I would like to correct a misrepresentation made by several of the preceding speakers. We are not celebrating the sixtieth anniversary of Murray's birthday. We are celebrating the sixtieth anniversary of his conception. His actual birthday is in September.

We are, of course, celebrating Murray Gell–Mann, whom I've known now since 1951. We joined the University of Chicago the same year, a few months apart. And before I go into the more scientific part of my lecture, I think you might be interested in the origin of the name “Murray.” Presumably it was, like some other first names, derived from a surname. And these, in turn, often come from geographical names, in the present case, from a Scottish province, “Muraih.” Already in 1203 we find a William de Moravia, and in 1317 an Orland de Morris, and in 1327, an Andrew Muraih. [This does not prove the point, because these family names could well have come from “Murie,” the Middle English form of Merry.] As a first name, it has also been surmised, as I see from a book by Partridge, Name This Child, that “Murray” comes from “Murrey” a word for dark red or eggplant colored, an adjective which in turn presumably comes from mulberry, in turn connected to maroon. Which brings us back to Murray's favorite color of corduroy jackets at the University of Chicago.

Now having explained the word Murray, I cannot refrain from giving you the origin of the name Gell–Mann.

It is an honor to have been selected among Murray's many friends and colleagues to speak to you this afternoon. No doubt I have been chosen because of the mathematical component present in high-energy theory today. Before concentrating on the interface of elementary particle physics and modern geometry, I'd like to record my own pleasure in knowing Murray this past decade. Perhaps it's just as well we didn't get acquainted earlier; I think he would have frightened me to death. You all are aware of Murray's great intellectual powers; but to me, equally amazing, is his enthusiasm for all creative endeavors, large and small. More than anyone, he firmly believes that the human mind and the human spirit can cure the ills of society. This birthday celebration expresses his personality in several ways. The diversity of topics reflects his many interests. And the theme stresses his positive view of the future.

Our charge was to pick some subject — mine is mathematics and physics — and discuss its present status and future prospects. Like twin stars, the two subjects have influenced each other greatly over the centuries, sometimes overlapping significantly, sometimes going their separate ways. In the fifties and sixties there was little contact — perhaps even some hostility. Physicists believed that too much mathematics hindered physical insight; some older ones still do. Mathematicians required more mathematical precision than physics deemed necessary and were developing abstract structures for their own sake.

In the summer of 1970 I attended as a graduate student from MPI Munich the Brandeis Summer School on Theoretical Physics at Brandeis University. Afterwards I drove in a car which I had to deliver eventually in Long Beach, California, throughout the United States. This trip was not only my first encounter with the magnificent sceneries of the United States. On a short stay at the Physics Center in Aspen, Colorado, I met in a discussion with colleagues on problems of broken scale invariance Murray Gell–Mann for the first time.

The year 1970 was an exciting one in particle physics. After several years of frustration and little progress in experimental studies, the observation of the scaling phenomena in inelastic electron–nucleus scattering at SLAC had started a new era in particle physics. I had the hunch, like numerous other theorists, that the “SLAC scaling” might have something to do with scale invariance in field theory, the topic of my Ph. D. – thesis, which had been given to me by Heinrich Mitter at the MPI in Munich. In 1970 Gell–Mann was working, partially together with Peter Carruthers, on the problem of scale invariance and its breaking in hadron physics, a topic, which at a first sight seemed unrelated to the “scaling phenomenon” seen at SLAC. I remember a number of conversations I had with Murray at the Aspen Physics Center, in which we talked about possible connections.

I find I am three and a half years older than Gell-Mann although I have always prided myself on belonging to the same generation as he does. I shall give you a contemporary's views and some early recollections of Gell-Mann and his influence on the subject of Particle Physics.

I believe I first saw Gell-Mann at the Institute for Advanced Studies in Princeton in April 1951. He had brought from MIT the expression in terms of Heisenberg fields which would give the equation of the Bethe-Salpeter amplitude. I remember him and Francis Low working on this problem and producing the most elegant of papers, which has been the definitive contribution to this subject ever since.

