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1 Nobel Lectures physics

2 Nobel Lectures I ncluding P resentation S peeches and L aureates B iographies Physics Chemistry Physiology or Medicine Literature Economic Sciences

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4 Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore USA office: 27 Warren Street, Suite , Hackensack, NJ UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE NOBEL LECTURES IN PHYSICS ( ) The Nobel Foundation ( ) Published with permission from Nobel Media AB in 2014 by World Scientific Publishing Co. Pte. Ltd. Nobel Prize and the Nobel Prize medal design mark are the registered trademarks of the Nobel Foundation. ISBN ISBN (pbk) Printed in Singapore by Mainland Press.

5 v PREFACE Alfred Nobel was one of the greatest inventors, engineers, entrepreneurs and industrialists of the 19th century. His most profitable invention was dynamite that he patented in His most remarkable and lasting invention though was his founding of the Nobel Prizes. In his will from 1895 he stipulated that most of his wealth should be handled such that the interests from it should be divided into five equal shares which should be used for yearly Prizes in Physics, Chemistry, Physiology or Medicine, Literature and Peace to those who, during the preceding year, shall have conferred the greatest benefit on mankind. Alfred Nobel died in 1896 and in 1901 an organization, the Nobel Foundation, was in place to hand out the first Prizes. Apart from some war years the Prizes have been given every year since then. The only real change that happened to the will was that it was realized that the sentence during the preceding year could not be implemented literally. It is instead interpreted to mean that a discovery should have had renewed interest in recent years if it is of older date. For the Physics Prize, which Nobel ranked as the first one, he stipulated that it should be given to the person who shall have made the most important discovery or invention within the field of physics. This is the criterion that the Nobel Committee has had to work with since the beginning. It is not to the most deserving person, it is not for a lifetime achievement, nor is it for the clearest explanation of a physical phenomenon. It is to the discoverer of a physical phenomenon that changed our views, or to the inventor of a new physical process that gave enormous benefits to either science at large or to the public. This was an ingenious focus for the Prize. You do not need to be Albert Einstein to get the Prize but it helps. The discoverers are our scientific heroes and they are eligible for the Prize. In this volume we will meet the laureates from the five years It contains the presentation speeches of the Nobel Committee members given at the ceremony. It further contains the biographies and the Nobel lectures of all the laureates. We will learn to know the laureates, follow their lives up to their great discoveries or inventions and also follow them after these events that led to a Nobel Prize. We can learn how the great minds work and we will see that Nobel laureates are also human beings of flesh and blood. At the same time the Nobel lectures give us detailed explanations of the phenomena for which the laureates have been awarded. The 2006 Nobel Prize in physics honored the discovery of the small anisotropy of the cosmic microwave background radiation that was discovered by the COBE satellite, and the Prize was given to two of its

6 vi Preface leaders, John C. Mather and George F. Smooth. Everyone knows that our universe is not homogeneous. We only have to look at ourselves and at the night sky on a clear night. Even so Albert Einstein assumed without any experimental indications already in 1917 that on large enough scales the universe should be homogeneous. This was finally verified in 1964 by Penzias and Wilson, who discovered the cosmic microwave background radiation that is the remnant of the Big Bang that we can detect today. This rendered them the Nobel Prize in It was a remarkable discovery to find that the background radiation seemingly have the same temperature whichever direction it comes form. However, there must be some anisotropy in order for galaxies to form at some time in the history of the universe. The COBE mission that started its planning in the late 1970 s and was launched in 1989 finally found this anisotropy in the black body radiation which has a temperature of 2.7 above the absolute zero. The deviation is 1 part in 105, i.e. in the fifth digit, but this is enough for our universe to develop the structures we now see. In the memoirs and the Nobel lectures the reader can follow all the travails and brainstorming needed to successfully detect such a small but important discrepancy. The 2007 Nobel Prize honored an important discovery that was also a great invention, namely the Giant Magnetoresistance. The Prize was shared by Albert Fert and Peter Grünberg. It has long been known that the electric resistance of materials such as iron may be influenced by a magnetic field. The British physicist Lord Kelvin demonstrated this already in The resistance diminishes along the lines of magnetization when a magnetic field is applied to a magnetic conductor. If the magnetic field is applied across the conductor the resistance increases instead. This (anisotropic) magnetoresistance was used early on for example for reading out data. When the new techniques to produce material at the nanometer scale were developed, new possibilities arose. Both laureates realized that by sandwiching layers of non-magnetic material between layers of magnetic ones, electrons with different spin directions would scatter differently leading to differences in the resistance, when a magnetic field is switched on. The real discovery was that the effect was huge and this led directly to the invention of new miniaturized read-out heads revolutionizing techniques for retrieving data from hard disks. The discovery also played a major rôle in various magnetic sensors as well as for the development of a new generation of electronics called spintronics. In the memoirs the reader can follow the development of this new exciting field and also get an understanding of some of the enormous progress that has occurred in the IT-world. The 2008 Nobel Prize was a shared prize with a common denominator, broken symmetries. One half was awarded to Yoichiro Nambu for the discovery of the mechanism of spontaneous broken symmetry in subatomic physics and the other half jointly to Makoto Kobayashi and Toshihide Maskawa for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in Nature. It had long been known that physical systems could have ground states which have a smaller symmetry than the underlying equations that

