QUANTUM WALK
1D Discrete Quantum Walk — Hadamard Coin & Interference
A quantum walker on a line uses a coin operator (Hadamard matrix) to create superposition, then shifts left and right simultaneously. Unlike classical random walks (σ∝√t), quantum walks spread ballistically (σ∝t) due to constructive/destructive interference between paths. The initial coin state |↑⟩e^{iφ} breaks left-right symmetry.