I left the Institute for Advanced Studies in June 1951 and went back to Lahore. Later, in 1954, I returned to Cambridge and found that in the intervening period, the subject of new particles, the so called V0-particles (Λ0, K0) had developed into a full-fledged new activity. There was the Gell-Mann-Nishijima formula which gave the connection between the charge, the isotopic spin and the strangeness - the prototype formula for other similar equations which followed this in later years and whose influence in Particle Physics one cannot exaggerate.

In July 1954, there was a conference in Scotland where Blackett took the chair and where young Gell-Mann was an invited speaker.

I first met Murray when he was a small child, a 19 year old graduate student at the Caltech of the East. I was an ancient of 26 at the time and was quite surprised when he announced upon meeting me that he knew who I was and that he had read all my papers. That was not such a monumental task at that time, but I found out that he had indeed read them. I discovered much more quickly than Viki Weisskopf that Murray was different from me and thee. We became friends and have remained so for nearly forty years.

When I went to Chicago in 1950 I began immediately agitating to hire Murray. It was no easy task to convince my senior colleagues that this was sensible since he had identically zero publications to his name. I did, however, prevail and we began a long collaboration that continued episodically for nearly 20 years. This was an exciting time in particle physics when there was a vast amount of experimental data and a paucity of theoretical tools to cope with it. It was a pleasure to work with Murray as we used everything we could lay our hands on theoretically to try to pick our way toward an understanding of what was a bewildering and complex landscape. His ingenuity, intensity, enthusiasm, and confidence that we could understand a great deal if we stuck to general principles and were not afraid to make bold conjectures was contagious.

A two-day symposium in celebration of Murray Gell-Mann's 60th birthday was held at the California Institute of Technology on January 27–28, 1989. The theme of the Symposium was “Where are Our Efforts Leading?” Each speaker was asked to choose one (or more) of the great challenges in science or human affairs and try to answer, in connection with our present effort to respond to that challenge, “Where do we stand? What kind of progress are we making? In fifty or a hundred years, how do you think today's efforts will appear?”. The topics discussed spanned a very broad range, representative of Murray's remarkably diverse interests and activities. These included particle physics and quantum cosmology, studies of complex adaptive systems, environmental challenges and studies, education and equality of opportunity, arms control and governmental issues.

Given the unusually broad scope of the Symposium, we decided it would be appropriate to publish separately a ‘physics volume,’ including all of the more technical contributions in theoretical physics and related topics. There were many marvelous contributions in other areas that we hope to publish elsewhere. The present volume includes the texts of presentations at the Symposium by Professors J. B. Hartle, E. Witten, H. Fritzsch, T. D. Lee, I. M. Singer, and V. L. Telegdi. It also includes ten additional contributed papers by well-known physicists who are close personal friends of Murray Gell-Mann.

QUANTUM COSMOLOGY

It is an honor, of course, but also a pleasure for me to join in this celebration of Murray Gell-Mann's sixtieth birthday and to address such a distinguished audience. Murray was my teacher and more recently we have worked together in the search for a quantum framework within which to erect a fundamental description of the universe which would encompass all scales – from the microscopic scales of the elementary particle interactions to the most distant reaches of the realm of the galaxies – from the moment of the big bang to the most distant future that one can contemplate. Such a framework is needed if we accept, as we have every reason to, that at a basic level the laws of physics are quantum mechanical. Further, as I shall argue below, there are important features of our observations which require such a framework for their explanation. This application of quantum physics to the universe as a whole has come to be called the subject of quantum cosmology.

The assignment of the organizers was to speak on the topic “Where are our efforts leading?” I took this as an invitation to speculate, for I think that it is characteristic of the frontier areas of science that, while we may know what direction we are headed, we seldom know where we will wind up.

