Quantum mechanics is a first quantized quantum theory that supersedes classical mechanics at the atomic and subatomic levels. It is a fundamental branch of physics that provides the underlying mathematical framework for many fields of physics and chemistry.
Quantum mechanics is sometimes used in a more general sense, to mean quantum physics.
- … that what is proved, by impossibility proofs, is lack of imagination.
- John Stewart Bell, On the impossible pilot wave, Ref.TH.3315-CERN, 1982, p. 15
- I am a Quantum Engineer, but on Sundays I Have Principles.
- If the price of avoiding non-locality is to make an intuitive explanation impossible, one has to ask whether the cost is too great.
- David Bohm et al. Physc. Rep. 144, 321 (1987)
- For those who are not shocked when they first come across quantum theory cannot possibly have understood it.
- Niels Bohr, quoted in Heisenberg, Werner (1971). Physics and Beyond. New York: Harper and Row. pp. 206.
- The power of the new quantum mechanics in giving us a better understanding of events on an atomic scale is becoming increasingly evident. The structure of the helium atom, the existence of half-quantum numbers in band spectra, the continuous spatial distribution of photo-electrons, and the phenomenon of radioactive disintegration, to mention only a few examples, are achievements of the new theory which had baffled the old.
- Arthur Compton, Foreword to the English edition of The Physical Principles of the Quantum Theory by W. Heisenberg (1930)
- However unfamiliar this direct interparticle treatment compared to the electrodynamics of Maxwell and Lorentz, it deals with the same problems, talks about the same charges, considers the interactions of the same current elements, obtains the same capacitances, predicts the same inductances and yields the same physical conclusions. Consequently action-at-a-distance must have a close connection with field theory.
- ...the "paradox" is only a conflict between reality and your feeling of what reality "ought to be."
- Richard Feynman, in The Feynman Lectures on Physics, vol III, p. 18-9 (1965)
- I think I can safely say that nobody understands quantum mechanics.
- Richard Feynman, in The Character of Physical Law (1965)
- We have always had a great deal of difficulty understanding the world view that quantum mechanics represents. At least I do, because I'm an old enough man that I haven't got to the point that this stuff is obvious to me. Okay, I still get nervous with it.... You know how it always is, every new idea, it takes a generation or two until it becomes obvious that there's no real problem. I cannot define the real problem, therefore I suspect there's no real problem, but I'm not sure there's no real problem.
- Richard Feynman, in Simulating Physics with Computers appearing in International Journal of Theoretical Physics (1982) p. 471.
- Quantum theory was split up into dialects. Different people describe the same experiences in remarkably different languages. This is confusing even to physicists.
- Erwin with his psi can do
Calculations quite a few.
But one thing has not been seen:
Just what does psi really mean?
- Erich Hückel, translated by Felix Bloch and quoted in Traditions et tendances nouvelles des études romanes au Danemark (1988) by Ebbe Spang-Hanssen and Michael Herslund, p. 207; also in The Pioneers of NMR and Magnetic Resonance in Medicine : The Story of MRI (1996) by James Mattson and Merrill Simon, p. 278
- It is often stated that of all the theories proposed in this century, the silliest is quantum theory. In fact, some say that the only thing that quantum theory has going for it is that it is unquestionably correct.
- Michio Kaku, in Hyperspace (1995), p. 263
- Respectable scientists like de Broglie himself accept wave mechanics because it confers coherence and unity upon the experimental findings of contemporary science, and in spite of the astonishing changes it implies in connection with ideas of causality, time, and space, but it is because of these changes that it wins favor with the public. The great popular success of Einstein was the same thing. The public drinks in and swallows eagerly everything that tends to dispossess the intelligence in favor of some technique; it can hardly wait to abdicate from intelligence and reason and from everything that makes man responsible for his destiny.
- Simone Weil, “Wave Mechanics,” On Science, Necessity, and the Love of God, R. Rees, trans. (1968), p. 75