Does quantum mechanics apply to macroscopic objects? How to define macro?

TL;DR

This paper explores whether quantum mechanics applies to macroscopic objects, questioning how to define 'macro' and examining the implications of quantum behavior at large scales.

Contribution

It critically analyzes the ambiguity in defining macroscopic objects in quantum mechanics and discusses the potential for micro-miniaturization to clarify quantum-classical boundaries.

Findings

Quantum wave-packets of macroscopic objects should spread out over time.

Heavy masses are assumed to prevent observable spreading, but this remains unverified.

The paper raises questions about the micro-macro threshold and the role of miniaturization.

Abstract

According to Quantum Mechanics a narrow wave-packet of the center of mass of any macroscopic object should smear out after some time. The problem is usually waved out by assuming that due to their heavy masses this occurs over astronomical times. Without a clear definition of macroscopic objects this remains ambiguous. On the other hand, Quantum Mechanics allows and energetically even prefers largely smeared out c.m. states that never been seen. Why is this the real state of the world we know? Does it suggest a micro-macro threshold with different theoretical descriptions? Does offer micro-miniaturization a hope for answering these questions?