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Rated 2 out of 5 by ms234 from Very disappointed String theory is a fascinating topic, and one about which I wanted to know more. Unfortunately, I found the lectures very disappointing. It was not their content, which was reasonably well presented, especially considering the topic's complexity. The problem was the lecturer's delivery, which was monotone, stilted, and lacked any enthusiasm or enjoyment of teaching the material. In that regard these lectures were very disappointing.

Date published: 2023-09-23

Rated 1 out of 5 by Nras from A narrator, not a lecturer I've been studying string theory, particle physics, and cosmology for several years. I find Dr. Kachru's lectures to be dull and uninspiring. He only narrates the material, but he does not unfold the material effectively. There are existing books that do a much better job. Other Great Courses lecturers such as Dr. Don Lincoln, Dr. Sean Carroll, and Dr. Erica Carlson are far superior. I am disappointed in this product.

Date published: 2023-09-20

Rated 5 out of 5 by Bobby the Clown from I really appreciate this program People who say it s too difficult to follow are right, this course is simply not for everyone.

Date published: 2023-09-18

Rated 2 out of 5 by Jarbini from Mind Bending Physics of String Theory I am sure that the professor has vast knowledge of this subject, however he does not appear to consider that all, or might I say any, of his audience is able to follow his explanations of very complex concepts. He also tends to drop his voice amplitude at the end of his narrations.

Date published: 2023-09-14

Rated 2 out of 5 by Wolfeman from Far Too Advanced for Noviice I was hoping I had finally found a lecture series and professor who could explain the basics of string theory in a comprehensible way for someone like myself who is only familiar with the basics of quantum mechanics. This was not to be in spades! From the very get-go any one without a solid grounding in advanced physics will be lost at sea. The professor is articulate and organized and this would be an ideal course for those already well-versed in theoretical physics.

Date published: 2023-09-14

Rated 2 out of 5 by Jonty from Hard To Understand, not for commoners Although this course is informative, it already requires you to have a working knowledge of string theory. Yes, you heard that right. This is for people who are already familiar with concepts in string theory as the professor doesn't explain much about any topic. No hate to him but the course seems more being a script being read out rather than being taught. If you anything but a practicing physicist, this course might not make the best sense to you.

Date published: 2023-09-12

Rated 2 out of 5 by Donncha123 from Made for insiders The instructor doesn't build a strong foundation or explain the underlying concepts. I've only watched the first two episodes but quickly got lost and I have an MS in Physics. He sits in his chair quickly rattles through supersymmetry, Calabi-Yau manifolds, etc. Interestingly he references a book by Brian Greene, who I have read a few of his books. When I've read Brian Greene's books I always thought I understood the material. I actually didn't but at least he carried me along while I was reading. This course was not like that. So unless you are already knowledgeable in this subject, you probably won't get anything from these lessons.

Date published: 2023-09-11

Rated 4 out of 5 by kuro4564646 from Better than the last course This is better than the last course, although it feels more like an audiobook because of how rigid the manuscript is. I don't tend to go around and recommend string theory courses....

Date published: 2023-09-09

Overview

Taught by Professor Shamit Kachru of Stanford University, this course introduces the cutting-edge science of string theory, which holds that tiny strings are the bedrock of all matter and energy. You’ll explore the history of string theory, its promise as a theory of everything, its major thinkers, and objections and alternatives to string theory.

About

Shamit Kachru

How did the universe begin and what's matter made of? These types of questions first led me to study string theory, which to physicists is the theory of everything.

ALMA MATER

Princeton University

INSTITUTION

Stanford University

Shamit Kachru is a Professor of Physics at Stanford University, where he has also served as the chair of the Physics Department. Additionally, he is the director of the Stanford Institute for Theoretical Physics. He earned a PhD in Physics from Princeton University, and he coedited the book Strings, Branes and Gravity. His research focuses on string theory and quantum field theory as well as their application to particle physics, cosmology, and condensed matter physics.

By This Professor

The Mind-Bending Physics of String Theory

Trailer

01: What Led to String Theory?

