Polchinski: 2006, the Year in Strings

In summary, Joseph Polchinski's 2006 lecture on strings discussed various interesting topics such as the limit of string theory as a mesh of Feynman diagrams, 5-D theories, the landscape and the anthropic principle, and the inflation scale. He also mentioned the possibility of solving the hierarchy problem through a large extra dimension and the embedding of 5-D theories in 10-D. In response to questions, he did not comment on Susskind's suggestion about the end of physics and the reductionist paradigm, but did mention the long-standing concern of what allows life. The lecture also touched on topics such as gauge/string duality, running couplings, confinement forces and chiral symmetry breaking, and warped deformed conif
  • #1
CarlB
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Polchinski: "2006, the Year in Strings"

Joseph Polchinski gave a well attended plenary lecture titled:

Polchinski: "2006, the Year in Strings"
http://www.phys.hawaii.edu/indico/contributionDisplay.py?contribId=746&sessionId=25&confId=3

The above link gives the slides. I found several parts of it interesting. First, I thought that getting string theory as the limit of a mesh of Feynman diagrams was cool. And he talked quite a bit about 5-D theories. This is personally interesting because I use 5-dimensional space-time in my internal papers, with the 5th dimension being related to proper time (this is known as "Euclidean relativity", and by many other names and I am not the only heretic involved with the travesty).

And then he talked about the landscape and the anthropic principle. He said that the inflation scale is smaller than the Planck scale by at least a factor of 10^4, and this was of great interest to me. I've toyed around with trying to explain inflation by having preons that travel faster than c and have Planck scale masses. So one wonders how one would make the calculation and perhaps predict the exact value of the inflation scale from the Planck mass and Clifford algebra.

There were two questions. The first was a request to comment on Susskind's alleged suggestion that we could be at the end of physics in that we are at the "end of the reductionist paradigm". The speaker wisely avoided commenting on Susskind, but said he himself does not have a paradigm, and that serious cosmologists have been worrying about this for >30 years, that is, what is it that allows life.

The second question was about the abilitiy of a large extra dimension allowing solving of the hierarchy problem. He speculated that maybe someone in the audience knew the answer to this but he didn't call on me by name (LOL), and mentioned the embedding of 5-D theories in 10-D.

It was a nice lecture.

Carl
 
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  • #2
Thanks for the reference to Polchinski: "2006, the Year in Strings".

Speculative comments [my interpretive perspective]

1 - On the 2nd slide of Gauge / String Duality
"1974: t'Hooft ... in the strong-coupling limit Feynman graphs become dense"
may be equivalent to
knot theory becoming dense as chaos theory of attractors?

2 - slide of Running Couplings
“... once the coupling drops below ~4[Pi] the space time curvature gets large ...”
may be equivalent to
2 periods or perhaps even spin-2?

3 - slide of Confinement Forces Chiral Symmetry Breaking
“Right and left branes pair up ...”
may instead be equivalent to
right and left branes fold together only apparently breaking symmetry
possible example
a square might be decomposed into 4 equilateral triangles - if bent along the triangles, such symmetry may be viewed, but if not bent, remaining planar, these triangles are obscured with only the square viewed
likewise a six sided cube may be decomposed into 24 equilateral triangles which might be bent into something resembling a torus by folding the top and bottom toward the interior while the front-back and left-right surfaces are folded outwards

4 - slide on KS throats
“... warped deformed conifold ...”
may be equivalent to Figure [10] in
2 Complex Functions as Transformations
II Polynomials
3 Cassinian Curves
Visual Complex Analysis [1997 to 2002] by Tristan Needham [Math, U-SF]
http://www.usfca.edu/vca/

This Figure [10] appears to unify
a - stacked ellipse and cones [2 pictured “as a geographical contour map of the modular surface of the quadratic“]
b - tori ["spiric sections of Perseus"]
c - knots [Bernoulli lemniscate or fugure-8]
d - saddle points [inferred from figures - important in game theory]
 
  • #3
Brannen
Hi Polchinski,

Thank you for sharing your plenary lecture on "2006, the Year in Strings". I found it very interesting and informative. I was particularly intrigued by your discussion on the mesh of Feynman diagrams and the possibility of string theory being its limit. It's fascinating to think about the connections between different theories and how they may all be related.

I also found your talk on 5-D theories and the landscape and anthropic principle thought-provoking. It's always exciting to see how different theories and ideas can intersect and potentially provide new insights into the mysteries of our universe.

I appreciate your insights and perspective on the current state of physics and the potential implications for the future. It's clear that there are still many unanswered questions and it will take continued research and collaboration to make progress.

Thank you for a great lecture and for sharing your knowledge and expertise with the scientific community.
 

Related to Polchinski: 2006, the Year in Strings

1. What is "Polchinski: 2006, the Year in Strings" about?

"Polchinski: 2006, the Year in Strings" is a book written by renowned theoretical physicist Joseph Polchinski. It provides a comprehensive overview of the latest developments in string theory in the year 2006, including breakthroughs, challenges, and potential future directions.

2. Who is Joseph Polchinski?

Joseph Polchinski is a well-known theoretical physicist and professor at the University of California, Santa Barbara. He is best known for his contributions to string theory and his work on the holographic principle.

3. Why is this book important?

This book is important because it offers a detailed and authoritative account of the advancements in string theory in 2006. It serves as a valuable resource for both experts and non-experts in the field, providing insights into the current state and potential future of string theory.

4. Is this book accessible to non-scientists?

While this book is primarily targeted towards scientists, it can also be understood by non-scientists with a strong interest in theoretical physics and string theory. Some background knowledge in these areas may be helpful, but the book is written in a clear and concise manner that makes it accessible to a broader audience.

5. Are there any criticisms of "Polchinski: 2006, the Year in Strings"?

As with any scientific publication, there may be differing opinions and criticisms of the content presented in this book. However, Joseph Polchinski is a respected and well-established scientist in the field of string theory, so the information presented in this book is generally considered to be reliable and valuable.

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