Arnold Sommerfeld
With respect to the fine structure constant we are in the rather humiliating position of people who have to wrap a piece of string around a cylinder to determine pi. There are many constants in physics, but there are only a few fundamental constants and they are special because they have universal significance. Although the fine-structure constant is the subject of this chapter, let's begin with six other basic constants of nature. These six, with their current best values, are the...
Exotic Hydrogenlike Atoms From Theory to Technology
Muonic hydrogen, the H-p+ bound state, . . . is more sensitive to the . . . structure of the proton. The hydrogen atom has been such a provocative and productive window onto the physical universe that physicists have gone to every length possible to create hydrogen-like systems. Such hydrogen-like atoms consist of two particles, one positively charged (like the proton) and the other negatively charged (like the electron), bound together by the mutual attraction of their opposite charges. Just...
The Bose Einstein Condensate for Hydrogen
Satyendranath Bose, 1924 Albert Einstein, 1925 Eric A. Cornell and Carl E. Wieman, 1995 Daniel Kleppner and Tom Greytak, 1998 When Thomas Greytak and Daniel Kleppner at MIT started out 22 years ago to form a Bose-Einstein condensate by cooling and compressing a gas of hydrogen atoms, they did not realize just how arduous the journey would be. There are various ways that fame comes to a scientist. For Satyen-dranath Bose it was asking Albert Einstein to run interference for him. Eventually his...
In the Beginning Hydrogen and the Big Bang
If God did create the world by a word, the word would have been hydrogen. Harlow Shapley The story of hydrogen begins before there was anyone to notice. Long before the Earth and its planetary siblings existed, before the Sun and the Milky Way existed, and even before chemical elements like oxygen, sodium, iron, and gold existed, the hydrogen atom was old, old news. According to current wisdom, our universe began about 15 billion years ago at a point with infinite density and infinite...
Werner Heisenberg and Wolfgang Pauli Paul Dirac
We now come to the crucial question for the whole new theory Is it able to account for the properties of the hydrogen atom In the 1960s, physicists were asked to identify the greatest physicist who ever lived. Competing for the top spot were Isaac Newton and Albert Einstein. Coming up third was a scientist who lived in the third century bc, Archimedes. For many reasons, Newton and Einstein qualify for this honor. Newton essentially brought heaven and Earth together by demonstrating convincingly...
William Prout
Hydrogen seems almost aware of its illustrious history, for the atom behaves in a regal fashion. All of us, from infant to most senior, are aware of the world around us. The breadth and depth of this awareness varies dramatically from person to person, but the same world is there for all to observe. When we look not only with our eyes, but also with our minds and souls, we can see very different worlds. For example, we might interpret the world as diverse each face in a throng of people is...
Paul Dirac
With relativity and quantum mechanics, antimatter was part of the general framework . . . of modern physics. The reputation of a physicist can be built upon a body of work so important that it defines a field of research and influences all other investigators in the field. Or a physicist may write one paper that is so prominent in a domain of research that the identity of the physicist becomes linked to that epochal paper. Although the British physicist P. A. M. Dirac wrote many important...
Willis Lamb
The spectrum of the hydrogen atom has proved to be the Rosetta stone of modern physics. Theodor W. Hansch, Arthur L. Schawlow, and George W Series Hundreds of physics conferences have been held since World War II, but with little doubt, the most influential conference of them all occurred on June 2, 3, and 4, 1947 on Shelter Island at the eastern end of Long Island. This conference occurred soon after physicists had returned from their wartime work designing the atomic bomb in Los Alamos,...
The Rydberg Constant A Fundamental Constant
Johannes Robert Rydberg, 1890 Theodor W. Hansch, 1992 The Rydberg constant is one of the most important constants of atomic physics because of its connection with the fundamental atomic constants e, h, me, c and because of the high accuracy with which it can be determined. The Rydberg constant first appeared in the literature of physics in 1890. Today, more than a century later, this constant still challenges physicists as they carefully design experiments with state-of-the-art instruments to...
