Physicists From The United States

"Intellectually, technically and philosophically, physics and television are two separate cultures with almost no bridges between... [I]t is... time consuming and arduous... to span the gap... [T]here is no one... [at] Caltech... capable of reading, much less writing, a television script competently. ...[T]here is no one on the production side who knows enough... physics... to plan an important sequence, much less write a script or produce a program. This situation is a symptom of the malady of science illiteracy that ' is intended to help cure...""

"Let me be more explicit about the differences between a conventional telecourse and The Mechanical Universe. In the conventional course, the production company begins by convening a panel of hired academic consultants. ...Courses ...are basically education by committee, with the crucial job of teaching mainly in the hands of scriptwriters and producers. But... college education is to give... the benefit of learning from people who have spent a lifetime mastering their subjects and... adding new knowledge... The crucial part is organizing a subject and seeing the connections... precisely what telecourses entrust to scriptwriters. ...The Mechanical Universe ...arises out of a real physics course at a real—and excellent—university. It represents a single, unified vision of what physics is about, and how it's connected to its roots in mathematics, history and society. ...[N]ew techniques for had to be invented."

"[T]he primary audience was to be the "nontraditional student," especially "distance learners,"... [I]t was hoped that with a resourceful, dedicated local teacher... the teaching of introductory physics at any level could be enriched... [A]lso... that a large, casual, nonstudent audience would watch... for pleasure and instruction. ...[T]hat ideal target audience was the high-school physics teacher."

"[A] program is devoted to Millikan's oil-drop experiment, partly as an application of Newton's second law, and... to induce... philosophical ideas about how science is... done. ...The solution ...create a ..."Millikan Museum" ...in the Norman Bridge Laboratory where he had worked. The set involved thousands of artifacts, many ...Millikan's own ...After ...shooting ...the museum was disassembled, to live on only on videotape."

"The problem of how to present detailed mathematical derivations is confronted... in the animated scenes. ...The comprimise solution... invented while designing the pilot program, is called the "algebraic ballet." ...done in detail, but rapidly and entertainingly. The viewer was not expected to absorb every detail... [b]ut every step was displayed... [A]ttention is never lost during these [rapid] mathematical passages."

"The real numbers are the dependable breadwinner of the family, the complete ordered field we all rely on. The complex numbers are a slightly flashier but still respectable younger brother: not ordered, but algebraically complete. The quaternions, being noncommutative, are the eccentric cousin who is shunned at important family gatherings. But the octonions are the crazy old uncle nobody lets out of the attic: they are nonassociative."

"Besides their possible role in physics, the octonions are important because they tie together some algebraic structures that otherwise appear as isolated and inexplicable exceptions."

"The most popular approach to quantum gravity is string theory. Despite decades of hard work by many very smart people, it's far from clear that this theory is successful. It's made no predictions that have been confirmed by experiment. In fact, it's made few predictions that we have any hope of testing anytime soon! Finding certain sorts of particles at the big new particle accelerator near Geneva would count as partial confirmation, but string theory says very little about the details of what we should expect. In fact, thanks to the vast "landscape" of string theory models that researchers are uncovering, it keeps getting harder to squeeze specific predictions out of this theory."

"The conformal invariance of the Yang-Mills equations in four dimensions greatly facilitates the study of the temporal asymptotic behavior of their solutions."

"Quantum theory may be formulated using Hilbert spaces over any of the three associative normed division algebras: the real numbers, the complex numbers and the quaternions. Indeed, these three choices appear naturally in a number of axiomatic approaches. However, there are internal problems with real or quaternionic quantum theory. Here we argue that these problems can be resolved if we treat real, complex and quaternionic quantum theory as part of a unified structure. Dyson called this structure the "three-fold way". ... This three-fold classification sheds light on the physics of time reversal symmetry, and it already plays an important role in particle physics."

"D-branes provide a simple description of various nonperturbative objects required by string duality, and give new insights into the quantum mechanics of black holes and the nature of spacetime at the shortest distances. ... D-branes are extended objects, topological defects in a sense, defined by the property that strings can end on them."

"And then, on October 5, 1995, a paper appeared that changed the whole discussion, forever. It was Joe, explaining D-branes to those of us who’d barely heard of his earlier work, and showing that many of these black holes, black strings and black surfaces were actually D-branes in disguise. His paper made everything clearer, simpler, and easier to calculate; it was an immediate hit. By the beginning of 1996 it had 50 citations; twelve months later, the citation count was approaching 300."

