nobel-laureates-in-physics

"In my considered opinion the peer review system, in which the proposals rather than the proposers are reviewed, is the greatest disaster to be visited upon the scientific community in this century"

"The idea that there might exist small particles with no electrical charge has been put forward several times. , for example, suggested that a neutral particle might be formed by a negative electron and an equal positive charge, and that these "s" might possess many of the properties of the ether; while at one time suggested that the s emitted by radioactive substances consisted of small neutral particles, which, on breaking up, released a negative electron. The first suggestion of a neutral particle with the properties of the neutron we now know, was made by Rutherford in 1920. He thought that a proton and an electron might unite in a much more intimate way than they do in the hydrogen atom, and so form a particle of no nett charge and with a mass nearly the same as that of the hydrogen atom. His view was that with such a particle as the first step in the formation of atomic nuclei from the two elementary units in the structure of matter — the proton and the electron — it would be much easier to picture how heavy complex nuclei can be gradually built up from the simpler ones. He pointed out that this neutral particle would have peculiar and interesting properties."

"It has been shown by and others that when bombarded by s of emits a radiation of great penetrating power, which has an absorption coefficient in lead of about 0.3 (cm.)–1. Recently and found, when measuring the ionisation produced by this beryllium radiation in a vessel with a thin window, that the ionisation increased when matter containing hydrogen was placed in front of the window. The effect appeared to be due to the ejection of protons with velocities up to a maximum of nearly 3 × 109 cm. per sec. They suggested that the transference of energy to the proton was by a process similar to the , and estimated that the beryllium radiation had a quantum energy of 50 × 106 s."

"… the technical question was, “Is the Big Bang the right story? Is the expanding universe the right story?” And there are a lot of sub-questions in that. If it is the right story, then how did the galaxies come? Where did they come from? Because it seemed quite mysterious. People were just beginning to realize that there was a structure that had been seen in the maps of where the galaxies are located, and that we had no clue what made that happen. So what is there to measure? Well, there’s not very many things to measure. You can measure the galaxies or you can look for this cosmic background radiation. And if you could measure it, it would tell you something that you never knew before."

"The Cosmic Background Explorer (COBE) satellite, under study by NASA since 1976, will map the spectrum and the angular distribution of diffuse radiation from the universe over the entire wavelength range from 1 micron to 1.3 cm. It carries three instruments: a set of differential s (DMR) at 23.5, 31.4, 53, and 90 , a far infrared absolute (FIRAS) covering 1 to 100 cm-1, and a covering 1 to 300 s. They will use the ideal space environment, a one year lifetime, and standard instrument techniques to achieve orders of magnitude improvements in sensitivity and accuracy, providing a fundamental data base for cosmology. The instruments are united by common purpose as well as similar environmental and orbital requirements. The data from all three experiments will be analyzed together, to distinguish nearby sources of radiation from the cosmologically interesting diffuse background radiations."

"NASA’s Cosmic Background Explorer satellite mission, the COBE, laid the foundations for modern cosmology by measuring the spectrum and anisotropy of the and discovering the . ... The COBE observed the universe on the largest scales possible by mapping the cosmic microwave and infrared background radiation fields and determining their spectra. It produced conclusive evidence that the hot Big Bang theory of the early universe is correct, showed that the early universe was very uniform but not perfectly so, and that the total luminosity of post–Big Bang objects is twice as great as previously believed."

"[After the publication of his 1934 paper proposing meson theory] I felt like a traveler who rests himself at a small tea shop at the top of a mountain slope. At that time I was not thinking about whether there were any more mountains ahead... I do not want to write beyond this point, because those days when I studied relentlessly are nostalgic to me; and on the other hand, I am sad when I think how I have become increasingly preoccupied with matters other than study."

"Yukawa is explicit in acknowledging that the growth of modern science from the seeds sown in Western, mainly Greek, antiquity could not have occurred in the East, given the nature of Eastern, mainly Chinese, ways of thought... Physics, he believes, has moved and will move further in future in directions more in harmony with Eastern thinking."

