Use cases · Physics

Physics, from first principles to a number.

Simulations, observational data and theory worked through carefully, with error bars, finite-size checks and the literature value beside every result.

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Real runs

Open a real physics run.

Each one is a complete run in production: the question as it was asked, every step Propab took, and everything it made.

Reproduce the 2D Ising model ferromagnetic phase transition from first principles. Run Monte Carlo (Metropolis, plus a Wolff cluster algorithm near criticality) on square lattices of several sizes, measure magnetisation, susceptibility, specific heat and the Binder cumulant, and estimate the critical temperature by finite-size scaling. Compare your estimate with Onsager's exact result and with values reported in the literature.

ObservablesFinite-size fitPDF report

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75 physics workflows, set up and tested.

Start from one of these, or ask in your own words. Propab combines them when your question needs more than one.

Astrophysics

Known-exoplanet population study

Mass-radius and period-radius diagrams (e.g. the radius valley) from the NASA Exoplanet Archive, with the selection cuts stated.

Astrophysics

Redshifts and emission lines from SDSS spectra

Redshift, line fluxes and a BPT classification for a galaxy sample, from SDSS line catalogues or the spectra themselves.

Astrophysics

Hubble constant from Pantheon+ supernovae

H0 / Omega_m posterior from the Pantheon+SH0ES distance moduli with the full covariance matrix, with a corner plot.

Astrophysics

Gravitational-wave population from published posteriors

Mass and spin distribution of merging black holes by hierarchical inference over the GWTC posterior samples.

Astrophysics

Analyse my cosmological simulation output

Halo profiles, projections and power spectra from a simulation snapshot the researcher uploads.

Computational physics

Check an integrator's order and conservation

Measured convergence order and energy/momentum drift of an integrator (symplectic vs Runge-Kutta) on a test problem.

Computational physics

Long-term stability of a planetary system

MEGNO / Lyapunov map and survival time of a multi-planet system over millions of orbits.

Computational physics

Solve a PDE and prove the convergence order

Finite-difference solution of a heat/wave/Poisson problem with a grid-refinement study against the exact solution.

Computational physics

Monte Carlo estimate with an honest error bar

Monte Carlo integral or expectation with variance reduction and a convergence plot.

Computational physics

Spectrum of my time series

Power spectral density (Welch/multitaper), peaks and their significance for a signal the researcher supplies.

Computational physics

Derive equations of motion and simulate them

Lagrangian to equations of motion symbolically, then integrated and plotted (phase portraits, energy).

Computational physics

Fit a simulation's parameters by gradient

Differentiable simulation fitted to data by automatic differentiation.

Computational physics

Solve a stiff ODE or DAE system

Stiff kinetics or an index-reduced DAE solved with an implicit integrator, with a solver-tolerance study.

Condensed matter

Tight-binding bands and density of states

Band structure and DOS of a lattice model, checked against the analytic dispersion.

Condensed matter

Topological invariant of a model

Chern number or Z2 invariant of a Hamiltonian, with the Berry-curvature or Wilson-loop plot.

Condensed matter

Ground state of an interacting 1D model by DMRG

Energy, correlations and entanglement entropy of a spin or Hubbard chain with TeNPy or quimb.

Condensed matter

Exact diagonalisation of a small interacting cluster

Spectrum and correlation functions of a Heisenberg or Hubbard cluster by Lanczos.

Condensed matter

Screen a materials database for a property

Candidates ranked by band gap, stability or magnetism from open DFT databases.

Condensed matter

Classical spin Monte Carlo for a magnetic transition

Ordering temperature and susceptibility of a Heisenberg/Ising magnet on a lattice.

Fluid and continuum mechanics

2D incompressible flow benchmark

Lid-driven cavity or flow past a cylinder with drag, lift and Strouhal number against published reference values.

Fluid and continuum mechanics

Linear stability of a shear flow

Orr-Sommerfeld eigenvalues, neutral curve and critical Reynolds number.

Fluid and continuum mechanics

Structural finite-element check against a reference

Stress and deflection of a beam/plate/solid against an analytic or NAFEMS benchmark value.

Fluid and continuum mechanics

Topology optimisation of a structure

Minimum-compliance layout at a volume fraction (SIMP), with a mesh-independence check.

Fluid and continuum mechanics

Bifurcations and chaos in a low-dimensional system

Bifurcation diagram, Lyapunov exponent and period-doubling constants.

Fluid and continuum mechanics

Recover governing equations from data

Sparse identification (SINDy) of a dynamical system from measured trajectories, with a noise-robustness test.

Nuclear physics

Decay an inventory forward in time

Activities, decay heat and gamma lines of a nuclide inventory over time.

Nuclear physics

Binding energies against a mass model

AME2020 binding energies vs the semi-empirical mass formula, with shell-closure residuals.

Nuclear physics

Measured cross sections against evaluated libraries

EXFOR measurements plotted and compared against ENDF/B-VIII and JEFF evaluations for a reaction.

Nuclear physics

Nucleosynthesis reaction network

Energy generation and abundance flow for a burning stage from a REACLIB network.

Nuclear physics

Astrophysical reaction rate from a cross section

Thermonuclear rate vs temperature from an S-factor or narrow resonances, with its uncertainty.

Nuclear physics

Analyse my gamma-ray spectrum

Peak fits, energy/efficiency calibration and nuclide identification for a detector spectrum.

Optics and electromagnetism

Mie scattering of particles

Extinction, scattering and backscatter efficiencies vs size parameter and wavelength.

Optics and electromagnetism

Thin-film stack reflectance

Reflectance/transmittance spectra of a multilayer coating from real dispersion data.

