Goodbye Sidney!


A visit to a bookstore is generally a good idea. I say generally because I started reading the book on Black Swan written by Nassim Nicholas Taleb and it has distracted me from some serious work. Taleb has an interesting theory as to attributing everything to the chance. Well one cannot argue much with such theories but the question that I could not resist is, so what? 

In the world of complexity,there are obviously several


many variables. However, as a physicist I think of understanding the universe in much complex phenomena into simple elegant natural principles. Obviously understand such complexity with some physical principle gives us predicitive power. 

Where I agree with Taleb is the black swan idea is as good when it applies to human domains such as stock market, wars and climate.  David Hume called it problem of induction.  However, using history as a guide I can confidently say that the seeming nonlinear randomness there is a more fundamental principle that governs the nature of the universe.

I have been slightly occupied with some stuffs. Hence, I was not able to post as frequently as I would have liked. In the week(s) to follow I will discuss some of the  important problems in high energy theoretical physics and cosmology. Also, I will try to give a skinny on attempts by people to answer these fundamental questions. Although, I have never seen the original painting, I am really fond of this painting of Rembrandt. This is me in the last few days, although I am much younger than the handsome thoughtful man in the painting.

Rembrandt, Philosopher Meditating

In the similar spirit to Kallosh, Thomas grimm has a paper in arxiv on axion inflation in the context of type II string theory. The general outline is Grimm considers type IIB string theory on a compact CY with non trivial vanishing two cycles(example being a conifold). These two cycles are associated with axions whose fields depend on geometric moduli and also NS-NS and B-field.

I am experimenting with themes and this one looks clean and clear. Suggestions are welcome.

 If string theory is the most fundamental theory, many feel that string theory should be part of the inflationary picture. Renata Kallosh has been working with stringy inflationary models and she and her collaborators have a new paper at arxiv titled “Axion Inflation and Gravity waves in string theory.” 

The paper outlines the problems of embedding string theoretic models to inflationary cosmology and they have found it difficult to to get rid volume moduli to obtain a flat axion.  So after no success in stringy models, they look at supergravity models with axion independent Kahler models where they show that inflationary graviatational wave (IGW) to be possible. An interesting thought that is suggested is the study of type IIB orientfold models which may give axion independent(quadratic shift symmmetric) Kahler models.

Here is the link:


Also one may be interested in Kallosh’s earlier paper (talk) which is much more general and describes the string theoretics inflationary models with flux compactification and moduli stablization.


Any comments(general or specific) are welcome.

Update: Incidentally Lubos Motl has a small comment on a paper by Bezrukov and Shapsoshnikov where they think about inflation from Higgs Boson. Their claim requires non-minimal coupling of the Higgs scalar field to gravity which leads to the amplitude of scalar perturbation to be proportional to square of Higgs Mass with coefficient terms.

Although I do not have much interest in the Schrodinger equation, it is nice to see mathematicians write about Schrodinger equation. Most fundamental physicist are generally happy with non relativistic quantum mechanics. However for many mathematicians Schrodinger’s equation is an interesting PDE and Terrence Tao notes how he is interested in non linear Schrodinger equation. Here is  Tao’s blog link which has a link to his article on Schrodinger’s equation.