"Hideki Yukawa's mind throughout his life remained very much an oriental one. We learn that of the ancient Chinese writings that he discovered early in life, the ones that made the greatest and most lasting impression on him were those of Taoism in general and of Chuangtse in particular... this school centre on man's relation with the world of nature, and his oneness with it. ... To Yukawa the awareness of nature in a much more intuitive way than any Westerner would accept as part of scientific thinking appeared to be a vital ingredient in creativity. He felt not only that his own success in moving theoretical physics a step further owed something to this way of thinking, but that an element of it can be seen in such creative acts as Heisenberg's formulation of the uncertainty principle."

"While accepting the fact that his later mental struggles to discern the nature of particles – 'drawing circles on the blackboard', so he relates, being a visible sign of his mental activity – did not lead to any breakthrough, he expresses the conviction that a more oriental approach is a better way to deeper understanding than the present pursuit of ever greater detail with an ever greater mass of facts produced by more and more sophisticated experimentation. To him all this activity produces barriers between the individual scientist and his ability to perceive Nature as a whole."

"As quoted in Laura Martellini, The Nobel Prize winner Giorgio Parisi and feminicides: «The mathematics of the fifth century Hypatia victim of a patriarchal mentality that still survives today" (28 November 2023)"

"The story of Hypatia has greatly affected the collective imagination, even outside the circle of experts. She is a scientist who is killed also because a woman who was not in her place, had a public life, spoke in public and took public positions. We must never be sure that the development of science is unstoppable. Blindly trusting in the inevitability of the need that technological development has for scientific development can be a tragic mistake. The Romans preserved Greek technology without much concern for Greek science, and the Christian fanatics led by Bishop Cyril of Alexandria calmly tore Hypatia to pieces without caring at all about the long-term consequences, rather rejoicing in the disappearance of profane knowledge considered useless, if not harmful."

"The existence of God cannot be used as any scientific hypothesis: it is something different that transcends science. [...] I would be a terrible theologian if I tried to do an experiment to prove the existence of God, and a terrible scientist if I tried to explain my experimental data by hypothesizing the existence of God. [...] I'm always annoyed when people ask me about my religious opinions in interviews. I don't think they ever ask that of footballers, singers, models, categories for which I have the utmost respect. Interviewers implicitly assume that scientists possess privileged knowledge of God, but this is not true."

"I think a lot people had this idea that science advances through eureka moments and it's true to some extent. But my experience has been that it's a lot of really hard work, where finally you have figured out what's going on and you can then move on to the next stage."

"The idea of magnetic trapping is that in a magnetic field, an atom with a magnetic moment will have quantum states whose magnetic or Zeeman energy increases with increasing field and states whose energy decreases, depending on the orientation of the moment compared to the field. The increasing-energy states, or low-field-seekers, can be trapped in a magnetic field configuration having a point where the magnitude of the field is a relative minimum. [No dc field can have a relative maximum in free space (Wing, 1984), so high-field-seekers cannot be trapped.] The requirement for stable trapping, besides the kinetic energy of the atom being low enough, is that the magnetic moment move adiabatically in the field. That is, the orientation of the magnetic moment with respect to the field should not change."

"While in high school, I spent a summer working in a university research lab. The graduate student who mentored me shared this insight: physicists are people who get paid for working at their hobby. For me, that has been a joyous truth. Physicists don’t get paid much, but we sure have a lot of fun. And so, my first wish for you is that, whatever you do, you will work at something you love."

"Wineland and Haroche realized a long-standing dream of quantum physics: studying the behavior of single quantum objects. The founders of quantum mechanics believed that studying a single quantum system, like a single atom or a single photon, was beyond the realm of experimental possibility. Many believed that it did not even make sense to talk about a single atom; only the behavior of an ensemble could be meaningful. In fact, Schrödinger asserted: “…we never experiment with just one electron or atom ... In thought experiments, we sometimes assume that we do; this invariably entails ridiculous consequences…” ... The groups of Haroche and Wineland turned this idea on its head; not only did they use individual atoms and photons to elucidate some of the strangest aspects of quantum mechanics, they have even used them to make practical devices."