Optics and electromagnetism

Diffraction pattern or telescope PSF

Fraunhofer/Fresnel propagation of an aperture and the PSF with aberrations.

Optics and electromagnetism

Resonator modes and Q factor (2D FDTD)

Cavity resonances, Q factors and transmission of a 2D photonic structure.

Optics and electromagnetism

Photonic-crystal band structure

Band diagram and band gaps of a photonic crystal slab.

Optics and electromagnetism

Grating diffraction efficiency (RCWA)

Diffraction efficiencies of a periodic grating vs wavelength and angle.

Optics and electromagnetism

Lens design and ray tracing

Sequential ray trace of a lens with real glasses: spot diagrams, aberrations and a tolerance check.

Optics and electromagnetism

Analyse my measured S-parameters

Touchstone network data de-embedded, fitted and plotted (Smith chart, return loss).

Particle physics

Rediscover the Z and J/psi in collision data

Dimuon invariant-mass spectrum from CMS open data with fitted resonance masses and widths.

Particle physics

Bump hunt with local and global significance

Search for a resonance in a mass spectrum with a look-elsewhere-corrected significance.

Particle physics

Upper limits with a HistFactory model

95% CL CLs limits on a signal from binned templates.

Particle physics

Jet clustering and substructure

Anti-kt jets and substructure observables of boosted objects on open data or supplied events.

Particle physics

Standard Model prediction vs the world average

Literature synthesis of a precision observable (e.g. muon g-2): each value, source and tension in sigma.

Particle physics

Efficiency and scale factor by tag-and-probe

Reconstruction/ID efficiency vs pT/eta in data and simulation, and their ratio.

Plasma physics

Characterise a plasma regime

Debye length, plasma frequency, beta, collisionality and the regime they imply, for stated conditions.

Plasma physics

Kinetic dispersion relation

Roots of the plasma dispersion function (Landau damping, ion-acoustic waves) against analytic limits.

Plasma physics

1D electrostatic particle-in-cell

Two-stream instability growth rate from a PIC run against linear theory.

Plasma physics

Solar-wind driving of geomagnetic storms

OMNI solar-wind coupling functions against Dst/AE over a storm set, with lag correlations.

Plasma physics

Turbulence spectrum from spacecraft magnetometer data

Spectral index and break frequency of solar-wind or magnetosheath turbulence (Wind, MMS).

Plasma physics

Free-boundary tokamak equilibrium

Grad-Shafranov equilibrium and the coil currents that produce a target shape.

Plasma physics

MHD benchmark problem

Brio-Wu shock tube or Orszag-Tang vortex with a finite-volume MHD solver, checked against reference solutions and div B.

Plasma physics

Analyse my Langmuir-probe sweep

Electron temperature, density and floating/plasma potential from an I-V characteristic.

Quantum physics

Decoherence of a driven qubit

T1/T2 and Rabi dynamics from a Lindblad master equation.

Quantum physics

Variational algorithm on a spin Hamiltonian

VQE or QAOA with gradients, converged energy and comparison with exact diagonalisation.

Quantum physics

Noisy circuit simulation at scale

Circuits under a device noise model, up to the memory limit of a statevector/density matrix.

Quantum physics

Surface-code error-correction threshold

Logical error rate vs physical error rate across code distances, and the crossing point.

Quantum physics

Tomography and randomised benchmarking

State/process tomography and RB decay on a simulated device.

Quantum physics

Bound a Bell scenario by semidefinite programming

NPA-hierarchy bound on a Bell expression with the SDP certificate.

Quantum physics

Tensor-network simulation of many qubits

MPS/tensor-network simulation of a low-entanglement circuit beyond statevector size.

Quantum physics

Molecular Hamiltonian and VQE

Qubit Hamiltonian of a small molecule and a VQE energy against full CI.

Quantum physics

Optimal control of a quantum gate

GRAPE/CRAB pulse that implements a gate at target fidelity under constraints.

Relativity and mathematical physics

Curvature of a metric

Christoffel, Riemann, Ricci and Einstein tensors, and whether the metric solves the field equations.

Relativity and mathematical physics

Geodesics in a curved spacetime

Orbits, perihelion precession, light bending or a black-hole shadow by geodesic integration.

Relativity and mathematical physics

Random-matrix spectral statistics

Level-spacing distribution and spectral form factor against GOE/GUE predictions.

Relativity and mathematical physics

Asymptotic expansion of an integral or special function

Series/asymptotic forms derived symbolically and checked numerically to high precision.

Relativity and mathematical physics

Small lattice gauge simulation

Pure-gauge U(1)/SU(2) Monte Carlo with Wilson loops and the string tension.

Relativity and mathematical physics

Bethe ansatz vs exact diagonalisation

Bethe-ansatz energies of an integrable chain checked against exact diagonalisation.

Statistical mechanics

Critical point and exponent by finite-size scaling

Critical temperature and an order-parameter exponent with statistical and systematic errors separated.

Statistical mechanics

Cluster Monte Carlo that beats critical slowing down

Wolff/Swendsen-Wang updates with measured autocorrelation times vs Metropolis.

Statistical mechanics

Density of states by Wang-Landau

g(E) of a lattice model and thermodynamics at any temperature from one run.

Statistical mechanics

Error bars for correlated Monte Carlo data

Integrated autocorrelation time and binning/blocking error for a Monte Carlo series.

Statistical mechanics

Percolation threshold and cluster scaling

p_c and cluster-size exponents by finite-size scaling.

Statistical mechanics

Lennard-Jones fluid against NIST reference data

Energy and pressure of LJ configurations compared with the NIST Standard Reference Simulation values.

Statistical mechanics

Stochastic-process simulation

Exclusion processes, kinetic Monte Carlo or Gillespie simulations with scaling exponents.

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