Texte zur Quantentheorie

2020 ◽  
Author(s):  
Moritz Schlick
Keyword(s):  
Werner Heisenberg ◽  
Max Planck ◽  
Wolfgang Pauli ◽  
Hans Reichenbach ◽  
Max Born ◽  
Erwin Schrödinger

Die in diesem Band zusammengestellten Texte Schlicks aus den Zwanziger- und Dreißigerjahren vermitteln vor dem Hintergrund der Einstein’schen Relativitätsrevolution das Bild einer Zeit des radikalen Umbruchs und der Entstehung des Neuen in der Physik. Als Protagonist einer Epoche intensiver Wechselwirkung zwischen naturwissenschaftlicher Forschung und philosophischer Reflexion stand Schlick, der bei Max Planck promoviert wurde, in einem intensiven Gedankenaustausch mit der Gemeinschaft der Quantenphysiker, wozu u. a. Max Born, Werner Heisenberg, Erwin Schrödinger, Pascual Jordan und Wolfgang Pauli zählten. Während sie der noch jungen Theorie der Quanten zum Durchbruch verhalfen, lieferte Schlick vor allem in Auseinandersetzung mit Hans Reichenbach und unter dem Einfluss der sprachphilosophischen Wende Ludwig Wittgensteins stehend zentrale Beiträge zum neuen Verständnis der physikalischen Realität, zu den Begriffen von Kausalität und Wahrscheinlichkeit, aber auch zum Problem der Messung und zum Verhältnis zwischen Physik und Biologie.

4. Enthusiastic resignation

2020 ◽  
pp. 64-83
Author(s):  
J. L. Heilbron
Keyword(s):  
Uncertainty Principle ◽  
Correspondence Principle ◽  
Spectral Lines ◽  
Werner Heisenberg ◽  
Wolfgang Pauli ◽  
Mathematical Solution ◽  
Erwin Schrödinger ◽  
Symbolic Value ◽  
Atomic Electrons

‘Enthusiastic resignation’ describes Bohr’s work with Wolfgang Pauli and Werner Heisenberg. ‘Resignation’ refers to their realization that the electron orbits that had served as the basis of Bohr’s theory had only ‘symbolic’ value. They took the correspondence principle as a guide to translating symbols describing the orbits, like position and momentum, into symbols specifying the values of observable products of atoms, like the frequency and intensity of spectral lines. Heisenberg’s breakthrough in the summer of 1925, based on a particulate view of matter, provided a basis for a coherent description of the phenomena to which atomic electrons give rise. Almost simultaneously, Erwin Schrödinger found another route to the same mathematical solution, based on a wave picture of matter, which avoided discontinuity and made calculations easier. In answering Schrödinger’s challenge, Heisenberg invented the Uncertainty Principle and Bohr worked out a more general reconciliation of the quantum puzzles, which he called ‘complementarity’.

Creating Quantum Mechanics

2017 ◽  
Author(s):  
Frank S. Levin
Keyword(s):  
Quantum Mechanics ◽  
Wave Equation ◽  
Wave Functions ◽  
Werner Heisenberg ◽  
Wolfgang Pauli ◽  
Classical Physics ◽  
Matrix Mechanics ◽  
Erwin Schrödinger ◽  
Specific Formula ◽  
The Creation

In addition to recounting some contemporary scientific history, Chapter 6 describes the hypothesis that matter, like light, can display wavelike properties, and the creation of the various formulations of quantum mechanics. That matter could have a wavelength was proposed in 1924 by Louis de Broglie, who presented a specific formula for calculating it, one that was verified experimentally in 1927. However, de Broglie’s hypothesis was overshadowed by the creation of three versions of quantum mechanics in 1925/26. The first, denoted matrix mechanics, was proposed by Werner Heisenberg. It was quickly and successfully applied by Wolfgang Pauli to the hydrogen atom. Paul Dirac introduced the next version, which was followed by that of Erwin Schrödinger via a wave equation whose solutions, denoted wave functions, were soon interpreted byMax Born to be related to the probability that certain outcomes or events will occur: classical-physics determinism was thereby removed from quantum mechanics.

Introductory Considerations

2018 ◽  
Author(s):  
John von Neumann
Keyword(s):  
Quantum Theory ◽  
Theoretical Description ◽  
Statistical Interpretation ◽  
Wave Mechanics ◽  
Transformation Theory ◽  
Max Born ◽  
Erwin Schrödinger ◽  
Physical Problems ◽  
Starting Point ◽  
New System

This chapter presents the origins of the transformation theory and related concepts. It shows how, in 1925, a procedure initiated by Werner Heisenberg was developed by himself, Max Born, Pascual Jordan, and a little later by Paul Dirac, into a new system of quantum theory—the first complete system of quantum theory which physics has possessed. A little later Erwin Schrödinger developed the “wave mechanics” from an entirely different starting point. This accomplished the same ends, and soon proved to be equivalent to the Heisenberg, Born, Jordan, and Dirac system. On the basis of the Born statistical interpretation of the quantum theoretical description of nature, it was possible for Dirac and Jordan to join the two theories into one, the “transformation theory,” in which they make possible a grasp of physical problems which is especially simple mathematically.

Born’s Interpretation of the Wavefunction

2020 ◽  
pp. 111-132
Author(s):  
Jim Baggott
Keyword(s):  
Transition Probability ◽  
Electrical Charge ◽  
Complex Conjugate ◽  
Wave Mechanics ◽  
Wolfgang Pauli ◽  
Max Born ◽  
Specific Position

Schrödinger hoped that his wave mechanics would help to re-establish some sense of ‘visualizability’ of the physics going on inside the atom. In searching for a suitable interpretation of the wavefunction, he focused on the density of electrical charge, which he associated with the wavefunction ψ‎ multiplied by its complex conjugate. Hidden in his words is the interpretation that would eventually come to dominate our understanding of the wavefunction. Max Born had no hesitation in concluding that the only way to reconcile wave mechanics with the particle description is to interpret the modulus-square of the wavefunction as a probability density. It was Wolfgang Pauli who proposed to interpret this not only as a transition probability or as the probability for the system to be in a specific state, as Born had done, but as the probability of ‘finding’ the electron at a specific position in its orbit inside an atom.

Fundamentals of Quantum Mechanics

2020 ◽  
pp. 73-80
Author(s):  
M. Suhail Zubairy
Keyword(s):  
Quantum Mechanics ◽  
Formal Theory ◽  
Uncertainty Relations ◽  
Quantum Superposition ◽  
Conceptual Foundation ◽  
Classical Physics ◽  
Max Born ◽  
Erwin Schrödinger ◽  
Heisenberg Uncertainty ◽  
Probabilistic Nature

The laws of quantum mechanics were formulated in the year 1925 through the work of Werner Heisenberg, followed by Max Born, Pascual Jordan, Paul Dirac, and Wolfgang Pauli. A separate but equivalent approach was independently developed by Erwin Schrödinger in early 1926. The laws governing quantum mechanics were highly mathematical and their aim was to explain many unresolved problems within the framework of a formal theory. The conceptual foundation emerged in the subsequent 2–3 years that indicated how radically different the new laws were from classical physics. In this chapter some of these salient features of quantum mechanics are discussed. The topics include the quantization of energy, wave–particle duality, the probabilistic nature of quantum mechanics, Heisenberg uncertainty relations, Bohr’s principle of complementarity, and quantum superposition and entanglement. This discussion should indicate how different and counterintuitive its fundamentals are from those of classical physics.

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