Letter: We need to burst another quantum bubble, too

From Robert Masta, Ann Arbor, Michigan, US

“Bursting the bubble”, about quantum ideas that could do away with the multiverse, was excellent, but it is troubling that theorists still consider Schrödinger’s cat and Wigner’s friend to be valid thought experiments. They assume that a human observer is required for quantum collapse, which is absurd (11 January, p 32).

How did the universe get along without us for 13 billion years?

Quantum superpositions are so fragile that designers of qubits for quantum computers must go to great extremes to isolate them, yet still they collapse in milliseconds as a result of stray interactions.

Schrödinger and Wigner (and friend) are simply ignorant of the collapse until they peek.