Product Description
Developing a theory that seamlessly combines relativity and quantum mechanics, the most important conceptual breakthroughs in twentieth century physics, has proved to be a difficult and ongoing challenge. Thisbook details how two distinguished physicists and Nobel laureates have explored this theme in two lectures given in Cambridge, England, in 1986 to commemorate the famous British physicist Paul Dirac. Given for nonspecialists and undergraduates, the talks transcribed in Elementary Particles and the Laws of Physics focus on the fundamental problems of physics and the present state of our knowledge. Professor Feynman examines the nature of antiparticles, and in particular the relationship between quantum spin and statistics. Professor Weinberg speculates on how Einstein's theory of gravitation might be reconciled with quantum theory in the final law of physics. Highly accessible, deeply thought provoking, this book will appeal to all those interested in the development of modern physics. ... Read more

Customer Reviews (7)

Great book
Feynman's lecture is the simplest and the most intuitive explanation of the connection between spin and statistics that I have ever seen! This is a very readable book, no knowledge of quantum field theory is required, but a good understanding of relativity and quantum mechanics is essential for understanding the book. I think every physicist should read these lectures, although very simple, they add a lot to our understanding and even to our knowledge of fundamental physics.

Summary of Paul Dirac Memorial Lectures
This book is a summary of 1986 Paul Dirac memorial lectures delivered by physicists, Richard Feynman and Steven Weinberg. This book requires the knowledge of undergraduate level physics and perturbation theory, and it is described in two chapters; the first is by Feynman under the title "The reason for antiparticle." This section describes the first attempt of Dirac in 1928 to "wed" newly discovered quantum mechanics and theory of relativity. When relativity was included into Schrodinger's pure wave equations, the relativistic equation (Dirac equations) would only be satisfied if there were two solutions corresponding to positive and negative energy states, and in the case of the electron, an electron with a positive charge was required for negative energy state. Thus the existence of antiparticles (positron) was predicted as a direct result of combining the relativity with quantum mechanics. Paul Dirac was also able to explain the origin of the electron magnetic moment and spin. Feynman postulated one of the revolutionary thought in quantum field theory, that antiparticles could be viewed as particles going back in time. This should not be taken as a physical reality in which cause - effect sequence could be revered. Because during the Lorentz transformation the time sequence of two events gets reversed, one of them could not have been the cause of the other because the two events are outside each other's sphere of influence. In frame A, if event 1 occurs first and event 2 occurs after event 1, but in frame B, event 2 occurs before event 1. This is possible in relativity because the time ordering of two events is not an absolute concept; one event can be in the past of another event in one frame, and in its future in a different frame. An observer in frame A will see an electron before event 1, an electron between events 1 and 2, and an electron after event 2, but in frame B, he will see one electron before event 2 and only one electron after event 1.

In the second part under the title, Toward the final laws of physics, Steven Weinberg discusses the developments in physics to explain physical reality with one set of physical laws. This has lead to several unsuccessful theories to unify relativity and quantum physics, finally leading to String theory.

Paul Dirac believed that physical laws should have mathematical beauty. Both Feynman and Weinberg have made beautiful theories. Weinberg played a key role in the unification of electricity and magnetism with the weak forces of radioactivity, and Feynamn expanded the understanding of quantum electrodynamics; they were best suited to deliver the Paul Dirac memorial lectures.

1. Paul Dirac: The Man and his Work
2. Paul Adrien Maurice Dirac: Reminiscences about a Great Physicist
3. Dirac: A Scientific Biography
4. Lectures on Quantum Mechanics
5. Surely You're Joking, Mr. Feynman! (Adventures of a Curious Character)
6. Classic Feynman: All the Adventures of a Curious Character
7. Positron Physics (Cambridge Monographs on Atomic, Molecular and Chemical Physics)
8. Dreams of a Final Theory: The Scientist's Search for the Ultimate Laws of Nature
9. QED: The Strange Theory of Light and Matter (Princeton Science Library)
10. Cosmology

Tougher than the Lectures on Physics
When I readThe Feynman Lectures on Physics including Feynman's Tips on Physics: The Definitive and Extended Edition, I was hoping to understand the reasoning behind the exclusion principle, and was disappointed to find that RPF felt that this was too complex for undergraduates, so he asked them to take it on faith for the moment.

Here he is talking to a more advanced audience, and explains it - he was right, it's tough.I'm still struggling to understand it, but I have confidence that this is a good book to help.