"No physicist could tolerate religious dogma or extremism, but I have found that Christianity provides answers to the deeper questions about life and purpose which are beyond the range of science to answer. To me it is nonsense to claim, as some atheists do, that there is nothing worth knowing that is beyond the range of science. Religion is unfashionable in our current materialistic and consumer society, but I have not found Nobel Laureates to be especially atheistic. Accurate statistics are not available, and atheists tend to make more noise, but I know at least 6 examples amongst living physics laureates who are Christians. Being religious means accepting mystery, but so does physics. Things like quantum entanglement, where I can do something to an electron in the lab, and another electron at the edge of the Universe will respond instantly, are not understandable."

"You shouldn’t choose a problem on the basis of the tool. You start by thinking about the physics problem, and the computational method should be a tool like any other. Maybe you’ll solve it using computer techniques, maybe using a contour integral; but it’s very important to approach it starting from the physics because otherwise you get lost in the use of the tool, and lose track of where you’re trying to go."

"Sometime toward the end of my second year, I started working with Gell-Mann. I went to Gell-Mann and he gave me a problem to work on and suggested I start working with fixed source theory of K-particles, where he wanted me to do things involving strong and weak interactions. And it's when I read about fixed source theory that I began to learn about renormalization group and realized it could be applied to fixed source theory, and I don't know whether there were papers that I read about renormalization group and fixed source theory, or I worked it out for myself, but in playing around with this, sort of trying to learn what was going on, I discovered that there were great simplifications that took place when you took the fixed source equation and took them to high energies, and when you did a leading log approximation. In the end, I discovered that those equations, simplified at the high energies -- you could get exact solutions. That was part of my thesis. And that was the initial thing that sparked my interest in the renormalization group. I remember when I presented my thesis to a seminar, and this was when Feynman was there, but not Gell-Mann. I went through all this exciting mathematics and toward the end, someone said, "Yes, that's fine, but what good is it?" I remember Feynman's answer as "Don't look a gift horse in the mouth!""

"An especially intractable breed of problems in physics involves those with very many or an infinite number of degrees of freedom and in addition involve “renormalization.” Renormalization is explained as the existence of very many length or energy scales of importance in the physics of the problem. The renormalization group approach is a way of reducing the complexity of these problems to the point where numerical methods can be used to solve them. The Kondo problem (dilute magnetic alloys) is used as an illustration."

"The fourth aspect of renormalization group theory is the construction of nondiagrammatic renormalization group transformations, which are then solved numerically, usually using a digital computer. This is the most exciting aspect of the renormalization group, the part of the theory that makes it possible to solve problems which are unreachable by s. The Kondo problem has been solved by a nondiagrammatic computer method."

"Wilson was quick to appreciate the promise of QCD, but he realized that to calculate the theory’s consequences at (relatively) low energies or long distances would be a demanding task. Wilson’s approach ... was revolutionary in its directness: He formulated the theory in computer-friendly form, essentially as a complicated definite integral in a space of enormously large dimension, and then set out to perform the integral numerically. Many years passed before computers and algorithms were up to the job, but lattice gauge theory amply fulfilled Wilson’s vision. The highest award in the field, awarded annually at the major international conference in Lattice Field Theory, bears Wilson’s name."

"The first efforts to turn quantum field theory into a rigorous mathematical subject occurred in the 1950s, when Wightman in particular formulated a set of axioms which define what we mean by a relativistic quantum field theory ... The subject took a significant step forward around 1970 largely through the work of Ken Wilson, who taught us to think of quantum field theory as a kind of second-order phase transition ... The Standard Model of particle physics was also formulated in the 1970s, and still stands as our best description of the strong and electroweak interactions after decades of thorough vetting in high-energy-physics experiments. ... Ken Wilson is a hero to me and many others because he provided a satisfying answer to the question: What is quantum field theory? (His was not the first answer, nor was it the complete and final answer, but nevertheless it transformed our understanding of the subject.) Wilson understood more deeply than his predecessors the meaning of renormalization."

"Ken Wilson was one of a very small number of physicists who changed the way we all think, not just about specific phenomena, but about a vast range of different phenomena."