When Murray Gell-Mann was starting out in physics, one of the big mysteries in the field was to understand the strong interactions, and especially the hadron resonances that proliferated in the 1950's. The existence of these resonances showed clearly that something very new was happening in physics at an energy scale of order one GeV. Another important mystery was to find the correct description of the weak interactions, and among other things to overcome the problems associated with the unrenormalizability of the simple though relatively successful Fermi theory. This problem pointed to a new development at a significantly higher energy scale.

Murray Gell-Mann played a tremendous role in advancing the understanding of these mysteries. His great contributions include his work on the strange particles; the “renormalization group” introduced by Gell-Mann and Low; early ideas about intermediate weak bosons; contributions to the proper description of the structure of the weak current; the unearthing of the SU(3) symmetry of strong interactions, and his contributions to the understanding of current algebra; the introduction of the quark model, and early ideas about QCD. His insights on these and other scientific problems are part of the foundation on which we now attempt to build, and his enthusiasm for science is an inspiration to all of us.

If we ask today what are some of the key new mysteries in particle physics, there are at least three that seem particularly pressing.

ABSTRACT:

We discuss how Murray Gell-Mann contributed to the theory of nuclear rotational motion.

Introduction

Nuclear physics could hardly be called one of Murray Gell-Mann's primary interests, but it is our aim in the present note to show, nonetheless, that Murray did in fact make basic contributions to the theory of nuclear rotational motion. Of course—from the perspective of the next century—Murray Gell-Mann's introduction of quarks and SU3(color) will be seen as laying the very foundations of theoretical nuclear physics itself, so it will not be surprising to anyone (in that era) that he contributed to nuclear rotational theory.

Murray Gell-Mann developed his ideas, which we will discuss below, in the 1960's entirely in the context of particle physics and, although aware of their importance for other fields, he did not himself publish applications outside particle physics or field theory. By good fortune one of us (LCB) was a visiting faculty member at Cal Tech at this critical time and one day an invitation came to visit his office. During this visit he explained at some length the significance of his approach for nuclear physics, and for nuclear rotational motion in particular, and suggested that these ideas be followed up. It was in this way that Murray's ideas made their way into the nuclear physics literature.

Abstract

We consider heat engines that take both energy and information from their environment. To operate in the most efficient fashion, such engines must compress the information that they take in to its most concise form. But the most concise form to which a piece of information can be compressed is an uncomputable function of that information. Hence there is no way for such an engine systematically to achieve its maximum efficiency.

Heat engines take heat from their environment and turn it into work. We consider here engines that gather both heat and information and turn them into work. An example of such an engine is the Szilard engine, a one-molecule heat engine that turns information into work. Practical examples include engines that run off of fluctuations, and car engines that use microprocessors to achieve greater efficiency.

For an ordinary heat engine a Carnot cycle can in principle be carried out reversibly. Following a suggestion of Zurek, we show that engines that process both heat and information cannot attain the Carnot efficiency even in principle. We prove that to operate at the maximum efficiency over a cycle, such an engine must reversibly compress the information that it has acquired to its most compact form. But Gödel's theorem implies that the most compact form to which a given piece of information can be compressed is an uncomputable function of that information. Accordingly, there is no systematic way for an engine to achieve its maximum efficiency.

Introduction

Why good broadband seismic isolation is an essential design feature for laser interferometric antennas

One of the key features of laser interferometric detectors is the potential wideband nature of their operation. Proposed long baseline detectors are intended to achieve sensitivities in the region h ∼ 10–21 to 10–22 or better over a range of frequencies f from a few tens of hertz (possibly as low as 10 Hz) to a few kilohertz in a bandwidth Δf ≈ f / 2. If the performance of such detectors is limited by photon shot noise in the output light, for constant light power the effect of this noise source decreases towards lower frequencies for a constant light intensity, when the detectors are operated in searches for burst sources or a stochastic background. However, other sources of noise have spectra which rise towards lower frequencies. These include thermal noise from the pendulum suspensions of the masses, and, more particularly, seismic noise. In fact it is likely that the extent to which these detectors can be operated with reasonable sensitivity at the lower end of the frequency spectrum will depend crucially on the level of seismic and mechanical isolation achievable. Since there are interesting sources of gravitational waves in the region of ten to a few hundred hertz, such as fast pulsars and coalescing compact binary systems, it is advantageous to incorporate as much seismic isolation as practicably possible into the design of these detectors.

