A picture is worth a thousand words" is one of the rare maxims phrased as an understatement.A high-resolution colour picture contains in fact more information (bit-wise) than a million words.It is in gene ral also faster, easier and more pleasant to grasp than mere words.Our brain is equipped with a rapid and efficient mechanism dedicated to analysing pictures and extracting meaning from them.In spite of our tremendous handicap in arith metic computations, we can still easily beat any computer when it comes to versatile image recognition.We are indeed so good at it that we like the exercise even better when the images are projected at the rate of at least 24 per second, in the form of video or film.For better or for worse, the dominant means of communication today is the ani mated image, and it is here to stay.But there are things we, as humans, would rather express in words, and there are things -quantum mechanics and field theory among them -that we, as scientists, would express more universally in equations and numbers.This should come as no sur prise, you might say: any fundamental theo ry is naturally presented in terms of defini tions, equations and constants of nature.True: but any fundamental theory is then developed and taught with the help of examples, demonstrations, experiments, applications, and images.Practitioners of quantum mechanics somehow managed with few of the last.The reasons for the scarcity of quantum images have very different origins, some valid, some unjustified.The following re marks illustrate the situation: -Quantum mechanics is manifest mainly at the molecular, atomic and subatomic scales.Only recently did microscopes beco me capable of producing "real" images at these scales.Some isolated coherent quan tum effects are known at larger scales (neu tron stars, lasers, superconductivity, liquid helium, etc.), but real images demonstrating clearly their quantum aspect are lacking.-In the domain of "theoretical" images, an overwhelming hurdle has been the rather
A picture is worth a thousand words" is one of the rare maxims phrased as an understatement.A high-resolution colour picture contains in fact more information (bit-wise) than a million words.It is in gene ral also faster, easier and more pleasant to grasp than mere words.Our brain is equipped with a rapid and efficient mechanism dedicated to analysing pictures and extracting meaning from them.In spite of our tremendous handicap in arith metic computations, we can still easily beat any computer when it comes to versatile image recognition.We are indeed so good at it that we like the exercise even better when the images are projected at the rate of at least 24 per second, in the form of video or film.For better or for worse, the dominant means of communication today is the ani mated image, and it is here to stay.But there are things we, as humans, would rather express in words, and there are things -quantum mechanics and field theory among them -that we, as scientists, would express more universally in equations and numbers.This should come as no sur prise, you might say: any fundamental theo ry is naturally presented in terms of defini tions, equations and constants of nature.True: but any fundamental theory is then developed and taught with the help of examples, demonstrations, experiments, applications, and images.Practitioners of quantum mechanics somehow managed with few of the last.The reasons for the scarcity of quantum images have very different origins, some valid, some unjustified.The following re marks illustrate the situation: -Quantum mechanics is manifest mainly at the molecular, atomic and subatomic scales.Only recently did microscopes beco me capable of producing "real" images at these scales.Some isolated coherent quan tum effects are known at larger scales (neu tron stars, lasers, superconductivity, liquid helium, etc.), but real images demonstrating clearly their quantum aspect are lacking.-In the domain of "theoretical" images, an overwhelming hurdle has been the rather
Wave equations -wave functions -are the mathematical way of describing the behavior of things in quantum mechanics. The physical basis of this is that on the microscopic level every object is at the same time both a particle a bundle of waves. So the mathematics that describes dynamics on this level turns out to be the mathematics of wave functions. Wave functions are far from being the easiest things in mathematics to solve compute with. To calculate the behavior of an atomic nucleus, for instance, involves working with dozens or hundreds of wave functions (each proton neutron has its own) that are related to one another in such a way that the solution to each one depends on all the others. They cannot be solved one by one; they have to be solved ensemble, dozens or hundreds of simultaneous equations, as mathematicians would describe By hand the task is formidable, perhaps practically impossible. However, at the Lawrence Livermore National Laboratory, a Cray 1, one of the latest, biggest fastest of computers has now come to the rescue. Using it M. S. Weiss co-workers have been able to calculate what happens in various kinds of collisions of a krypton nucleus with a lanthanum nucleus. Then, with the latest computer graphics they are able to display these processes in an animated film. The two nuclei approach each other, collide, in some cases fuse, in others come apart, everything is decorated with bright false colors representing the density levels of matter inside the nuclei. The pictures the information in them represent the solution of 146 simultaneous wave functions, one for every two nucleons, every two particles in the two nuclei. There is one function for