Quantum theory revolutionized our understanding of reality. Previously it was thought that the matter that is part of the external world was undeniably and clearly reality. However, understanding that the matter of the external world is made up of microscopic elements governed by the paradoxical laws of quantum physics, it becomes increasingly difficult to understand what is what we call reality.

This is a fascinating odyssey of humanity. Let us remember that in order to explain the emission spectrum of a hot body -called the black body problem- Max Planck in 1900 proposed that energy can only be emitted or absorbed in small energy packets called “quanta”.

For Planck, this proposal was initially only considered as a mathematical artifice with which he obtained a formula that perfectly explains the spectrum of radiation emitted by a hot body and therefore solved the problem of the so-called black body. Soon Planck had to recognize that the energy quantization proposal was not just a mathematical trick, but actually expressed the quantum nature of energy. Based on this proposal, in 1905 Albert Einstein explained the so-called photoelectric effect consisting of the emission of electrons by materials when they are illuminated and in 1913 Niels Bohr proposed a model to explain the atomic structure.

Other important experiments carried out in 1922 also corroborated the existence of the Planck energy quanta, these were the Compton scattering, and the Stern-Gerlach experiment to determine the atomic magnetic moment. Faced with this evidence, Planck eventually recognized that the energy quanta were indeed part of the reality of the world.

In 1924 Satyendra Nath Bose explains Planck’s law from a new statistical law that governs particles called bosons. This would give rise to what we now know as Bose-Einstein condensates. In that same year Wolfgang Pauli presents the so-called Exclusion Principle that establishes that two fermions cannot occupy the same quantum state, this principle allows in a natural and elegant way to explain many facts of the periodic table of elements.

In 1925 George Uhlenbeck and Samuel Goudsmit postulated the existence of electron spin and in that same year Werner Heisenberg, Max Born, and Pascual Jordan proposed the so-called matrix mechanics, which is a formulation of quantum mechanics. The following year, in 1926, Erwin Schrödinger, using the wave proposal presented by De Broglie in 1924, develops the equation that describes the evolution of the quantum wave function, this is known as the wave formulation of quantum mechanics. Schrödinger’s equation would be generalized by Paul Dirac in 1927, obtaining a relativistic wave equation.

Albert Einstein, Boris Podolsky, and Nathan Rosen published in 1935 what is now known as the EPR Paradox, which questions the completeness of quantum mechanics. If local realism is valid, they show that hidden parameters are required to explain how measuring the quantum state of one particle can influence the quantum state of another particle without apparent contact between them.

That same year Schrödinger proposes the mental experiment now known as Schrödinger’s Cat which shows the paradoxical situation of particles that are simultaneously in two contradictory quantum states. In 1936 Garrett Birkhoff and John von Neumann develop quantum logic in an attempt to resolve inconsistencies in classical logic and Boolean logic with Heisenberg’s uncertainty principle, from there non-commutative logics and non-associative logics have been developed, among others. others.

From the results mentioned, a new vision of reality has been developed, which is very different from what was originally thought. The subject is so interesting that it deserves to continue in a second part.

### Opinion in your mailbox

Leave your email and receive AM’s editorial columns for free, from Monday to Sunday