5 hours ago
(This post was last modified: 2 hours ago by C C.)
Chemistry is not explained by quantum mechanics
https://iai.tv/articles/chemistry-is-not..._auid=2020
INTRO: We assume the world is made of particles, but this is mistaken at even the most fundamental levels of science, argues Olimpia Lombardi, a leading philosopher of science and critic of the idea of “a theory of everything.” The interactions and transformations of chemical substances cannot be explained in terms of the sub-atomic particles that make them up. Quantum mechanics, our best theory of these particles, cannot account for what happens when substances interact, from rusting to combustion. The realm of chemical transformations appears to be independent of the realm of physical things...
EXCERPTS: This so-called “clamping the nuclei” strategy is clearly in tension with quantum mechanics. It simultaneously assigns fixed positions and fixed velocities (namely, zero) to the nuclei, which is incompatible with quantum uncertainty and contextuality, whereby quantum items cannot simultaneously have definite values of position and velocity.
To overcome this, some quantum chemists have proposed “non‑Born-Oppenheimer” calculations to describe molecules, which dispense with the clamping of nuclei. These methods have achieved relative success in computing the energy levels of molecules, but remain unable to fully predict molecular geometries. The reason is that there exists an obstacle to the quantum description of molecular structure that is even more fundamental than, and independent of, the Born-Oppenheimer approximation.
[...] The common strategy employed to recover compatibility between quantum and chemical descriptions is to argue that molecules are never truly isolated: it is the environment that breaks the symmetry of the quantum description. Yet if the environment is composed of other, similarly symmetric molecules, the interaction between the original molecule and its environment cannot break the symmetry of the description. Consequently, the usual argument appeals to asymmetric environments. However, this move introduces further conceptual difficulties.
[...] What should we conclude about the relationship between chemistry and physics? Some are convinced that physics must explain chemical phenomena. Accordingly, if quantum mechanics fails to do so, another physical theory must be employed. For example, one might move from quantum mechanics to quantum field theory. And if this were still insufficient, one would have to await the formulation of a sufficiently powerful “fundamental” theory capable of accounting for chemistry in its entirety. This solution, however, merely defers the resolution of the problem to the future, resting on faith in a physics that will eventually be able to explain everything.
Another strategy to try to recover the idea that physics can, in principle, explain everything, is to modify the formalism of quantum mechanics in favor of a different theory such as Bohmian mechanics. While empirically equivalent to standard quantum mechanics, Bohmian mechanics diverges substantially in the picture of reality it provides. The Bohmian universe is constituted by particles with definite positions and velocities, fully distinguished at a given time by their positions, and across time by their continuous and deterministic trajectories. Since the world depicted by Bohmian mechanics is significantly closer to the classical world than that of standard quantum mechanics, it is unsurprising that the theory has been applied to the description of atoms and molecules. Nevertheless, difficulties persist both from the technical and the conceptual points of view.
A more philosophical reaction is to renounce from the very beginning the search for full compatibility between quantum and chemical descriptions by adopting a pluralistic view of science... (MORE - missing details)
Two dimensions of time explain quantum physics, scientists argue
https://youtu.be/8e_JSOxaEVQ
INTRO: You've probably heard that quantum mechanics is spooky, that measuring one particle instantly affects another across any distance. A physicist now says there's a reason: the universe doesn't have one dimension of time, but two. It sounds absurd, but he's got the maths and even a way to test it. Genius or nonsense? Let's take a look. .... PAPER: https://arxiv.org/abs/2606.12457
SABINE HOSSENFELDER ... https://youtu.be/8e_JSOxaEVQ
https://www.youtube-nocookie.com/embed/8e_JSOxaEVQ
https://iai.tv/articles/chemistry-is-not..._auid=2020
INTRO: We assume the world is made of particles, but this is mistaken at even the most fundamental levels of science, argues Olimpia Lombardi, a leading philosopher of science and critic of the idea of “a theory of everything.” The interactions and transformations of chemical substances cannot be explained in terms of the sub-atomic particles that make them up. Quantum mechanics, our best theory of these particles, cannot account for what happens when substances interact, from rusting to combustion. The realm of chemical transformations appears to be independent of the realm of physical things...
EXCERPTS: This so-called “clamping the nuclei” strategy is clearly in tension with quantum mechanics. It simultaneously assigns fixed positions and fixed velocities (namely, zero) to the nuclei, which is incompatible with quantum uncertainty and contextuality, whereby quantum items cannot simultaneously have definite values of position and velocity.
To overcome this, some quantum chemists have proposed “non‑Born-Oppenheimer” calculations to describe molecules, which dispense with the clamping of nuclei. These methods have achieved relative success in computing the energy levels of molecules, but remain unable to fully predict molecular geometries. The reason is that there exists an obstacle to the quantum description of molecular structure that is even more fundamental than, and independent of, the Born-Oppenheimer approximation.
[...] The common strategy employed to recover compatibility between quantum and chemical descriptions is to argue that molecules are never truly isolated: it is the environment that breaks the symmetry of the quantum description. Yet if the environment is composed of other, similarly symmetric molecules, the interaction between the original molecule and its environment cannot break the symmetry of the description. Consequently, the usual argument appeals to asymmetric environments. However, this move introduces further conceptual difficulties.
[...] What should we conclude about the relationship between chemistry and physics? Some are convinced that physics must explain chemical phenomena. Accordingly, if quantum mechanics fails to do so, another physical theory must be employed. For example, one might move from quantum mechanics to quantum field theory. And if this were still insufficient, one would have to await the formulation of a sufficiently powerful “fundamental” theory capable of accounting for chemistry in its entirety. This solution, however, merely defers the resolution of the problem to the future, resting on faith in a physics that will eventually be able to explain everything.
Another strategy to try to recover the idea that physics can, in principle, explain everything, is to modify the formalism of quantum mechanics in favor of a different theory such as Bohmian mechanics. While empirically equivalent to standard quantum mechanics, Bohmian mechanics diverges substantially in the picture of reality it provides. The Bohmian universe is constituted by particles with definite positions and velocities, fully distinguished at a given time by their positions, and across time by their continuous and deterministic trajectories. Since the world depicted by Bohmian mechanics is significantly closer to the classical world than that of standard quantum mechanics, it is unsurprising that the theory has been applied to the description of atoms and molecules. Nevertheless, difficulties persist both from the technical and the conceptual points of view.
A more philosophical reaction is to renounce from the very beginning the search for full compatibility between quantum and chemical descriptions by adopting a pluralistic view of science... (MORE - missing details)
Two dimensions of time explain quantum physics, scientists argue
https://youtu.be/8e_JSOxaEVQ
INTRO: You've probably heard that quantum mechanics is spooky, that measuring one particle instantly affects another across any distance. A physicist now says there's a reason: the universe doesn't have one dimension of time, but two. It sounds absurd, but he's got the maths and even a way to test it. Genius or nonsense? Let's take a look. .... PAPER: https://arxiv.org/abs/2606.12457
SABINE HOSSENFELDER ... https://youtu.be/8e_JSOxaEVQ