|19 Dec 2006 @ 18:37, by Beto Hoisel|
Rutherford has shown that atoms were not tiny pellets but an immense void modestly occupied by a lonesome nucleus one hundred times smaller, surrounded by still more minute electrons madly circling in relatively distant orbits. Latter, more sophisticated repetitions of the two slit experiment made light brake the barrier of logic, revealing its twofold and contradictory nature of a wave which is also a projectile.
Science was banished from the paradise installed by Newton and consecrated by Descartes.
The atom has lost its post of elementary and indivisible constituent of matter: it was made of still minor particles – a nucleus and an electronic crown – shaped somewhat like a minute solar system, the metaphor then used. The atomic nucleus turned to be formed of protons and neutrons and could be broken yielding fantastic energies. By the middle of the century, an astonishing cast of supposedly elementary particles has begun to set foot on stage. They were engendered under special high energy conditions, such as the cosmic rays coming from the depths of the sky or inside powerful machines developed by man to violently penetrate in the intimacy of matter.
The ambiguous nature of light soon extended to all electromagnetic radiation, from long radio waves to the shortest gamma rays, which differ only in the amount of energy conveyed. And more: to deepen the vexation, it was verified that other particles known as elementary, as the electron, the nucleons and all varieties produced in experiments – more than two hundred, then – were also waves, or vibrations, depending on the kind of experiment accomplished. It's important to keep in mind that both electromagnetic radiation and elementary particles have shown to be simultaneously waves and particles. They didn't behave as waves or particles in different situations, rather they incarnate that double personality simultaneously. Only the nature of the experiment carried on would allow the researcher to be aware of one of those faces, but never both at once.
Additional difficulties appeared when scientists tried to know exactly a particle's position and velocity. It was confirmed these two data couldn't be obtained at once: or the position or the speed could be measured separately, but never both at same time. Moreover, the higher the precision of one of those measures, the lesser the other can be known. This hindrance, however, isn't due to the accuracy of the equipment or methods used. Heisenberg has proved this impossibility is an intrinsic property of nature itself in these submicroscopic realms, where all the knowledge we can gather is of statistic and probabilistic nature; it's impossible to learn exactly what happens to a sole particle, even using the most precise instruments. And this was just the beginning of a series of ghostly features that the quantum world has been exhibiting to the astonished researchers.
Perhaps the most incredible is the astounding success of quantum theory in every field where applied, although it's known to rest on paradoxes that challenge logic and bewilder scientists. It's really surprising: technologists and researchers have never found a case to reveal quantum theory is flawed or imprecise. On the contrary, at same time we witness quantum realms vanishing into a bundle of logic paradoxes and cognitive impossibilities, quantum technology lavishly yields wonders like computers, liquid-crystal video screens and holography, brought into being by skilled wizards of electronics and photonics. Technology is still far from exhausted, and the near future will deliver surprises prone to amaze our most daring expectations. It's rather impossible to foresee what's coming ahead.
However, side by side of these joys stood the shadow of a disturbing certainty that's already changing the directions of our philosophical inquiries. It's the proved certitude that solid barriers exist in the path to a rational approach on the intimate organization of matter, energy and the universe. We're wrapped up with an ever increasing variety of communication resources, almost uniting our planet into an integrated interactive information network, unthinkable just a few years ago. Notwithstanding we also must accept our utter cognitive limitations to reach the deepest realms of the universe, in its real, material slope.
The restraint installed by Heisenberg's principle of indetermination is peremptory: it's impossible to know both velocity and position of a particle simultaneously. By the same token our logic mind cannot conceive a vibration which is also a bullet, although every electromagnetic radiation and particle which constitute the stuff of the universe show this is the way they are. After Heisenberg many science warlocks entered the stage, putting their curses on the dreams of absolute knowledge of reality, usually defined as "everything that exists" in the physical universe. Let's hear what they have said.
The year 1927 was particularly prolific as to insights that induced the turnover of our expectancy of a deeper knowledge on the constituents of matter and reality. In that very year, Heisenberg formulated his principle of uncertainty and Niels Bohr – widely recognized as the grand master of the quanta vision of the world – has pushed ahead that new conception, advancing his principle of complementarity. The new principle acknowledged the dual nature wave/particle in every micro-entity, installing a phlegmatic schizophrenia about the interpretations of quantum phenomena or, in other words, abolishing any ambitions on understanding them. "It's a mistake to suppose the objective of physics is to determine what nature is. Physics only tries to establish what we can say about nature." So said the master.
Schrödinger and Max Born have shown, in 1926 that an elementary particle can never be anywhere until it's measured, or became the object of an observation, an experiment. The most we can say on that particle is that possibly, or probably, it could be here or there. Schrödinger propounded his famous wave function which established that probability, and Bohr has shown it's not a wave of anything we could call matter or energy; rather it's an abstract wave of a mere mathematical possibility that such particle appears in this or that place. The ghostliest property of that abstract wave is that, in spite of its nonmaterial character – we should say imaginary, nonphysical – it's submitted to the same phenomenon of interference that characterize real waves, already studied by physics. Now, we ask: how can mathematical abstractions interfere? What interferes with what? Schrödinger's equation doesn't determine where a particle is, only where it can be, and the probability of that occurrence in each point; only when a measure is taken – or an observation –the so called wave function collapse and the particle "chooses" one point and materializes up there. If the experimental procedure continues and many waves are collapsed, we will see particles arranging themselves according to the calculated probabilities, even if it's impossible to know where each one separately will materialize. In this quantum world logic works differently, and determinism is replaced by random occurrences.
