VERY BRIEF HISTORY OF PHYSICS

From de book: Misticismo Cuántico.

Author: Luis Eduardo Sierra S.

Director of ARIEL MAGAZINE

Classical or Newtonian physics – Emergence of quantum physics – Einstein and relativity – Everything remains in constant motion – Maxwell's electric and magnetic forces and the entry into modern physics – Planck, progenitor of quantum and quantum physics – Einstein and the photoelectric effect – Bohr and the new image of the atom – Nobel laureates in physics – Davison & Germer and Quantum Mechanics – Einstein's relativity and his dilemmas with physics Quantum physics – The debates between Bohr and Einstein – Whoever understands quantum physics suffers from vertigo – Strict causality and certainty do not operate in the subatomic realm – Electromagnetic forces and waves – Feynman: no one understands quantum mechanics.

For neophytes in the field, and in order to better understand the emergence and progressive development of quantum physics, it is convenient to place ourselves first in the starting point, classical physics, to establish comparative points of reference. Gradually we will be immersed in the quantum world.

Before quantum physics assumed its leading role, especially from the first quarter of the last century, what we were taught in educational institutions, and which is still taught, due to the validity it has in the macroscopic world, is classical or traditional physics, also called Newtonian, by his father Isaac Newton (1643-1727), although it also includes Einstein's general relativity, which adds what is inherent to gravity and explains in detail facts incompatible with the Newtonian model. Newton deserves a special place in the history of science, he was a great philosopher, theologian, inventor, alchemist and mathematician.

For his work he relied on thinkers such as Galileo Galilei, René Descartes and Johannes Kepler, and other older thinkers such as Plato, Eudoxius, Euclid, Archimedes and Apollonius with their geometric ideas. Much has been said about Newton's work. Some go so far as to describe him as the greatest scientist and genius of all time and his work is classified as the culmination of the scientific revolution. With him the starting signal for modern science was given. He changed the character of physical scientific research by putting mathematics at its service, inventing those that did not yet exist for his purposes. Over the years, his equations served to elaborate a more elaborate mathematical structure.

Newtonian physics studies mechanics, thermodynamics, electromagnetism, optics, acoustics, fluid dynamics, among other disciplines. It describes the movement of objects on earth and in the heavens as a mechanical system. The Universe is assimilated to a machine, a precise clock in full operation, inside which its smallest detail of operation could be predicted. It is deterministic (every cause has a specific effect). It is reductionist (the composite is made up of the sum of its parts, and they never interpenetrate, each part functions independently, and is studied in isolation). Only if you know the different parts will you be able to understand the whole. It is rational (it abides by the rigorous scientific and logical method). It presupposes total objectivity (it does not matter who analyzes or observes it). Space and time are absolute (not relative). Each thing is at a specific point in space and time. The laws of gravity, heat, light and magnetism, gases, fluids and solids, all fit into a vast and logical mechanism, coherent, comprehensible, rational.

This is how physics worked, without setbacks for 200 years, until the beginning of the twentieth century, when relativistic and quantum mechanics appeared, with the consequent loss of prominence of Cartesian coordinates (a system for locating a point in a two-dimensional space), Euclidean geometry (three dimensions) and the Aristotelian and Newtonian universe in general. In 1900, William Thompson, physicist and inventor of intercontinental telegraphy, said: "There is nothing left to discover in physics. All that's left is more and more accurate measurement." He was not the only physicist of the time who expressed himself in this sense, in fact, such an assertion was generally accepted. These statements would be shattered a few years later with the emergence on the scene of quantum physics, the theory of relativity, nuclear fusion and fission, the discovery of galaxies beyond our own and the Big Bang theory.

In secondary school physics, things in space are quantified with measurements of length, width, and height, or if you prefer, forward, backward, right-left, up-down, a three-dimensional space in accordance with Euclidean geometry.. Everything was verifiable with the senses and reason. We suffered, however, some confusions with psychological time – a minute of love is shorter than a minute under water – but it was clear to everyone that a second was a sixtyth minute, this one a sixtieth of an hour, and this one a twenty-fourth of a day. Einstein's Theory of Relativity at the beginning of the twentieth century would turn all this upside down. Since 1967, it was no longer so elementary: a second turned out to be "the duration of 9,192,631,770 oscillations of the radiation emitted in the transition between the two hyperfine levels of the ground state of the isotope 133 of the cesium atom, at an absolute temperature of zero degrees Kelvin !!!." Of course, we are not going to meddle in this exhibition with such puzzles and phantasmagorical entities.