7 Preface vii determine the systems. This came to be called spontaneous symmetry breaking. Ferromagnetism is a typical example. The equations are rotationally invariant but the ground state is not. Yoichiro Nambu first explained the Bardeen-Cooper-Schrieffer theory of superconductivity (Nobel Prize 1972) as a theory where the electromagnetic gauge symmetry is spontaneously broken and proceeded to take this knowledge over to pion physics and the strong nuclear forces. This explained the low mass of the pion and is a background to our understanding of the strong nuclear forces. The relevant work by Nambu was made around 1960 but the consequences of his work on spontaneous symmetry breaking has been important ever since and is a pillar of modern fundamental physics. The work by Kobayashi and Maskawa addressed a different issue of broken symmetries, namely the so-called CP-invariance. One of the most remarkable discoveries of the 20th century was that there is a difference between left and right in Nature. The so-called parity invariance P or mirror symmetry is indeed broken in the weak interactions. This led to the Nobel Prize in 1957 to Chen Ning Yang and Tsung-Dao Lee. However, if one also combines P with the charge symmetry C into CPinvariance it was believed to be a true symmetry. In 1964 James W. Cronin and Val L. Fitch discovered that also this symmetry could be violated, which rendered them the Nobel Prize in With the advent of the Standard Model for Particle Physics from 1971 on there did not seem to be any possibility to build in this symmetry violation in the theories for the weak interactions without destroying the model s good predictions. In 1972 Makoto Kobayashi and Toshihide Maskawa examined the possibility of introducing more fundamental particles quarks and found that if there are six different quarks, the theory can indeed break this symmetry. It was a daring assumption, since at that time the everyday world seemingly needed only two different kinds of quarks, whereas three had been discovered. Over the years the other three quarks were discovered and it was shown that Nature is indeed following the ideas of Kobayashi and Maskawa. It had in fact been pointed out by Andrei Sacharov (Nobel Peace Prize in 1975) that we need a violation of the CP-invariance in order to understand why our world consists of matter and no antimatter. The theory of Kobayashi and Maskawa does not explain the whole violation that is necessary but shows that it is possible to have a violation. In 2009 it was time for a genuine invention prize. One half of the Nobel Prize was awarded to Charles Kuen Kao for for groundbreaking achievements concerning the transmission of light in fibers for optical communication and the other half to Willard S. Boyle and George E. Smith for for the invention of an imaging semiconductor circuit the CCD sensor. We have all grown up with copper fibers leading the electric currents and when the telephones started to be used, they also utilized such fibers to lead the information in terms of weak electric currents. During the 1960 s the young Chinese-British engineer Charles Kao started to experiment with transmitting light through glass fibers in order to send information. In the beginning the fibers were not transparent enough so

8 viii Preface the signal would disappear after a very short distance. (Think about how much you see through a thick glass.) In order to succeed one had to produce the purest glass in the world. In 1971 Corning Glass Works in the USA, a glass manufacturer with over 100 years experience, produced a 1-kilometer long optical fiber. This was the signal that it was possible to use glass fibers. Since then this technique has completely taken over. It has led to cheap telephone calls between any two places on earth, to internet, to sending s also without any costs, also leading to spams. The modern communication society is totally dependent on the optical fiber. With the old system with for example satellites transmitting information between different parts of the world, we were used to delays in the transmission. Now all information flows on earth at the speed of light. Since light is used the frequencies are also much higher and one can pack much more information in each channel than before, which also explains how most of the present world can be connected. The biography and the Nobel lecture by Charles Kao are remarkably interesting to read. They show what one can achieve with persistence and hard work and belief in one s ideas. The invention of the CCD-camera was done in one discussion between the two laureates one day in 1969 in the Bell Laboratories. It uses the photoelectric effect for which Albert Einstein got the 1921 Nobel Prize. The digital image sensor, CCD, is made out of silicon. The size of a stamp, the silicon plate holds millions of photocells sensitive to light. The effect occurs when light hits the silicon plate and knocks out electrons in the photocells. The liberated electrons are gathered in the cells which become small wells for them. The larger the amount of light, the larger the number of electrons is that fills these wells. The engineering problem was now to read out these numbers. An ingenious shifting of the wells so that each original well can be read off in a certain order does this. With this information the picture can be reconstructed. This is a very different technique from the old one using films that had to be developed. It has revolutionized the possibilities to take pictures. It started with TV cameras and since more than ten years electronic digital cameras occur not only as ordinary cameras but most telephones have them. They are everywhere. This is really what Big Brother should have used. It does not cost anything essentially to take a picture, and with the optical fiber technique it can be sent anywhere in the world at the velocity of light. The CCD-cameras have also played an enormous role for many science disciplines, such as astronomy where one camera can follow hundreds of thousands of stars for years. Also in medicine the use of small CCD-cameras have revolutionized the techniques to see inside the body. There are also other similar techniques to the CCD-concept that are used these days and they have also contributed much to our modern world of communications. For this prize it is interesting to read how an invention of this kind suddenly is ripe to be found. In 2010 the Nobel Prize was awarded to two Russian-British scientists, Andre Geim and Konstantin Novoselov for groundbreaking experiments regarding the two-dimensional material graphene. We know that carbon exists in many forms on Earth. It is very important for life and is the

