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. …
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. …
In 2005 we celebrate the hundredth anniversary of the publication of five seminal papers by Albert Einstein establishing the basis of three fundamental fields of physics: the theory of relativity, quantum theory and the theory of Brownian motion. This happened at a time when the reality of atoms and molecules was still far from certain. The microscopic view Einstein took of molecular motion led to the calculation of Avogadro's number and the size of molecules by studying the motion of small particles in liquids. Combining kinetic theory and classical thermodynamics finally led Einstein to the conclusion that the displacement of a microparticle under Brownian motion varies as the square root of time. The experimental demonstration of this law three years later was considered as the striking proof that atoms and molecules are physically real. Today single atoms are probed directly in experiments, and we are able to observe the individual paths of colliding or dissociating particles. These new techniques are described in some of the papers of this issue in a very impressive way. An even more exciting development was initiated with the demonstration of Bose–Einstein condensation of dilute gases of ultracold atoms, a phenomenon first predicted by Einstein in papers published between 1916 and 1924. The first paper of Einstein's famous series of 1905, 'On an heuristic point of view about the creation and conversion of light', was an explanation of the photoelectric effect, demonstrated in several experiments over the previous few years. The explanation was based on the quantum hypothesis introduced by Max Planck five years earlier, and was considered as an additional and important proof of Planck's hypothesis. Today quantum theory and photons are the basis for much of modern science and technology. We have learned to experiment with single photons, and we have demonstrated the advantages of information transfer by single photons. Photons permit new and incredibly precise time and frequency standards. These are not only technically important, but may also lead to even more stringent tests of relativity and other fundamental laws and concepts of physics. Examples of these applications and many other uses of modern optics are discussed in this issue. Special relativity, the third of Einstein's 1905 topics, has always been closely connected with atomic, molecular and optical physics. Today atomic physics provides some of the most stringent tests of special relativity. Furthermore, fast electron beams are used in advanced light sources such as synchrotron radiation generators and free electron lasers. Those aspects and related applications are also discussed here. We hope that this special issue will be of great interest to the reader by highlighting recent advances in atomic, molecular and optical physics. This field continues to provide one of the most fertile areas for research one hundred years after it first emerged from the work of Einstein published in 1905, his 'miraculous year'.
In the 20th century, two new terms were added to the scientific lexicon: relativistic mechanics and quantum mechanics. The challenge to the concept of the absoluteness of space and time started at the end of the 19th century and gave birth to Einstein's special relativity theory in 1905. This unified space and time to a single entity, space–time, and we have been introduced to many new concepts such as time dilation, space contraction, mass–energy relation, and the space–time continuum in relativity theory. We have also learned that the highest possible velocity in this universe is that of light and that nothing in the universe can move faster than light. Einstein's general theory of relativity took into consideration gravitation and established the chronogeometric concept of gravity. Quantum mechanics developed by Bohr, de Broglie, Heisenberg, Schrödinger, and others gave us knowledge in the atomic and subatomic domain and led to the wave–particle duality of de Broglie, the uncertainty principle of Heisenberg, the wave mechanics of Schrödinger, and so forth. We have learned that three distinct chords are at the heart of quantum mechanics—granularity, relational, and indeterminism. Although quantum mechanics is a weird subject, as we will discuss, the modern physics is totally based on it.
‘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 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.
‘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.
The two towering achievements of modern physics are quantum theory and Einstein's general theory of relativity. Together, they explain virtually everything about the world we live in. But, almost a century after their advent, most people haven't the slightest clue what either is about. Did you know that there's so much empty space inside matter that the entire human race could be squeezed into the volume of a sugar cube? Or that you grow old more quickly on the top floor of a building than on the ground floor? And did you realize that 1% of the static on a TV tuned between stations is the relic of the Big Bang? These and many other remarkable facts about the world are direct consequences of quantum physics and relativity. Quantum theory has literally made the modern world possible. Not only has it given us lasers, computers, and nuclear reactors, but it has provided an explanation of why the sun shines and why the ground beneath our feet is solid. Despite this, however, quantum theory and relativity remain a patchwork of fragmented ideas, vaguely understood at best and often utterly mysterious. They have even gained a reputation of being beyond the understanding of the average person. Author Marcus Chown emphatically disagrees. As Einstein himself said, Most of the fundamental ideas of science are essentially simple and may, as a rule, be expressed in a language comprehensible to everyone. If you think that the marvels of modern physics have passed you by, it is not too late. In Chown's capable hands, quantum physics and relativity are not only painless but downright fun. So sit back, relax, and get comfortable as an adept and experienced science communicator brings you quickly up to speed on some of the greatest ideas in the history of human thought.
Unlike special relativity, quantum mechanics was not the inspired product of one mind. It developed, in fits and starts, over a period of 25 years (1900–1925), and many cooks stirred the broth. Even now, a century later, quantum mechanics raises profound conceptual questions. Every competent physicist can “do” quantum mechanics, and the predictions it makes are in spectacularly good agreement with experimental results; there can be little doubt that quantum mechanics is “right.” On the other hand, as Richard Feynman once remarked, “nobody understands quantum mechanics.” I'll tell the story in two parts. First the history (how the essential pieces of the puzzle were assembled), and then the implications (what the finished picture has to say about our world). Photons Like relativity, quantum mechanics began with the study of light. In both cases, this historical association is misleading. Relativity, really, has nothing to do with light – to be sure, it involves that magic speed limit, c , and of course the most familiar thing that travels at speed c is light. So light is a convenient vehicle for introducing the subject. But it is perfectly possible to imagine a universe in which there is no such thing as light, and yet relativity might still be valid. Quantum mechanics, too, starts with light – in this case the “quantum” of light (the photon). But, as it turns out, this is just one rather specialized example of much more general principles – in fact, a rather bad example, because photons are by their nature relativistic (they travel at the speed of light), and it would be more natural to begin with the quantum mechanics of slow-moving objects, in analogy with Newtonian mechanics.