"My greatest failure as head of the Theory Group here in Austin was to lose Joe to Santa Barbara."

"In the open string the gauge charges are carried by the Chan-Paton degrees of freedom at the endpoints. In the closed string the charges are carried by fields that move along the string."

"On notable classmate was Dan Friedan. Friedan stunned me, and I think everyone else, at his Ph.D. seminar, when he showed that Einstein's equation, the basic equation of general relativity, could be interpreted in terms of one of the basic objects in QFT, the β function that governs the energy scale. I did not see what this could possibly mean, but a few years later it showed up as one of the key ideas in string theory."

"In all there are four arguments here for the multiverse: the failure of conventional methods for understanding why the cosmological constant is not large, the success of the environmental theories for doing so, the successful prediction of the nonzero cosmological constant, and the string landscape."

"The second superstring revolution (1994-??) has brought non-perturbative string physics within reach. The key discoveries were the recognition of amazing and surprising "dualities." They have taught us that what we viewed previously as five theories is in fact five different perturbative expansions of a single underlying theory about five different points! It is now clear that there is a unique theory, though it may allow many different vacua. ... Three different kinds of dualities, called S, T, and U have been identified.""

"Supergravity theories generically contain non-compact global symmetry groups. The general rule is that the scalar fields of the theory in question parametrize a symmetric space. Thus, if the non-compact symmetry group is G, and its maximal compact subgroup is H, the scalar fields map the space-time into the symmetric space G/H, and the number of scalar fields is dim G – dim H. The first supergravity example of this type to be found, N = 4 supergravity is one of the most interesting. In this case there are two scalar fields and the symmetric space is SL(2,R)/SO(2)."

"As I once told a newspaper reporter, in order to be sure to be quoted: discovery of supersymmetry would be more profound than life on Mars."

"String theory is an ambitious approach to the construction of a mathematical description of the physics that governs the properties of elementary particls and their interactions as well as the structure of space and time. It incorporates (and maybe even explains) well-established principles such as quantum mechanics and relativity. In fact, many string theorists (myself included) believe that string theory constitutes the third big physics revolution of the century, following relativity and quantum mechanics. It certainly requires conceptual advances every bit as bizarre and unexpected as was the case in the prior two revolutions."

"In the early 1960s there existed a successful quantum theory of the electromagnetic force (QED), which was completed in the late 1940s, but the theories of the weak and strong nuclear forces were not yet known. In UC Berkeley, where I was a graduate student during the period 1962 – 66, the emphasis was on developing a theory of the strong nuclear force. I felt that UC Berkeley was the center of the Universe for high energy theory at the time. Geoffrey Chew (my thesis advisor) and Stanley Mandelstam were highly influential leaders. Also, Steve Weinberg and Shelly Glashow were impressive younger faculty members. David Gross was a contemporaneous Chew student with whom I shared an office."

"One of the facts of nature is that there is what's called parity violation, which means that the fundamental laws are not invariant under mirror reflection. For example, a neutrino always spins clockwise and not counterclockwise, so it would look wrong viewed in a mirror. When you try to write down a fundamental theory with parity violation, mathematical inconsistencies often arise when you take account of quantum effects. This is referred to as the anomaly problem. It appeared that one couldn't make a theory based on strings without encountering these anomalies, which, if that were the case, would mean strings couldn't give a realistic theory. Green and I discovered that these anomalies cancel one another in very special situations. When we released our results in 1984, the field exploded. That's when Edward Witten [a theoretical physicist at the Institute for Advanced Study in Princeton], probably the most influential theoretical physicist in the world, got interested. Witten and three collaborators wrote a paper early in 1985 making a particular proposal for what to do with the six extra dimensions, the ones other than the four for space and time. That proposal looked, at the time, as if it could give a theory that is quite realistic. These developments, together with the discovery of another version of superstring theory, constituted the first superstring revolution."

"While spectacularly successful at predicting the behavior of atoms and subatomic particles, the quantum laws looked askance at Einstein's formulation of gravity. This set the stage for more than a half-century of despair as physicists valiantly struggled, but repeatedly failed, to meld general relativity and quantum mechanics, the laws of the large and small, into a single all-encompassing description. Such was the case until December 1984, when John Schwarz, of the California Institute of Technology, and Michael Green, then at Queen Mary College, published a once-in-a-generation paper showing that string theory could overcome the mathematical antagonism between general relativity and quantum mechanics, clearing a path that seemed destined to reach the unified theory."

