Physicists From The United States

"Schwinger had... been working on and solved some radar related... electrodynamic problems, classical electrodynamic theory problems that nobody else could approach... [A]s a calculator he was amazing... phenomenal. ...You can well argue that radar... as well as new developments in bomb technology, in fuses, played a more important role than nuclear weapons [in World War II]."

"Is the purpose of theoretical physics to be no more than a cataloging of all the things that can happen when particles interact with each other and separate? Or is it to be an understanding at a deeper level in which there are things that are not directly observable (as the underlying quantized fields are) but in terms of which we shall have a more fundamental understanding?"

"For two years in the late 1950s I was a postdoc at Harvard. Julian Schwinger was the leading light in theoretical physics at the time. We, the postdocs and junior faculty, audited whatever course he happened to be teaching. The material was always original. The lectures were on Wednesdays, and afterward the small group of us would have lunch with Schwinger at Chez Dreyfus in Cambridge. We would be joined by another small group from MIT that included Vikki Weisskopf. If Schwinger had any new ideas, he would try them out on Weisskopf. As it happened on this occasion, he had developed a “theory of everything.” Some of this theory survives in the work of other people. In 1962, he published a paper on “Gauge invariance and mass.”9 … In it he raised the question of whether one could have a massive vector meson in a theory that had an underlying gauge invariance. This possibility … inspired P. W. Anderson to use these ideas in condensed matter physics.10... 9 J. Schwinger, “Gauge invariance and mass,” Phys. Rev. 125, 397–398 1962 . 10 P. W. Anderson, “Plasmons, gauge invariance and mass,” Phys. Rev. 130, 439–442 1963."

"During this period I attended two sessions of the Michigan summer school at which Schwinger (1948) and Feynman (1949) described their respective reformulations of QED. Schwinger’s was deeper and more complete while Feynman’s was easier to use but at that time incomplete. One may give a feeling for the impact of Schwinger by quoting Dyson who wrote home that ”in a few months we shall have forgotten what pre-Schwinger physics was like.” Bethe at that time described this period as the most exciting in physics since the great days of 1925-30 when quantum mechanics was being discovered."

"Perhaps the most important contribution to science that the Royal Society has made in its three centuries of existence is its early role in publishing Newton's masterful account of his discoveries: Mathematical Principles of Natural Philosophy—the Principia."

"It's true that he had a funny style. His lecture was precise. He had the voice of a radio announcer. Everything was in perfect sentences, grammatically perfect. The formulas were all clearly written on the board. The talk was so designed that he would be at the blackboard nearest the exit door at the end of the lecture. He would end the lecture and... immediately slip out the door and disappear so that his graduate students could not track him down too easily."

"Time appears in quantum mechanics as a continuous parameter which represents an abstraction of the dynamical role of the measurement apparatus. The requirement of invites the extension of this abstraction to include space and time coordinates. The implication that space-time localized measurements are a useful, if practically unrealizable idealization may be incorrect, but it is a grave error dismiss the concept on the basis of a priori notions of measurability."

"If my history lesson has done nothing else, it should have reminded you that, during any given period in the evolving history of physics, the prevailing, main line, climate of opinion was likely as not to be wrong, as seen in the light of later developments. And yet, in those earlier times, with relatively few individuals involved, change did occur, but slowly... What is fundamentally different in the present day situation in high energy physics is that large numbers of workers are involved, with corresponding pressures to conformity and resistance to any deflection in direction of the main stream, and that the time scale of one scientific generation is much too long for the rapid pace of experimental discovery. I also have a secret fear that new generations may not necessarily have the opportunity to become familiar with dissident ideas."

"He argued to me that electrons and s, which are particles, charged s we call them, were known... He said that if we're going to have a that distinguishes electrons from muons, then surely... it should not be e- and μ- that have... , it should be the e- and the μ+. So... that way... charge and the new can distinguish electrons from muons... and it followed that there had to be two kinds of s in nature. So built into the way he taught... particle physics was the fact that there are two kinds of neutrinos. ...It was acknowledged as a technical possibility by some people, but it... wouldn't be known until 1963. This was in the 1950s."

