Comment on "Quantum theory cannot be extended" [arXiv:1005.5173v1]: Falsification of non-covariant extensions requires the before-before experiment

TL;DR

This paper critiques a recent claim that quantum theory cannot be extended, arguing that non-covariant models like Suarez-Scarani are not refuted by certain experiments, and that covariant extensions are self-contradictory.

Contribution

It clarifies the limitations of recent experimental tests on nonlocal quantum models and highlights issues with covariant extensions.

Findings

Non-covariant Suarez-Scarani model remains viable after recent tests.

Covariant extensions are shown to be self-contradictory.

Experimental falsification of non-covariant models requires before-before experiments.

Abstract

The Suarez-Scarani model is a non-covariant (frame-dependent) relativistic (time-ordered causal) nonlocal extension of quantum theory, which is not refuted by the experiments proposed in Reference [arXiv:1005.5173v1]. The covariant extensions considered in this Reference are actually self-contradictory and do not require experimental falsification.