Related papers: Ultraviolet divergences in extended supergravity
U-duality imposes strong constraints on the structure of divergences in supergravity. But Gaillard-Zumino Sp$(2n_v, \mathbb{R})$ duality in D=4 has more symmetries than U-duality. For example, in $N = 8$ the dimension of Sp(56) is 1596,…
The vacuum ultraviolet offers a unique perspective on galaxy morphology, stellar populations, and interstellar material which is of particular relevance to interpreting high redshift galaxies and the history of cosmic star formation. Here…
It is important in many applications to be able to extend the (outer) unit normal vector field from a hypersurface to its neighborhood in such a way that the result is a unit gradient field. The aim of the paper is to provide an elementary…
Supergravity theory in $2+\epsilon$ dimensions is studied. It is invariant under supertransformations in 2 and 3 dimensions. One-loop divergence is explicitly computed in the background field method and a nontrivial fixed point is found. In…
Theories such as massive Galileons and massive gravity can satisfy the presently known improved positivity bounds provided they are weakly coupled. We discuss the form of the EFT Lagrangian for a weakly coupled UV completion of massive…
We construct the three-loop four-point amplitude of N=8 supergravity using the unitarity method. The amplitude is ultraviolet finite in four dimensions. Novel cancellations, not predicted by traditional superspace power-counting arguments,…
Some recent results in supersymmetric grand unified theories are reviewed.
We propose and test a novel conjectural relation satisfied by the superconformal index of maximally supersymmetric $U(N)$ gauge theory in four dimensions. Analogous relations appear to be also valid for the superconformal indices of a large…
Multiwavelength observations may help us understand the physical nature of the ultraluminous X-ray sources (ULXs) found in external galaxies. Enabled by the arcsecond X-ray source positions now available from Chandra, there has been…
Refraction is a well-known optical phenomenon that alters the direction of light waves propagating through matter. Microscopes, lenses and prisms based on refraction are indispensable tools for controlling the properties of light beams at…
We study counterterms (CT's), candidates for UV divergences in the four-dimensional N=8 supergravity. They have been constructed long ago in a Lorentz covariant on shell superspace and recently in the chiral light-cone (LC) superspace. We…
Positivity bounds coming from consistency of UV scattering amplitudes are in general insufficient to prove the weak gravity conjecture for theories beyond Einstein-Maxwell. Additional ingredients about the UV may be necessary to exclude…
We use very deep (R_lim=27) UGRI imaging to study the evolution of the faint end of the UV-selected galaxy luminosity function from z~4 to z~2. We find that the number of sub-L* galaxies increases from z~4 to z~3 while the number of bright…
We study the non-perturbative renormalization group flow of higher-derivative gravity employing functional renormalization group techniques. The non-perturbative contributions to the $\beta$-functions shift the known perturbative…
A generic feature of viable exponential $F(R)$-gravity is investigated. An additional modification to stabilize the effective dark energy oscillations during matter era is proposed and applied to two viable models. An analysis on the future…
Candidate counterterms break E7 type U-duality symmetry of $N \geq 5$ supergravity theories in four dimensions \cite{Kallosh:2011dp}. A proposal was made in \cite{Bossard:2011ij} to restore it, starting with a double set of vector fields…
Astrophysical bounds severely limit the possibility of observing collider signals of gravity with less than 3 flat extra dimensions. However, small distortions of the compactified space can lift the masses of the lightest graviton…
I review electric-magnetic duality from the perspective of extended supergravity theories in four spacetime dimensions
Using data from the ROSAT Wide Field Camera all-sky survey, we have established upper limits to the extreme ultraviolet (EUV) flux from a sample of 30 bright, nearby, non-active spiral galaxies. These galaxies were chosen to be those most…
Using the duality between color and kinematics, we construct the two- and three-loop amplitudes of half-maximal supergravity with matter multiplets and show that new divergences occur in D=4 and D=5. Bossard, Howe and Stelle have recently…