"Asymptotic freedom arises as follows. The fundamental interactions of quarks and gluons are modified by “radiative” corrections of higher order in the quark-gluon coupling constant. These radiative corrections depend on the quark and gluon momenta. A careful analysis shows that the cumulative effect of radiative corrections to all orders can be characterized by a momentum-dependent effective coupling constant. The effective coupling is found to vanish in the limit of large momenta (to be precise, large momentum transfers between the quarks and gluons). This is called asymptotic freedom. As a result of asymptotic freedom the quarks can behave as nearly free particles at short distances; this is required to explain the high energy electron scattering experiments ... Meanwhile the interactions of quarks at long distances can be strong enough to bind the quarks into the observed bound states; protons, mesons, etc."

"The long and imposing list of physicists (among them Bohr, Heisenberg and Feynman) who had tried or were trying their hand at superconductivity should have given me pause. Even Einstein, in 1922 — before the quantum theory of metals was in place — had attempted to construct a theory of superconductivity. Fortunately, I was unaware of these many unsuccessful attempts. So when John invited me to join him (he, somehow, neglected to mention these previous efforts), I decided to take the plunge."

"How do we get emotions and feelings out of neurons which, presumably, don't have emotions and feelings?"

"The fundamental qualitative difference between the superconducting and normal ground state wave function is produced when the large degeneracy of the single particle electron levels in the normal state is removed. If we visualize the Hamiltonian matrix which results from an attractive two-body interaction in the basis of normal metal configurations, we find in this enormous matrix, sub-matrices in which all single-particle states except for one pair of electrons remain unchanged. These two electrons can scatter via the electron-electron interaction to all states of the same total momentum. We may envisage the pair wending its way (so to speak) over all states unoccupied by other electrons."

"Consider a pair of electrons which interact above a quiescent Fermi sphere with an interaction of the kind that might be expected due to the phonon and the screened Coulomb fields. If there is a net attraction between the electrons, it turns out that they can form a bound state, though their total energy is larger than zero. The properties of a noninteracting system of such bound pairs are very suggestive of those which could produce a superconducting state."

"Relativity, from one viewpoint the beginning of twentieth-century physics, is from another the capstone of classical physics, the final and most elegant variation of the world view initiated by Galileo and Newton. In a sense, after Einstein, classical physics, just as after Mozart classical music, could go no further."

"Is that all, really? I thought there might have been more. We need to celebrate women physicists, because we’re out there. Hopefully, in time, it will start to move forward at a faster rate. I’m honoured to be one of those women."

"We wondered if it was a prank. But then I knew it was the right day, and it would have been a cruel prank."

"In high school, I was very good in math and physics. I wasn’t good at much of anything else. Some people are good at a lot of things. I don’t know how they choose what to do. I couldn’t do athletic stuff, I wasn’t artistic, I have no musical ear, and I wasn’t good at writing. So I was pretty narrow in what I could do. I wasn’t thinking, “Can I do science?” I was thinking, “That’s the only thing I can do, so let’s do it.""

"I never applied."

"If somebody else thinks something that you don't believe in, just think they're wrong and you're right and keep going. That's pretty much the way I always think."

"The idea of spontaneous symmetry breaking was introduced into particle physics by Nambu ... in 1960. He suggested that the low mass and low-energy interactions of s could be understood as a reflection of a spontaneously-broken chiral symmetry, would have been exact if the up and down quarks were massless. His suggestion was that light quarks condense in the vacuum, much like the s of superconductivity. When this happens, the ‘hidden’ chiral symmetry causes the pions’ masses to vanish, and fixes their low-energy s to s, s and each other."

"It was the great multiplicity of the hadrons that led to the formulation of the quark model. Without some organizing principle such a large collection of particles seemed unwieldy, and the possibility that they might all be elementary offended those who hold the conviction, or at least the fond wish, that nature should be simple."

"Yoichiro Nambu was one of the most influential theoretical physicists of the twentieth century. His deep and unexpected insights often took years for others to understand and fully appreciate. They include: spontaneous symmetry breaking, for which he was awarded half of the 2008 Nobel Prize in Physics; the theory of quarks and gluons; and string theory."

"Ideas and techniques known in quantum electrodynamics have been applied to the Bardeen-Cooper-Schrieffer theory of superconductivity. In an approximation which corresponds to a generalization of the Hartree-Fock fields, one can write down an integral equation defining the self-energy of an electron in an electron gas with phonon and Coulomb interaction. The form of the equation implies the existence of a particular solution which does not follow from perturbation theory, and which leads to the energy gap equation and the quasi-particle picture analogous to Bogolyubov's."

