- I confess to mostly finding “philosophy of physics” arguments not very helpful for understanding anything, but for those who feel differently, some new things to look at are a Scientific American article Physicists Debate Whether the World is Made of Particles or Fields or Something Else Entirely, an interview with Jonathan Bain, an interview with Tim Maudlin, a debate between John Ellis, Lawrence Krauss and theologian Don Cupitt about Why is there something rather than nothing?, and the talks at a UCSC Philosophy of Cosmology Summer School. Since the last of these was funded by the Templeton Foundation, it ended with several talks on “Implications of cosmology for the philosophy of religion”. These included a detailed argument that the explanation for the laws of nature is “there is a perfect being”, contrasting this to another argument favored at the Summer School “the multiverse did it”.
- This week the Perimeter Institute will host Loops 13, devoted to loop quantum gravity and other quantum gravity approaches. While it’s also funded by Templeton, the organizers seem to have managed to keep God out of this one.
- At CERN, Amplitudes, Strings and Branes is on-going. Philip Gibbs has an amusing argument that this and Loops 13 are The Same Bloody Thing.
- One thing the LQG and Amplitudes people do share is that some of their most important ideas come from the same person: Roger Penrose (who, but the way, would be a good candidate for the Fundamental Physics Prize, although his distaste for string theory might be a disqualifier). There’s a long interview with him at The Ideas Roadshow, mainly about his “Cyclic Universe” ideas.
- The Simons Foundation has been publishing some excellent science reporting, and now has an online publication they’re calling Quanta Magazine. The latest story there is a very good piece on the search for dark matter from Jennifer Ouellette. The Simons Center at Stony Brook now has a newsletter about their activities.
- Another on-going conference is one of the big yearly HEP conferences, EPS HEP 2013 in Stockholm. CMS and LHCb have impressive new results about rare B decays, timed for this conference. For the details, see Tommaso Dorigo. There are also CMS and CERN press releases.
Last year similar but less accurate results were advertised as putting SUSY “in the hospital”, which some people objected to, on the grounds that it was already in trouble and this kind of result doesn’t make things much worse. Resonaances had the details, summarizing this a “another handful of earth upon the coffin”. The CERN press office tries to put the best SUSY spin on this that it can:

One popular theory is known as supersymmetry, SUSY for short. It postulates the existence of a new type of particle for every Standard Model particle we know, and some of these particles would have just the right properties to make up a large part of the dark universe. There are many SUSY models in circulation, and SUSY is just one of many theoretical routes to physics beyond the Standard Model. Today’s measurements allow physicists to sort between them. Many are incompatible with the new measurements, and so must be discarded, allowing the theory community to work on those that are still in the running.

- Finally, for those with mathematical interests who have waded through the above, Terry Tao has a remarkable long expository piece about the Riemann hypothesis, ranging from analytic number theory aspects through the function field case and l-adic cohomology.

**Update:** For more from Penrose, see this recent talk in Warsaw.

**Update**: Studies in History and Philosophy of Modern Physics is planning a special issue on the significance of the Higgs discovery, the call for papers is here.

Peter, what about your hike on the AT in Maine?

What section?

Mud? Black flies?

— David

(AT 1994: NJ to MA

AT 1996: GA to MA)

To the Templetons: The name and identity of the Perfect Being has been known for some time now. Mila Jovovic.

The link to Terry Tao’s blog post is broken.

This link to Terry Tao’s page works:

http://terrytao.wordpress.com/2013/07/19/the-riemann-hypothesis-in-various-settings/

There was an extra http:// at the end of Peter’s link.

Terry Tao has more grey matter in the very tip of the nail of his little pinky finger than I have in my entire head! How he finds the energy and time to write with such breath and wherewithal on such a large variety of math related topics is beyond me.

–Nick

Tao link fixed.

David,

I was staying near Gulf Hagas, in the 100 mile wilderness in Maine. Only did a few miles of hiking on the Appalachian trail, nothing strenuous. Trail a bit muddy in places, but not too bad. No black flies, a bit late for them, and evidently this year a late frost took care of most of them.

The “Perfect Being” should really be “The Best Imaginable Being”, i.e. a maximal element in the set of all imaginable beings ordered by the “goodness” of their imaginable properties. One can then easily show that the existence of such a being is equivalent to the Axiom of Choice (this is a mathematical formulation of the so called “ontological argument” ). That means that the existence of this “Perfect Being” is undecidable (from the Zermelo-Fraenkel axioms), a fact that was already essentially known to Hume.

PS. This is not meant “seriously”. But a lot of serious people have discussed this issue quite seriously http://en.wikipedia.org/wiki/Ontological_argument

Dear Peter,

Many thanks for mentioning the Loops 13 conference. I might mention that the 21 plenary talks and more than 130 parallel session talks will be available on line at http://www.pirsa.org/C13029. This year we saw an increase of registrations for LQG conferences to more than 220, which is evidence for the growing vitality of the field. Indeed the majority of our plenary speakers are young and have not given a plenary talk at a loops conference before, they will report on the strong progress in areas such as black hole entropy and temperature, quantum cosmology, phenomenology and increased understanding of the emergence of general relativity in the classical limit.

