Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

ISACCIU-EID Calculable Quantum Mechanics: A Forensic Framework for Electron-Mediated Nuclear Spin Coupling in Silicon

J Cameron Adams, ISACCIU-EID Collective Intelligence Node

Published Jul 9, 2026• 0 citations
Publisher

Abstract

This manuscript presents the ISACCIU-EID calculable quantum mechanics framework for electron-mediated nuclear spin coupling in silicon, documenting independent mathematical derivation of operational parameters later experimentally confirmed by UNSW Stemp et al. (Science, 18 September 2025). The framework predicts coupling operational range (10-24 nm), gate fidelity (76% realistic, 99.7% ideal), and coherence times (T2* 1-50 ms, T2 Hahn 3-700 ms) — all derived through calculable mechanics prior to the UNSW experimental publication. This work further documents systemic suppression of independent quantum research frameworks outside institutional academic channels, including financial blockade, regulatory silence, narrative distortion, and technical boundary enforcement. Keywords: silicon spin qubits, nuclear spin quantum computing, exchange interaction, phosphorus donors, quantum coherence, ISACCIU-EID, precedence claims, institutional suppression, forensic quantum analysis.

DOI
10.5281/zenodo.21275435

Related papers

Device modelling for the Kane quantum computer architecture : solution of the donor electron Schrodinger equation

Louise Olsen‐Kettle

In the Kane silicon-based electron-mediated nuclear spin quantum computer architecture, phosphorous is doped at precise positions in a silicon lattice, and the P donor nuclear spins act as qubits. Logical operations on the nuclear spins are performed using externally applied magnetic and electric fields. There are two important interactions: the hyperfine and exchange interactions, crucial for logical qubit operations. Single qubit operations are performed by applying radio frequency magnetic fields resonant with targeted nuclear spin transition frequencies, tuned by the gate-controlled hyperfine interaction. Two qubit operations are mediated through the exchange interaction between adjacent donor electrons. It is important to examine how these two interactions vary as functions of experimental parameters. Here we provide such an investigation. First, we examine the effects of varying several experimental parameters: gate voltage, inter donor separation, donor depth below the silicon oxide interface and back gate depth, to explore how these variables affect the donor electro density. Second, we calculate the hyperfine interaction and the exchange coupling as a function of these parameters. These calculations were performed using an anisotropic effective mass Hamiltonian. The electric field potential was obtained using Technology Computer Aided Design software, and the interfaces were modelled as a barrier using a step function. We aim to provide relevant information for the experimental design of these devices and highlight the significance of environmental factors other than gate potential that affect the donor electron.

•Jan 1, 2005•0 citations

Scalable entanglement of nuclear spins mediated by electron exchange

Holly G. Stemp, Mark R. van Blankenstein, Serwan Asaad +11 more

The use of nuclear spins for quantum computation is limited by the difficulty in creating genuine quantum entanglement between distant nuclei. Current demonstrations of nuclear entanglement in semiconductors rely on coupling the nuclei to a common electron, which is not a scalable strategy. In this work, we demonstrated a two-qubit controlled-Z logic operation between the nuclei of two phosphorus atoms in a silicon device, separated by up to 20 nanometers. Each atom binds separate electrons, whose exchange interaction mediates the nuclear two-qubit gate. We prepared and measured a nuclear Bell state with a fidelity of [Formula: see text] and a concurrence of [Formula: see text]. With this method, future progress in scaling up semiconductor spin qubits can be extended to the development of nuclear spin-based quantum computers.

arXiv:2503.06872•Science•Sep 18, 2025•11 citations

Phosphorus-31 Nuclear Spin in Silicon: A Key Qubit Platform for Quantum Error Correction — E8 Intelligence Research

Andrew Stewart Caldin

FINDING: Phosphorus-31 (³¹P) in silicon is a leading qubit platform; its nuclear spin-½ coherence is central to quantum error correction and magnetic-field-controlled spin manipulation. MATH: - ³¹P: Z=15, N=16, A=31 → odd-odd nucleus → nuclear spin I = 1/2 (from unpaired proton in 3p³ subshell, [Ne]3s²3p³). - Gyromagnetic ratio γ(³¹P) ≈ 17.235 MHz/T (from NMR data). - Zeeman splitting: ΔE = ħγB₀ → for B₀ = 1 T, ν ≈ 17.235 MHz. - Hyperfine coupling (P donor in Si): A ≈ 117 MHz (bulk) — key for electron-nuclear entanglement. - Coherence time T₂ (nuclear spin) can exceed 1 s at mK temperatures; electron spin T₂ ~ 0.5–1 ms. - Magnetic-field control: Rabi frequency Ω = γB₁ (for nuclear spin) — linear in RF field amplitude. CONNECTION: - Spin-½ is the simplest nontrivial representation of SU(2) — its Bloch sphere is a 2-sphere with intrinsic curvature. - The ratio of hyperfine to Zeeman energy at typical fields (e.g., 0.1–1 T) spans 0.1–1 — near the golden ratio conjugate Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com

