A 1923 paper by John Slater, a young American physicist, introduced the idea of a virtual radiation field to explain light-matter interactions, suggesting a wave-like nature for electrons. While initially embraced by Bohr, Kramers, and Slater as a potential challenge to Einstein's light quanta, subsequent experiments by Bothe and Geiger, and Compton and Simon, disproved the theory's central tenet: the lack of energy-momentum conservation in individual atomic processes. Although ultimately wrong, the BKS theory, as it became known, stimulated crucial discussions and further research, including important contributions from Born, Heisenberg, and Jordan that advanced the development of matrix mechanics, a key component of modern quantum theory. The BKS theory's failure also solidified the concept of light quanta and underscored the importance of energy-momentum conservation, paving the way for a more complete understanding of quantum mechanics.
In the annals of quantum mechanics, Niels Bohr, a towering figure, is revered for his contributions, particularly his model of the atom and his profound insights into the complementarity principle. However, even titans of science are not infallible. A Physics World article delves into a relatively obscure episode in the history of quantum theory, highlighting a specific instance where Bohr's interpretation faltered, and how this misstep inadvertently spurred advancements in the field. The article centers around a 1923 paper authored by John C. Slater, a young American physicist then working with Bohr in Copenhagen. This paper introduced the concept of "virtual oscillators," a theoretical construct intended to bridge the gap between classical electromagnetic theory and the emerging quantum picture of radiation emission and absorption by atoms.
Bohr, deeply committed to his own perspective on radiation phenomena, incorporated Slater's idea into his own theoretical framework, known as the Bohr-Kramers-Slater (BKS) theory. This theory proposed a radical departure from established principles, suggesting that energy and momentum conservation might not hold true in individual atomic processes, but only statistically over a large number of events. This proposition was met with skepticism within the physics community, yet the weight of Bohr's authority lent the BKS theory considerable influence.
However, the pivotal moment arrived with the meticulous Compton scattering experiments conducted by Walther Bothe and Hans Geiger. Their findings unequivocally demonstrated that energy and momentum were indeed conserved in individual scattering events, directly contradicting the core premise of the BKS theory. This experimental refutation, meticulously documented and presented, effectively dismantled Bohr's elaborated theoretical edifice built upon Slater's initial concept. While a setback for Bohr, the demise of the BKS theory proved to be a crucial turning point in the development of quantum mechanics. It highlighted the essential role of rigorous experimental verification in theoretical physics and underscored the limitations of attempting to shoehorn quantum phenomena into classical frameworks.
Furthermore, the article elucidates how Slater's original idea, though ultimately incorporated into a flawed theory, contained the seeds of future progress. The notion of "virtual oscillators," while not fully understood at the time, prefigured later developments in quantum field theory, specifically the concept of virtual particles mediating interactions. Thus, although Slater's contribution was initially overshadowed by its association with the failed BKS theory, its underlying principle ultimately found vindication in the more sophisticated and successful theoretical frameworks that followed. The episode serves as a compelling illustration of the complex and often circuitous path of scientific progress, where even incorrect theories can catalyze crucial insights and propel the field forward. The article concludes by emphasizing the importance of recognizing and examining such overlooked historical moments to gain a deeper appreciation for the evolution of scientific thought.
Summary of Comments ( 14 )
https://news.ycombinator.com/item?id=42917434
HN commenters discuss the historical context of the article, pointing out that "getting it wrong" is a normal part of scientific progress and shouldn't diminish Bohr's contributions. Some highlight the importance of Slater's virtual oscillators in the development of quantum electrodynamics (QED), while others debate the extent to which Kramers' work was truly overlooked. A few commenters express interest in the "little-known paper" itself and its implications for the history of quantum theory. Several commenters also mention the accessibility of the original article and suggest related resources for further reading. One commenter questions the article's claim that Bohr's model didn't predict spectral lines, asserting that it did predict hydrogen's spectral lines.
The Hacker News post titled "When Bohr got it wrong: the impact of a little-known paper on quantum theory" has generated a moderate discussion with several insightful comments.
Several commenters delve into the historical context of Bohr's mistake and its implications. One commenter highlights the iterative nature of scientific progress, emphasizing that even brilliant minds like Bohr can make errors, and that these errors often pave the way for crucial refinements in scientific understanding. This commenter also points out the importance of Slater's contribution, which was seemingly overlooked at the time, and how the subsequent work of Kramers and Heisenberg built upon this foundation.
Another commenter discusses the specific nature of Bohr's error, explaining that Bohr attempted to apply the correspondence principle beyond its valid domain. They suggest that Bohr's stature in the field might have contributed to the delayed recognition of the error. This comment also mentions how the article highlights the crucial role of "younger, less established physicists" in pushing the boundaries of scientific understanding, referencing Slater's initial work and its eventual influence.
A further comment focuses on the idea of "virtual oscillators," a concept introduced by Slater. The commenter suggests that while the idea of virtual oscillators might seem intuitive now, it represented a significant departure from classical physics at the time. They also mention how Slater's idea, though initially dismissed, later resurfaced in different forms within quantum field theory.
One commenter draws a parallel between Slater's experience and the general challenge of having unconventional ideas recognized within the scientific community. They emphasize the importance of open-mindedness and the willingness to consider ideas that challenge established paradigms.
Another commenter expresses their appreciation for the article's clarification of the historical timeline and the contributions of various scientists, particularly Slater, in the development of quantum mechanics. They also mention how the article corrected their own misconceptions about the history of the field.
Finally, a thread discusses the nuances of scientific attribution and the difficulty of pinpointing the exact origin of ideas, especially in a collaborative field like theoretical physics. This thread touches upon the subtle differences between independently arriving at a conclusion and being directly influenced by another's work.