By the end of the twenties the random and probabilistic principles of quantum mechanics were established. Regular logic turned to be subverted, making us live together with uncertainty and paradox. In the beginning, uncertainty and paradox seemed to be confined to the submicroscopic realm, leaving our macroworld quietly ruled by the ordinary principles of logic and causality. Schrödinger himself undertook the grim task of liberating us from that illusion with the help of his famous cat. Surely, being a self-respecting sorcerer, Schrödinger also had a cat. As a matter of fact, an imaginary cat.
The proposed experiment is only mental. Imagine a cat in a sealed box where a radioactive source can release a hammer that will break a bottle containing a venomous gas, if in the term of an hour it emits a particle. If this happens the cat dies, otherwise he will be alive after that period. That arrangement settles something of the macroworld – the survival of the cat – as dependent of something that happens in the quantum microworld. If the radioactive source is calibrated to a fifty per cent chance of releasing that deadly particle in the period of one hour, the poor cat has fifty per cent possibilities of survival when the box is open. Quantum theory doesn't allow to forecast if the particle will or not be released, it only informs the chances of that event to occur are fifty per cent. In conformity to master Bohr's sentence, until the end of the crucial sixty minutes, we cannot speak of a dead or alive cat, since it wasn't object of an observation, requisite to the particle opt for one of two states: released or not. Only such an option would make the hammer to fall or not, killing or not the unfortunate cat. Before the opening of the box, thus proceeding an observation, the cat should not be alive or dead, according to Niels Bohr's interpretation – also known as the Copenhagen interpretation. Before the opening of the box the state of the cat should be described through a probabilistic wave-equation, unfit to determine if he is dead or alive. Nonetheless, apart of our awareness on his state, how would be the cat objectively? Answer: the cat should be in a state simultaneously alive and dead, since there wasn't the wave-function collapse and he could be in any of these two conditions at the moment the box was open.
Our reason insists the cat's fate should be decided before the box was opened, that would be a verification of a previously occurred fact. "It's not this way!", declares emphatically master Niels Bohr. The experiments, the mathematical calculations and all theoretical formulations of quantum physics assure a wave-function cannot collapse alone, without an observer's participation. Thus a particle is not able to decide if it will or will not be liberated, so the cat cannot turn into a definite state of being, be it dead or alive.
But ultimately what is the existential status of the cat, in that distressing period of one hour? Heisenberg replies with an old concept introduced by Aristotle: the cat remains in a potentially dead and potentially alive condition, unable to turn into a definitive status. Poor Schrödinger's cat! Involved with a warlock he cannot even to know whether he is alive or dead!
What happened to that cat submitted to such a cruel experiment – fortunately only imaginary – usually occurs not only with electrons, photons and every particle of the quantum realm, but also with large portions of our macroscopic reality, granted we are not observing. New experiments, not only imagined as that one with the cat but actually proceeded, have shown in a conclusive form that quantum schizophrenia extends to the world we live in, lurking in disguised nooks of daily life – provided no one is observing!
The unbelievable feature shown by electrons to cross simultaneously two side by side slits is a broadly acknowledged fact among researchers, as well as the crazy property of light to fit out its wave or particle mask, according to the experiment done. In the optical interferometry laboratories, where extremely precise switchers capable of commuting a light beam opening or closing its passage 300 million times per second, it's been verified that light can change its mask still faster, even changing the mask it had shown a nanosecond before, just to fit another experiment that would only work with the other.
Many scientists, bound up in the logic they learned and in prevalent perceptions of objective reality have performed laborious mental and experimental juggling to keep appearances up and make certain that quantum realm lunacy would not extend to everyday world. However, each new experiment, each new mathematical theorem confirms the certitude that reality is a concept we must entirely review, as much as locality of a physical event, what in fact is an observer – which I prefer to name a subjectivity – and also its interaction process within the so-called objective world.
In this quantum sabbath mathematician warlocks are the most dangerous. They usually demonstrate their curses, making them invulnerable to exorcism. German born Kurt Gödel has demonstrated in 1931 his theorem of incompleteness – which in its innocent enunciation states that we cannot build an arithmetic based on a system of axioms both complete and consistent. In the same way of Heisenberg's curse, we need to chose: or that arithmetic is complete or consistent (non contradictory); never both at once. This statement simply implies that our rational knowledge of the world has an upper limit: it will never be complete and devoid of contradictions. Isn't that distressing?
Von Neumann, the megasorcerer who created the modern computer, published a portentous treaty named Die Mathematische Grundlagen der Quantenmechanik in 1932, soon to be worshipped as "the Bible of quantum physics". In that book Von Neumann simply proves that if quantum physics is correct, then the world cannot be made of common, real, objective things. He even said that "physical objects do not have any attributes if a conscious observer is not looking at". This is known as "Von Neumann's proof". Shouldn't it be more properly called "Von Neumann's curse"?
More recently, another perilous mathematician warlock candidly named John Bell has utterly demonstrated that "no local model of reality can correspond to quantum facts". In other words reality, if it expects to exist, must be non-local: its events and phenomena undergo influences from everything in the universe, even from the most remote galaxy; and that influence is instantaneous, unfettered by the laws of relativity. That achievement has guaranteed him more powerful than Albert Einstein who, displaying that handsome granddad bearing could never become a genuine wizard.
In the 1930's he joined Boris Podolsky and Nathan Rosen to suggest a mind experiment – he was very fond of mind experiments – that would show quantum theory as flawed or incomplete by way of preposterous outcome. As time went by, thanks to the accomplishments of more powerful sorcerers, the absurd revealed true and the proposed witchcraft has proved the opposite. Sometimes I wonder if this happened to Einstein by reason of his rejection of quantum theory, being one of her founding fathers (he even proposed the term quantum). Till the end of his life, he never pardoned her anarchist ideas and naughty behavior. This could well be a lesson to parents who refuse to understand the new generations.