The Course of Theoretical Physics is a ten-volume series of books covering theoretical physics that was initiated by Lev Landau and written in collaboration with his student Evgeny Lifshitz starting in the late 1930s.
It is said that Landau composed much of the series in his head while in an NKVD prison in 1938-1939. However, almost all of the actual writing of the early volumes was done by Lifshitz, giving rise to the witticism, "not a word of Landau and not a thought of Lifshitz". The first eight volumes were finished in the 1950s, written in Russian and translated into English in the late 1950s...
The Copenhagen interpretation is an expression of the meaning of quantum mechanics that was largely devised from 1925 to 1927 by Niels Bohr and Werner Heisenberg. It remains one of the most commonly taught interpretations of quantum mechanics.According to the Copenhagen interpretation, physical systems generally do not have definite properties prior to being measured, and quantum mechanics can only predict the probability distribution of a given measurement's possible results. The act of measurement affects the system, causing the set of probabilities to reduce to only one of the possible values...
The classical limit or correspondence limit is the ability of a physical theory to approximate or "recover" classical mechanics when considered over special values of its parameters. The classical limit is used with physical theories that predict non-classical behavior.
== Quantum theory ==
A heuristic postulate called the correspondence principle was introduced to quantum theory by Niels Bohr: in effect it states that some kind of continuity argument should apply to the classical limit of quantum systems as the value of Planck's constant normalized by the action of these systems becomes very small...
In physics, the correspondence principle states that the behavior of systems described by the theory of quantum mechanics (or by the old quantum theory) reproduces classical physics in the limit of large quantum numbers. In other words, it says that for large orbits and for large energies, quantum calculations must agree with classical calculations.The principle was formulated by Niels Bohr in 1920, though he had previously made use of it as early as 1913 in developing his model of the atom.The term codifies the idea that a new theory should reproduce under some conditions the results of older...
I saw a thought provoking answer to my question: How many worlds are there during branching in the many worlds interpretation?
Is there anyway for me to re-see the answer before it was deleted?
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I found an article on the "Reference Frame" titled Simple QM proof implies many worlds don't exist. I tried to read it, but being a complete layman, I did not understand a thing. Could somebody tell me if this proof is valid and the many worlds interpretation is no longer considered as an option?...
Non-Hermitian quantum mechanics is the study of quantum-mechanical Hamiltonians that are not Hermitian. Notably, they appear in the study of dissipative systems. Also, non-Hermitian Hamiltonians with unbroken parity-time (PT) symmetry have all real eigenvalues.
== Parity-time (PT) symmetry ==
In 1998, physicist Carl Bender and former graduate student Stefan Boettcher published in Physical Review Letters a landmark paper in quantum mechanics, "Real Spectra in non-Hermitian Hamiltonians Having PT Symmetry." In this paper, the authors overturned a longstanding incorrect assumption of quantum mechanics...
Could anyone tell me what I did wrong to have my question on hold?
I think the question is clear and I worked to find the answer.
How to solve this projectile motion problem?
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