The design of the Multimodal Instrument for Spin Ensemble Characterization(MIMS v7.4.1) is presented. The instrument executes seven independent measure-ment protocols on solid-state spin ensembles, operating under controlled vacuum con-ditions to minimize environmental decoherence.• Standard Protocol: Multi-exponential relaxation dynamics.• RAE Protocol: Controlled interruption of entanglement.• TEBC Protocol: Response under magnetic field near the correlation loss threshold(effective phenomenological model).• PDE Protocol: Diagnosis of response patterns under magnetic constraint.• REU Protocol: Correlational restoration with synchronized pulses.• SBR Protocol: Edge-of-rupture sensor (regulated phenomenological model).• SBR-REU Protocol: Combined amplification and restoration mode.Eight sensor channels (expandable to nine with Mössbauer in Plan B) monitor fourspin ensembles. Entanglement operates in micro-windows (∼ 100 µs–1 ms) withineach macroscopic cycle.The vacuum chamber (< 10−5 mbar) eliminates collisional decoherence. PlanB incorporates Mössbauer for independent cross-validation.Computational simulation (Appendix E) validates the statistical architecture.All protocols achieve positive detection under controlled conditions. ChannelsCH4 (SQUID) and CH6 (SERF) dominate magnetometric sensitivity; secondarychannels provide instrumental veto, cross-validation, and pattern classification.Construction cost: $850,000–$5,000,000+ USD. Timeline: 66–78 months.
The design of the Multimodal Instrument for Spin Ensemble Characterization(MIMS v7.4.1) is presented. The instrument executes seven independent measure-ment protocols on solid-state spin ensembles, operating under controlled vacuum con-ditions to minimize environmental decoherence.• Standard Protocol: Multi-exponential relaxation dynamics.• RAE Protocol: Controlled interruption of entanglement.• TEBC Protocol: Response under magnetic field near the correlation loss threshold(effective phenomenological model).• PDE Protocol: Diagnosis of response patterns under magnetic constraint.• REU Protocol: Correlational restoration with synchronized pulses.• SBR Protocol: Edge-of-rupture sensor (regulated phenomenological model).• SBR-REU Protocol: Combined amplification and restoration mode.Eight sensor channels (expandable to nine with Mössbauer in Plan B) monitor fourspin ensembles. Entanglement operates in micro-windows (∼ 100 µs–1 ms) withineach macroscopic cycle.The vacuum chamber (< 10−5 mbar) eliminates collisional decoherence. PlanB incorporates Mössbauer for independent cross-validation.Computational simulation (Appendix E) validates the statistical architecture.All protocols achieve positive detection under controlled conditions. ChannelsCH4 (SQUID) and CH6 (SERF) dominate magnetometric sensitivity; secondarychannels provide instrumental veto, cross-validation, and pattern classification.Construction cost: 850,000–5,000,000+ USD. Timeline: 66–78 months.
