The idea

Quantum mechanics, taken literally, predicts that a measuring device ends up in a superposition of outcomes: the cat both alive and dead, the pointer at every reading at once. We never see that. The textbook patch is the collapse postulate, where at measurement the state jumps to one outcome, by hand, outside the unitary law. The many-worlds picture keeps unitarity but pays with an unobservable branching multiverse. Both are answers to the same question: why one world?

The hypothesis

QIQT-H starts from a single physical premise drawn from black-hole thermodynamics and holography: a bounded region of space has only a finite amount of operational information capacity, on the order of its boundary area in Planck units, $Q_R = A/4\ell_P^2$ (in natural entropy units). Finite, as a postulate of the program.

A wave function that recorded two macroscopically distinct outcomes at once, pointer-left and pointer-right with all their correlated environmental traces, would be a far richer object than one recording a single outcome. Now, finite capacity by itself does not forbid the superposition — a finite-dimensional space still contains plenty of superposed distinguishable states. The load-bearing, nonstandard claim is sharper: physically instantiating two macroscopic records in a region would cost more information than its bound allows, so the two-record state is inadmissible there. That claim — the Macroscopic Definiteness Conjecture — is the crux of the whole program, and it is unproven.

What this buys, and what it doesn’t

If the hypothesis holds, definiteness of the macroscopic world becomes a consequence of finite information rather than a separate postulate. No collapse term, no branching ontology.

It does not, by itself, hand you the probabilities. That a given run yields outcome $k$ with frequency $|c_k|^2$, the Born rule, is argued separately from the typicality of microscopic initial conditions across runs, and that argument is still open. Until it is settled, QIQT-H is an account of definiteness — why there is one outcome — not yet a complete interpretation that also says with what frequency.

Where it stands

This is a research program with a sharp core, not a finished interpretation. It stakes itself on a falsifiable claim: that a region cannot be held in a coherent superposition of two macroscopically distinct records once instantiating them would exceed its holographic budget. The mathematical substrate it borrows — modular theory and relative entropy, the bookkeeping of regional information cost — is machine-verified in Lean 4. The load-bearing physical conjecture, that two records genuinely overflow the bound, is stated precisely and remains to be proved. Read on for the mathematics or the open problems.