"History proves abundantly that pure science, undertaken without regard to applications to human needs, is usually ultimately of direct benefit to mankind. Within recent years it has become possible for purely scientific work of this character to be carried out with the support of industries, which are, of course, primarily interested in the commercial applications. The scientist who works in this way is frequently especially fortunate in that he not only derives the satisfactions which are characteristic of scientific work in general, but is able to see that many of his results are almost immediately put into a form which directly benefits mankind. Happy indeed is the scientist who not only has the pleasures which I have enumerated, but who also wins the recognition of fellow scientists and of the mankind which ultimately benefits from his endeavors. To my mind, the most important aspect of the Nobel Awards is that they bring home to the masses of the peoples of all nations, a realization of their common interests. They carry to those who have no direct contact with science the international spirit."

"In general, the rate of evaporation (m) of a substance in a high vacuum is related to the pressure (p) of the saturated vapor by the equation m=\sqrt{\frac{M}{2\pi RT}}p. Red phosphorus and some other substances probably form exceptions to this rule."

"To me, [it's] extremely interesting that men, perfectly honest, enthusiastic over their work, can so completely fool themselves."

"Science, almost from its beginnings, has been truly international in character. National prejudices disappear completely in the scientist’s search for truth. Medicine also disregards national boundaries. And literature frequently rises to heights that make it international. The scientist is motivated primarily by curiosity and a desire for truth. His attitude is objective rather than subjective. In his work he finds great satisfaction in discovering new facts or new relationships between known facts, but even greater pleasure is derived from seeing his results incorporated into the body of scientific knowledge and from seeing them willingly used by others in the further development of science."

"Everything with a quantum in it, with 'h' in it, was exciting."

"There is an ancient Chinese saying "He who labours with his mind rules over he who labours with his hand". This kind of backward idea is very harmful to youngsters from developing countries. Partly because of this type of concept, many students from these countries are inclined towards theoretical studies and avoid experimental work. In reality, a theory in natural science cannot be without experimental foundations; physics, in particular, comes from experimental work."

"Feynman was not a theorist's theorist, but a physicist's physicist and a teacher's teacher. Feynman's theoretical concepts opened up research opportunities for experimenters, and his approach to physics dignified the role played by their work."

"What is very important to me is two points: A theory should be internally consistent and it should have some contact with observation. Well, I’m told by all the experts that this theory String theory] is internally consistent, although they think up new interpretations every time I turn my back. But contact with reality? Nobody’s given me anything. I just watch. I’m somewhat unhappy that so many people are working on it. To me, as a physicist, it’s sort of sad that so many people at the same time work at something that doesn’t seem to have any contact with experiment. But that, to some extent, is due to the fact that we don’t have any great experimental puzzle to be thinking about. We have to supply the puzzles, and there aren’t that many puzzles right now."

"The trouble with theorists is, they never pay attention to the experiments!"

"Cosmology is a science which has only a few observable facts to work with."

"I think of physics as the liberal arts of technology. You understand the fundamental aspects of physics, and then you can learn the technology and understand how it relates to current world problems. I'm teaching the elementary physics that is most useful for someone who is trying to live in a technological world, to contribute to that world, and to make correct decisions."

"The most important discoveries will provide answers to questions that we do not yet know how to ask and will concern objects that we can not yet imagine."

"John Bahcall, an astronomer on the Institute of Advanced Study faculty since 1970 likes to tell the story of his first faculty dinner when he found himself seated across from Kurt Gödel a man dedicated to logic and the clean certainties of mathematical abstraction Bahcall introduced himself and mentioned that he was a physicist Gödel replied“I don’t believe in natural science."

"We often frame our understanding of what the space telescope will do in terms of what we expect to find, and actually it would be terribly anticlimactic if in fact we find what we expect to find. … The most important discoveries will provide answers to questions that we do not yet know how to ask and will concern objects we have not yet imagined."

"I often liken the process of physics research to solving a jigsaw puzzle. As we put together pieces to form patches, a certain image of the overall picture emerges, but until the game is sufficiently progressed, we are not quite sure. I feel much the same way about the wealth of signs for new particles. We have patches that have been put together, but we are not quite sure how all pieces will fit together into a coherent whole. There are also certain pieces which do not seem to fit into any patches at all. For the most part, the experimental findings have not been completely unexpected, but there have been certain surprises that I, for one, had not foreseen. This is what makes particle physics exciting and tantalizing. At moments of despair and frustration, I feel as though somebody has scrambled two boxes of jigsaw puzzles for me to put together."