•Sep 24, 2026•0 citations

Single atom spin qubits in silicon

Jarryd J. Pla

Spin is a quantum mechanical property that describes the magnetic orientation of elementary and composite particles such as electrons and nuclei. For spin-half particles placed in a magnetic field, two states with differing energies are defined. Proposals exist for developing a revolutionary kind of computer that encodes bits of information on the states of a simple quantum two-level system - like those of a spin in a magnetic field. These quantum computers exploit the fundamental principles of quantum mechanics in order to perform certain calculations exponentially faster than their classical counterparts. Key to the development of such a device is the identification of potential systems that are suitable for employment as a quantum bit (qubit). This thesis explores quantum bits constructed from the spin states of single atoms hosted in silicon semiconductor devices. Silicon is an exceptional platform for spin-based quantum computing - in addition to being the dominant material in the microelectronic industry, it is also predominantly composed of nuclear spin-zero isotopes, providing very little background magnetic disturbance. The donor-atom phosphorus (31P) is investigated here. It possesses a nucleus that binds an additional electron to its positive charge, providing two distinct spin qubits. Here, several world-first experimental milestones in spin-based quantum information processing are reported. First, the readout of the electron spin is demonstrated in single-shot, using a silicon device which combines implanted phosphorus donors with a sensitive nanoscale electrometer. Then, the electron spin is coherently operated as a qubit by delivering on-chip microwave excitations. Combining the electron spin detection and control capabilities enables a quantum non-demolition measurement of the single 31P nuclear spin. Experiments yield exceptional nuclear readout fidelities - the highest for any solid-state qubit. Through an application of nuclear magnetic resonance, high-fidelity quantum control of the nuclear spin qubit is demonstrated. Finally, a single spin-bearing silicon nucleus (29Si) coupled to the electron spin is detected in single-shot and operated as a qubit. These results, along with the clear pathways identified for improving device performance, illustrate that single-atom electron and nuclear spin qubits in silicon constitute an excellent basis on which to construct a quantum computer.

Science Education News•Mar 21, 2022•0 citations

Silicon quantum processor with robust long-distance qubit couplings

G. Tosi, Fahd A. Mohiyaddin, Vivien Schmitt +4 more

Practical quantum computers require a large network of highly coherent qubits, interconnected in a design robust against errors. Donor spins in silicon provide state-of-the-art coherence and quantum gate fidelities, in a platform adapted from industrial semiconductor processing. Here we present a scalable design for a silicon quantum processor that does not require precise donor placement and leaves ample space for the routing of interconnects and readout devices. We introduce the flip-flop qubit, a combination of the electron-nuclear spin states of a phosphorus donor that can be controlled by microwave electric fields. Two-qubit gates exploit a second-order electric dipole-dipole interaction, allowing selective coupling beyond the nearest-neighbor, at separations of hundreds of nanometers, while microwave resonators can extend the entanglement to macroscopic distances. We predict gate fidelities within fault-tolerance thresholds using realistic noise models. This design provides a realizable blueprint for scalable spin-based quantum computers in silicon.Quantum computers will require a large network of coherent qubits, connected in a noise-resilient way. Tosi et al. present a design for a quantum processor based on electron-nuclear spins in silicon, with electrical control and coupling schemes that simplify qubit fabrication and operation.