If someone asks us where we are, we respond with an address or a reference from some known place. If we were more precise, we would talk in terms of altitude and latitude, and if we were more sophisticated (although it is already the norm nowadays) we would send by digital means the exact location provided by a GPS with an application, for example through a cell phone. Someone perceptive would answer without hesitation: 'I am still here'. But where is that here, an astronomer could reply. A person at rest sitting in an armchair is not stationary at a static point, he is actually rotating with the rotation of the Earth at 1.674 km/hour. The Earth also revolves around the Sun at thirty kilometers per second, equivalent to 108,000 km/hour, and the solar system in turn orbits the center of our galaxy, the Milky Way, at a speed seven times faster, and the Milky Way and other galaxies (about 100,000 million) are also moving frenetically.  just like the billions of universes that coexist with our own, everything expands since the Big Bang. So, by the time you finish pronouncing 'I'm here', you're already quite far from where you were when you thought about saying it.

Despite such speeds, the notions of the space between two points and the time to travel it were understandable with Isaac Newton's laws, whether we were talking about the cosmos, a bicycle or a person walking: the distance is always equal to the speed for the time it takes to travel it; to travel five hundred meters, at a hundred meters per minute, because it takes five minutes, easy, simple, logical!

Newton had included the force of gravity in his equations, but it was not until the 1860s that Scottish scientist James Clerk Maxwell (1831-1879) expanded the tool of classical physics by taking into account electric and magnetic forces, employing additional equations and more elaborate mathematics. Thanks to all this we were able to count on radio, television and telecommunications in general. Maxwell was a great pillar of physics who made it possible to enter the era of modern physics and who laid the foundations for fields such as relativity and quantum mechanics. Such was his contribution that he is considered by many to be the scientist of the nineteenth century who had the most influence in the twentieth century. To highlight, his equations and the formulation of the classical theory of electromagnetic radiation, which unified for the first time electricity, magnetism and light as different manifestations of the same phenomenon. He promulgated the existence of forces that could not be explained by Newtonian physics. His research, supported by the work of Michael Faraday (1791-1867), led to the discovery of the universe as energy fields that are related to each other. Albert Einstein had a portrait of Faraday hanging on the wall of his study next to Newton and Maxwell, a fact that is more than eloquent of the genius of these characters and what they represented in the world of physics.

The great "quantum" emergence occurred with Max Planck (1858-1947) when he introduced us to the universe of atomic particles and subparticles. Thanks to his discoveries, he is considered the father of quantum physics, in addition to providing the foundations for research in fields such as atomic energy. In 1900 he proposed that energy was not continuous, as Newton claimed, but that it was given in small "discrete packets" called quanta, quantum or quantum, later baptized as photons, then formulating the "Planck's Constant", which would be used to calculate the energy of a photon. The photon became the elementary particle responsible for quantum manifestations. In other words, photons are the smallest packets of light that can exist. Its energy is proportional to its frequency. Quanta determine all dynamics in the submicroscopic world. With Planck, a completely new window was opened to look at the Universe and the enigma of radiated light was understood.

In 1905, the most popular scientist of the twentieth century, Albert Einstein (1879-1955), based on the fact that light consisted of these tiny "discrete packets", postulated the photoelectric phenomenon, which would earn him the Nobel Prize in Physics in 1921, according to which metals that receive light emit electrons. For laymen in the field this does not tell us anything nor do we understand what it is for, but we do understand when we are told that thanks to the photoelectric effect and the photon television, lasers, solar cells and a good part of modern electronics were possible. We do not understand many of the things in nature, we do not understand, for example, what electrical energy consists of, but we use it in multiple ways, unfailingly, day after day.

