A Lost Schrödinger Manuscript Reveals a Surprising Twist in Quantum Physics

A three-page manuscript by Erwin Schrödinger, uncovered in an Austrian library by historian Flavio Del Santo, revisits a mid-20th-century debate over whether quantum unpredictability is fundamental or could be explained by hidden variables. In response to arguments by Whittaker and others claiming hidden-variable explanations were impossible, Schrödinger constructs a model where each photon carries a continuous hidden variable (not just a binary instruction) and where that variable is updated deterministically after passing through a polarizer. With appropriate rules his model reproduces the statistical predictions of quantum mechanics for single and successive measurements, showing Whittaker’s polarizer thought experiment does not categorically rule out hidden-variable descriptions. The manuscript remained unpublished - possibly because Heinrich Pelzer had already published a related model - but Del Santo’s reconstruction highlights Schrödinger’s explicit mathematical contribution.

The find also clarifies Schrödinger’s philosophical stance: he had argued long before quantum formalism that nature might be essentially statistical and was skeptical of classical determinism as a priori dogma. His unpublished note defends the logical possibility of determinism against alleged impossibility proofs, not as a dogmatic advocacy but as a proof of principle. The work, now available on arXiv via Del Santo, underscores that questions about determinism versus indeterminism remain open and that historical debates still yield instructive models.