every two nucleons rather than every one because the mathematics contains one important approximation. Nucleons can come with two directions of spin, spin up or spin down. This theory does not distinguish between the two spin states, so each function actually represents the average of one of each. The pictures show a dozen instances, starting from a head-on collision proceeding to instances of greater greater offset between the centers of the two nuclei until they arrive at a sideswipe in which the nuclei hardly touch each other. The collisions near head-on result in fusion. A little offset contributes an angular momentum: The fusion product rotates. More offset the nuclei collide, losing a lot of energy, but retaining enough to come apart again. This is known as deep inelastic scattering. Finally, an instance where the two nuclei do not touch, but where distortions vibrations are produced in them by the force between them when they are close. Weiss says the film wakes physicists up when he shows it at the end of a talk. He mentions one experimentalist who came up said how nice it was to be able to actually see these things. At least four levels of abstraction, Weiss comments, and he talks about seeing it. Yet viewing the film, one can understand what the experimentalist meant. The calculations behind the film are quite accurate in predicting the main events of the collisions, that is what is really important. According to Weiss, they predict accurately the conditions under which fusion is likely, the proper range of deep inelastic scattering so forth. In the pictures the behavior looks like that of a fluid, liquid drops coming together. Weiss stresses that it is actually the sum of discrete motions, those 146 individual wave functions. One of the purposes of the exercise was to see whether it was possible to derive a macroscopic theory that is, one that would give a simpler mathematical expression for the over-all behavior of the nuclei, that would yield the desired predictions without having to start from the 146 individual wave functions. It turns out, Weiss says, that a macroscopic theory is possible in some particular cases, but the microscopic one, starting from the individual wave functions, remains the general one. Computation was the serious hindrance to doing it before now. As Weiss says, the theory itself was written down years ago by P. A. M. Dirac, one of the pioneer theorists of quantum mechanics. It took Weiss co-workers a year to figure out how to feed the computation to the Each of the dozen collisions which takes about 10-21 seconds in real time, but is displayed in extreme slow motion in the film-took an hour of computation time using the core of the Cray That's expensive computing, but, says Weiss, I would never try it on a lesser computer. O
Quantum mechanics is usually defined in terms of some loosely connected axioms and rules. Such a foundation is far from the beauty of, e.g., the `principles' underlying classical mechanics. Motivated, in addition, by notorious interpretation problems, there have been numerous attempts to modify or `complete' quantum mechanics. A first attempt was based on so-called hidden variables; its proponents essentially tried to expel the non-classical nature of quantum mechanics. More recent proposals intend to complete quantum mechanics not within mechanics proper but on a `higher (synthetic) level'; by means of a combination with gravitation theory (R Penrose), with quantum information theory (C M Caves, C A Fuchs) or with psychology and brain science (H P Stapp). I think it is fair to say that in each case the combination is with a subject that, per se , suffers from a very limited understanding that is even more severe than that of quantum mechanics. This was acceptable, though, if it could convincingly be argued that scientific progress desperately needs to join forces. Quantum mechanics of a closed system was a beautiful and well understood theory with its respective state being presented as a point on a deterministic trajectory in Liouville space---not unlike the motion of a classical N -particle system in its 6N -dimensional phase-space. Unfortunately, we need an inside and an outside view, we need an external reference frame, we need an observer. This unavoidable partition is the origin of most of the troubles we have with quantum mechanics. A pragmatic solution is introduced in the form of so-called measurement postulates: one of the various incompatible properties of the system under consideration is supposed to be realized (i.e. to become a fact, to be defined without fundamental dispersion) based on `instantaneous' projections within some externally selected measurement basis. As a result, the theory becomes essentially statistical rather than deterministic; furthermore there is an asymmetry between the observed and the observing. This is the point where consciousness may come in. Complemented by an introduction and several appendices, Henry Stapp's book consists essentially of three parts: theory, implications, and new developments. The theory part gives a very readable account of the Copenhagen interpretation, some aspects of a psychophysical theory, and, eventually, hints towards a quantum foundation of the brain--mind connection. The next part, `implications', summarizes some previous attempts to bridge the gap between the working rules of quantum mechanics and their possible consequences for our understanding of this world (Pauli, Everett, Bohm, Heisenberg). The last section, `new developments', dwells on some ideas about the conscious brain and its possible foundation on quantum mechanics. The book is an interesting and, in part, fascinating contribution to a field