On Non-linear Quantum Mechanics and the Measurement Problem I. Blocking Cats

TL;DR

This paper proposes a modification to quantum mechanics within the Schrödinger framework to prevent macroscopic superpositions, aiming to recover classical physics at large scales without altering microscopic predictions.

Contribution

It introduces a Hamiltonian modification based on Weinberg's method to eliminate macroscopic dispersion while preserving quantum predictions at small scales.

Findings

Prevents formation of macroscopic superpositions ('cats')

Restores classical physics at macro level

Maintains standard quantum predictions microscopically

Abstract

Working entirely within the Schroedinger paradigm, meaning wavefunction only, I present a modification of his theory that prevents formation of macroscopic dispersion (MD; "cats"). The proposal is to modify the Hamiltonian based on a method introduced by Steven Weinberg in 1989, as part of a program to test quantum mechanics at the atomic or nuclear level. By contrast, the intent here is to eliminate MD without affecting the predictions of quantum mechanics at the microscopic scale. This restores classical physics at the macro level. Possible experimental tests are indicated and the differences from previous theories discussed. In a second paper, I will address the other difficulty of wavefunction physics without the statistical (Copenhagen) interpretation: how to explain random outcomes in experiments such as Stern-Gerlach, and whether a Schroedingerist theory with a random component can violate Bell's inequality.