"In no other type of warfare does the advantage lie so heavily with the aggressor."

"Why was there a Big Bang? What, if anything, came before? What mechanisms generated the exponential inflation of the early Universe? What are dark matter and dark energy, which dominate today's Universe? How did the first stars and galaxies form? Why are the fundamental constants of nature what they are? Must we depend on the Cosmic Anthropic Principle to 'answer' such questions? Is our Universe unique, or must we appeal to a Multiverse? What will be the ultimate fate of our Universe?"

"... If a distant galaxy is moving relative to us, its entire spectrum is Doppler-shifted in frequency. Its spectral lines are displaced relative to those of stationary light sources. Thanks to this effect, we know that distant galaxies recede from the solar system at speeds proportional to their distances from us. That's the effect that told us of the expanding universe, and of its birth, long ago, in the Big Bang."

"... Why is the muon, some dumb particle, 200 times heavier than the electron? Why is the proton about 2,000 times heavier than the electron? Why is the electric charge of the electron what it is? Why are there six quarks in nature? Why not seven or eleven or five? There are many, many "why" questions. Also a number of 'how' questions. What is the mechanism that causes the weak interactions to be weak and the electromagnetic interactions not weak?"

"The color gauge theory postulates the existence of eight massless particles, sometimes called gluons, that are the carriers of the strong force just as the photon is the carrier of the electromagnetic force."

"All kinds of questions remain. Many have to do with cosmology. How did the universe originate? How did the galaxies become distributed in space like the suds in the kitchen sink, as one of my colleagues has described it? Why is the cosmological constant apparently very tiny but non-zero and has a peculiar value that leads the universe to expand more rapidly?"

"Strong, weak and electromagnetic interaction are evidently part of a grand unified theory. These temperatures are today quite inaccessible. They were achieved only in the earliest moments of the Big Bang. Since then, the universe has congealed, losing its symmetry."

"The BEH mechanism operates within the context of gauge theories. Despite the fact that grand unification schemes reach scales comparable to the Planck scale, there was, a priori, no indication that Yang-Mills fields offer any insight into quantum gravity. The only approach to quantum gravity that had some success, in particular in the context of a quantum interpretation of the black hole entropies, are the superstring theory approaches and the possible merging of the five perturbative approaches (Type IIA, IIB, Type I and the two heterotic strings) into an elusive M-theory whose classical limit would be 11-dimensional supergravity."

"What we hear about eternal inflation or the string landscape, seems somehow unavoidably to lead to some kind of multiverse. However, it seems to me there is a fundamental problem there. Once of course you have the multiverse, then you can start playing around and try to find probability or getting to the anthropic principle, or whatever. But the point is that the picture is essentially a classical one, and it is difficult to see that if you have many universes, coming essentially with an inflationary state, that there would not be plenty of horizons in this. Now the quantum mechanics of horizons is, I think, perfectly not understood. The simplest example is the black hole, where after all nobody knows really if the problem lies in the singularity or if it lies really already in the horizon."

"At the ULB, Brout and I initiated a research group in fundamental interactions, that is, in the search for the general laws of nature. Joined by brilliant students, many of them becoming world renowned physicists, our group contributed to the many fields at the frontier of the challenges facing contemporary physics. While the mechanism discovered in 1964 was developed all over the world to encode the nature of weak interactions in a "Standard Model," our group contributed to the understanding of strong interactions and quark confinement, general relativity and cosmology. There we introduced the idea of a primordial exponential expansion of the universe, later called inflation, which we related to the origin of the universe itself, a scenario, which I still think may possibly be conceptually the correct one. During these developments, our group extended our contacts with other Belgian universities and got involved in many international collaborations. With our group and many other collaborators I analysed fractal structures, supergravity, string theory, infinite Kac-Moody algebras and more generally all tentative approaches to what I consider as the most important problem in fundamental interactions: the solution to the conflict between the classical Einsteinian theory of gravitation, namely general relativity, and the framework of our present understanding of the world, quantum theory."