This registration is the confirmatory analysis plan and full protocol for The Silence Experiment, a multi-participant Phase 0 investigation of whether specific, EEG-verified states of consciousness can systematically modulate the decoherence time (T₂) of a shielded room-temperature NV-center diamond quantum sensor. The protocol is documented in three companion Zenodo papers: The Silence Paradigm v11 — https://doi.org/10.5281/zenodo.20326258 The Silence Experiment v13 — https://doi.org/10.5281/zenodo.20325967 Design Specifications for a Five-Layer Shielded Chamber (TSP-ENG-001 V5) — https://doi.org/10.5281/zenodo.20326311 The design places experienced meditators inside a 3.0 m cubic five-layer shielded chamber (acoustic/thermal, hydrogen-annealed mu-metal magnetic, welded OFHC copper RF, pneumatic vibration isolation, aluminum structural Faraday cage). Cognitive state is the independent variable, operationalised as seven EEG-verified conditions C1–C7 ordered by descending cognitive excitation — C1 active cognition, C2 ordinary resting, C3 focused attention (Shamatha), C4 open monitoring (Vipassana), C5 non-directed openness, C6 Minimal Phenomenal Experience / luminous bare awareness, C7 cessation / objectless awareness — plus an empty-chamber instrumental baseline run as separate sessions. Real-time 64-channel wireless EEG verifies state attainment (EEG signature is the primary inclusion criterion for C6 and C7). Comprehensive synchronous environmental monitoring (SQUID magnetometers, fluxgate magnetometer, 3-axis accelerometer, Pt100 RTDs to ±0.001 K, RF, humidity, barometric pressure, acoustic SPL) is recorded via GPS-disciplined 10 MHz common time base for artifact-correlation analysis. The pre-registered primary analysis is a family of three tests: a Jonckheere–Terpstra ordered test on the C1 → C7 ordering, plus two orthogonal planned contrasts — Contrast 1 ([C6, C7] vs. [baseline, C1–C5]) and Contrast 2 (C7 vs. C6) — evaluated at family-wise α = 0.005 one-sided with Bonferroni correction (per-test α ≈ 0.00167), accompanied by a parallel Bayesian analysis with pre-specified Bayes Factor thresholds (BF > 10 strong, BF > 100 decisive). The threshold follows Benjamin et al. (2018) for novel discovery claims. The Phase 0 minimum detectable effect is d ≥ 0.4 on Contrast 1 at n = 50 sessions per condition. Analysis is outcome-blinded and conducted by an independent statistician who does not see condition labels until the locked dataset is delivered. Any positive primary result is subjected to artifact analysis against the full environmental channel set and requires independent replication by a non-affiliated laboratory before being treated as established. No data of any kind have been collected as of this update. All raw data, analysis code, and any deviations will be publicly deposited here with full transparency upon completion. Amendment history is visible in the Updates panel; v1 (April 2026 original), v2 (terminology), v3 (V9-aligned methodology), and v4 (V13-aligned, pending moderator approval) constitute the full version record.
Solid-state spin ensembles have emerged as a leading platform for micro- and nanoscale sensing, combining high sensitivity, nanoscale spatial resolution, and operation under ambient conditions. At high spin densities, magnetic dipole–dipole interactions typically limit sensing performance by reducing coherence, but can in principle be harnessed to enhance sensitivity. Realizing such interaction-enhanced sensing in practice, however, remains challenging due to the intrinsic anisotropy of dipolar interactions and the random spatial distribution of spins. This thesis presents a series of experimental works that culminate in a practical interaction-enhanced magnetometer based on ensembles of nitrogen-vacancy (NV) centers in diamond. Our approach is based on collective, one-axis-twisting-like (OAT-like) dynamics engineered from native dipolar interactions using controlled nanoscale spin textures, in combination with a dressed-state qubit encoding that significantly extends the sensor coherence time. These results open the door to practical deployment of interaction-enhanced quantum sensors for nanoscale biological imaging and material characterization.
Abstract Optical quantum sensors based on alkali-metal atoms enable highly sensitive magnetic-field measurements in warm vapor. Their performance can become limited by intrinsic spin noise once technical noise sources are sufficiently suppressed. Characterizing temporal spin correlations is therefore important both for optimizing sensor sensitivity and for investigating quantum-enhanced sensing protocols. Here we investigate correlated spin fluctuations in a radio-frequency optical quantum sensor based on a high-density potassium vapor cell using pulsed probe readout. Orthogonal pump and probe beams establish and detect the spin polarization, while a bias magnetic field defines the sensing frequency and the probe pulses are synchronized electronically with the driven spin response. The protocol combines periodic probing, phase cycling, and variable-delay window subtraction. Phase cycling suppresses reproducible probe-induced coherent transients between experimental cycles, whereas window subtraction probes correlations between two measurements within the same cycle. The measured difference noise increases toward an asymptotic value with delay, demonstrating temporal correlations in the processed signal. This behavior is compatible with correlations expected from a conditional quantum non-demolition mechanism, but the present experiment does not independently establish spin squeezing below the standard quantum limit or uniquely exclude residual technical correlations. The protocol provides a practical framework for studying correlated noise in warm-vapor radio-frequency optical quantum sensors.
