Can you think quantum logically

Quantum theory

Quantum theoryw [from Latin. quantum = how much],E.quantum theory, theoretical description and explanation of microphysical phenomena, which are characterized by quantities such as energy, charge, spin, momentum, etc., which have no equivalent in classical physics or are quantized in contrast to it, that is, cannot continuously assume any values, but rather each only certain discrete multiples of a certain value. In recent years, numerous highly speculative hypotheses and discussions have arisen about the connection between the apparently so distant topics of quantum theory on the one hand and brain and consciousness on the other (mind and brain, body-soul problem). - The quantum theory, together with the general relativity theory, is the physical theory that has been experimentally best confirmed. Nevertheless, Richard Feynman, for example, claimed that, apart from its practical applications, "nobody understands quantum theory" (see additional info 1). Their results, predictions and interpretations are too paradoxical and bizarre: a hybrid existence of waves and particles; apparently self-interacting or interfering particles; the uncertainty of certain quantities such as momentum (mass times speed) and location or such as energy and time; spatially and temporally "smeared" states; reversible measurements; "spooky long-range effects" (Albert Einstein) between so-called entangled quantum systems; Teleportation of states of one photon or atom to another without loss of time; apparently faster than light signals; non-caused coincidences (spontaneous energy jumps, tunnel effects during radioactive decay, matter-antimatter pair creation); and the so-called measurement problem, which is related to the "collapse" of the wave function (reduction of the state vector): The Schrödinger equation (Psi or wave function) describes the state or the development of a quantum system as a statistical superposition of states. Which of these is real at a certain point in time cannot be predicted exactly, but can only be determined experimentally through a measurement (collapse of the wave function, the physical meaning of which is however controversial). But where does a measurement begin and where does it end? Aren't measuring devices, including human brains, also physical objects that obey the laws of quantum theory? How does the transition from the macro to the micro world or from classical physics to quantum physics take place (experimentally, the boundary proves to be shifting more and more)? What is the meaning of the state wave function, what is the status of an observer, what is it really? - Erwin Schrödinger saw this unsatisfactory situation and tried to illustrate it in 1935 with a thought experiment: "You can also construct very burlesque cases. A cat is locked in a steel chamber, together with the following infernal machine (which must be secured against direct access by the cat ): In a Geiger counter tube there is a tiny amount of radioactive substance, so little that in the course of an hour one of the atoms might disintegrate, but just as probably none; if it does, the counter tube responds and activates a little hammer via a relay that smashes a small flask with hydrogen cyanide. If this whole system has been left to its own devices for an hour, one will say that the cat is still alive if no atom has decayed in the meantime. The first atomic disintegration would have poisoned it. The function of the whole system would express this in such a way that in it the living and the dead cat are in equal parts are mixed or smeared. " - This parabola was intended as an example of how quantum theory can be misused in other areas, and how inappropriately transferring microphysical phenomena (e.g. the smeared hybrid states, i.e. the superposition or superposition) to macroscopic objects of the everyday world (e.g. cats) is. But many physicists and philosophers took Schrödinger's cat seriously and literally. But does it really make sense to assume that the cat in the box is dead and alive at the same time, or neither of the two, as long as no one is watching it? Or does the observation even provide a clear cat's condition? This radical view actually has its supporters and leads straight to a philosophical idealism: "To be is to be perceived" (George Berkeley). However, there are considerable difficulties: where does the observer come from? Why can't he just see the world the way he wants; why is it often so uncomfortable? Doesn't the smeared condition of Schrödinger's cat pass over to the observer? Suppose a man opens the chamber and looks after the cat. Journalists are waiting in front of the door to find out about the animal's fate. As long as he has not reported anything to them, shouldn't the man for his part find himself in a state of overlap between someone who has seen a dead cat in a box and someone whom it has jumped into the arms, creaking alive? On the other hand: Could the cat, which is probably also conscious, observe itself and thereby keep it alive? It is also questionable whether the Schrödinger equation can even be applied to cats, since they consume energy and are not a closed system. And: could an observer not be able to determine the time of death of the cat retrospectively, e.g. by measuring the oxygen consumption in the crate? In addition, the quantum effects on macroscopic objects are far too small. The basic measurement inaccuracy of a tennis ball is, for example, only 1:10 due to Heisenberg's uncertainty principle-16that of nerve impulses 1:10-9. In other words: quantum effects should not actually affect the brain more than stomping on the ground the orbit of the earth. In addition, quantum states such as radioactive decay cannot normally be amplified without destroying the superposition. Through an interaction with the environment, the originally pure