Quantum foundations for quantum technologies in the International Year of Quantum (2025)

TL;DR

This paper reviews the evolution of quantum foundations from philosophical questions to experimental tests and technological applications, highlighting the ongoing interplay between foundational insights and quantum technology development.

Contribution

It provides a comprehensive overview of how foundational questions in quantum mechanics have been transformed into experimental and technological advancements, emphasizing their mutual influence.

Findings

Foundational questions have driven experimental verification and technological innovation.

Quantum technologies are increasingly used to test and explore foundational principles.

The dialogue between theory and experiment continues to deepen our understanding of quantum phenomena.

Abstract

From the very beginning, Quantum Mechanics has been accompanied by crucial foundational questions: the possibility of visualizing physical processes, the limits of measurement epitomized by the Heisenberg uncertainty principle, the existence of a deeper underlying reality with additional degrees of freedom, the role of measurements, and the status of locality. Long regarded as philosophical speculations, these issues were progressively reformulated into precise mathematical statements and ultimately subjected to experimental verification. The trajectory proved unpredictable: questions once dismissed as metaphysical gave rise to experimental platforms, which in turn matured into devices and technologies powering quantum computation, communication, and sensing. Yet this development is not unidirectional: advances in technology also feed back into foundations, enabling tests of principles that were previously out of reach, for example, whether quantum superposition persists at larger and larger scales and whether reality, gravity included, is fundamentally quantum. In this way, the dialogue between foundational inquiry and technological progress continues to shape both our theoretical understanding and the practical realization of quantum phenomena.