"Among the problems of the known string theories, as a theory of hadrons, was the fact that the spectrum of open strings contains massless spin 1 particles, and the spectrum of closed strings contains a massless spin 2 particle (as well as other massless particles), but there are no massless hadrons. In 1974, Joël Scherk and I decided to take string theory seriously as it stood, rather than forcing it to conform to our preconceptions. ... Specifically, Scherk and Schwarz (1974) proposed trying to interpret string theory as a unified quantum theory of all forces including gravity. Neveu and Scherk (1972) had shown that string theory incorporates the correct gauge invariances to ensure agreement at low energies (compared to the scale given by the string tension) with Yang-Mills theory. Yoneya (1973,1974) and Scherk and Schwarz (1974) showed that it also contains gauge invariances that ensure agreement at low energies with general relativity."

"[T]he author, whose work on nuclei is well known, describes a number of investigations carried out with his fog-chamber apparatus. The apparatus having been sufficiently improved, it was used for various experiments, including the growth of persistent nuclei, the production of water nuclei by evaporation, the results obtained when X-rays are allowed to strike the fog-chamber from different distances, the effect due to radium, &c. Other problems dealt with in the book are the distribution of colloidal nuclei and of ions in media other than air-water, the simultaneous variation of the nucleation and the ionization of the atmosphere of Providence, and the variations of the colloidal nucleation of dust-free air in course of time."

"I make... a cursory survey of certain pyro-electric properties of the alloys of . Curiously... the data... led to a striking result.. it appears that the zero resistance f(0), if the resistance at t^O be r = f(t), and the zero coefficient f^{\prime}(0)/f(0), are related to each other by a law which during the stages of low percentage alloying is independent of the ingredients of the alloy, except in so far as they modify its electrical conductivity."

"When the history of the progress of physics in the United States during the late nineteenth and early twentieth century is written, the name of Carl Barus will occupy an important place."

"I develop a method for the direct and expeditious comparison of the thermo-couple with the air thermometer. A comparison of the data... gives me a criterion of the accuracy with which the data in the region of high temperature are known. This indirect method... is not apparently as rigorous as their direct evaluation by means of the air thermometer; but the indirect method requires much smaller quantities of substance and may be conveniently extended to much higher temperatures. Taking all liabilities to error into consideration, its inferior accuracy is only apparent."

"At Brown University Carl Barus and Alpheus Packard are undoubtedly the most eminent scientists who ever occupied faculty chairs. Professor Barus was a hero-worshipper and in his home was a genius corner from which pictured faces of great scientists looked down upon him. ...The breadth of his interest and achievements was extraordinar—recall his reading of Greek tradedies in the original, his knowledge of French and Italian literatures, and the proficiency he attained in playing the violin, flute, clarinet, oboe, cornet, trumpet and trombone, in addition to the piano and organ. The brilliancy of his intellect, the modesty of his bearing, the beauty of his personality, and the kindliness of his spirit have left most precious and inspiring memories..."

"[T]he rooms which had been placed at my disposal by the American Museum of New York became temporarily unavailable. ...[W]e determined to rent a house in New Haven, Conn., and thither the laboratory was removed in November, 1882. ...[T]he city offered excellent library and other facilities for scientific work, such as can be met only in the immediate vicinity of a large university [Yale College]. ...The work in New Haven was not satisfactorily completed. In July, 1883, with the appointment of Prof. F. W. Clarke as chief chemist of the Geological Survey, our laboratory was officially connected with the chemical laboratory. Conformably with the further decision of the Director, by which the divers laboratories of the Geological Survey were united in one central laboratory in Washington, it was again necessary to change our basis of operations, this time... from New Haven to Washington. In the quarters assigned to us in the U. S. National Museum, temperature work on so large a scale... appeared impracticable, and it was therefore abandoned. ...In place of the dangerous and cumbersome apparatus of the former laboratory, the endeavor is made to reduce all apparatus to the smallest dimensions compatible with reasonable accuracy of measurement."

