Tessera Lens

See what your circuit actually does.

Tessera Lens is a 3D quantum circuit builder, statevector simulator, and state-space visualizer. You build a circuit, it runs on an exact simulator, and the quantum state itself, every probability and every phase, renders in 3D and updates as the circuit runs.

It's the visual companion to Tessera. Where the transpiler prepares circuits for real hardware, Lens is the intuition engine for seeing what those circuits do. It runs entirely in the browser with no backend, no install, and no account.

Launch Tessera Lens

The full Tessera Lens interface — The full instrument: 3D state view on the left, circuit builder on the right, transport along the bottom.

The idea

The metaphor is exact, not decorative.

A tesseract is a 4-cube with 16 vertices. Four qubits have exactly 16 computational basis states (|0000⟩ … |1111⟩).

So the hero visualization is literally a tesseract whose sixteen vertices are the basis states. Two vertices share an edge exactly when their basis states differ in a single qubit: the hypercube graph, at Hamming distance one. Apply a gate and amplitude flows along those edges. Measure and the whole thing collapses to a single lit vertex.

It generalizes past four. For any n qubits you get the projected n-cube (a line, a square, a cube, a tesseract, a penteract), rendered as nested cubes, where each qubit beyond the third selects a concentric shell.

The tesseract view with a GHZ state — A 4-qubit GHZ state. Only |0000⟩ and |1111⟩ carry amplitude, so two opposite vertices light up and the rest fade to grey.

Three views

The same state, three ways.

Tesseract

The 2ⁿ basis states are the vertices of a hypercube, a literal tesseract at four qubits. Vertex size is probability, hue is phase.

Bloch

One Bloch sphere per qubit, each vector coloured by that qubit's phase. The vector shrinks toward the centre as the qubit becomes entangled.

Amplitudes

A 3D bar chart of the full probability distribution, for when you want the raw numbers rather than the geometry.

The Bloch sphere view — One Bloch sphere per qubit. Vectors shrink toward the centre as a qubit becomes entangled, and in a GHZ state they collapse to nothing.

The amplitude bar chart view — The whole probability distribution as a 3D bar chart, coloured by phase.

Build a circuit

Click a gate, click a cell.

One to six qubits, and a palette covering H, the Paulis, S, T, √X and their daggers, the Rx/Ry/Rz rotations, phase gates, the general U(θ, φ, λ), CNOT, CY, CZ, controlled-phase, SWAP, Toffoli, and mid-circuit measurement.

Two-qubit gates take two clicks: control, then target. Parametric gates are editable: click a placed gate to set its angle with a slider, a number field, or π-presets, and the state updates live as you drag. Hit sweep to animate an angle on a loop and watch the state trace a path across the tesseract.

The circuit builder and gate palette — Pick a gate, click a cell. Parametric gates open a slider, a number field, and π-presets that update the state live.

Debug & verify

Tools for when it doesn't do what you expected.

Qubit splits

Toggle a barrier per qubit that cuts the hypercube into the half where that qubit reads 0 and the half where it reads 1. Each side is labelled with the probability sitting on it, so you can read a qubit's marginal straight off the scene. A faded side means that qubit is deterministic.

Verify inverse

Append the circuit's own inverse and check the state returns to |0…0⟩, reporting the fidelity. It confirms every gate you placed has a correct inverse and reveals precision loss on deep circuits.

Measurement histogram

Sample 128 to 4096 shots from the current state and watch the counts distribution converge on the dashed ideal probabilities as sampling noise shrinks.

Step through it

Scrub the circuit gate column by gate column, or press play and watch amplitude flow across the hypercube. Measure collapses the state; uncollapse restores the superposition.

Import and export

Round-trip circuits as OpenQASM 2.0, Qiskit, or native JSON. Paste a circuit in to visualize it, or build one here and take it out to Tessera and real hardware.

Undo, redo, keyboard

Every edit is undoable, with slider drags collapsing into a single step. Space runs and pauses, arrows step, Home and End jump to either end.

Qubit split barriers cutting through the tesseract — Qubit splits: a barrier separating the vertices where a qubit reads 0 from the ones where it reads 1, each side labelled with its probability mass.

The measurement histogram — Sample up to 4096 shots and watch the counts converge on the dashed ideal probabilities.

Exact simulation

No approximations.

Lens runs on a hand-written statevector simulator with no simulation dependencies: the full 2ⁿ complex amplitudes, carried exactly. Everything on screen is the real quantum state, not an artist's impression of one. The statevector table lists every basis state's amplitude, probability, and phase alongside the 3D view, so you can always check the geometry against the numbers.

Try it

It loads with a GHZ state already running.

No install, no sign-up. Open it, drag the tesseract around, and step through the circuit that's already there.

Launch Tessera Lens