Thanks,

Lee

Dear Peter,

thanks for mentioning my coverage of the Bs – Bd search in dimuon final states. I have added a discussion of the two Bd measurements (both at 2-sigma, from CMS and LHCb) today. They can be of interest for believers of the SM4 model (four generations).

Personally I don’t buy into that stuff much, especially after we found a Higgs-like particle that smells like the Higgs and does couple to photons and has the correct production rate (a fourth generation of fermions would spoil both things). But I have to say that among all extensions of the SM the presence of additional generations of matter is the one which I found the most credible, so I’ll keep my eyes open. For the record, both CMS and LHCb measure the Bd rate to μμ pairs to be 3.5 times the SM expectation, albeit with big error bars. A SM4 model would easily fit this in, with a Bs rate equal to the SM one.

Hope you’re having a relaxing summer,

T.

The other works by the author, Meinard Kuhlmann, of the Scientific American piece are here:

http://philpapers.org/s/Meinard%20Kuhlmann

Interesting story within a story: Will Sawin’s impressive list of corrections to Terry Tao’s exposition. Who is Will Sawin? Just another 17 year old kid:

http://www.ctpost.com/news/article/Wisdom-beyond-his-years-1390299.php

Correction: now he is a 19 year old third year Princeton math grad student.

I think the interview with Jonathan Bain is very interesting, many thanks for the link. Re “philosophy of physics arguments not very helpful for understanding anything”, I think philosophy can be useful in understanding and articulating the assumptions one is already making. There are many points in the history of 20th century cosmology where a small examination/attempted justification of underlying assumptions could have been beneficial, from Einstein’s static universe to Hoyle’s steady-state

Regarding Tim Maudlin, this is interesting:

It turns out slated for February 2014, is the first of Maudlin’s two planned books on Linear Structures. ‘New Foundations for Physical Geometry: The Theory of Linear Structures’,

http://www.amazon.com/New-Foundations-Physical-Geometry-Structures/dp/0198701306

The book description is:

“Topology is the mathematical study of the most basic geometrical structure of a space. Mathematical physics uses topological spaces as the formal means for describing physical space and time. This book proposes a completely new mathematical structure for describing geometrical notions such as continuity, connectedness, boundaries of sets, and so on, in order to provide a better mathematical tool for understanding space-time. This is the initial volume in a two-volume set, the first of which develops the mathematical structure and the second of which applies it to classical and Relativistic physics. The book begins with a brief historical review of the development of mathematics as it relates to geometry, and an overview of standard topology. The new theory, the Theory of Linear Structures, is presented and compared to standard topology. The Theory of Linear Structures replaces the foundational notion of standard topology, the open set, with the notion of a continuous line. Axioms for the Theory of Linear Structures are laid down, and definitions of other geometrical notions developed in those terms. Various novel geometrical properties, such as a space being intrinsically directed, are defined using these resources. Applications of the theory to discrete spaces (where the standard theory of open sets gets little purchase) are particularly noted. The mathematics is developed up through homotopy theory and compactness, along with ways to represent both affine (straight line) and metrical structure.”

This is the first time I have heard of Tim Maudlin and his “linear structures” so this may be way off the mark but the description above sounds like they could be related to directed algebraic topology, a subject that has been around for a couple of decades.

http://en.wikipedia.org/wiki/Directed_algebraic_topology

Actually, I just realised, it was not “the first time” … 😉

I had noticed that work of Maudlin’s, for more, see for instance

http://fqxi.org/data/documents/conferences/2011-talks/maudlin.pdf

Somehow the idea seems to be that replacing the standard mathematical conception of topology (in terms of open sets), by something quite different Maudlin has come up with, he can explain the nature of time. I don’t see that he gets anything out of this. Interesting though that one way to get the time and freedom to pursue radically different ideas about mathematics and physics that you’d never get a math or physics department to support, is by becoming a philosophy professor.

Thanks for the pointer to Jennifer Ouellette’s article and Quanta Magazine in general.

Your readers might also enjoy the article on the Minimalist Conjecture: https://www.simonsfoundation.org/quanta/20130709-mathematicians-shed-light-on-minimalist-conjecture.

Hey, does anyone know if videos for “Amplitudes, strings, and branes” will be available online? Thank you. I have for a long time appreviated the information from this blog.

dan,

It looks like slides for some of the talks are appearing here:

http://indico.cern.ch/materialDisplay.py?materialId=slides&confId=229656

What Tim Maudlin is seeking:

http://www.ge.infn.it/~zanghi/filo/Tim.pdf