"[F]ew important steps in dynamical geology will be made until the methods for the accurate measurement of high temperatures and high pressures have not only been perfected but rendered easily available. On the basis of this conviction the present memoir on high temperatures has been prepared... [I]f the investigation be of any fullness, it is almost essential that the observer master the component parts of his research separately; and not until he has satisfactorily done this can he apply them conjointly."

"Looking over such famous old books as Montmort's 'Analyse des jeux de hasard' or Moivre's 'Doctrine of Chances' one regrets that so much excellent mathematics should have been wasted on games most of which are wholly obsolete. Coriolus in his '[Théorie Mathématique des Effets du] Jeu de billard' (1835) fared better, for the game is still very much alive and its dynamical terrors unsubdued."

"[L]et me refer to my original work. Naturally, if a student has been hammering away ever since 1979... he must have accumulated a lot of litter, much of which, perhaps, should have long since been swept away. But the fates are not to be bribed either by pother or importunity. Out of 1,000 men who are called, one (probably the ratio is much smaller) is chosen to do glorious scientific work. The others? Their lot is failure. They may be equally or even more industrious, they may have equal or even greater brain power—the other 999 exist merely to make the illustrious one in whom they culminate, possible. After that, the world will say to each in words of poetic brevity: "The man has done his duty, the man can go." And they do, pretty quickly, to a gentler lethe, flowing between the banks of amaranth and asphodel. Gentlemen, I am one of the 999 about to be forgotten."

"Carl Barus loved music, and composed about fifty compositions, among them a March to Pembrok Hall... and an Ode to the Steam Shovel, inspired by the daily noise outside his laboratory and was presented by him to President Faunce."

"In even greater measure is this true of the top. The top has been everybody's toy and must, therefore, at one time or another have piqued everybody's curiosity. Lagrange, Poinsot, Jacobi, not to mention other great names, have in turn paid their tribute; yet the top may be set spinning to-day, unhampered by a completed theory to account for its evolutions."

"The boon of an appropriate lemma is ideal generosity, and not even a mathematician can scorn its almost mathematical elegance."

"A man may be a thoroughgoing soldier enough on land; but put him in the foot ropes of the flying jibboom in a storm, and he is apt to cut a most ludicrous figure. Shift a physicist's foothold of Cartesian differential coordinates, suspend him over an abyss of non-Euclidean space, and he will kick sturdily. Poor policy this, for a missionary!"

"The presiding officer of this [Physics] section was Prof. Carl Barus, who fills the chair of Physics in Brown University. His inaugural address was on "Long Range Temperature and Pressure Variables in Physics." He began by giving a history of the various attempts to provide suitable apparatus for high-temperature measurement. Fusion first played an important part in the manufacture of s, and later those instruments based on specific heat showed an advantage over the fusion instruments. The was referred to as the only fruitful method of absolute pyrometry. The speaker dwelt at length on high-temperature work, the first thorough-going instance of which was by Prinsep in 1829. Then the experiments down to 1887 were considered in detail, and the conclusion reached that the data furnished by the Reichsanstalt will eventually be standard. ...Turning to the applications of pyrometry, he referred to the variation of metallic ebullition with pressure. Results already attained show an effect of pressure regularly more marked as the normal boiling point is higher. Igneous fusion was considered in its relation to pressure and with regard to the solidity of the earth, and the inference was drawn that the interior solidity of the earth, now generally admitted, is due only to superincumbent pressure, withholding fusion. The question of heat conduction was next taken up, and the results deduced by various writers as to the discussed. High pressure measurement was lengthily dealt with. Passing from this subject, the of liquids was considered. ...The paper ended with a reference to isothermals and several kindred subjects."

"Among recent contributions we may refer in particular to Professor A. G. Greenhill's noteworthy papers... when one remembers that these complex curves reach only especially simple cases of motion, one may get some notion of the difficulty of the problem involved."

"Turning to Klein's little book, one is astonished in finding the most general aspects of the subject treated almost without computation and in so little space. ...It would have cost little to give the expanded form of the σ-function. ...Weierstrass's original notation was in terms of Abelian functions. The tremendous development of s is out of proportion with their application to natural phenomena. Meeting them rarely one forgets them. Memory peters out like the infinite series of a ζ-function."

"Mathematicians will do well to observe that a reasonable acquaintance with theoretical physics at its present stage of development, to mention only such broad subjects as electricity, elastics, hydrodynamics, etc., is as much as most of us can keep permanently assimilated. It should also be remembered that the step from the formal elegance of theory to the brute arithmetic of the special case is always humiliating, and that this labor usually falls to the lot of the physicist."