Version 6.1 develops an integral framework for an analog quantum simulator of spin modelsbased on programmable superconducting-qubit arrays.The principal objective is not merely to construct a quantum device, but to establish atraceable mappingcontrol parameters −→ Hreal −→ quantum evolution −→ observables −→ classical reference.The framework supports transverse-field Ising, XY, XXZ, Heisenberg, long-range, anddisordered spin Hamiltonians.Version 6.1 introduces an explicit Hamiltonian- identification layer between hardwarecalibration and scientific validation.The realized Hamiltonian is decomposed into target terms, static calibration errors, dynamiccontrol errors, crosstalk, leakage, decoherence, and residual unwanted interactions.Validation is organized hierarchically:1. hardware calibration;2. Hamiltonian identification;3. state-preparation validation;4. readout calibration;5. static observable validation;6. dynamical observable validation;7. finite-size benchmarking;8. statistical equivalence testing;9. cross-device reproducibility;10. independent analytical reproduction. The statistical framework replaces the inadequate criterion of “statistical significance ofagreement” with an equivalence framework based on preregistered tolerances.The primary hypothesis is therefore formulated using two one-sided tests (TOST) or anequivalent confidence interval criterion:|∆O| < ϵO.Version 6.1 additionally specifies:• a supplementary Bayesian posterior probability of equivalence as a robustness check;• an explicit distinction between engineering no-go and physical falsification.The framework also specifies negative controls, positive controls, blind analysis, lockedanalysis code, exclusion rules, uncertainty propagation, data provenance, and reproducibilityrequirements.No experimental result or quantum advantage is claimed.
This repository provides the figure data and numerical simulation codes supplement to the manuscript “Dynamical freezing and enhanced magnetometry in an interacting spin ensemble” (arXiv:2507.22982). Contents:--Main_text_figures--Extended_Data_figures Each folder contains the numerical or experimental data used to generate the corresponding figures in the manuscript. All figures can be reproduced by straightforward plotting of the included .csv files. A short description of each dataset is provided within the file headers. --Exact_diagonalization_code--Discrete_truncated_Wigner_approximation_code These directories contain the codes used in the numerical simulations presented in the paper. Each code package includes a detailed README file explaining the workflow, parameters, and usage.
Dayem Bridge Based Nano-SQUID for High Sensitive Nanoscale Applications A recent progress in nanotechnology formulates the fabrication of SQUIDs loop less than 100 nm; its obtaining an adequate sensitivity to detect the magnetic nano-objects. These nano-SQUIDs can be employed to measure small clusters of atomic magnetic moment, to obtain an inductive readout sensor in single-photon detectors and they have been proposed as a magnetic qubit for quantum computing. The research activities at CNR-ICIB has been devoted to the design, fabrication and characterization of nano-SQUIDs based on niobium Dayem Bridge and its magnetization measurements of nanoparticles for advance study of nanomagnetism. Here, I have reported the designs, the fabrication processes and the experimental performances (voltage flux characteristics, spin noise performance) of these nano-devices and also the groundwork measurement of nanoparticles magnetization using switching current measurement method operating in CNR-ICIB laboratory. Design and Fabrication: Many devices are fabrication using advanced electron beam lithography techniques with conventional photolithography, lift off and reactive ion etching techniques. The fabricated devices can be divided into two categories, first bilayer device or non hysteretic device and second single layer device or hysteretic device. a)Non-Hysteretic Device: The bilayer device consists of a niobium loop with a hole of 200nm interrupted by two bridges having length and width dimensions of 100nm X 80nm, 80nm X 60nm etc. The superconducting loop has a washer shape in order to enhance the heat dissipation during the working operations when the sensor is current