[Added nearly a year later] Having reread the book several times, I finally understand Feynman's lecture!As is often the case, once I understand the principle, I see relationships to various other things I had not fully understood before.

I should also comment on Weinberg's lecture: he's talking about more speculative areas than Feynman, which is perhaps one reason I found him less enlightening than Feynman, but in a rather vague way I follow what he's saying.Certainly these are fascinating ideas, but they don't sing to me like Feynman's lecture.

Recommended
From Richard Feynman, with love. Need more to be said? Read it, and read it again. This one can be read all over again once in a while and does not get boring.

Great Lectures.Requires Math Background.
This short book, Elementary Particles and the Laws of Physics, offers two lectures: Richard Feynman's The Reason for Antiparticles and Steven Weinberg's Toward the Final Laws of Physics. These two talks comprise the 1986 Dirac Memorial lectures at Cambridge University. Both presentations are cogently structured and make fascinating reading.

The talks were directed at an advanced audience, one that was familiar with quantum mechanics. Unlike many popular presentations by Feynman and Weinberg, these lectures are not suitable for the general layman.

However, these lectures are accessible to a persistent (perhaps, stubborn) layman with a calculus background and a deep interest in particle physics. I am not a physicist, but I did take my share of physics, chemistry, and math courses several decades ago. I encountered Schrodinger's equation in more than one class, but not relativistic quantum mechanics. However, having recently read Bruce Schumm's wonderful review of particle physics (titled Deep Down Things), I was sufficiently motivated to work my way through both Dirac memorial lectures.

Richard Feynman's lecture, The Reason for Antiparticles, is decidedly the more difficult. Feynman first demonstrates that quantum mechanics and relativity together require the existence of antiparticles, and then shows that they also establish the spin-statistics connection. Within a few pages advanced mathematical expressions appear and then persistently stay in the foreground for nearly the entire talk.

Although understanding Feynman's mathematics is critical for a full and deep appreciation of his exposition, with careful, repeated readings the stubborn layman will have sudden moments of enlightenment and can come away with a deeper understanding of antiparticles and spin statistics.For readers engaged in some self-tutorial readings, it may prove helpful to return occasionally to this classic Feynman lecture to qualitatively measure progress.I have no doubt that, on a deeper level, Feynman's lecture will similarly challenge and enlighten physics majors as well.

Steven Weinberg discusses his speculations on the shape of a final underlying theory of particle physics.Initially, his talk is deceptively easy as few mathematical expressions are used.However, about midway a Lagrangian density equation appears, ratcheting the difficulty several notches, as Weinberg considers a theoretical framework based on quantum mechanics and a few symmetry principles, that is also mathematically consistent with the Lagrangian dynamical principle. After discussion of some limitations of the Standard Model, Weinberg concludes his talk with a somewhat mathematical introduction to string theory. ... Read more

Product Description
High Quality Content by WIKIPEDIA articles! In physics, a state space is a complex Hilbert space within which the possible instantaneous states of the system may be described by a unit vector. These state vectors, using Dirac's bra-ket notation, can often be treated as vectors and operated on using the rules of linear algebra. This formalism of quantum mechanics is extremely powerful, in that it can replace calculation of complicated integrals with a few basic vector operations.Physics is one of the oldest academic disciplines, perhaps the oldest through its inclusion of astronomy. Over the last two millennia, physics had been considered synonymous with philosophy, chemistry, and certain branches of mathematics and biology, but during the Scientific Revolution in the 16th century, it emerged to become a unique modern science in its own right. However, in some subject areas such as in mathematical physics and quantum chemistry, the boundaries of physics remain difficult to distinguish. ... Read more

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This digital document is an article from UXL Encyclopedia of Science, brought to you by Gale®, a part of Cengage Learning, a world leader in e-research and educational publishing for libraries, schools and businesses.The length of the article is 414 words.The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase.You can view it with any web browser.This collection of entries covers major areas of science including: biology, genetics, microbiology, astronomy, chemistry, physics, engineering, technology, geology, weather, archaeology, psychology, mathematics, and medicine, and provides readers with a wide range of up-to-date, relevant, and accurate information. ... Read more

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This monograph contains a functional analytic introduction to Dirac's formalism. The first part presents some new mathematical notions in the setting of triples of Hilbert spaces, mentioning the concept of Dirac basis. The second part introduces a conceptually new theory of generalized functions, integrating the notions of the first part. The last part of the book is devoted to a mathematical interpretation of the main features of Dirac's formalism. It involves a pairing between distributional bras and kets, continuum expansions and continuum matrices. ... Read more