Showing papers by "Richard Phillips Feynman published in 1965"

Quantum Mechanics and Path Integrals

Abstract: Au sommaire : 1.The fundamental concepts of quantum mechanics ; 2.The quantum-mechanical law of motion ; 3.Developing the concepts with special examples ; 4.The schrodinger description of quantum mechanics ; 5.Measurements and operators ; 6.The perturbation method in quantum mechanics ; 7.Transition elements ; 8.Harmonic oscillators ; 9.Quantum electrodynamics ; 10.Statistical mechanics ; 11.The variational method ; 12.Other problems in probability.

The Character of Physical Law

Abstract: In these Messenger Lectures, originally delivered at Cornell University and recorded for television by the BBC, Richard Feynman offers an overview of selected physical laws and gathers their common features into one broad principle of invariance. He maintains at the outset that the importance of a physical law is not "how clever we are to have found it out, but...how clever nature is to pay attention to it," and tends his discussions toward a final exposition of the elegance and simplicity of all scientific laws. Rather than an essay on the most significant achievements in modern science, The Character of Physical Law is a statement of what is most remarkable in nature. Feynman's enlightened approach, his wit, and his enthusiasm make this a memorable exposition of the scientist's craft.The Law of Gravitation is the author's principal example. Relating the details of its discovery and stressing its mathematical character, he uses it to demonstrate the essential interaction of mathematics and physics. He views mathematics as the key to any system of scientific laws, suggesting that if it were possible to fill out the structure of scientific theory completely, the result would be an integrated set of mathematical axioms. The principles of conservation, symmetry, and time-irreversibility are then considered in relation to developments in classical and modern physics, and in his final lecture Feynman develops his own analysis of the process and future of scientific discovery.Like any set of oral reflections, The Character of Physical Law has special value as a demonstration of the mind in action. The reader is particularly lucky in Richard Feynman. One of the most eminent and imaginative modern physicists, he was Professor of Theoretical Physics at the California Institute of Technology until his death in 1988. He is best known for his work on the quantum theory of the electromagnetic field, as well as for his later research in the field of low-temperature physics. In 1954 he received the Albert Einstein Award for his "outstanding contribution to knowledge in mathematical and physical sciences"; in 1965 he was appointed to Foreign Membership in the Royal Society and was awarded the Nobel Prize.

Consequences of SU_3 Symmetry in Weak Interactions

Abstract: These lectures will cover the relationship of SU_3 and the weak interactions. The lectures will be geared for experimental people so that they may get an idea of how our theoretical predictions arise. At first, I will speak a little bit about how calculations are made for the weak decays, then we shall consider SU_3 , and finally the effects of unitary symmetry upon the weak interactions. The subject matter is split in this way so that one may get a clearer idea of the origins of the various problems in the theory of weak interactions. Not all of our difficulties arise from SU, nor do all of the successes, and it is important to realize this. The theory of weak decays is very unsatisfactory except that it agrees with experiment. To understand that remark let us consider the muon. A muon is a particle which has exactly the same properties as the electron except that its mass is 207 times the mass of the electron. This statement completely describes our experiments with the muon, but such a comment is also unsatisfactory for a true theorist. Experimentalists find a beautiful and simple thing which is easy for the theorists to describe . Nevertheless, we must be unhappy about this situation because we have no idea of why this particle exists. Similarly, the theory of weak decay, up to the point where we encounter strangeness changing interact ions, is accurate but unsatisfactory. There are various mysterious properties which I shall mention as I go on, but I should like to remind you that the most mysterious aspect of the weak decays is that they exist at all. It seems so much simpler just to forget them. There is no clue from electromagnetism, from gravity, or from nuclear forces that the weak interactions must exist. They seem to have no connection with the rest of the world.