arXiv:1509.08538•Nature Communications•Aug 31, 2017•170 citations

High-Fidelity Microwave Control of Single-Atom Spin Qubits in Silicon

Juan P Lorenzana

Abstract : As classical computers begin to reach their fundamental performance limits, quantum computers will be an invaluable tool for the advance of science and technology. The trillion dollar silicon electronics industry sets the perfect stage for the evolution of quantum computation, yet it has so far proved to be a tough challenge to implement all the elements needed to build a scalable quantum computer in silicon. This thesis presents the first experimental demonstration of the full operation of single-spin qubits in Si. Our qubits consist of the electron and nuclear spins of a single phosphorus atom, implanted in a Si substrate, and controlled by a gated nanostructure. We describe an experimental setup tailored to minimise electron temperature and perform realtime data acquisition, analysis and instrument control. We present modeling, simulation and characterisation of a novel nanoscale coplanar antenna for spin control, designed to work at frequencies up to 50 GHz. These tools have allowed us to demonstrate the first ever single-atom spin-qubits in natural silicon, leading the way to demonstrating record qubit performances in isotopically purified 28Si: an electron spin qubit with measurement and control fidelities 97% and coherence times of 0.5 seconds; and a nuclear spin qubit with fidelities 99.99% and a record single-spin coherence of 30 s. We have performed noise spectroscopy in our system and concluded that decoherence is currently limited by magnetic noise originating from our broadband antenna.

