Recent content by Osiris

Any tips will be greatly appreciated. :)

Generally, Gamma matrices with one lower and one upper indices could be constructed based on the Clifford algebra. \begin{equation} \gamma^{i}\gamma^{j}+\gamma^{j}\gamma^{i}=2h^{ij}, \end{equation} My question is how to generally construct gamma matrices with two lower indices. There...

Thanks Simon. I am a newbie of Mathematica and not quite clear about using pattern recognition. Could you please show an example for an operation above? How about a more general case: Sum[a*f[i], {i, 0, m}] - b*f[0] I expect to get Sum[a*f[i], {i, 1, m}]+(a-b)*f(0) where a and b are...

I wish to compute Sum[f[i], {i, 0, m}] - Sum[f[i], {i, 0, j}] but can't get the expected result Sum[f[i], {i, j+1, m}] I also tried Sum[f[i], {i, 0, m}] - f[0] but can't get the expected result Sum[f[i], {i, 1, m}] It seems that mathematica can't change the minimum/maximum...

i read this statement in the Vol I of "Quantum Field Theory and Strings: A Course for Mathematicians" by Pierre Deligne et al. (eds.). But there's no further explanation there.

"N" I mean here is the number of supersymmetries. For 10D, there is one supercharge with maximally 32 SUSY components. But for low dimension, why it is said that we could have good superspace formulation for at most 4 supersymmetries for any theory and at most 8 SUSY for pure gauge theories...

Why superspace formulation works only for at most 4 supersymmetries? For more than 4 supersymmetries, why some of the supersymmetries would not be manifested? What's the consideration here? &_&

When N=1, is the superspace formulation of 10D SYM the same as the 4D SYM, except the differences of the coefficient and gamma matrices? For the extended SUSY in 10D, are the superspace formulation available for N=2, 4? How about N=8, 16, and 32? Thanks for any tips you may tell me.

e.g. For D=11, the M-theory, we require N=8, ... For D=10, we require N=16, or 32... ... So how to determine the number of supercharges, the \thetas, for arbitrary dimension, e.g. D=1, 2, ...

Since now time is 2-dimensional, coordinates of points X\mu are dependent on both (\tau1, \tau2), and if \tau2 is infinite, it's a open string; if \tau2 is finite, it's a closed string. How do you think so?

Just guess and imagine... Nomination for the Nobel Prize in Physics http://nobelprize.org/nomination/physics/ Nomination to the Nobel Prize in Physics is by invitation only. The Nobel Committee for Physics sends confidential forms to persons who are competent and qualified to nominate...

What related questions could we ask here? How about coherent states of gravitons arising from such spaces?

Here R^4 is a flat 4-dimensional space, and M is a 6-dimensional Calabi-Yau manifold; and the other side, R^10, is a flat 10-dimensional space. Is there any careful talk and reference about the equivalence of theories in those two spaces above? Great thanks.

How masons can be massless while their composites quark (q) and antiquark (\bar{q}) are both massive? Is there any clear physical scenario to understand this?

Is there any lattice model for String Theory? If there is such models, can anyone any good literature? Many Thanks.