After a quick review of 20th-century physics, Professor Kachru introduces the concept of unimaginably minute strings. These appear to solve longstanding problems in quantum mechanics and achieve Einstein’s dream of a quantum theory of gravity. Learn why string theory predicts extra dimensions of space—10 in total, according to some models. Then explore the startling implications.

25 min

02: The Hidden Dimensions of the Universe

Delve deeper into string theory by probing the geometries of the extra dimensions. In the simplest cases, these could be curled into tiny circles. Also explore branes, analogous to two-dimensional membranes. See how elementary particles are a reflection of underlying string states, and learn what “spherical cows” have to do with the unifying principle of supersymmetry.

22 min

03: Strings, Branes, and the Standard Model

The Standard Model of particle physics accounts for the fundamental particles and forces of the universe, apart from gravity. Use the framework developed so far in the course to construct a streamlined version of the Standard Model. Key concepts include D-branes (which connect open strings), scalar fields (generated by D-branes), and superpartners (a byproduct of supersymmetry).

24 min

04: Oscillating Strings and Supersymmetry

In the Standard Model oscillating strings are still a dream since they create particles beyond the reach of current particle accelerators. But what would happen if scientists could dial up the energy to produce highly excited strings? Draw on the work of Indian mathematician Srinivasa Ramanujan to count the almost limitless string states for a given energy level. Then see something bizarre happen.

21 min

05: How String Theory Explains Black Holes

Investigate the physics of black holes, focusing on their entropy, a measure of disorder that is proportional to the black hole’s event horizon—or its “point of no return.” Find that string theory can explain this property, providing a tool to study one of the most puzzling objects in the universe. As in Lecture 2, utilize a spherical cow model and supersymmetry.

20 min

06: How Strings Imply a Holographic Universe

Dive into the mystery of a black hole’s event horizon through the medium of hyperbolic art. Utilize the concept of anti-de Sitter space in conjunction with the holographic principle to probe the peculiar properties of this region. Discover how Argentine theorist Juan Maldacena harnessed these concepts, along with string theory, to enhance our understanding of quantum gravity.

18 min

07: The Origin of the Universe

Shift from the study of black holes to the problem of the Big Bang. Both phenomena involve singularities, where matter is infinitely dense, and the known laws of physics break down. How did the universe get from a point-like singularity to a vast, geometrically “flat” realm, filled with the particles and fields of the Standard Model? See how a theory called cosmic inflation accounts for this fact.

18 min

08: Strings and Inflation

Continue your investigation of the aftermath of the Big Bang. Analyze the evidence for a mysterious “dark” energy that is causing the expansion of the universe to accelerate. Then apply string theory to this phenomenon as well as to cosmic inflation. Although the answers are not yet definitive, string theory provides a powerful theoretical tool for understanding the earliest instant of the universe.

24 min

09: The Many Avatars of String Theory

Step back to inspect the simplest features of string theory. Professor Kachru has already shown that string theories are well suited to 10 space-time dimensions. But why is this, and how many separate string theories are possible in 10 dimensions? To address these questions, appeal to the spherical cow approach introduced earlier. Also, see how supergravity theories fit into this framework.

19 min

10: Duality: Which String Theory Is Fundamental?

Explore a key feature of modern theoretical physics: the equivalence between apparently dissimilar theories, a property known as duality. Probe a pair of examples in string theory: type IIA and heterotic theories. Markedly different, they can nonetheless be shown to be mathematically equivalent under certain conditions, suggesting that a more fundamental theory underlies them.

19 min

11: Finding Evidence for String Theory

The energies needed to prove the existence of strings are far beyond today’s research tools. Is it even possible to test the theory? Learn how resourceful physicists have come up with several indirect methods of inferring the reality of strings. Hunt for the extra dimensions required by the theory, and search for the hypothesized cosmic strings left over from the era of cosmological inflation.

20 min

12: Emergence: Can We Test String Theory?

Why has it been so hard to verify or disprove string theory? Close the course by looking at other cases in physics where what researchers saw in an experiment and what they got as an underlying theory were vastly different. String theory has already been enormously productive in particle physics, cosmology, and mathematics. The theory is beautiful and powerful—and it may even be right!

24 min