inter-dot distance increases.”
paper / michellesimmons / Apr 24
Researchers have demonstrated a significant, two orders of magnitude enhancement of spin-orbit coupling (SOC) in multi-donor quantum dots within silicon, compared to single donors. This advancement, previously only seen in holes or specific two-donor systems, enables the potential for all-electrical control of donor-bound spins in silicon via electric dipole spin resonance (EDSR). The intrinsic weakness of SOC in bulk silicon is overcome by local enhancement in these multi-donor structures.
quantum-computingspin-qubitssilicon-quantum-dotsspin-orbit-couplingelectric-dipole-spin-resonancemesoscale-physics
“Spin-orbit coupling strength can be locally enhanced by over two orders of magnitude in multi-donor quantum dots in silicon.”
paper / michellesimmons / Apr 12
Researchers have successfully implemented Grover's algorithm on a novel four-qubit silicon processor, achieving approximately 95% probability of finding the marked state. This was possible due to a unique architecture integrating three phosphorus atoms and one electron spin within a 1.5 nm² isotopically pure silicon, which minimizes crosstalk and leverages all-to-all connectivity of nuclear spins. The system demonstrates high fidelity for single-qubit operations (>99.9%), controlled-Z gates (>99%), and a three-qubit GHZ state (96.2%), marking significant progress towards scalable fault-tolerant quantum computing with semiconductor spin qubits.
quantum-computingsilicon-qubitsgrovers-algorithmfault-tolerancequantum-processorsquantum-physics
“A four-qubit silicon processor successfully implemented Grover's algorithm with a high probability.”