söndag 2 februari 2025

Standard Quantum Mechanics as Classification without Physics vs RealQM

This is a continuation of the previous post but can be enjoyed independently.

Science and religion both arise from human minds seeking to find mental interpretations of the Word as the creation of superhuman mind. Quantum Mechanics QM as the mechanics of atoms and molecules came out from a perceived shortcoming of classical Newtonian physics in the late 19th century, so immensely successful in describing the macroscopic world, to capture the microscopic world of atoms and molecules. 

The German physicist Erwin Schrödinger in 1926 took the first step out of a deadlock into the modern physics of QM by formulating a mathematical model of the Hydrogen atom with one electron surrounding a proton kernel in the form of an eigenvalue problem for a partial differential equation for a negative charge density subject to Coulomb attraction from a positive kernel. 

The success was complete since the  eigenvalues precisely agreed with the observed spectrum of excited states of the Hydrogen atom with corresponding eigenfunctions as wave functions representing vibrational spatial modes of the electron taking the following form:


to be compared with those of e g a circular membrane    


The complete success of the Schrödinger equation capturing the spectrum of the Hydrogen atom with one electron demanded generalisation to atoms with more than one electron, which was accomplished  by formally adding a new set of 3d coordinates for each electron into a linear Schrödinger equation (S) in $3N$ spatial dimensions for an atom/molecule with $N>1$ electrons like a Gold atom with 79 electrons in $237$ spatial dimensions, as a partial differential equation of a completely new form with solutions named wave functions for which the physics had to be invented as probabilities of electron configurations. 

(S) has come to serve as the foundation of the modern physics in the form of Standard QM StdQM filling text books of modern physics. 

The first task for (S) was to explain the "Aufbau" of the  Periodic Table in terms of wave functions and then the following strange idea came up: 
  • Describe ground state electron configurations of atoms/molecules with $N>1$ as linear combinations of excited states of the one electron of the Hydrogen atom.                                  
To see the strangeness compare with an idea of
  • describing a complex system as a copy of a simple component building the system
  • preformatism of the 17th century as a tiny human ("homunculus") inside the egg of a female. 
We understand that this is illogical: A complex system cannot be copy of its simple parts. Nevertheless it serves as a fundamental principle of StdQM: Excited states of a Hydrogen atom describe all atoms/molecules. It defies logic but is state of the art, still 100 years after conception. It does not help to recall that the eigenfunctions of the Hydrogen atom form a complete orthonormal system and so can describe anything. 

The fact that StdQM comes out from a formal extension from one to many electrons, means that StdQM appears as an (ad hoc) classification system rather than as model of real physics. This is evident by looking at the rich classification imposed by StdQM culminating in the Standard Model:
  • symmetric and antisymmetric wave functions as bosons and fermions
  • electrons with spin-up and spin-down
  • paired and unpaired electrons 
  • Hund's rule, Madelung rule, octet rule
  • s, p, d, f states in atoms 
  • quarks, leptons, gluons, weak force, strong force...
It is natural to compare with the plant classification system of Linné (18th century) based on the number of stamens and pistils in flowers, which is artificial and not reflective of natural relationships, but anyway still is used.  

RealQM offers an alternative to StdQM as a atom/molecule model based on Coulomb interaction between atomic kernels and non-overlapping electron densities as a natural system without need of elaborate classification. 

We can put StdQM ve RealQM into a broader perspective of idealism and realism with StdQM imposing atomic form and RealQM uncovering natural atomic form. RealQM gives a different rationale of the Periodic Table as an electron density packing problem. 

If you force a metal through a square die in an extrusion process, it will come out with quadratic cross section. If you force Hydrogen eigenfunction form upon general atomic states, everything will look Hydrogenic but you will violate natural physics.