Monium
Get Monium

iPhone · Android coming soon

Simulate superconducting qubits.

Monium brings transmons, tunable transmons, and fluxonium to mobile — interactive energy spectra, wavefunctions, matrix elements, and coherence times, computed on-device.

  • Transmon
  • Tunable transmon
  • Fluxonium
Download Monium on the App StoreAndroid coming soon
Monium showing a fluxonium's wavefunctions over its double-well potential
What it does

What it computes

  • Energy spectra

    Eigenenergies swept over the parameters each qubit exposes — EJ, EC, charge offset, and flux where the qubit has one — with transition readouts.

  • Wavefunctions

    Plot |ψ|², Re ψ, Im ψ, or the charge basis over the qubit potential, level by level.

  • Matrix elements

    Operator matrix-element heatmaps with magnitude, real, and imaginary views and LaTeX labels.

  • Matrix-element scans

    Watch individual matrix elements evolve as you sweep a circuit parameter.

  • Coherence times

    Per-channel T₁ and Tφ plus effective T₁/T₂ versus the swept parameter, on a log scale.

  • Convergence built in

    An always-on convergence estimate flags levels that may not be converged, with one-tap refinement.

See it

Every view, computed live on-device.

  • Monium — Energy spectrum
    Energy spectrumLevels vs. flux
  • Monium — Circuit & Hamiltonian
    Circuit & HamiltonianThe physics, defined
  • Monium — Wavefunctions
    Wavefunctionsψ over the potential
  • Monium — Matrix elements
    Matrix elementsOperator heatmap
  • Monium — Element scan
    Element scanElements vs. parameter
  • Monium — Coherence
    CoherenceT₁ / T₂ channels
Depth

Start from what you measure

Monium is for exploring the physics — convergence you can check and matrix elements in full — and it takes the quantities you measure — critical current, junction inductance, normal-state resistance — and turns them into spectra.

  1. Monium’s parameter-entry sheet converting between EJ, critical current, Josephson inductance and normal-state resistance
    For the bench

    Enter what you measure

    Set the energies the way your wafer reports them: the junction energy from critical current I_c, Josephson inductance L_J, or room-temperature normal-state resistance R_n (via Ambegaokar–Baratoff, with a cryo/room correction and a material gap — aluminum by default); the charging energy from a capacitance; the inductive energy from an inductance. On a tunable transmon, split E_J into its two junctions and the SQUID asymmetry follows.

  2. Monium’s convergence sheet reporting an estimated relative error and a re-verify control
    Convergence

    Check for convergence issues

    The spectrum on screen carries a convergence check at the parameters you have set. Monium re-diagonalizes at a larger cutoff or finer grid, estimates the relative error, and flags levels that may not be converged — good evidence, not a guarantee. Re-verify on demand.

  3. Monium’s matrix-element plot options: operator, component, and per-element selection
    Matrix elements

    Choose the operator and the transitions

    Inspect ⟨i|Ô|j⟩ for the operator you care about — n̂, φ̂, cos φ, or sin φ — as real part, imaginary part, magnitude, or |·|², and toggle exactly which transitions appear.

Built on scqubits

A port of scqubits, tested against it.

Monium’s engine is a port of scqubits, the open-source library for superconducting qubits, and follows its conventions. The spectra, matrix elements and coherence times of the transmon, tunable transmon and fluxonium are tested against scqubits.

Explore scqubits

Now on the App Store.

Monium is available on the App Store for iPhone. The Android version is coming soon.

Download Monium on the App StoreAndroid coming soon