biased in resistive mode. The device includes a micrometric integrated niobium coil located very close to the nano-sensor in order to modulate, tune and operate the SQUID in FLL mode. b)Hysteretic Device: The single layer devices having two Dayem Bridges of 90nm x 250nm and loop sizes of 2, 1 and 0.75μm, consist of a single niobium layer 20nm thick pattern by electron beam lithography and shaped by lift-off. The SQUIDs were designed to have a hysteretic current-voltage characteristic in order to work as a magnetic flux-current transducer. Performances: a)Non-Hysteretic Device: An intrinsic voltage swing and a maximum responsivity of 75 μV and 1.5 mV/Φ0 can be estimated from the experimental data. Our interest is focused on the characterization in small signal mode, because the magnetic flux coupled into device is expected to be much smaller than Ф0. In fact, such devices are designed to measure very small magnetic fields arising from a local nano-object. The sensor exhibits a magnetic flux noise level of 1.5μΦ0/Hz1/2 in the white region corresponding to a spin noise, in unit of Bohr magneton, of Sn1/2=2aSΦ1/2/(μBμ0)~60 spin/Hz1/2 where a is the radius of the SQUID loop, μ0 is the magnetic vacuum permeability and μB = 9.27 × 10−24 J/T. This value is comparable with the best value reported in the literature. It is worth noting that these sensors show a wide linear region in the V- Φ characteristics; the non-linearity effects are not evident up to 0.02 Φ0. b)Hysteretic Device: The second single layer device shows hysteretic I-V characteristics which are used as magnetic flux-current transducer. The magnetic pattern determines the responsivity of the SQUID, defined as the variation of the critical current as function of the external magnetic flux variation dIc/dΦ; in the present work responsivity up to 30μA/Φ0 have been obtained. The maximum magnetic flux coupled to the 2 and 1 micron loop size is about 2 and 0.5 Φ0 respectively. A critical current modulation is about 20%. An intrinsic sensor magnetic flux resolution less than 1 mΦ0, can be estimated from the intrinsic current fluctuation. The main interest of such devices is magnetization measurement of small magnetic particles by switching current techniques. Simulation Results: We have computed performance of nano-superconducting-quantum-interference devices (SQUIDs) in view of their employment in the detection of small spin populations. The analysis has been focused on nano-SQUID sensors having a square loop with a side length of 200 nm. We have calculated the spin sensitivity and the magnetic response relative to the single Bohr magneton (single spin), as a function of its position within the SQUID hole. The results predict that the SQUID response depends strongly on the spin position. The projected information’s are very useful to optimize the sensor performance in view of the most nanomagnetism applications. Preliminary Measurements of Nanoparticle Magnetization: We have effectively employed non-hysteretic sensor for nanoparticle magnetization investigation in view of nano-magnetism applications. We have performed preliminary measurements with and without iron oxide nanoparticles on the SQUID loop showing that the presence of magnetic nanoparticles can be easily detected and the magnetic relaxation curve measured. To test the capability of our devices in order to detect the magnetization of nanoparticles, we deposited iron oxide nanoparticles, having an average diameter of about 16nm, on chips containing characterized sensors. Here we report the measurement performed on the device with 1μm loop. The presence of iron nanoparticles did not change appreciably the magnetic pattern obtained using the integrated coil (magnetic field normal to the SQUID plane), however the nanoparticle presence was evident by the critical current measurement performed with magnetic field generated using the external solenoid (magnetic field parallel to the SQUID plane). Using the measured responsivity for this particular device (27μA/Φ0) the critical current variation was converted to magnetic flux variation. It is worth to note that with the present electronic at 100Hz to acquire 104 measurements it takes about 100s. The above results clearly indicating that the sensor can be effectively used in nano-magnetism applications.