The detection of gravitational radiation will not only be a milestone in scientific achievement; it will also be of immense cultural and philosophical significance. It will perhaps complete the process by which Western culture has gradually been forced to let go of its absolutist heresy. The heresy goes back to Aristotle and beyond. It is intimately tied up with the Judeo-Christian prejudice of an unchanging homocentric universe. It is epitomised by the ancient belief in a heavenly crystalline celestial sphere rigidly rotating and unchanging above us.

This heretical edifice has been tumbling slowly under the onslaught of scientific investigation. Newton gave us absolute space, but contributed to the demolition of the geocentric universe brought about by Galileo, Tycho, Kepler and Copernicus. Darwin discovered the impermanence of species; the plate tectonic theory gave us impermanent continents. Einstein demolished Newtonian absolute space and time, and gave us both spacetime curvature and the theory of gravitational radiation. The observation of gravitational radiation will demonstrate that spacetime not only curves predictably in the presence of matter, but is also subject to unpredictable perturbations as gravitational waves ripple through the universe.

Absolutism is surely connected with prejudice. The absolutist prejudice has led to a lingering battle in the case of Darwinism, and most relativists suffer minor irritations from the Einstein-was-wrong brigade. Tycho Brahe wrote of ‘his’ supernova in 1572:

Introduction

Laser-interferometric gravitational wave antennas face one of the most formidable data handling problems in all of physics. The problem is compounded of several parts: the data will be taken at reasonably high data rates (of the order of 20 kHz of 16 bit data); they may be accompanied by twice as much ‘housekeeping” data to ensure that the system is working appropriately; the data will be collected 24 hours a day for many years; the data need to be searched in real time for a variety of rare, weak events of short duration (one second or less); the data need to be searched for pulsar signals; the data from two or more detectors should be cross-correlated with each other; and the data need to be archived in searchable form in case later information makes a re-analysis desirable. One detector might generate 400 Mbytes of data each hour. Even using optical discs or digital magnetic tapes with a capacity of 3 Gbytes, a network of four interferometers would generate almost 5000 discs or tapes per year. The gathering, exchange, analysis, and storage of these data will require international agreements on standards and protocols. The object of all of this effort will of course be to make astronomical observations. Because the detectors are nearly omni-directional, a network of at least three and preferably more detectors will be necessary to reconstruct a gravitational wave event completely, from which the astronomical information can be inferred.

Introduction

To be able to detect gravitational radiation, resonant mass antennae must achieve a dimensionless strain sensitivity of ∼10–19–10–20 (Thorne, 1987). Such a high sensitivity can only be obtained by the use of well isolated, massive, high acoustic Q antennae which are cooled to liquid-helium temperatures, and use ‘quantum limited” transducers to read out the antenna's vibrations. Modern resonant mass antennae generally consist of a high Q cylindrical bar to which is attached one or more smaller masses which are resonant at the antenna frequency, to form a two-mode or multi-mode antenna (see Richard and Folkner's chapter 7). The coupled resonators mechanically amplify the bar's vibrations thereby reducing the effect of transducer wideband noise. It is important that the acoustic Q of the entire antenna be high so as to minimise noise due to Brownian motion of the masses.

Initially, resonant mass antennae used passive PZT crystal transducers which were mounted near or around the girth of the bar. These were subsequently superseded by passive, modulated inductance and capacitance transducers which have proven to be much more sensitive, and are still being developed (see chapter 7). More recently, several groups have started to investigate another class of transducers: the parametric or active transducer (Bordoni et al., 1986; Braginsky, Panov and Popel'nyuk, 1981; Oelfke and Hamilton, 1983; Tsubono, Ohashi and Hirakawa, 1986; Veitch et al., 1987). This type of transducer differs from passive transducers in that it requires an external power source (a pump oscillator), and it has intrinsic power gain.