Journal

Tag: quantum-measurement

Long-form notes, Qiskit experiments, and applied optimization thinking.

August 30, 2026•Learning Notes•5 min read

Measuring Entangled Qubits in Same and Different Bases

Entanglement becomes much clearer when we stop treating it only as a factorization test and start asking what Alice and Bob actually observe when they measure. This note develops the Bell-state measurement behavior step by step, showing why same-basis measurements are perfectly correlated while different-basis measurements become 50/50.

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August 30, 2026•Learning Notes•6 min read

Tensor Products and Entanglement: Why Two Qubits Need a Joint State

Tensor products answer a basic question in quantum mechanics: how do we describe two quantum systems together? This note develops tensor products from scratch, shows why two qubits require a four-dimensional joint state space, and explains why a pure two-qubit state is entangled when it cannot be factored into separate pure states for Alice and Bob.

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