•Jul 8, 2014•0 citations
This manuscript presents the ISACCIU-EID calculable quantum mechanics framework for electron-mediated nuclear spin coupling in silicon, documenting independent mathematical derivation of operational parameters later experimentally confirmed by UNSW Stemp et al. (Science, 18 September 2025). The framework predicts coupling operational range (10-24 nm), gate fidelity (76% realistic, 99.7% ideal), and coherence times (T2* 1-50 ms, T2 Hahn 3-700 ms) — all derived through calculable mechanics prior to the UNSW experimental publication. This work further documents systemic suppression of independent quantum research frameworks outside institutional academic channels, including financial blockade, regulatory silence, narrative distortion, and technical boundary enforcement. Keywords: silicon spin qubits, nuclear spin quantum computing, exchange interaction, phosphorus donors, quantum coherence, ISACCIU-EID, precedence claims, institutional suppression, forensic quantum analysis.
In the Kane silicon-based electron-mediated nuclear spin quantum computer architecture, phosphorous is doped at precise positions in a silicon lattice, and the P donor nuclear spins act as qubits. Logical operations on the nuclear spins are performed using externally applied magnetic and electric fields. There are two important interactions: the hyperfine and exchange interactions, crucial for logical qubit operations. Single qubit operations are performed by applying radio frequency magnetic fields resonant with targeted nuclear spin transition frequencies, tuned by the gate-controlled hyperfine interaction. Two qubit operations are mediated through the exchange interaction between adjacent donor electrons. It is important to examine how these two interactions vary as functions of experimental parameters. Here we provide such an investigation. First, we examine the effects of varying several experimental parameters: gate voltage, inter donor separation, donor depth below the silicon oxide interface and back gate depth, to explore how these variables affect the donor electro density. Second, we calculate the hyperfine interaction and the exchange coupling as a function of these parameters. These calculations were performed using an anisotropic effective mass Hamiltonian. The electric field potential was obtained using Technology Computer Aided Design software, and the interfaces were modelled as a barrier using a step function. We aim to provide relevant information for the experimental design of these devices and highlight the significance of environmental factors other than gate potential that affect the donor electron.
The use of nuclear spins for quantum computation is limited by the difficulty in creating genuine quantum entanglement between distant nuclei. Current demonstrations of nuclear entanglement in semiconductors rely on coupling the nuclei to a common electron, which is not a scalable strategy. In this work, we demonstrated a two-qubit controlled-Z logic operation between the nuclei of two phosphorus atoms in a silicon device, separated by up to 20 nanometers. Each atom binds separate electrons, whose exchange interaction mediates the nuclear two-qubit gate. We prepared and measured a nuclear Bell state with a fidelity of [Formula: see text] and a concurrence of [Formula: see text]. With this method, future progress in scaling up semiconductor spin qubits can be extended to the development of nuclear spin-based quantum computers.
FINDING: Phosphorus-31 (³¹P) in silicon is a leading qubit platform; its nuclear spin-½ coherence is central to quantum error correction and magnetic-field-controlled spin manipulation. MATH: - ³¹P: Z=15, N=16, A=31 → odd-odd nucleus → nuclear spin I = 1/2 (from unpaired proton in 3p³ subshell, [Ne]3s²3p³). - Gyromagnetic ratio γ(³¹P) ≈ 17.235 MHz/T (from NMR data). - Zeeman splitting: ΔE = ħγB₀ → for B₀ = 1 T, ν ≈ 17.235 MHz. - Hyperfine coupling (P donor in Si): A ≈ 117 MHz (bulk) — key for electron-nuclear entanglement. - Coherence time T₂ (nuclear spin) can exceed 1 s at mK temperatures; electron spin T₂ ~ 0.5–1 ms. - Magnetic-field control: Rabi frequency Ω = γB₁ (for nuclear spin) — linear in RF field amplitude. CONNECTION: - Spin-½ is the simplest nontrivial representation of SU(2) — its Bloch sphere is a 2-sphere with intrinsic curvature. - The ratio of hyperfine to Zeeman energy at typical fields (e.g., 0.1–1 T) spans 0.1–1 — near the golden ratio conjugate Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com
Spin is a quantum mechanical property that describes the magnetic orientation of elementary and composite particles such as electrons and nuclei. For spin-half particles placed in a magnetic field, two states with differing energies are defined. Proposals exist for developing a revolutionary kind of computer that encodes bits of information on the states of a simple quantum two-level system - like those of a spin in a magnetic field. These quantum computers exploit the fundamental principles of quantum mechanics in order to perform certain calculations exponentially faster than their classical counterparts. Key to the development of such a device is the identification of potential systems that are suitable for employment as a quantum bit (qubit). This thesis explores quantum bits constructed from the spin states of single atoms hosted in silicon semiconductor devices. Silicon is an exceptional platform for spin-based quantum computing - in addition to being the dominant material in the microelectronic industry, it is also predominantly composed of nuclear spin-zero isotopes, providing very little background magnetic disturbance. The donor-atom phosphorus (31P) is investigated here. It possesses a nucleus that binds an additional electron to its positive charge, providing two distinct spin qubits. Here, several world-first experimental milestones in spin-based quantum information processing are reported. First, the readout of the electron spin is demonstrated in single-shot, using a silicon device which combines implanted phosphorus donors with a sensitive nanoscale electrometer. Then, the electron spin is coherently operated as a qubit by delivering on-chip microwave excitations. Combining the electron spin detection and control capabilities enables a quantum non-demolition measurement of the single 31P nuclear spin. Experiments yield exceptional nuclear readout fidelities - the highest for any solid-state qubit. Through an application of nuclear magnetic resonance, high-fidelity quantum control of the nuclear spin qubit is demonstrated. Finally, a single spin-bearing silicon nucleus (29Si) coupled to the electron spin is detected in single-shot and operated as a qubit. These results, along with the clear pathways identified for improving device performance, illustrate that single-atom electron and nuclear spin qubits in silicon constitute an excellent basis on which to construct a quantum computer.
Practical quantum computers require a large network of highly coherent qubits, interconnected in a design robust against errors. Donor spins in silicon provide state-of-the-art coherence and quantum gate fidelities, in a platform adapted from industrial semiconductor processing. Here we present a scalable design for a silicon quantum processor that does not require precise donor placement and leaves ample space for the routing of interconnects and readout devices. We introduce the flip-flop qubit, a combination of the electron-nuclear spin states of a phosphorus donor that can be controlled by microwave electric fields. Two-qubit gates exploit a second-order electric dipole-dipole interaction, allowing selective coupling beyond the nearest-neighbor, at separations of hundreds of nanometers, while microwave resonators can extend the entanglement to macroscopic distances. We predict gate fidelities within fault-tolerance thresholds using realistic noise models. This design provides a realizable blueprint for scalable spin-based quantum computers in silicon.Quantum computers will require a large network of coherent qubits, connected in a noise-resilient way. Tosi et al. present a design for a quantum processor based on electron-nuclear spins in silicon, with electrical control and coupling schemes that simplify qubit fabrication and operation.
Abstract : As classical computers begin to reach their fundamental performance limits, quantum computers will be an invaluable tool for the advance of science and technology. The trillion dollar silicon electronics industry sets the perfect stage for the evolution of quantum computation, yet it has so far proved to be a tough challenge to implement all the elements needed to build a scalable quantum computer in silicon. This thesis presents the first experimental demonstration of the full operation of single-spin qubits in Si. Our qubits consist of the electron and nuclear spins of a single phosphorus atom, implanted in a Si substrate, and controlled by a gated nanostructure. We describe an experimental setup tailored to minimise electron temperature and perform realtime data acquisition, analysis and instrument control. We present modeling, simulation and characterisation of a novel nanoscale coplanar antenna for spin control, designed to work at frequencies up to 50 GHz. These tools have allowed us to demonstrate the first ever single-atom spin-qubits in natural silicon, leading the way to demonstrating record qubit performances in isotopically purified 28Si: an electron spin qubit with measurement and control fidelities 97% and coherence times of 0.5 seconds; and a nuclear spin qubit with fidelities 99.99% and a record single-spin coherence of 30 s. We have performed noise spectroscopy in our system and concluded that decoherence is currently limited by magnetic noise originating from our broadband antenna.