state of the quantum system is converted into a mixed state, which can no longer be described by a state vector of the psi function; an entangled state develops between the quantum system and the environment in an extremely short time, so that interferences between different macrostates become unobservable (they disappear locally, but pass over to the overall system, as it were). Based on these Decoherence Schrödinger's cat therefore always appears either dead or alive. - This persistent ambiguity of the natural philosophical interpretation Quantum physics (see additional info 2) is the background against which attempts must be seen to connect or even explain neural processes and consciousness with quantum physical processes (see additional info 3). Since quantum mechanics seems to contradict the determinism of classical physics, Max Planck already saw a new possibility for human free will, but only in the epistemic sense: the future is open, i.e. not exactly predetermined and predictable. Pascual Jordan went one step further and saw in the indeterministic quantum processes "loopholes" in the causal structure of physics through which mental processes can intervene in nature. John C. Eccles argued similarly. He did not believe in a purely neural origin of the human mind, but considered it to be a divine creation and an independent form of existence independent of the physical world. But how can this supposedly free spirit intervene in matter? Together with Friedrich Beck, Eccles formulated a bold hypothesis: It is quantum effects that the mind sets in motion or at least uses (see additional info 4). According to Eccles, this happens at the synapses, the connection points between nerve cells. The consciousness should release neurotransmitters via quantum leaps, which could activate or inhibit the downstream cell. Beck has supplemented this with a biophysical model that takes into account the electron transport in the synapses. The problems for Eccles' neural quantum theory of consciousness are enormous (see additional info 5). Nevertheless, it is not nonsensical from the outset. In a certain sense, the question of the influence of a nonphysical consciousness on quantum processes can even be investigated experimentally: with the help of an apparatus in which two pointers register radioactive decays, an observer can try to convey a message to another by using the pointer of his own Either looking at the meter or not. However, previous experiments have not found convincing evidence of such an information transfer. - Matthew J. Donald's approach has a different perspective. Here consciousness does not intervene in the world, but is, as it were, an epiphenomenon. The wave function does not collapse either, but all alternatives are realized in different states of consciousness. In this many-consciousness interpretation (E. many minds interpretation) the different transitions are based on quantum physical switches. Donald sees ion channels in nerve cell membranes that are either open or closed as a neural correlate. Of course, it is unclear why such individual switchings can generate or change consciousness, why other molecules with conformational changes (e.g. rhodopsin) cannot also be considered and why the development of a quantum system has anything to do with mental processes at all. - Roger Penrose is also working on a quantum theory of consciousness. He is convinced that thinking is based on unpredictable processes that cannot be simulated in the computer in principle, and that current physics is not yet sufficient to describe them. Penrose combines the mystery of the human mind with the great goal of theoretical physics: a unification of quantum theory and general relativity. This theory of quantum gravity, Penrose hopes, will kill three birds with one stone: the riddle of the big bang, the measurement problem in quantum physics and the secret of consciousness. "I don't just mean that we need new physics, but that this new physics must also be relevant to the processes in the brain." For critics, on the other hand, quantum theories of consciousness are not only an impermissible physical reductionism, because mental processes can be explained on other levels of description, but also mere wishful thinking. In the meantime, Penrose and Stuart Hameroff suspect that microtubules conjure up the mind. Penrose and Hameroff believe that, like Schrödinger's cat, both dead and living, they are often in coherent superimposed states. According to the presumed laws of quantum gravity, these are supposed to collapse by themselves into a definite state every second and thereby generate the flow of moments of consciousness. How this should happen in detail, however, nobody understands. In addition, it is extremely improbable or even a contradiction that the quantum effects on the one hand remain shielded from the environment long enough, but on the other hand can spread well-ordered over the whole brain. Physiological data also speak against the participation of microtubules in consciousness processes, especially since these occur in every eukaryotic cell, i.e. not only in neurons. - "Fifty years of careful thought have given me the answer to the question 'What are light quanta?' Not brought closer. Today, Hinz and Kunz imagine they know. But they are mistaken, "wrote Albert Einstein in a 1951 letter. Until his death he was skeptical of the upheavals in quantum physics. He would certainly have amused that quantum effects are now, 50 years later, haunted even in the minds of consciousness researchers. Whether this is to be understood literally or polemically remains to be seen at the moment. It is well known that even unconventional paths can lead to completely new insights. And Joseph Joubert already knew 200 years ago: "It is better to discuss a question without deciding than to decide a question without discussing it."

