Deterministic quantum computation with one quantum bit (DQC1) has got plenty of attention due to demonstrating a rather surprising premise - a single gain bit of purity appears sufficient for a quantum computer to exhibit exponential speed over classical counterparts. In this article, we explored how these ideas map to metrology - where the goal is estiate some unknown parameter. It turns that metrology exhibits analogous behaviour. Using just one pure qubit, together with a reservoir of complete mixed qubits
