Albert Einstein and relativity If I were to ask a number of people in the street what they think was the most important new theory in physics in the twentieth century, and who has been the greatest physicist, I am fairly sure that – of those able to express an opinion at all – a substantial majority would say that relativity has been the greatest theory, and Einstein the greatest physicist. Indeed Albert Einstein has probably achieved the remarkable feat of not just becoming the best-known practitioner of any branch of science among the general public, but retaining that position for 85 years, 50 of those years since his death in 1955. It was in 1905, when he was 26, that Einstein astonished the scientific community by producing four pieces of work of the very highest quality. These included his first paper on relativity, in which he introduced what is now called the special theory of relativity (a term I shall explain in Chapter 3). The three other papers will be referred to in due course. What was astonishing was not just the quality of the work, but that the author was not an academic of note, or even of promise, but was working as a patent inspector after rather a mediocre student career. (A recent pleasantly written biography of Einstein is that of Abraham Pais [1], himself a well-known physicist; Pais gives references to many other accounts of Einstein's life. Another, more recent, biography is that by Fölsing [2].
Albert Einstein and relativity If I were to ask a number of people in the street what they think was the most important new theory in physics in the twentieth century, and who has been the greatest physicist, I am fairly sure that – of those able to express an opinion at all – a substantial majority would say that relativity has been the greatest theory, and Einstein the greatest physicist. Indeed Albert Einstein has probably achieved the remarkable feat of not just becoming the best-known practitioner of any branch of science among the general public, but retaining that position for 85 years, 50 of those years since his death in 1955. It was in 1905, when he was 26, that Einstein astonished the scientific community by producing four pieces of work of the very highest quality. These included his first paper on relativity, in which he introduced what is now called the special theory of relativity (a term I shall explain in Chapter 3). The three other papers will be referred to in due course. What was astonishing was not just the quality of the work, but that the author was not an academic of note, or even of promise, but was working as a patent inspector after rather a mediocre student career. (A recent pleasantly written biography of Einstein is that of Abraham Pais [1], himself a well-known physicist; Pais gives references to many other accounts of Einstein's life. Another, more recent, biography is that by Fölsing [2].
Quantum theory, the most successful physical theory of all time, provoked intense debate between the twentieth century's two greatest physicists, Niels Bohr and Albert Einstein. Quantum information theory has emerged from intensive study of the structure and interpretation of quantum theory to become one of the fastest growing areas of twenty-first century science. This second edition has been extensively revised and updated to cover recent developments, including the findings of papers published since the well-received first edition. A substantial new chapter is devoted to the development and structure of quantum information theory. Developments in the experimental and theoretical study of Bell's Theorem are also covered in detail, and the accounts of ongoing work have been brought up to date. A fascinating account of the development of quantum theory, this book will appeal to anyone with an interest in the fundamental questions of physics, its philosophy and its history.
Along with the exciting experiments that changed the face of physics in the twentieth century, work proceeded feverishly on the theoretical side to rebuild the conceptual world that had been severely shaken. Sometimes the theorists lagged behind the experimentalists, and certain experimental results waited for several years to be explained. And sometimes experiment lagged behind theory, and a new theoretical model waited for years to be verified experimentally. Two great theories left their mark on physics in this century: the theory of relativity, and quantum mechanics. In this chapter we shall briefly review the main ideas of these theories which are vital for the understanding of the atomic world. The theory of relativity The theory of relativity was formulated by the great physicist Albert Einstein. The first part of it (and the important one for us) — the special theory of relativity — was published in 1905, and sprang from the need to explain a puzzling question that exercised the physicists of the nineteenth century: why was it impossible to alter the speed of light, which remained constant (299 792.5 kilometres per second) even when the detector was moving relative to the source of light? In contrast to other physicists, Einstein did not try to explain this phenomenon.
