Quantum Mechanics as Quantum Information (and only a little more)

TL;DR

This paper advocates for understanding quantum mechanics primarily through quantum information theory, aiming to simplify its foundations by reducing it to a few physically meaningful principles, and clarifies the role of Hilbert-space dimension.

Contribution

It proposes a perspective that emphasizes quantum information as the core of quantum mechanics and clarifies the significance of Hilbert-space dimension as an objective element.

Findings

Quantum information theory offers a promising approach to foundational issues.

Hilbert-space dimension is an objective property of quantum systems.

The paper corrects a previous mistake and extends the discussion on quantum foundations.

Abstract

In this paper, I try once again to cause some good-natured trouble. The issue remains, when will we ever stop burdening the taxpayer with conferences devoted to the quantum foundations? The suspicion is expressed that no end will be in sight until a means is found to reduce quantum theory to two or three statements of crisp physical (rather than abstract, axiomatic) significance. In this regard, no tool appears better calibrated for a direct assault than quantum information theory. Far from a strained application of the latest fad to a time-honored problem, this method holds promise precisely because a large part--but not all--of the structure of quantum theory has always concerned information. It is just that the physics community needs reminding. This paper, though taking quant-ph/0106166 as its core, corrects one mistake and offers several observations beyond the previous version. In particular, I identify one element of quantum mechanics that I would not label a subjective term in the theory--it is the integer parameter D traditionally ascribed to a quantum system via its Hilbert-space dimension.