This preprint introduces and characterises a collective Fisher-information-inspired magnetisation-feedback term for Kuramoto--XY quantum simulations. The model augments a heterogeneous XY Hamiltonian with a diagonal term proportional to minus lambda times total magnetisation squared, normalised by qubit count, creating explicit magnetisation-sector energy shifts while preserving ideal XY magnetisation conservation. Artefact-generated exact diagonalisation on n = 4, 6, and 8 qubits shows systematic changes in ground energy, spectral width, and spectral gap as the feedback strength varies. The manuscript also reports adjacent-gap statistics, low-energy bipartition entropy trends, and a small n = 4 VQE benchmark comparing a K_ij-informed ansatz against generic TwoLocal and EfficientSU2 baselines. The record archives the source, bibliography, and PDF for a hardware-falsifiable modelling contribution. Claims are limited to the stated exact diagonalisation grid, VQE benchmark configuration, and associated committed artefacts.
The quantum phase transitions provide a paradigm for studying collective quantum phenomena that are a result of competing non-commuting interactions. This paper will study the ground state properties and quantum critical dynamics of the one-dimensional transverse field Ising model through a combined perspective that includes exact diagonalisation, variational quantum eigensolver (VQE) simulations, and simulations on realistic physical quantum devices. We focus on a lattice of four spins, where we calculate the ground-state energies, magnetic order parameters and correlation functions at uniformly applied conditions, which is repeated by all systems. Precise diagonalisation provides both a benchmark, which is symmetry-conserving, and a depth-two, physics inspired variational approximation, which provides simulations accessible to hardware. The circuits that have been optimised identically are then placed on the IQM Garnet quantum processor, using a resource-efficient batched protocol. We find that the ground-state energies of shallow variational circuits are reliably captured by the circuit over the entire parameter space; the magnetic arrangement parameters and observables sensitive to correlation signal significantly more noise. The error analysis of quantitative analysis reveals a strong broadening of critical crossover on hardware, which is consistent with the noise attenuation of long-range correlations. These findings highlight the current capabilities as well as the fundamental limitations of noisy intermediate-scale quantum systems in modelling quantum critical phenomena as a benchmark to future enhancements in obtaining quantum hardware and quantum algorithms development.
We work in the universal information hydrodynamics (UIH) framework developed in two companion papers, where reversible quantum dynamics and irreversible response are organised in a local metriplectic geometry generated by a convex free energy, a Fisher metric, and an antisymmetric no work channel. In this setting the irreversible drift is always a Fisher gradient flow in a weighted
H−1 geometry, equipped with a cost entropy inequality and a curvature coercivity bound that are invariant under the addition of any compatible reversible dynamics. In the present paper we show that this structure has a canonical realisation for Fokker Planck equations, finite Markov chains and GKLS semigroups, and that it can be reconstructed operationally from process and state tomography on real quantum hardware. First, starting from overdamped Langevin dynamics and its Fokker Planck generator, we identify a canonical Fisher Dirichlet operator
G=Qdiag(π) that plays the role of the symmetric mobility on a periodic lattice and saturates the cost entropy inequality mode by mode. We then demonstrate that in a wide class of thermal and driven GKLS models the symmetric part of the real generator in the stationary BKM metric has a density block that coincides exactly with this classical Fisher operator, including nonreversible chains and random qubit and qutrit ensembles, and that the global decay of entropy and Fisher energy is governed by the Markov spectral gap while the Fisher gap controls only local curvature. Finally, we implement a suite of IBM Quantum experiments on a superconducting qubit that realises the full UIH picture on hardware. Process tomography of idle circuits yields an effective real generator
K in the Pauli basis whose metric adjoint split in the BKM metric at the device stationary state produces a clean metriplectic decomposition
K=G+J, with
G metric symmetric and
J metric skew. Independent idle depths are consistent with a single time homogeneous generator, the dissipative spectrum of
G sets an information theoretic speed limit for BKM Fisher decay, and a curvature test shows that the same BKM metric is the local Hessian of quantum relative entropy at the stationary state. All claims are backed by a reproducible Python archive that includes constructive Fokker Planck to Markov to GKLS lifts, hypocoercive decay diagnostics, and hardware K tomography. Taken together, the results in this paper show that this programme is not only mathematically coherent, but experimentally visible, showing strong signatures of universality.
This preprint reports a cost-bounded reduced-Pauli entanglement and tomography check for promoted Phase 3 DLA-parity and Fisher-information-modified Kuramoto--XY circuit families. The purpose is to distinguish parity-sector leakage structure from layout, prepared-state, and readout artefacts in small superconducting-hardware experiments. The archived IBM execution used physical qubits [1,2,3,4] on ibm_marrakesh, 162 main circuits, four readout-calibration circuits, 2048 shots per main circuit, and 8192 shots per readout circuit. A preregistered reducer produced 54 observable rows; the manuscript reports measured-minus-exact deviations, identifies the largest transverse two-qubit correlator deviations, and compares readout-mitigated replay and same-day ibm_fez replication. The record includes manuscript source, bibliography, and PDF. The claim boundary is hardware-observation and artefact-reduction evidence for these named circuit families, not a backend-independent universal promotion.
This methods preprint describes the software and experimental workflow behind scpn-quantum-control, an open-source framework for mapping heterogeneous Kuramoto-type oscillator networks to XY spin Hamiltonians, compiling topology-informed variational ansatze, benchmarking simulation paths, and executing reproducible NISQ hardware experiments. The workflow combines Python/Qiskit orchestration with a Rust/PyO3 acceleration layer for hot-path kernels including coupling-matrix construction, Hamiltonian assembly, trajectory features, hybrid digital--analog partitioning, and protected-subspace diagnostics. The manuscript reports artefact-generated timings across local workstation, ML350, Vertex AI CPU, and Vertex AI Tesla T4 contexts, with checksum parity across Python, Rust, and Go kernels. The record includes manuscript source, notes bibliography, and PDF. It is an archival methods record for the repository and its reproducibility artefacts, not an independent claim of broad quantum advantage.