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Rethinking Collapse: Coupling Quantum States to Classical Bits with quasi-probabilities

Quantum Physics 2025-12-04 v1

Abstract

We propose a formulation of quantum measurement within a modified framework of frames, in which a quantum system - a single qubit - is directly coupled to a classical measurement bit. The qubit is represented as a positive probability distribution over two classical bits, a and a', denoted by p(aa'). The measurement apparatus is described by a classical bit α=±1\alpha = \pm 1, initialized in the pure distribution p(α)=12(1+α)p(\alpha) = \frac{1}{2}(1 + \alpha). The measurement interaction is modeled by a quasi-bistochastic process S(bbβaaα) S(bb'\beta \mid aa'\alpha) - a bistochastic map that may include negative transition probabilities, while acting on an entirely positive state space. When this process acts on the joint initial state p(aa)p(α)p(aa')p(\alpha), it produces a collapsed state p(bbβ)p(bb'\mid\beta), yielding the measurement outcome β\beta with the correct quantum-mechanical probability p(β)p(\beta). This approach bypasses the von Neumann chain of infinite couplings by treating the measurement register classically, while capturing the nonclassical nature of measurement through the quasi-bistochastic structure of the interaction.

Keywords

Cite

@article{arxiv.2512.03929,
  title  = {Rethinking Collapse: Coupling Quantum States to Classical Bits with quasi-probabilities},
  author = {Dagomir Kaszlikowski and Pawel Kurzynski},
  journal= {arXiv preprint arXiv:2512.03929},
  year   = {2025}
}

Comments

12 pages

R2 v1 2026-07-01T08:07:57.491Z