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.
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.
The two towering achievements of modern physics are quantum theory and Einstein's general theory of relativity. 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? Get set for the most entertaining science book of the year.
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. …
Even the experts do not understand it the way they would like to, and it is perfectly reasonable that they should not, because all of direct, human experience and of human intuition applies to large objects. Richard P. Feynman Two great intellectual triumphs occurred in the first quarter of the twentieth century: the invention of the theory of relativity, and the rather more labored arrival of quantum mechanics. The former largely embodies the ideas, and almost exclusively the vision, of Albert Einstein; the latter benefited from many creative minds, and from a constant interplay between theory and experiment. Probability plays no direct role in relativity, which is thus outside the purview and purpose of this book. However, Einstein will make an appearance in the following pages, in what some would claim was his most revolutionary role – as diviner of the logical and physical consequences of every idea that was put forward in the formative stages of quantum mechanics. It is one of the ironies of the history of science that Einstein, who contributed so importantly to the task of creating this subject, never accepted that the job was finished when a majority of physicists did. As a consequence, he participated only indirectly in the great adventure of the second quarter of the century: the use of quantum mechanics to explain the structure of atoms, nuclei, and matter.
The early twentieth century was a revolutionary time in the history of physics. People often think of Einstein's special theory of relativity of 1905, which changed our conceptions of time and space. But among physicists, quantum mechanics is usually regarded as an even more radical change in our thinking about the physical world. Quantum mechanics, which was developed between 1900 and 1926, began as a theory of atoms and light but has now become the framework in terms of which all basic physical theories are expected to be cast. We need quantum ideas not only to understand atoms, molecules, and elementary particles, but also to understand the electronic properties of solids and even certain astronomical phenomena such as the stability of white dwarf stars. The theory was radical in part because it introduced probabilistic behavior as a fundamental aspect of the world, but even more because it seems to allow mutually exclusive situations to exist simultaneously in a “quantum superposition.” We will see later that the possibility of quantum superposition is largely responsible for a quantum computer's distinctive advantage over an ordinary computer. The present chapter is devoted to introducing the basic principles of quantum mechanics. There are essentially four components of the mathematical structure of quantum mechanics. We need to know how to represent (i) states, (ii) measurements, (iii) reversible transformations, and (iv) composite systems. We will develop the first three in stages, starting with a very simple case – linear polarization of photons – and working toward the most general case.
Everybody has heard that we live in a world made of atoms. But far more fundamentally, we live in a universe made of quanta. Many things are not made of atoms: light, radio waves, electric current, magnetic fields, Earth's gravitational field, not to mention exotica such a neutron stars, black holes, dark energy, and dark matter. But everything, including atoms, is made of highly unified or "coherent" bundles of energy called "quanta" that (like everything else) obey certain rules. In the case of the quantum, these rules are called "quantum physics." This is a book about quanta and their unexpected, some would say peculiar, behavior--tales, if you will, of the quantum. The quantum has developed the reputation of being capricious, bewildering, even impossible to understand. The peculiar habits of quanta are certainly not what we would have expected to find at the foundation of physical reality, but these habits are not necessarily bewildering and not at all impossible or paradoxical. This book explains those habits--the quantum rules--in everyday language, without mathematics or unnecessary technicalities. While most popular books about quantum physics follow the topic's scientific history from 1900 to today, this book follows the phenomena: wave-particle duality, fundamental randomness, quantum states, superpositions (being in two places at once), entanglement, non-locality, Schrodinger's cat, and quantum jumps, and presents the history and the scientists only to the extent that they illuminate the phenomena.
There was a time when the newspapers said that only twelve men understood the theory of relativity. I do not believe there ever was such a time. There might have been a time when only one man did, because he was the only guy who caught on, before he wrote his paper. But after people read the paper a lot of people understood the theory of relativity in some way or other, certainly more than twelve. On the other hand I think I can safely say that nobody understands quantum mechanics. Richard P. Feynman Introduction: the quantum theory The quantum theory was born in 1900, with the twentieth century, and future centuries will list it among our own's most remarkable achievements. Designed to account for the puzzling behavior of matter at the submicroscopic scale of individual atoms, the theory has enjoyed phenomenal success. It has accounted in a quantitative way for atomic phenomena with a numerical precision never before achieved in any field of science. When it was subsequently applied within the atom to the atomic nucleus – an object some hundred thousand times smaller – no further modification in the theory was needed. More recently, when applied within the particles making up the nucleus to describe their own internal structure – an investigation on a scale as much smaller than atoms as atoms are smaller than us – the quantum theory still shows no signs of requiring extension or revision.