"The reviewer is aware... he has given an imperfect account of this remarkable book. That Klein's researches constitute a splendid advance in dynamics of the rotation of a rigid body there can be no question. One cannot but hope that the outline given in these Princeton lectures may soon be expanded and put in shape more easily assimilated by persons more moderately versed in the theory of elliptic functions."

"In the decade between 1882 and 1892 contributions to gas thermometry and the measurement of high temperatures are few and unimportant, but work was begun in those years on both sides of the Atlantic which, for the experimental skill and persistence with which the experimental difficulties and limitations were pursued and successively overcome, surpasses any effort which has been made either before or since that time. These were the investigations of Barus at the U.S. Geological Survey in Washington and of [Ludwig] Holborn and his colleagues at the Reichsanstalt in Charlottenburg. Barus (1889) recognized as no observer who preceded him had done, the superlative importance of a uniform temperature distribution about the gas thermometer bulb for purposes of high-temperature measurement, and he took the most extraordinary precautions to maintain it. A temperature of 1000° C or more is not attained without very steep temperature gradients in the region immediately surrounding the zone of highest temperature. It is therefore a problem of great difficulty to introduce a bulb of from 10 to 20 cm. in its largest dimension into this hot zone without leaving some portion of it projecting out into a region 200° or 300° lower in temperature. Burning mixtures of gas and air for heating purposes also contributed to the irregularity and uncertainity of the temperature distribution about the bulb. Barus sought to avoid this by a method of great ingenuity, but also of great technical difficulty. He inclosed his bulb within a rapidly revolving muffle which by its motion protected every portion of the bulb from direct exposure to a particularly hot or a particularly cold portion of the adjacent furnace. This complicated furnace structure and consequently inaccessible position of the bulb made it impossible to introduce into the region about the bulb the substances whose temperature constants were to be measured and compelled him to use thermo-elements which were first calibrated by exposure in the furnace with the bulb and then used independently to measure other desired temperatures. The thermo-element has continued in general use in this intermediary rôle since that time. In the preparation and use of thermo-elements Barus also made much more extensive and elaborate studies than any one who has followed him. ...It is an unfortunate accident that history has failed to record Barus's name along with that of Le Chatelier in the development of the thermo-element for purposes of high-temperature measurement. It hardly admits of question that Barus contributed incomparably more to our knowledge of the thermo-electric properties of the different metals and their use than his distinguished French contemporary, but the 10 per cent iridium alloy which he finally selected proved to be less serviceable than the 10 per cent rhodium alloy developed by Le Chatelier... And so we find the Le Chatelier platin-rhodium thermo-element in use to-day the world over, while the magnificent pioneer work of Barus remains but little known."

"The lecture concludes with a demonstration showing that a free body in hyperbolic non Euclidean space may be so fashioned as in real time to carry out the actual motions of the top. The form of such a body and the forces to actuate it are specified. Klein lays great stress on the beauty of this generalization. ...The full geometry of this case is not carried out in these lectures, however, and Klein regrets that the development of the s has recently fallen into abeyance."

"Physics is always a gamble; it is a game of exploration. That’s the fun of it. We never know for sure what will happen. Sometimes, we theorists can anticipate, but nature is the final judge."

"Intellectual property is an oxymoron."

"Nelson rejected the prevailing views to the effect that nonstandard analysis operates with some fictional elements that extend the standard world of mathematical entities. In his approach, nonstandard objects inhabit the realm of the most ordinary mathematical objects. Nelson emphasized the creative syntactic contribution of the new approach in the following terms: “Really new in nonstandard analysis are not theorems but the notions, i.e., external predicates.” (Nelson 1988 ...)"

"The subject matter of mathematics is the expressions themselves together with the rules for manipulating them—nothing more."

"Are all the (measurable) dimensionless parameters that characterize the physical universe calculable in principle or are some merely determined by historical or quantum mechanical accident and incalculable?"

"... From the age of 13, I was attracted to physics and mathematics. My interest in these subjects derived mostly from popular science books that I read avidly. Early on I was fascinated by theoretical physics and determined to become a theoretical physicist. I had no real idea what that meant, but it seemed incredibly exciting to spend one's life attempting to find the secrets of the universe by using one's mind."