In Search of Schrodinger's Cat - Quantum Physics and Reality

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In Search of Schrodinger's Cat was one of very few popular science books published in the early 1980s on the subject of quantum mechanics. The title of the book refers to a famous thought experiment (paradox) devised by Austrian physicist Erwin Schrodinger. The thought experiment presents a hypothetical cat that apparently can be simultaneously dead and alive (or neither dead nor alive), depending on an earlier random event, and assuming that the Copenhagen interpretation of quantum mechanics can be applied to everyday objects.

For those of us who are not physicists, the book covers, in a rather accessible manner (especially in its first half), a number of key theories, ideas, and paradoxes such as the dual nature of light, the double-slit experiment, the structure and the inner workings of atoms, Plank's constant and its history and significance, the probabilistic nature of quantum mechanics and its possible far-reaching philosophical implications, the Compton effect, the Copenhagen interpretation, etc. Often incorrectly depicted as just an experimental limitation, the Heisenberg uncertainty principle (the central idea of quantum mechanics), is explained quite nicely (and I believe correctly) in this book. The author also gives a couple of great examples of the unreasonable effectiveness of mathematics in physics (e.g., Dirac's mathematical prediction of the existence of positrons, the electron's antiparticle).

The author's style of writing is engaging and pleasant to read. The book is filled with relevant historic references, which I personally always find useful, as they help with putting everything in a right prospective and context. Even though it is thought provoking, the second half of the book, which deals with more speculative questions related to quantum mechanics (e.g., the many-worlds theory), is less satisfactory and less focused.

I recommend this book as an easy, non-mathematical introduction to the basic concepts of quantum mechanics, arguably the most fascinating scientific theory ever formulated by human mind. To fully understand and truly appreciate quantum mechanics, however, one has to sharpen one's mathematical pencil and dig deep into vector algebra with all its eigenvectors and eigenvalues. There are no shortcuts. Thus, my caveat lector: advanced students will almost certainly learn nothing new of importance in this book.

Critique of Carl Sagan's Book: Billions And Billions

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In life and in his book, this eminent scientist hoped to heighten awareness to the exponential immensity constituting our interstellar existence, to quantification in microscopic beginnings, to infinite potential in meaning and purpose for our own existence, and to "Thoughts on Life and Death at the Brink of the Millennium." Early on, Sagan advises, "If you know a thing only qualitatively, you know it no more than vaguely. If you know it quantitatively -- grasping some numerical measure that distinguishes it from an infinite number of other possibilities -- you are beginning to know it deeply."

An outspoken iconoclast, to both leftist and rightist extremes, Sagan advocated urgent attention to our headlong plunge toward an uninhabitable earth. And, of course, he was right; differing political systems attempt to advance agreement with his notion of patrimony and environment preservation. Even so, we call attention to Sagan's rise to the top of his profession; thus, he becomes the greater consumer rather than greater environmentalist. At the ladder top, he urges lower rung climbers to lesser energy expenditures as they attempt ladder ascendance; yet, despite these imposed limitations, even those at the bottom would, like Sagan, spend the necessary energy to enjoy a view from the top. At the top, Sagan recommends global effort to bring living standards to optimum levels. Yet, to elevate plebeian from the bottom rung to like-levels, society must, in itself, require a greater expenditure of natural resources; therewith, such ambition defeats the very conservatism advocated to inspire environmentalism ploys and, simultaneously, to alleviate the starving masses syndrome. Basically, inhering a socialist mindset, Sagan politicizes mankind's primitive inherence so faithfully replicated in genes, man's propensity to hunt and gather as impelled. To circumvent this inherency, Sagan would make all consumers subject to the state (though he did not directly state the means): thus would man be made to observe environmental dictates, to reside in industrial conformity, to live indistinctively in miscegenation, and to lesser rung submission.

