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SemM
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By fresh42's invitation, I here attach a paper which is related to the post on non-standard qm-models
https://arxiv.org/pdf/cond-mat/9705290
https://arxiv.org/pdf/cond-mat/9705290
SemM said:By fresh42's invitation, I here attach a paper which is related to the post on non-standard qm-models
https://arxiv.org/pdf/cond-mat/9705290
A. Neumaier said:Nonhermitian quantum mechanics is just quantum mechanics with Hamiltonians that are selfadjoint not in the standard inner product but in a nonstandard one.
Actually, I had not looked closely enough at the paper. I thought it was about PT-symmetric quantum mechanics, as in http://aip.scitation.org/doi/pdf/10.1063/1.532860SemM said:It's not apparent to me which metric space do they use, and how do they derive physically sound eigenvalues without an inner product.
A. Neumaier said:Actually, I had not looked closely enough at the paper. I thought it was about PT-symmetric quantum mechanics, as in http://aip.scitation.org/doi/pdf/10.1063/1.532860
But the paper is about dissipative quantum mechanics, where the dissipation is modeled by a complex potential, often called an optical potential. In this case, the usual inner product is used, the eigenvalues typically have a nonzero imaginary part related to the decay rate, and eigenvectors are usually no longer orthogonal. Just like in the eigenvalue problem for nonhermitian matrices.
Except for problems with a single degree of freedom (or with only spin degree of freedom), one always has PDEs, not ODEs (or ODEs in function spaces, which is the former in disguise).SemM said:Do you know of a paper that shows various models of ODE's for quantum physical phenomena, except the Schrödinger eqn and the Wave eqn?
A. Neumaier said:Except for problems with a single degree of freedom (or with only spin degree of freedom), one always has PDEs, not ODEs (or ODEs in function spaces, which is the former in disguise).
In nonrelativistic quantum mechanics based on wave functions you always have the Schroedinger equation, just with different Hamiltonians. The conservative case has a selfadjoint ##H## (in the PT symmetric case with respect to a nonstandard inner product), the dissipative case typically has an optical potential. There are also potentials derived by complex scaling (N. Moiseyev, Quantum theory of resonances: calculating energies, widths and cross-sections by complex scaling, Physics Reports 302.5-6 (1998): 212-293.)
But the dissipative case is often better modeled by using density operators/matrices, then the dynamics is that of a Lindblad equation.
Nice. I didn't know this book. Another useful book on the topic isDrClaude said:You should get your hands on a copy of Moiseyev's book Non-Hermitian Quantum Mechanics.
A. Neumaier said:Nice. I didn't know this book. Another useful book on the topic is
V.I. Kukulin, V.M. Krasnopol'sky and I. Horacek,
Theory of Resonances. Principles and Applications,
Kluwer, Dordrecht 1989.
Non-standard models in QM refer to any theories or interpretations of quantum mechanics that deviate from the commonly accepted standard model. These models seek to explain or address the limitations or paradoxes of the standard model, such as the measurement problem or the role of consciousness in quantum phenomena.
Non-standard models often introduce different mathematical frameworks, such as hidden variables or non-locality, to explain quantum phenomena. They also challenge the fundamental assumptions of the standard model, such as wave-particle duality or the probabilistic nature of quantum events.
Some examples of non-standard models in QM include the many-worlds interpretation, the pilot-wave theory, and the de Broglie-Bohm theory. These models offer alternative explanations for quantum phenomena and attempt to resolve the paradoxes and limitations of the standard model.
Non-standard models in QM are significant because they challenge our understanding of the quantum world and offer alternative perspectives on the nature of reality. They also inspire new experiments and research, pushing the boundaries of our knowledge and potentially leading to new breakthroughs in quantum mechanics.
The acceptance of non-standard models in the scientific community varies. While some physicists and researchers may support and explore these models, others may remain skeptical and adhere to the standard model. Ultimately, the debate and research surrounding non-standard models in QM contribute to the ongoing evolution and understanding of quantum mechanics.