Images in this review

Reviews with images

There was a problem filtering reviews. Please reload the page.

• 5.0 out of 5 stars Dirac, The Master....

  Reviewed in the United States on February 9, 2022

  This lectures that Dirac gave at Yeshiva University in 1964 deal with the problem of Quantization to systems that have constraints. He had been working all alone for the past years on these matters and was able to gave the correct steps necessary to quantize canonically the theory of General Relativity. I mean from the Hamiltonian point of view, the Hamiltonian of GR is a set of pure constrains so this lectures are basic to understand the quantization of GR. Here he defines Primary and secondary constraints and also First-Class and Second-class constraints and how to deal with them. Primary constraints are the constraints that already come with the theory while secondary are constraints that you can build using the primaries. First class constraints are the ones that commute with themselves and are the ones that generate gauge transformations. Dirac realized that when the system has second-class constraints you need to modify the Poisson brackets in order to get a consistent theory so therefore he introduced the Dirac bracket which has to be used whenever your constraints are second class. Upon his work others came latter and gave a full description of the Hamiltonian of GR and the way to quantize it using Dirac techniques, like Wheeler, Dewitt and Teitelboim. Dirac had a brilliant mind for Physics and this little book contains some of his latter work that should not be looked away, it is a brilliant introduction to the Dirac bracket, also he stablished Dirac quantization on which the constraints are elevated to operators and anhilate the physical states and only a Master can do that. Buy it!
  

  

  5.0 out of 5 stars

  Dirac, The Master....

  Reviewed in the United States on February 9, 2022

  This lectures that Dirac gave at Yeshiva University in 1964 deal with the problem of Quantization to systems that have constraints. He had been working all alone for the past years on these matters and was able to gave the correct steps necessary to quantize canonically the theory of General Relativity. I mean from the Hamiltonian point of view, the Hamiltonian of GR is a set of pure constrains so this lectures are basic to understand the quantization of GR. Here he defines Primary and secondary constraints and also First-Class and Second-class constraints and how to deal with them. Primary constraints are the constraints that already come with the theory while secondary are constraints that you can build using the primaries. First class constraints are the ones that commute with themselves and are the ones that generate gauge transformations. Dirac realized that when the system has second-class constraints you need to modify the Poisson brackets in order to get a consistent theory so therefore he introduced the Dirac bracket which has to be used whenever your constraints are second class. Upon his work others came latter and gave a full description of the Hamiltonian of GR and the way to quantize it using Dirac techniques, like Wheeler, Dewitt and Teitelboim. Dirac had a brilliant mind for Physics and this little book contains some of his latter work that should not be looked away, it is a brilliant introduction to the Dirac bracket, also he stablished Dirac quantization on which the constraints are elevated to operators and anhilate the physical states and only a Master can do that. Buy it!
  

  Images in this review

  

  4 people found this helpful

  Report

• 5.0 out of 5 stars How-and-why to build [from classical] relativistic quantized field theory via Lagrangian then Hamiltonian mathematics +++

  Reviewed in the United States on January 31, 2014

  Dirac's slim work is very general ~ but also very concise and precise and therefore the physical mathematics strategy and methods as presented are so direct as to be ever-valid ~ amounting to a short course on just HOW and WHY to construct [from appropriate classical theory] relativistic Lagrangian-based theory then directly pass into Hamiltonian-based quantum field theory [via Poisson brackets] ~ AND the nuances along the way. I cannot see flaws in Dirac's presentation as given. It seems that for any valid [and especially unified] physical field theory construction ~ it is necessary and sufficient to *pass thru the check-points* just as Dirac has outlined. A very clear and sharp analysis [via short lectures] in a modestly sized and priced slim work with no filler or fluff ~ just physical mathematics most directly derived and explained +++
  

  7 people found this helpful

  Report

• 4.0 out of 5 stars Dirac’s approach to physics

  Reviewed in the United States on July 11, 2020

  This book summarizes the four invited lectures PAM Dirac gave at Yeshiva University (New York). They are very sophisticated materials that required strong foundation in graduate level physics. The first chapter is focused on the Hamiltonian Approach to classical mechanics (details found in Goldstein) . Then in Chapter two he describes how to use the Hamilton principles to arrive at quantization of fields (details in Messiah) . The last two chapters describe his attempt to quantize gravity which is the subject of current research in theoretical physics. The content of this book is very illuminating but a significant challenge for beginners. It is Only 67 pages long but the content is very advanced and concise like Dirac’s classic book on principles of quantum mechanics
  

  3 people found this helpful

  Report

• 5.0 out of 5 stars Clear and Concise.

  Reviewed in the United States on July 18, 2017

  P.A.M. Dirac has a lot to say; and everything he says is to the point - explaining everything step by step.
  His approach in the YouTube lectures I've tried to watch is the same : but his verbal delivery makes them a chore to follow.
  When I received this book in the mail and started to read: What A Difference! Here is the brilliant man's thoughts and his reasoning laid out: Clear and Concise.
  

  6 people found this helpful

  Report

• 5.0 out of 5 stars I wonderful book from one of the leading physicist of the 20th century

  Reviewed in the United States on September 22, 2013

  Paul Dirac was one of the leading physicists of the first part of the 20th century
  and one of the founders of the theory of quantum mechanics. In these lectures
  he discuss the quantization of systems with constrains. The lectures
  discussed in the book are very clear and precise. They are very important
  for anyone who wants to learn about the subject.
  

  One person found this helpful

  Report

• 5.0 out of 5 stars Excellent book by one of the best

  Reviewed in the United States on July 25, 2014

  Dirac covers a lot of ground here in this short book, The lectures contained within are interesting, however an important caveat is that it is presumed one has a strong knowledge of quantum mechanics and mathematics beforehand.
  

• 3.0 out of 5 stars Important text, but meandering content

  Reviewed in the United States on August 17, 2020

  Much of the mathematical formalism we can attribute to Paul Dirac. As part of my graduate study in physics I was familiar with works by Feynman, Heisenberg, Bohr and others. Unlike Feynman's style which took an advanced concept and broke it down in an approachable manner, Dirac's works often suffer from his brilliance: He was such an accomplished master of the material that his written works would often run up and down the conceptual ladder (layers of concepts and their associated mathematics) to the point that anyone with less background than him might find it bewildering to say the least. He does try to keep to a small set of central themes, but he fails to explain in a conversational way the mathematics that he is following as he jumps from one conceptual lily pad to another. In short, this little book is technically very correct, involves concepts that are very advanced and (in my opinion) does little to bring the reader along for the ride (even if the reader has extensive background).
  

  9 people found this helpful

  Report

• 5.0 out of 5 stars A most important work about quantum by an hystorical view.

  Reviewed in the United States on June 24, 2011

  The famous author talks about the difference between Hamilton and Lagrange equations. That is a non-linear model, but with a certain approximation we can linearize it. That likes useful with the Brackets of Poisson. In this way the mathematical problem achieves a significative thecnics. When we transfer those conditions on a surface, it is very important to consider the flat case. Today because the string theory is hard to proof, we must return to the old physics of 70 years.
  

  3 people found this helpful

  Report