that continues to be a companion to `practical' quantum mechanics since its very beginning. It is doubtful whether such types of `quantum ontologies' will ever become (empirically) testable; right now one can hardly expect more than to be offered some consistent `grand picture', which the reader may find more or less acceptable or even rewarding. Many practicing quantum physicists, though, will remain unimpressed. The shift from synthetic ontology to analytic ontology is the foundation of the present work. This means that fundamental wholes are being partitioned into their ontologically subordinate components by means of `events'. The actual event, in turn, is an abrupt change in the Heisenberg state describing the quantum universe. The new state then defines the tendencies associated with the next actual event. To avoid infinite regression in terms of going from one state of tendencies to the next, consciousness is there to give these events a special `feel', to provide a status of `intrinsic actuality'. The brain of an alert human observer is similar in an important way to a quantum detection device: it can amplify small signals to large macroscopic effects. On the other hand, actual events are not postulated to occur exclusively in brains. They are more generally associated with the formation of records. Records are necessarily part of the total state of the universe: it is obvious that the state of the universe cannot undergo a Schrödinger dynamics and at the same time record its own history. `The full universe consists therefore of an exceedingly thin veneer of relatively sluggish, directly observable properties resting on a vast ocean or rapidly fluctuating unobservable ones.' The present ideas also bear on how the world should be seen to develop. While conventional cosmology encounters problems as to how to define the intial conditions, which would enter the governing equations of motion, here `the boundary conditions are set not at some initial time, but gradually by a sequence of acts that imposes a sequence of constraints. After any sequence of acts there remains a collection of possible worlds, some of which will be eliminated by the next act.' Connected with those acts is `meaning': there has always been some speculation about the special significance of local properties in our understanding of the world. One could argue that correlations (even the quantum correlations found, e.g., in the EPR-experiments) were as real as anything else. But also Stapp stresses the special role of locality: the `local observable properties, or properties similar to them are the natural, and perhaps exclusive, carriers of meaning in the quantum universe. From this point of view the quantum universe tends to create meaning.' This sounds like an absolute concept: meaning not with respect to something else, but defined intrinsically---not easy to digest. The role of consciousness in the developing quantum universe requires more attention. `The causal irrelevance of our thoughts within classical physics constitutes a serious deficiency of that theory, construed as a description of reality.' This is taken to be entirely different within quantum mechanics. `The core idea of quantum mechanics is to describe our activities as knowledge-seeking and knowledge-using agents.' `21st century science does not reduce human beings to mechanical automata. Rather it elevates human beings to agents whose free choices can, according to the known laws, actually influence their behaviour.' An example with respect to perception is discussed: `Why, when we look at a triangle, do we experience three lines joined at three points and not some pattern of neuron firings?' The brain `does not convert an actual whole triangle into some jumbled set of particle motions; rather it converts a concatenation of separate external events into the actualization of some single integrated pattern of neural activity that is congruent to the perceived whole triangle.' How convincing is this proposal? It is hard to tell. I think Henry Stapp did a good job, but there are tight limitations to any such endeavour. Quantum mechanics is often strange indeed, but it also gives rise to our classical world around us. For the emergence of classicality jumps and measurement projections (the basic phenomena connected with those fundamental events of choice) are not needed. Therefore, I doubt whether the explanation of the evolution of our world really allows (or requires) that much free choice. On the other hand, most scientist will agree that empirical science was not possible without free will: we could not ask independent questions if this asking was part of a deterministic trajectory. The fact that the result of a quantum measurement is indeterminate (within given probabilities) does certainly not explain free will. How about the type of measurment? The experimentalist will have to assume that he can select the pertinent observable within some limits. But given a certain design the so-called pointer basis (producing stable measurement results) is no longer a matter of free choice. `The main theme of classical physics is that we live in a clocklike universe.' Today it is often assumed that the universe was a big (quantum-) computer or a cellular automaton. Many would be all too happy to leave that rather restrictive picture behind. But where to go? Stapp suggests giving consciousness a prominent role: `The most profound alteration of the fundamental principles was to bring consciousness of human beings into the basic structure of the physical theory.' How far we are able to go in this direction will depend on the amount of concrete research results becoming available to support this view.