Rabi
You felt if you were measuring the properties of hydrogen, the most fundamental nucleus, you just measure it and do it as well as you can. When Isidor Isaac Rabi was a graduate student at Columbia University in the mid-1920s, his eye was on Europe, where intellectual fireworks were illuminating the minds of physicists, animating their discussions, and entertaining their ambitions. This was not the situation at Columbia University, where only a sputtering roman candle occasionally lit the...
Harold Urey
Because of its unique properties, the distribution of deuterium in the universe constitutes a powerful clue to the history of the development of matter. David N. Schramm and Robert V. Wagoner Nearly all the chemical elements that make up our material world occur in different isotopic forms. Every breath we inhale brings into the lungs oxygen in three isotopic forms O16, O17, and O18. Each of these oxygen atoms has eight electrons around a nucleus with eight protons. In addition, O16 has eight...
Johann Jakob Balmer
Historically, the simple and regular Balmer spectrum has inspired . . . pathbreaking discoveries. From 1859 until his death at age seventy-three, Johann Jakob Balmer 1825-1898 was a high-school teacher at a girls' school in Basel, Switzerland. His primary academic interest was geometry, but in the mid-1880s he became fascinated with four numbers 6,562.10, 4,860.74, 4,340.1, and 4,101.2. These are not pretty numbers, but for the mathematician Balmer, they became an intriguing puzzle Was there a...
Niels Bohr
The Bohr model scored a stunning success in accounting for major features of the observed spectrum of the hydrogen atom. Bretislav Friedrich and Dudley Herschbach As soon as I saw Balmer's formula, the whole thing was immediately clear to me. How logically neat it would be if Balmer's simple formula had, out of the blue, led Bohr directly to his model of the hydrogen atom. Unfortunately, neat logic must give way to the reality of events as they occurred. Bohr did see Balmer's formula, he did...
Edward M Purcell and Felix Bloch
I remember, in the winter of our first experiments, just seven years ago, looking at snow . . . around my doorstep great heaps of protons quietly precessing in the earth's magnetic field. The United States formally declared war on Italy and Germany on December 8, 1941. Long before the United States entered World War II, however, many American physicists were restive. Nuclear fission was discovered in Germany in late December 1938. Niels Bohr learned about this momentous event on January 3,...
Edward M Purcell and Harold Ewen
It was certainly apparent to Jan Oort right away . . . right away he saw it as a tool for learning something about the structure of the Galaxy. Sometimes the most brilliant people can be short-sighted. Sometimes they can even be wrong. For example, consider two mathematicians who were contemporaries 200 years ago. One of them, the German Carl Friedrich Gauss 1777-1855 , is universally regarded as one of the greatest mathematicians of all time. The other, Friedrich Wilhelm Bessel 1784-1846 ,...
David N Schramm
The last parameter of big bang nucleosynthesis . . . is being pinned down by measurements of the deuterium abundance in high-redshift hydrogen clouds. David N. Schramm and Michael S. Turner In the era of the Hubble Space Telescope it is a common experience to be both intellectually and emotionally stunned by the detailed beauty of images from space. Cosmic clouds, light years in their dimensions, are observed where fetal stars are moving toward birth and delicate nebula mark the graves of...
The Hydrogen Maser A High Precision Clock Norman F Ramsey and Daniel Kleppner
This is about the stillness in moving things, In running water, also in the sleep Of winter seeds, where time to come has tensed Itself, enciphering a script so fine Only the hourglass can magnify it, only The years unfold its sentence to the root. Time mystifies it goads the imagination, and always has. The earliest records of human existence document that even our distant ancestors were aware of the passage of time. Ancient frescos on the walls of caves in France, dating from approximately...
Otto Stern
When Otto Stern measured the proton moment in the early 1930s, he was advised not to bother elementary theory proved the result would be one nuclear magneton. Fortunately, Stern had a healthy disregard for elementary theory. The name of Otto Stern is identified with one of the most bizarre and influential experiments in quantum physics. The Stern-Gerlach experiment was carried out prior to the creation of quantum mechanics and for some physicists, this experiment, more than any other,...