Sagan's racial finiteness belongs in a fictional work, not scientific exposition. Like most white liberals, he capitulates to popular desideratum and proposes mankind to have evolved from black beginnings -- neglecting the paucity of evidence -- and ignoring natures neglect to deposit contradictory fossils in easy to find locations throughout the world. No! Mankind had to evolve from a wider potential in the chemistry environment necessary to produce early and diverse specimens. By Sagan's heuristic creation medium, all fish, all birds, all reptiles, all bacteria differentiated from individual protist and isolated into species. We should expect more from Carl Sagan. In paraphrased briefness, he said: 'Only in the visible (light spectrum, bw), with many transparent molecules can the anomaly of white skin be possible. Over much of the spectrum, all humans are black.' Nonsense! Would Sagan's 'light spectrum' explain the marked difference in physiognomy amongst ethnic diversity? And would not the following Sagan observation, concerning 'important discoveries,' treat the above mankind origins theory as mere speculation?

At the end, Sagan admitted: he would love to believe, at the advent of death, he would live again, that some thinking, feeling, remembering part of him would continue. But as much as he wanted to believe and despite the ancient and worldwide traditions asserting an afterlife, he knew of nothing to suggest it as more than wishful thinking. He lived as he died, setting forth logic as a guiding principle, at peace with himself, and trusting in scientific intellection. Was he correct in all his deductions? Yet, his was a strong voice condemning our selfish quest for industrial superiority, to energy foolhardiness, and to our tendency toward supernatural dependency. In this, he was right on target!

Truly, Carl Sagan's practicality regarding afterlife is confirmed by strict review of the only monotheism legal-historicity, the Bible; herein, limits to the theist experiment are found to circumscribe Ten Ages as a whole to the Covenant enterprise. Further bold conclusions are available to those with abiding interest in the symbols and numbers coded into the Bible's hidden language.

Ben Winter, particles physicist, Bible scholar, and author of "THE GREAT DECEPTION: Symbols And Numbers Clarified," reveals there 'is' something new under the sun -- that is, for modern Bible students. He addresses correctness of language and true intent of the major Bible topics: solves Bible mysteries, defines Gog and Magog, reveals Daniel He-goat's surprising identity, and dares to number the all important Ten Ages. Sign up for FREE book critiques at http://www.winterbriar.com/ and view more articles in blog format at http://blog.thegreatdeception.net/.

Crystal Structure Determination, And Indexing

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There are three major steps in order to determine the structure of an unknown material. First of all the shape and size of the unit cell are deduced from the angular positions of the diffraction lines. Then the number of atoms per unit cell computed from the shape and size of the unit cell, the chemical composition of the specimen, and its measured density. Finally, the position of the atoms within the unit cell is deduced from the relative intensities of the diffraction lines.

The process of finding the position of the atoms within the unit cell is generally the most difficult and there are many structures which are known only incompletely, in the sense that this final step has not yet been made.

The first step in which size and shape of the material is measured is same as the indexing of powder diffraction pattern which involves the accurate determination of peak positions, determination of the unit cell parameters from the peak positions such as Bragg's Law, inter planar d-spacing, and systematic absences.

In Bragg's Law when x-rays are scattered from a crystal lattice, peaks of scattered intensity are observed which corresponds to the two conditions. First condition is that the angle of incidence is equal to the angle of scattering, and the second is that the path length difference is equal to an integer number of wavelengths. The condition for maximum intensity helps to calculate details about the crystal structure, or if the crystal structure is know, to determine the wavelength of the x-rays incident upon the crystal.

Remember that crystals possess a regular, repetitive internal structure. The concept of symmetry describes the repetition of structural features. Symmetries are most frequently used to classify the different crystal structures. In general one can generate 14 basic crystal structures through symmetries. These fourteen basic crystal structures are called Bravais Lattices. Any crystal structure can be reduced to one of these 14 Bravais Lattices.

As it is mentioned above that the indexing is the process of determining the unit cell parameters from the peak positions. To index a powder diffraction pattern it is necessary to assign Miller indices, hkl, to each peak. Note that a diffraction pattern can not be analyzed until it has been indexed. It is always the first step in analysis. Unfortunately it is not just the simple reverse of calculating peak positions from the unit cell dimensions and wavelength.

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