Fundamentals of Quantum Mechanics Theory and Practice

Quantum mechanics is the newest science and should therefore be the most precise, but unfortunately, it's quite the opposite. If you don't understand quantum mechanics, ask yourself if I'm right, because others don't either. The field of experimental quantum mechanics is so vast and confusing that its theoretical practitioners will always have to adopt new explanations from their own context to conform to the facts of quantum mechanics. Quantum mechanics was created in the early 20th century to establish mathematical and physical laws or rules for subatomic objects subject to an external potential field in order to explain so-called quantum systems. Studying the spatiotemporal evolution of a quantum system, defined as a microscopic subatomic system of low energy density subjected to a potential field, external or internal, is a rather complex subject. However, in 1927, the well-known Schrödinger PDE, valid for infinite free space subject to Dirichlet boundary conditions, was introduced. Schrödinger's PDE must be complemented by the Bohr/Copenhagen interpretation of the wave function Ψ involving the rules of quantum systems of instantaneous entanglement and superposition. We all know that the Schrödinger equation is incomplete because it lives and operates in the incomplete space R^4 and therefore the wave function Ψ is incomplete in itself and cannot be defined as scalar, a vector, nor a tensor. The complex wave function Ψ has never been properly defined. Moreover, the Schrödinger PDE is not Lorentz invariant and is not compatible with the special theory of relativity, and is obviously even less so with the general theory of relativity. However, quantum mechanics has come a long way, both in theory and practice, since 1927, nearly a century ago. This long journey has added even more illogical and confusing properties to the Ψ wave function, such as causality and wave function collapse. Many attempts have been made over the last century to reform the Schrödinger equation, the most notable being to combine it with the general theory of relativity, but all these attempts have been in vain. The breakthrough came in 2020-2024 [2,3,4], when the author of this article claimed to replace the classical Schrödinger equation Ψ with the PDE for its square Ψ^2, which is logical and physical. Ψ^2 is needed to express the quantum energy density flux (U(x,y,z,t) = Ψ^2 (x,y,z,t)) and we therefore propose a new Schrödinger equation for Ψ^2 which should have the form of the energy density diffusion PDE such as that of thermal conduction. Equation 3 should be supplemented by the advanced artificial intelligence proposed by the author [5,6]. Comparing Schrödinger's classical PDE of 1927 with the PDE proposed for Ψ^2 in 2020 shows that we currently have two different or distinct theories of quantum mechanics! Which one is more theoretically true and more practically useful? This is the purpose of this article.