R.V.

Lit .:Baumann, K., Sexl, R.U .: The interpretations of quantum theory. Braunschweig, Wiesbaden 1987. Davies, P.C.W., Brown, J .: The spirit in the atom. Frankfurt am Main 1993. d'Espagnat, B .: Veiled Reality. Reading 1995. Donald, M.J .: Quantum Theory and the Brain. Proceedings of the Royal Society, London A 427 (1990), pp. 43-93. Eccles, J.C .: How the self controls its brain. Munich, Zurich 1996. Ghose, P .: Testing Quantum Mechanics on New Ground. Cambridge 1999. Giulini, D. et al .: Decoherence and the Appearance of a Classical World in Quantum Theory. Heidelberg 1996. Gribbin, J .: Schrödinger's kitten and the search for reality. Frankfurt am Main 1996. Herbert, N .: Quantum Reality. New York 1985. Lockwood, M .: Mind, Brain and the Quantum. Oxford 1989. Penrose, R .: The big, the small and the human mind. Heidelberg, Berlin 1998. Selleri, F .: The Quantum Theory Debate. Braunschweig, Wiesbaden 1984. Vaas, R .: Quantum spook. Bild der Wissenschaft 9 (2000), pp. 70-75. Changer, D .: The quantum philosophy of consciousness. Neuried 1999. Wheeler, J.A., Zureck, W.H. (Ed.): Quantum Theory and Measurement. Princeton 1983. Wick, D .: The Infamous Boundary. Boston 1995.

Quantum theory

1 enigmatic quantum world:
The status of the observer in quantum theory and the question of whether and how matter produces conscious experience is still a subject of controversial discussion. In the meantime, however, experiments have clearly confirmed that the conditions of locality and separability in classical physics have no equivalent in quantum theory. Instead, there are entangled states (EPR correlations) between quantum systems that may even soon be used: for encrypting messages (quantum cryptography) and for calculating problems that cannot be solved otherwise or only with huge effort (quantum computers). Despite the great success of quantum theory "for all practical purposes", its philosophical consequences are alarming and still far from being explored. Their indeterminism calls causality into question, and the formalism of the wave function generally an objective description of nature. Here it no longer makes sense to speak of identifiable individual particles, because there is no well-defined spatiotemporal path (because of the uncertainty relation) and no distinguishability based on the particle state (because of the permutation invariance in the formalism), i.e. only countability, no numbering ( individual naming). Objective are only quantum field states, characterized by occupation numbers, but the individual particles can no longer be differentiated due to their states within the framework of the formalism. If the trajectory of a particle is constitutive for its identity, and identity is a minimum requirement for objects, then the status of elementary particles becomes questionable. Self-interference, entanglement (no localization and separability), superposition and the wave-particle dualism break our everyday understanding and imagination of the nature of the quantum world. In a certain, strictly definable sense, the world is holistic; a position-independent description of reality has proven to be impracticable in quantum mechanics. The separation of individual objects and the subject-object separation are pragmatic abstractions and idealizations that have epistemological benefits, but apparently no ontological reality. Bohr's correspondence principle postulates a transition from the bizarre microscopic world of quantum phenomena to our mesoscopic or macroscopic everyday world, but does not change the fact that ultimately everything is based on quantum physical processes. Quantum theory makes three aspects of nature unquestioned for classical physics doubtful: its causality, its comprehensibility and its reality.

Quantum theory