In 1913 the Danish physicist Niels Bohr (1885-1962) revealed to us a completely new image of the atom. Previously, electrons could only move in orbits around the nucleus, with Bohr "jumping" from one shell to another innermost with less energy, emitting a photon (quantum jump. We will return to this given its significance). His contributions and affirmations about the structure of the atom as a nebulous, ghostly universe, acquired concrete reality when observations were made about it.

The theory of the atom was completed in 1925 with several physicists as protagonists, highlighting here Erwin Schrödinger (1887-1961) with the development of the Schrödinger Equation and his famous cat thought experiment, which shows the paradoxes and questions that quantum physics faces us. Let us include Werner Karl Heisenberg (1901-1976) as another of the illustrious physicists, with the Principle of Indeterminacy or Uncertainty, another topic that we will touch on later, as far as the brevity and objective of this work allow. In the 1930s, it was discovered that for every particle there is another twin, an antiparticle, the antielectron, called a positron because of its positive charge.

Planck received the Nobel Prize in Physics in 1918 for his discoveries on energy quanta. Bohr in 1922 for his research into the structure of atoms and the radiation emanating from them. Einstein, as already said, in 1921 for the photoelectric phenomenon. Heisenberg in 1932 for the creation of quantum mechanics. Schrödinger shares the prize with Paul Dirac in 1933 for the discovery of new productive forms of atomic theory. Then come a series of colleagues with their respective contributions in the subatomic universe. We are already fully immersed in modern physics, particle physics, high-energy physics, quantum physics.

"In the early 1920s, an American physicist, Clinton Joseph Davisson, began a series of investigations for the Bell Telephone Company by bombarding nickel crystals with an electron beam similar to the beam produced by the image on television screens. He noticed some curious regularities in the way electrons spread across the surface of the crystal, but he did not immediately understand their enormous importance. Several years later, in 1927, Davisson led an improved version of the same experiment with a younger colleague, Lester Halbert Germer."

"The regularities were very pronounced, but the most important thing was that they were now expected, on the basis of a remarkable new theory of matter developed in the mid-twenties. Davisson and Germer were directly observing for the first time a phenomenon that resulted in the collapse of a scientific theory that had been solidly established for centuries and that turned our notions of the meaning of reality, of the nature of matter and of our observation of it upside down. In reality, so profound is the revolution of knowledge consequent and so extravagant. The new theory is now known as quantum mechanics. It is not a mere speculative theory of the subatomic world, but a complex mathematical network that underpins most of modern physics" (Davies, 1983).

"Quantum physics was formulated in the 1920s, but it was not until the 1960s that its implications for the nature of our reality began to be more fully appreciated... Paul Dirac was one of the managers of the formulation of quantum theory, a prodigious mathematician from a humble background, who despite graduating with excellent grades could not find work in the post-war economic climate. In 1930 he wrote a manual on quantum theory. He formulated his famous Dirac Equation by combining relativity with quantum theory. Due to his introverted, technique-focused character, he was much less famous than other physical icons of the twentieth century, but his uniquely logical and mathematical mind allowed him to articulate the basic principles of quantum theory more clearly than anyone else" (Turok, 2015).

Dirac's equation predicted the existence of antimatter and the electron spin according to which subatomic particles can spin in a similar way to a spinning top or pyrinola. If he had patented this discovery, he would have accumulated a huge fortune with the royalties he would have received for each television, walkman, video game and computer manufactured.

It has already been said that quantum physics describes the behavior of atomic particles at nanoscopic scales. It never ceases to amaze that such a tiny universe, which escapes human sensory perception, turns everything upside down, or upside down, or sideways, or up and down or anywhere, or everywhere at the same time, as we will see in the following paragraphs, invalidating within this subatomic universe Newton's laws that work so wonderfully for the macro. The fact is that only thanks to quantum laws could a large number of puzzles be solved in the subatomic world.

