An Evolution of Quantum Mechanics Interpretation

Abstract

In this paper, my intention is to provide an overview of Quantum Theory's evolution, highlighting the ontological and epistemological questions associated with it. Although Quantum Mechanics is widely accepted, its interpretation remains an open question. This paper focuses on conceptual, rather than formalistic, approaches to reveal the new scientific and philosophical paradigm brought by Quantum Theory, from the first interpretation in Modern Quantum Theory to post-Bell theorem interpretations.

1. Historical Overview

Although readers may be familiar with the origins of quantum mechanics, a brief overview of the theory's evolution is always helpful for the following considerations.

Quantum mechanics is a highly abstract and counterintuitive theory, yet it was motivated directly by experimental results that lacked reasonable explanation. The story begins with Max Planck's explanation of black body radiation through discrete packages of energy. Einstein furthered this idea by describing light as a collection of discrete wave packets, which led to the quantized behavior of the photoelectric effect. These early ideas, along with the observation of wave-particle duality, became fundamental motivations for subsequent theoretical developments.

In 1925, W. Heisenberg developed matrix mechanics, and in 1929, E. Schrödinger introduced wave mechanics. These theories described quantum systems through different but complementary approaches, laying the groundwork for modern quantum mechanics.

2. First Interpretations and Opposition

Quantum mechanics introduced the concept of discrete quantities, replacing the classical notion of continuity in nature. The Copenhagen Interpretation, developed by Heisenberg and Bohr, was one of the earliest and most influential interpretations of quantum mechanics. It proposed that the observer influences the observed object, thus introducing a probabilistic and indeterministic nature to the system.

The Correspondence Principle played a critical role, bridging classical and quantum theories, though it conflicted with later ideas of incommensurability. Bohr and Heisenberg also introduced key ideas like Complementarity and Uncertainty, leading to intense philosophical debates, especially between Bohr and Einstein, who challenged the indeterminacy of quantum systems.

3. Clarification of Concepts - From Classical to Quantum

The shift from classical to quantum theory raised significant ontological and epistemological issues. Classical physics rested on principles such as locality, causality, and determinism, all of which were abandoned in quantum mechanics, leaving only the principle of energy conservation intact.

Bohr's interpretation emphasized the role of the observer and the need for a new conceptual framework. In contrast, Heisenberg’s uncertainty principle introduced limits to the knowledge we can have about quantum systems. These views led to further philosophical reflections on the nature of reality in quantum mechanics.

4. E.P.R Paradox and Others

The Einstein-Podolsky-Rosen (EPR) paradox presented a direct challenge to quantum mechanics, suggesting the theory was incomplete. EPR argued that quantum mechanics failed to account for certain elements of reality, proposing either the existence of hidden variables or a violation of local realism. Bohr countered these claims by emphasizing complementarity and the observer's role, although his exact stance on issues like non-locality remained ambiguous.

5. Bell's Inequality and its Experimental Attempts

Bell's Theorem provided a way to experimentally test the non-locality of quantum mechanics. Bell's inequality showed that quantum mechanics predicts violations of classical probability rules, particularly in experiments involving entangled particles. Experimental tests, such as those by Aspect and others, confirmed these violations, supporting the non-local nature of quantum mechanics and refuting the EPR argument.

6. Conclusion

This brief history of quantum mechanics highlights the ongoing debates about its interpretation. While quantum mechanics is widely accepted, its compatibility with general relativity and the underlying reality of quantum systems remain unresolved. Bell’s Theorem plays a critical role in the discussion, suggesting that future theories may redefine fundamental concepts like space, time, and reality.

References

1. Aitchison, I. J. R., MacManus, D. A., & Snyder, T. M. (2008). "Understanding Heisenberg’s 'magical' paper of July 1925: a new look at the calculational details." Oxford Press.
2. Schrödinger, E. (1926). "An Undulatory Theory of the Mechanics of Atoms and Molecules." Physical Review, Vol.28, No.6.
3. Faye, J. (2014). "Copenhagen Interpretation of Quantum Mechanics." The Stanford Encyclopedia of Philosophy, E. N. Zalta (ed.).
4. Howard, D. (2004). "Who invented the 'Copenhagen Interpretation'?" Philosophy of Science, 71, 669–682.
5. Oberheim, E. & Hoyningen-Huene, P. (2013). "The Incommensurability of Scientific Theories." The Stanford Encyclopedia of Philosophy, E. N. Zalta (ed.).
6. Bohr, N. (1935). "Can quantum-mechanical description of physical reality be considered complete?" Physical Review, 48, 696–702.
7. Bell, J. (2004). "Bertlmann’s socks and the nature of reality." In Speakable and Unspeakable in Quantum Mechanics (pp. 139–158). Cambridge: Cambridge University Press.
8. Fedaka, W. A., & Prentis, J. J. (2007). "The 1925 Born and Jordan paper 'On quantum mechanics'." American Journal of Physics.
9. Letter from Bohr to Sommerfeld, April 30, 1922.
10. Bacciagaluppi, G. (n.d.). "Did Bohr understand EPR?"
11. Cuffaro, M. (2010). "The Kantian Framework of Complementarity." arXiv:1008.2904.
12. Einstein, A., Podolsky, B., & Rosen, N. (1935). "Can Quantum-Mechanical description of physical reality be considered complete?" Physical Review, Vol.47.
13. Grifiths, J.D. (2005). Introduction to Quantum Mechanics, 2nd ed.
14. Aspect, A., Grangier, P., & Roger, G. (1982). "Experimental Realization of Einstein-Podolsky-Rosen-Bohm Gedankenexperiment: A New Violation of Bell’s Inequalities." Physical Review Letters, 49, 91.
15. Marshall, W., Simon, C., Penrose, R., & Bouwmeester, D. (2002). "Towards quantum superpositions of a mirror." Physical Review Letters, 91, 130401.
16. Fine, A. (1989). "Do Correlations Need to be Explained?" Philosophical Consequences of Quantum Theory.
17. Ramalho, V. (2014). "An Introduction to Reductionism." Introduction to Philosophy of Physics, Ludwig-Maximilians-Universität München.