T he S cience of C ryogenics B S J Nick Catrini Have you ever wondered how NASA launched their monumental space shuttles? Or perhaps you have heard of the scientists who can slow the speed of light to almost zero? Or about Walt Disney’s attempt at cryogenic stasis, where he waits to be awoken when a cure for lung cancer is developed? Unfortunately, Walt Disney being put into cryogenic stasis is a rumor and after his death he was cremated-but all three of these ideas have their roots in the field of cryogenics. Cryogenics is the art of achieving extremely low temperatures and observing phenomena that don’t normally occur in the chaotic, energy rich universe we experience from day to day. People have been freezing things for ages, but the age has come where there’s a demand for colder and colder temperatures, to the point where even the vacuum of outer space is a blazing inferno by comparison to what’s needed in the lab today. Simply put, the colder you get to absolute zero, the easier it is to observe the true quantum nature of atoms, where generalizations and models made for atoms at room temperature begin to break down, and what’s actually going on takes a different route. The ability to find and exploit these differences could lead to breakthrough technologies such as room temperature superconductors, quantum computers, improvements on existing technologies, and it could also answer questions about the origin and nature of the universe itself. Liquid nitrogen is cold, space is colder, but what scientists need is in nanokelvin, billionths of a degree. One historic study that used ultracold temperatures focused on slowing the speed of light to seventeen meters per second in “If quantum mechanics hasn’t profoundly shocked you, you haven’t understood it yet.” Niels Bohr an ultracold atomic gas. The method of getting of the gas to be ultracold was the focal point of the study, since the colder it would get, the slower light would travel through it. The scientists reached a whopping 435 nanokelvin, but in a surprising way to the unfamiliar layman (Hau, 1999). In order to slow light down to seventeen meters per second, lasers were used to cool the atoms down to 50 microkelvin, and then a magnetic field was applied to the cloud of cold atoms to filter out any atoms that do not have magnetic dipoles against the field, creating an effect similar to a coffee cup cooling off, where the improperly aligned atoms steamed off and out of the magnetic field, or cup, and the remaining aligned ones were the only ones left (Marangos, 1999). Now, nanokelvin temperatures are great, but in some cases even nanokelvin is too hot for simulating some phenomena (Campbell, 2011). Again, atomic gases are cooled with lasers put into arrays called optical lattices that “trap” atoms and prevent them from moving, lowering the temperature. Now, why are scientists studying this again? As Niels Bohr once said, “If quantum mechanics hasn’t profoundly shocked you, you haven’t understood it yet.” For one, the mere attempt to use advances in science and technology to tackle hard problems can lead to various discoveries in the process, such as the Bose-Einstein condensate or the slowing of light to 17 meters per second. But now, is the cost worth it? Slowing light promotes stronger light-matter interaction, which can benefit devices that clean up distortion and noise over long distance data transmission through optical fibers (Krauss, 2008). Last but not least, one of the most important discoveries in all of cryogenics’ time is nuclear magnetic resonance imaging over scanning. That handful of words is better known as an MRI or PET scan you’d get at a hospital. MRI is revolutionary since it performs non-invasive imaging of anatomical structures with no known adverse biological effects, it can determine data not available by other techniques, and it increases the specificity of a diagnosis (Partain, 1984). Research in these cooler temperatures today covers areas such as quantum magnetism and high temperature superconductivity, and the working memory needed for a quantum computer. The words “quantum computer” may sound very enticing, like some sort of science fiction mystery magic machine capable of solving any problem and running day to day tasks exponentially faster than even the most expensive supercomputer, but the reality is a stark contrast. In fact, the quantum computer got its roots in NMR-based technology (Ladd, 2010). A quantum computer is special because unlike a classical computer that has “bits” of information, a 1 or a 0, a quantum computer uses “qubits” which can be 1, 0, or anything in between. Qubits are particularly useful for a select set of problems, usually anything dealing with many 6 • B erkeley S cientific J ournal • E xtremes • F all 2014 • V olume 19 • I ssue 1
Quantum mechanics represents one of the great conceptual revolu- tions of the 20th century. It has raised a huge number of fundamental questions of both physical and philosophical kind. • What does matter mean at all? • What are the main properties or characteristics of matter? • Can matter be reduced to information? • Is our universe probabilistic at the most fundamental level? • Are there non-local correlations in nature? • Are non-causal interconnections between physical systems possible?
When the revolutionary conceptual structure for the description of the physical world which we know as quantum mechanics was first formulated nearly 90 years ago, and its predictions tested in the laboratory, most of the experiments in question were on systems which were both very well characterized and reasonably well isolated from their environments, such as single electrons and atoms, small molecules and near-perfect crystalline solids. While from the very start most physicists have taken it for granted that the formalism of quantum mechanics, when combined with appropriate system-specific information, can “in principle” account for all phenomena occurring in the physical world, including those usually regarded as the subject-matter of biology, until quite recently the overwhelmingly majority opinion has been that in a biological context the role of quantum theory is confined to elucidating the equilibrium structures of the relevant molecules and their reaction processes, and that subtle phenomena such as superposition and entanglement, of which we can now routinely exhibit spectacular effects at the level of a few well-isolated photons or atoms, play at most a very indirect role in any phenomena of biological interest. A major reason conventionally given for this view has been that biological systems, at least working ones, are by their very nature “warm and wet” – a phrase which in the physicist's lexicon translates to “prone to massive decoherence”; it looks as though any interesting superposition, say of different energy eigenstates of one's system, would be rapidly decohered by the ever-present, and usually microscopically very complex, environment.