Quantum Phase Estimation

Quantum Phase Estimation (QPE) is the algorithm that lets a quantum computer read out the eigenphase φ hidden inside a unitary operator's eigenvalue e^(2πiφ) — the core subroutine behind Shor's factoring algorithm and quantum chemistry eigensolvers. This simulator computes the exact closed-form probability distribution that the inverse Quantum Fourier Transform produces over the counting register's 2^n possible outcomes, rendered as a ring of 3D bars around a phase circle. Move the true-phase slider or jump to a clean fraction, change how many counting qubits sample the register, and watch the distribution sharpen around the correct answer — then hit Measure to sample one real Born-rule outcome, exactly as a physical quantum processor's readout would collapse to a single integer.