"This fact, that all charges are integral multiples of a fundamental unit, is still one of the unexplained puzzles of fundamental physics. It does not in any way contradict electromagnetic theory, but it is not predicted by it, and until we have a more fundamental theory that explains it, we shall not feel that we really understand electromagnetic phenomena thoroughly. Presumably its explanation will not come until we understand quantum theory more thoroughly than we do at present."

"The earth’s atmosphere is an imperfect window on the universe. Electromagnetic waves in the optical part of the spectrum (that is waves longer than X rays and shorter than radio waves) penetrate to the surface of the earth only in a few narrow spectral bands The widest of the transmitted bands corresponds roughly to the colors of visible light waves in the flanking ultraviolet and infrared regions of the optical spectrum are almost totally absorbed by the atmosphere. In addition atmospheric turbulence blurs the images of celestial objects even when they are viewed through the most powerful ground-based telescopes in an article promoting the construction of the Hubble Space Telescope."

"Lee's involvement with gauge theories dated back to 1964. He was concerned about the fact that superconductors appear to provide a counterexample to the general theorem, which requires that spontaneous symmetry breaking is always accompanied with massless spin-zero bosons. With Klein, he wrote an article suggesting that the same might occur in relativistic theories. It was soon realized that this is indeed the case, provided the broken symmetry is a gauge symmetry, as it is in a superconductor."

"Every time we get slapped down, we can say, Thank you Mother Nature, because it means we're about to learn something important."

"All we who can gauge the threats can do is soldier on, exploiting what tools we have, gaining as much ground as time permits: seizing issues when they are ripe, remaining patient and careful with facts, even when faced with relentless and reckless opposition, mounting sustained campaigns and avoiding simple shots across the bow, combining solid analysis with persistent outreach and public education, touching people as widely as we can, and, as Winston Churchill emphasized, never giving up. Many of us in science understand well what the costs of inattention and lack of care will be. … Yet neither we nor others have yet caught the sustained attention of our fellow humans, and, until we do, the world cannot escape from its troubles . Thus the deepest question before us all is: How will our species reach the understanding and gain the political will to alter the prospects on the horizon? No one now has the answer to that need. It is indeed a distant light."

"Innovation is everything. When you're on the forefront, you can see what the next innovation needs to be. When you're behind, you have to spend your energy catching up."

"I may be a minority of one in advocating that one should NOT separate science and politics—partly because I am old enough to remember the Weimar Republic before 1934..."

"The world's problems are pressing in on us all. The scale and impact of human activities now affects a great portion of the global resources important to human welfare. These activities are putting growing, often destructive pressure on the global environment, pressure that appears likely to increase as human numbers swell toward the doubling of the world's population that evidently lies ahead. These pressures can spawn or aggravate conflict that. in a world with so much destructive weaponry, generates important national security problems. Great changes are necessary to help ensure a humane future for the generations to come. Most of the world's scientific community and many people in the environmental movement are aware of the gravity of the problems. Yet despite sober warnings from these and other groups, in both the industrial and the developing world, re- medial efforts frequently appear powerless and ineffectual. The scientific community has not taken a sustained, powerful role in the public arena where this great cluster of issues is debated and where the problems must be resolved. There is much more that our community can contribute to assessment, warning, and proposals for new patterns of behavior."

"While science and technology play critical roles in sustaining modern civilization, they are not part of our culture in the sense that they are not commonly studied or well comprehended. Neither the potential nor the limitations of science are understood so that what can be achieved and what is beyond reach are not comprehended. The line between science and magic becomes blurred so that public judgments on technical issues can be erratic or badly flawed. It frequently appears that some people will believe almost anything. Thus judgments can be manipulated or warped by unscrupulous groups. Distortions or outright falsehoods can come to be accepted as fact."

"Distortion and false statements have a sturdy history in public discourse. Neither the government nor large organizations can be depended on to support their objectives honestly and with integrity. Replying in kind turns out not to be an option, not just to retain scientific integrity but for practical reasons. Critics, whether individuals or public interest groups, cannot afford to slant the truth, ever. Scientists are far more vulnerable to the consequences of their own ill-considered words than are laypeople, owing to the care and integrity that is believed to characterize the scientific approach to problems. Intentional distortions are almost always uncovered and the purveyors pilloried without mercy. It may not be forgotten for years and surfaces over and over again. So too will honest mistakes which, along with even minor exaggerations, are seized on and exploited mercilessly. Not a bad rule — one that I and some colleagues observe — is to pull back a bit in most argument. Not only should one never distort nor exaggerate, it is best, I believe, to understate."