In its beginnings, quantum physics was confronted with Einstein's general relativity, due to the incompatibility between the two, constituting for modern theoretical physicists its central problem, even today. When we address the section related to the Unified Field, we will touch on this crucial issue again. Quantum mechanics developed much more rapidly than the Theory of Relativity proposed by Einstein thanks to the enthusiastic performance of the physicists of the time, but it attracted less public interest than the Theory of Relativity. The debates between Einstein and Bohr on the interpretation of quantum mechanics are relevant episodes of this time. At first Einstein showed disinterest and skepticism in Quantum Theory, refusing to accept it completely. His refusal, however, was more philosophical than scientific, he could not accept that the microcosm could only be described probabilistically, invalidating the law of cause and effect. For a being who loved precision, who was at the same time a lover of a creator father, such a possibility was inconceivable, as if God were an inveterate dice player.

Bohr, one of the most important precursors of quantum theory and one of its most vehement defenders, nevertheless once stated that "whoever does not feel vertigo when he thinks of quantum mechanics, it is because he has not really understood it". Regarding Einstein, he would say that: "he was increasingly distant and skeptical with respect to the quantum discoveries he had pioneered. Many of us consider it a tragedy. Both Einstein and Planck laid the foundations of quantum mechanics, paradoxically, both rejected it when they observed that it undermined the concepts of strict causality and certainty that they revered so much.

In time Bohr would be right: strict causality and certainty did not operate in the subatomic realm. It made no sense to talk about a reality that was independent of our observations and measurements. Depending on the type of experiment chosen, light could be either a wave or a particle (this will be better understood as we progress through this discussion).

Einstein, who overthrew many of the pillars of Newton's universe, including absolute space and time, would later become, with the progress of quantum mechanics, a defender of the order established by Newton. He would remain a realist with a firm belief in an objective reality, rooted in certainty, that existed regardless of whether we could observe it or not, reluctant to the notion that in the realm of quantum mechanics nature was governed by probabilities and uncertainties. In 1951 he would say: "I have retired the theory of the unified field. It is so difficult to use mathematically that I have not been able to verify it."

In their purpose to merge special relativity and quantum mechanics, physicists focused on the electromagnetic force and its interactions with matter, giving rise to quantum electrodynamics, the most precise theory that has been developed on natural phenomena, from the work of Jordan, Heisenberg and Pauli, and formulated by Dirac between 1926 and 1934, with contributions from Bethe, Feynman, Schwinger and Tomonaga in the 40s. Electromagnetic waves carry energy, to such an extent that life on our planet depends entirely on the energy that is transmitted from the Sun to the Earth by electromagnetic waves.

For the consolation of many, if not all, let us take into account what was expressed by the Nobel Prize winner Richard Feynman (1965), considered by some to be the greatest physicist after Albert Einstein and one of the greatest experts in quantum mechanics: "There was a time when the newspapers said that only twelve men understood the theory of relativity. I don't think there was even a time like that. There might have been a time when only one man understood such a theory, before publishing it, because he was the only one who had realized that things could be so. But after others read its publication, many people understood, in one way or another, the theory of relativity. Surely there were more than twelve. On the other hand, I think I can safely say that no one understands quantum mechanics."

Today, unlike relativity, the question is whether there is truly anyone who understands quantum mechanics at a deep level. The public confession of this quantum colossus is thus added to that of other eminent colleagues, to serve as a palliative for those of us who feel stunned by all this gibberish.

What has been fully understood with quantum physics is that the basic conception of the world, of our environment, when the field of the microscopic and the laws that govern it is addressed, makes no total sense, allowing predictions that have been completely verified experimentally, supported by coherent mathematical formulas. "Without quantum theory, our global, multidimensional understanding of atoms, nuclei, molecules, crystals, light, electricity, subatomic particles, lasers, transistors, and many other things would disintegrate. No scientist seriously doubts that the fundamental ideas of quantum mechanics are correct" (Davies, 1983).

Quantum theory or mechanics was introduced, as we have seen, in the first three decades of the twentieth century, thanks to the successive contributions of an international group of physicists, among which Max Planck, Albert Einstein, Niels Bohr, Louis de Broglie, Erwin Schriklinger, Wolfgang Pauli, Werner Heisenberg and Paul Dirac deserve to be highlighted. To this elite would later be added another plethora of thinkers, not only physical, who have offered us a more integral conception of life and who have led us to a kind of scientific spirituality, a science with consciousness and a consciousness with science, according to which, in nature, everything is interconnected, in line with a dynamic that permeates the entire universe.