Niels Bohr was born on October 7, 1885. He was one of the great innovators in physical science in the twentieth century. It so happens that 1985 also marks fifty years since the long discussions, which had begun in the 1920s between Albert Einstein and Bohr on the philosophical problems of quantum physics, attained their apogee. An article co-authored by Einstein, B. Podolsky, and N. Rosen, "Can Quantum Mechanics Be Considered a Complete Description of Physical Reality?,"1 was published in 1935 in the journal Physical Review. According to Bohr, "by virtue of its clarity and, it would seem, flawless argumentation, the work of Einstein, Podolsky, and Rosen has created excitement among physicists and played a great role in the discussion of general philosophical questions of physics."2 Precisely as a result of the publication of this article, the critical position of Einstein concerning quantum mechanics became known to a broader circle of physicists. (Prior to this not many physicists had participated in the discussions.)3 In the same year, Bohr responded to Einstein and his co-authors with an article under the same title.4
Einstein in 1905 The next great steps were taken by Albert Einstein and it is no exaggeration to state that he was the first person to appreciate the full significance of quantisation and the reality of quanta. He showed that these are fundamental aspects of all physical phenomena, rather than just a ‘formal device’ for accounting for the Planck distribution. From 1905 onwards, he never deviated from his belief in the reality of quanta – it was some considerable time before the great figures of the day conceded that Einstein was indeed correct. Einstein completed what we would now call his undergraduate studies in August 1900. Between 1902 and 1904, he wrote three papers on the foundations of Boltzmann's statistical mechanics. In 1905, Einstein was 26 and employed as ‘technical expert, third class’ at the Swiss patent office in Bern. In that year, he completed his doctoral dissertation on A new determination of molecular dimensions , which he presented to the University of Zurich on 20 July 1905. In the same year, he published three papers which are among the greatest classics in the literature of physics. Any one of them would have ensured that his name remained a permanent fixture in the scientific literature. These papers are: (1) On a heuristic point of view concerning the production and transformation of light (Einstein, 1905a); (2) On the motion of small particles suspended in stationary liquids required by the molecular-kinetic theory of heat (Einstein, 1905b); (3) On the electrodynamics of moving bodies (Einstein, 1905c).
This paper takes a look at the two cornerstones of modern physics--Quantum Mechanics and The Theory of Relativity (Both Special and General). The differences and similarities for the two subjects are presented. More of their differences and similarities will emerge with new developments in physics. One can't rule out the possibility of the two being unified into one one fine day. That will herald another triumphant moment in physics. Introduction In 1905, Albert Einstein at the age of twenty-six formulated single-handedly, among others, the Theory of Special Relativity together with his other seminal papers on photoelectricity, Brownian motions of atoms and molecular dimensions. The year has been universally declared the Miraculous Year [1]. Ten years later, he came up with the theory of General Relativity--a new and revolutionary framework on gravity. Meanwhile in Europe a group of young physicists played pivotal role in the birth of Quantum Mechanics. Many of them went on to win Nobel prizes for their monumental contributions. Einstein also won the coveted prize not for Relativity but ironically for Photoelectric Effect. Irony has been part of physics in its history. Relativity with its weird 'Twin Paradox', constancy of the speed of light and the interchangebility between mass and energy (E=[mc.sup.2]) enthralls the public and scientists alike. It provides a way to measure particle masses [2]. The Quantum Theory has its fair share of weirdness and bewilderment. Both Quantum Mechanics and the Theory of Relativity bring forth new ideas in human thoughts. They are among Joanne Baker's 50 physics ideas [3]. Quantum Mechanics and the Theory of Relativity The quantum world where counterintuition reigns supreme is couched in uncertainty as epitomised by Heisenberg's uncertainty principle. Things do not behave in a deterministic way as enshrined and expected in classical Newtonian physics. The microscopic world of the electrons was dictated by randomness and indeterminacy. Albert Einstein was appalled by such dictates that he famously declared: 'God does not play dice with the universe.' The famous Danish physicist Neils Bohr sprang to his feet by saying: 'Stop telling God what to do with his dice.' The sparring between the two stalwarts in physics is legendary. According to Trefil [4], there are a couple of things that need to be said about the uncertainty principle: it does not imply that we cannot know either the position or the velocity of a particle, and it does not require the presence of a conscious mind. Marcus Chown [5] wraps up by saying 'The bitter irony, not lost on Einstein, was that he was the one who, by postulating the existence of the photon, had inadvertently set loose the genie of randomness of physics. The two theories of relativity by Einstein are not couched in randomness however. According to Smoot [6], both implied a radically new cosmology. Many people are of the opinion that with Einstein's theory of relativity, old classical physics is no more in vogue. According to Angier [7], Albert Einstein did not prove that Isaac Newton was wrong. Instead, he showed that Newton's theories of motion and gravity were incomplete, and that new equations were needed to explain the behavior of objects under extreme circumstances, such as when tiny particles travel at or near the speed of light. …
‘God’, said Albert Einstein, ‘does not play dice’. This famous remark by the author of the theory of relativity was not intended as an analysis of the recreational habits of a supreme being but expressed his reaction to the new scientific ideas, developed in the first quarter of the twentieth century, which are now known as quantum physics. Before we can fully appreciate why one of the greatest scientists of modern times should have been led to make such a comment, we must first try to understand the context of scientific and philosophical thought that had become established by the end of the nineteenth century and what it was about the ‘new physics’ that presented such a radical challenge to this consensus. What is often thought of as the modern scientific age began in the sixteenth century, when Nicholas Copernicus proposed that the motion of the stars and planets should be described on the assumption that it is the sun, rather than the earth, which is the centre of the solar system. The opposition, not to say persecution, that this idea encountered from much of the establishment of that time is well known, but this was unable to prevent a revolution in thinking whose influence has continued to the present day. From that time on, the accepted test of scientific truth has increasingly been observation and experiment rather than religious or philosophical dogma.