"We are immersed in one of the most significant revolutions in man's history. The force that drives this revolution is not social dissension or political ideology, but relentless exploitations of scientific knowledge. There is no prospect that this revolution will subside; on the contrary, it will continue to transform profoundly our modes of living and dying. That many of these transformations have been immeasurably beneficial goes without saying. But, as with all revolutions, the technological revolution has released destructive forces, and our society has failed to cope with them. Thus we have become addicted to an irrational and perilous arms race, and we are unable to protect our natural environment from destruction."

"What should thoughtful people do? Are there means to brighten future prospects in the face of such human myopia and stubbornness? There are many in the scientific community whose views are bleak. One biologist, speaking to me many years ago, remarked that many of his colleagues thought of the behavior of the human race as similar to a one-celled animal's. Such an animal may extend a pseudopod in search of food; if hurt or blocked, it pulls back, but otherwise its activity continues, mindlessly, without understanding, without end. With larger perils unperceived, it can destroy itself."

"… Dr. Lightman was an astrophysicist, a card-carrying wizard of space and time, with a Ph.D. from the California Institute of Technology and subsequent posts at Cornell and Harvard. In 1989, at the peak of his prowess as a physicist, he began to walk away from the world of black holes to enter the world of black ink and the uncertain, lonely life of the writer."

"Every object in the Universe with a temperature above absolute zero radiates in the infrared, so this part of the spectrum contains a great deal of information."

"The relationship between science and the humanities is two-way. Science changes our view of the world and our place in it. In the other direction, the humanities provide the store of ideas and images and language available to us in understanding the world. The exploding star of A.D. 1054, the Crab Nebula, was sighted and documented by the Chinese, but nowhere mentioned in the West, where the Aristotelian notion of the immortality of stars still held sway. We often do not see what we do not expect to see."

"In the 1950s, academics forecast that as a result of new technology, by the year 2000 we could have a twenty-hour workweek. Such a development would be a beautiful example of technology at the service of the human being. ...According to the Bureau of Statistics, the goods and services produced per hour of work in the United States has indeed more than doubled since 1950. ...However, instead of reducing the workweek, the increased efficiencies and productivities have gone into increasing the salaries of workers. ...Workers... rather have used their increased efficiencies and resulting increased disposable income to purchase more material goods. ...Indeed, in a cruel irony, the workweek has actually lengthened. ...More work is required to pay for more consumption, fueled by more production, in an endless, vicious circle."

"A patent is a legal analog of sticky fly paper: it attracts some of the lowest forms of life."

"I've reached the age where young people frequently ask for my advice. All I can really say is that electronics is a fascinating field that I continue to find fulfilling. The field is still growing rapidly, and the opportunities that are ahead are at least as great as they were when I graduated from college. My advice is to get involved and get started."

"It is a fantastic letter. Very understated. He calls it an optical maser, it’s as if a maser was made to run in the optical. No flamboyant phrase, just straightforward science."

"It is electromagnetism (EM) in all its many forms that has been so basic, that haunts us and guides us."

"The beauty of physics lies in the extent to which seemingly complex and unrelated phenomena can be explained and correlated through a high level of abstraction by a set of laws which are amazing in their simplicity."

"The reminds me of the scene in Mel Brooks's ' where asks his hunch-backed servant, , how he lives with his hump, and Igor answers, "What hump?" ... The potential of overcoming the ultraviolet problem is also the deeper reason for the allure of string theory, a microscopic model for the vacuum that has failed to account for any measured thing."

"The reason we believe in relativity today is not because we had a great transition in our beliefs about what should be so. We believe in relativity because we have no choice. It's true — measured to be true."

"Science is about measurement, dammit — it's not about ideas. (55:20 in video)"

"Newton would have been laughed out of the country if Kepler hadn't done the measurement. ... The facts speak for themselves. ... History has shown that you need a little luck — and if you don't have the luck, you're out of luck. (1:00:00 to 1:01:00 in video)"

"My rule is simply to do for my students exactly what I hope someone else will do for my sons when the time comes: I teach them to have faith in themselves and in their own compass, to listen to nature to find truth, to love knowledge for the sake of itself, and to strive for greatness."