9 Preface ix base for the DNA. The most common form of carbon is graphite, which consists of stacked sheets of carbon with a hexagonal structure. Under high pressure diamond is formed, which is a metastable form of carbon. A new form of molecular carbon is the so-called fullerenes. The most common one, called C60, contains 60 carbon atoms and looks like a football (soccer ball) made up from 20 hexagons and 12 pentagons which allow the surface to form a sphere. The discovery of fullerenes was awarded the Nobel Prize in Chemistry in Also a related quasi-onedimensional form of carbon, carbon nanotubes, has been known for quite some time. However, it was commonly believed that a one-dimensional layer could not be a stable material. In 2004 the laureates managed to isolate such a one-dimensional sheet. Using scotch tape to pull layers from graphite they managed to reach one layer. This came to be called graphene. They then succeeded to characterize its physical properties, and indeed it has remarkable properties. It has opened up a new world of possibilities for innovative electronics. It is practically transparent and a good conductor, and it is now a race around the world to find novel applications for it. Also for these laureates it is very instructive and interesting to read their biographies and Nobel lectures. Especially their description of Friday night experiments, where they tried odd ideas can teach many aspiring scientist the importance of playing and to have fun in science. I am convinced that aspiring young scientists as well as more advanced ones but also the interested public will learn a lot from and appreciate the geniuses of these narrations. Lars Brink

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11 xi CONTENTS Preface v 2006 John C. Mather and George F. Smoot Presentation by Per Carlson 3 Biography of John C. Mather 7 From the Big Bang to the Nobel Prize and Beyond 18 Biography of George F. Smoot 53 Cosmic Microwave Background Radiation Anisotropies: Their Discovery and Utilization Albert Fert and Peter A. Grünberg Presentation by Börje Johansson 123 Biography of Albert Fert 127 The Origin, Development and Future of Spintronics 133 Biography of Peter A. Grünberg 157 From Spinwaves to Giant Magnetoresistance (GMR) and Beyond Yoichiro Nambu, Makoto Kobayashi and Toshihide Maskawa Presentation by Lars Brink 185 Biography of Yoichiro Nambu 189 Spontaneous Symmetry Breaking in Particle Physics: A Case of Cross Fertilization 191 Biography of Makoto Kobayashi 199 CP Violation and Flavour Mixing 202 Biography of Toshihide Maskawa 221 What does CP Violation Tell Us? 227

12 xii Contents 2009 Charles Kuen Kao, Willard S. Boyle and George E. Smith Presentation by Joseph Nordgren 237 Biography of Charles Kuen Kao 241 Sand from Centuries Past: Send Future Voices Fast 253 Biography of Willard S. Boyle 265 CCD An Extension of Man s Vision 267 Biography of George E. Smith 271 The Invention and Early History of the CCD Andre Geim and Konstantin Novoselov Presentation by Per Delsing 293 Biography of Andre Geim 297 Random Walk to Graphene 310 Biography of Konstantin S. Novoselov 337 Graphene: Materials in the Flatland 346

chemistry Nobel Lectures Nobel Lectures in Chemistry ( ) Downloaded from

chemistry Nobel Lectures Nobel Lectures in Chemistry ( ) Downloaded from Nobel Lectures chemistry 2006 2010 Nobel Lectures I ncluding P resentation S peeches and L aureates B iographies Physics Chemistry Physiology or Medicine Literature Economic Sciences Nobel Lectures I ncluding