Decoherence Visualizer

Quantum channels and the loss of coherence

Start with a pure qubit state on the Bloch sphere surface. Apply amplitude damping (T1 decay), phase damping (T2 dephasing), or depolarizing noise repeatedly. Watch the Bloch vector shrink from the sphere surface toward the interior as the state becomes mixed. Track the density matrix entries and purity in real time.

Initial Pure State

Quantum Channel

Amplitude Damping-- Energy relaxation toward |0> (T1 decay)Phase Damping-- Pure dephasing — off-diagonals decay (T2 decay)Depolarizing-- Uniform shrinkage toward maximally mixed state I/2

Channel Strength γ: 0.000

Density Matrix ρ

0.5000

State Metrics

Purity tr(ρ²)1.0000

maximally mixed (0.5)pure (1.0)

Bloch vector length |r|1.0000

r = (1.000, 0.000, 0.000)

Amplitude Damping

\rho \to E_0 \rho E_0^\dagger + E_1 \rho E_1^\dagger

Energy relaxation toward |0> (T1 decay)

Decoherence drives pure states (Bloch sphere surface) toward mixed states (interior). The purity decreases as quantum coherence is lost to the environment.

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