Dark cover: a green wave oscillates toward an amber-edged barrier, decays as a pink exponential inside it, and emerges as a smaller green wave — beneath the title The Wall Is a Change of Sign

The Wall Is a Change of Sign

Classical mechanics forbids the crossing for an exact reason: inside the barrier there is no real number left to be the momentum. The Schrödinger equation carries on — one coefficient changes sign, oscillation becomes decay, and the faint exponential tail on the far side is why the Sun shines and how the first microscope to image atoms worked. Part Ten, for philosophers and theologians: tunnelling without the folklore. … readThe Wall Is a Change of Sign

Dark cover with the title Collapse Is Not a Rotation, the word Rotation in italic pink, and a large ghosted P-psi glyph in the lower right.

Collapse Is Not a Rotation

Quantum mechanics contains exactly two ways a state can change: a rotation that is reversible, deterministic and always running, and a projection that keeps one component and deletes the rest. A lesson for philosophers and theologians on what the geometry fixes about wave function collapse — its shape, its weights, its basis, even the impossibility of dating it — and the one question it leaves open. … readCollapse Is Not a Rotation

Dark cover with the title The Parts Do Not Determine the Whole, the word Determine in pink italic, over a faint tensor-product symbol: a circle with a diagonal cross through it.

The Parts Do Not Determine the Whole

Join two quantum systems and their state spaces multiply rather than add, and almost nothing in the product comes apart again into a state for each half. A lesson on entanglement for philosophers and theologians: what Bell actually ruled out, why entangled is not the same as non-local, and why the honest claim is a failure of supervenience rather than a disappearance of the parts. … readThe Parts Do Not Determine the Whole

Dark title card reading 'The i Is in the Equation' above two boxed equations: F equals m a in amber with a green tick marked 'Re Psi solves it', and the Schrodinger equation in pink with a cross marked 'Re psi does not'.

The i Is in the Equation

Classical physics uses complex numbers constantly and can always discard them at the end. Quantum physics cannot, and the reason is exact: take the real part of a classical solution and you still have a solution — take the real part of a wavefunction and you have nothing. A lesson for philosophers and theologians on what F = ma actually claims, and what quantum mechanics does and does not license. … readThe i Is in the Equation