Pascual Jordan, his contributions to quantum mechanics and his legacy in contemporary local quantum physics

TL;DR

This paper reviews Pascual Jordan's pivotal role in quantum field theory's development, his controversial history, and how his early ideas on intrinsic, local quantum physics have been validated by modern research.

Contribution

It highlights Jordan's early insights into intrinsic local quantum physics and connects them to contemporary developments in the field.

Findings

Jordan's 1929 expectations of future radical changes in quantum physics have been largely vindicated.

Modern local quantum physics addresses Jordan's call for an intrinsic formulation without classical fields.

Jordan's early work laid foundational ideas that continue to influence current quantum physics research.

Abstract

After recalling episodes from Pascual Jordan's biography including his pivotal role in the shaping of quantum field theory and his much criticized conduct during the NS regime, I draw attention to his presentation of the first phase of development of quantum field theory in a talk presented at the 1929 Kharkov conference. He starts by giving a comprehensive account of the beginnings of quantum theory, emphasising that particle-like properties arise as a consequence of treating wave-motions quantum-mechanically. He then goes on to his recent discovery of quantization of ``wave fields'' and problems of gauge invariance. The most surprising aspect of Jordan's presentation is however his strong belief that his field quantization is a transitory not yet optimal formulation of the principles underlying causal, local quantum physics. The expectation of a future more radical change coming from the main architect of field quantization already shortly after his discovery is certainly quite startling. I try to answer the question to what extent Jordan's 1929 expectations have been vindicated. The larger part of the present essay consists in arguing that Jordan's plea for a formulation without ``classical correspondence crutches'', i.e. for an intrinsic approach (which avoids classical fields altogether), is successfully addressed in past and recent publications on local quantum physics.