2025-10-07

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Quantum State Vectors, 5 pages.

Abstract

This paper examines four experiments in which quantum state vectors behave in surprising ways. Three approaches to modelling the Frauchiger-Renner extended Wigner’s friend setup each can end up with different probabilities for the same outcomes. An attack on a quantum key exchange appears to involve the zeroing of one qubit affecting the state of another qubit, which does not make physical sense. In quantum teleportation, it is difficult to define a state where two qubits agree in the x and z bases but can have arbitrary probabilities. A simple circuit features a gate that only has an effect in certain interpretations of quantum mechanics.