Quantum Computing by Hand: Qubit Amplitudes, Gates as Small Matrices, Measurement Probabilities, Entanglement & a Two-Qubit Search
Open up tiny quantum circuits in a spreadsheet: state vectors, gates as 2×2 and 4×4 matrices, measurement probabilities, entanglement and a two-qubit search, with every cell checked as you go – no physics degree needed.
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About this course
This course opens up tiny quantum circuits cell by cell, using only real amplitudes and plain spreadsheet formulas. You square amplitudes into measurement probabilities and normalise raw states, apply X, Z and Hadamard gates as 2 × 2 matrix rows with SUMPRODUCT, and simulate measurement shots from a fixed random column with MATCH. You build two-qubit states with the tensor product, create a Bell state with a 4 × 4 CNOT and count correlated shots with COUNTIFS. Then you see amplitudes cancel in H–H versus H–Z–H, run one round of a two-qubit search with an oracle and a diffusion step, and calculate why simulating n qubits needs 2ⁿ amplitudes.
Lessons
- One Qubit: Amplitudes, Probabilities & Normalising a State Pro
- Single-Qubit Gates: X, Z and Hadamard as Small Matrices Pro
- Measurement: Probabilities, Simulated Shots & Counts vs Expectation Pro
- Two Qubits: Four Amplitudes, Basis Labels & the Tensor Product Pro
- CNOT & Entanglement: A 4 × 4 Gate, a Bell State & Correlated Shots Pro
- Interference: Why H–H Returns |0⟩ and H–Z–H Returns |1⟩ Pro
- A Two-Qubit Search: Oracle Sign Flip, Diffusion & the Marked Item Pro
- Circuit Summary: Final Probabilities, a Shot Histogram & Why Simulation Grows as 2ⁿ Pro