Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A new spinfoam vertex for quantum gravity   We introduce a new spinfoam vertex to be used in models of 4d quantum gravity
based on SU(2) and SO(4) BF theory plus constraints. It can be seen as the
conventional vertex of SU(2) BF theory, the 15j symbol, in a particular basis
constructed using SU(2) coherent states. This basis makes the geometric
interpretation of the variables transparent: they are the vectors normal to the
triangles within each tetrahedron. We study the condition under which these
states can be considered semiclassical, and we show that the semiclassical ones
dominate the evaluation of quantum correlations. Finally, we describe how the
constraints reducing BF to gravity can be directly written in terms of the new
variables, and how the semiclassicality of the states might improve
understanding the correct way to implement the constraints.

11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph