Related papers: Ghost Loops are Indispensable in Unitary Gauge

In the one-loop approximation for Euclidean quantum gravity, the boundary conditions which are completely invariant under gauge transformations of metric perturbations involve both normal and tangential derivatives of the metric…

We show that the four-loop four-point amplitudes of N = 5 supergravity are ultraviolet finite in four dimensions, contrary to expectations based on supersymmetry and duality-symmetry arguments. We explain why the diagrams of any covariant…

The need to regularize loop integrals in a manner that preserves gauge invariance, for example, using the Pauli-Villars method, requires a subtraction that in the large mass limit hides its high momentum origin. This gives rise to the…

Poincar\'e gauge theories provide an approach to gravity based on the gauging of the Poincar\'e group, whose homogeneous part generates curvature while the translational sector gives rise to torsion. In this note we revisit the stability of…

In these lectures I describe the remarkable ultraviolet behavior of N=8 supergravity, which through four loops is no worse than that of N=4 super-Yang-Mills theory (a finite theory). I also explain the computational tools that allow…

"Physical theories of fundamental significance tend to be gauge theories. These are theories in which the physical system being dealt with is described by more variables than there are physically independent degree of freedom. The…

Simulations of lattice gauge theories on noisy quantum hardware inherently suffer from violations of the gauge symmetry due to coherent and incoherent errors of the underlying physical system that implements the simulation. These gauge…

We consider N=1 SUSY gauge theory in six dimensions in components and show that provided the Dynkin indices of the matter fields representations satisfy the relation $\sum T(R)= C_2(G)$, the gauge sector is completely one-loop finite. In…

We review some of the recent results which can be useful for better understanding of the problem of stability of vacuum and in general classical solutions in higher derivative quantum gravity. The fourth derivative terms in the purely…

We investigate the scattering of two scalar glueballs in pure YM theory, using the well known dilaton potential. We perform the calculations considering a glueball mass of about $m_G \approx 1.7$ GeV, as predicted by lattice QCD. We begin…

In this note we investigate the impact of some "new-physics", beyond the electro-weak Standard Model of elementary particles, on the Higgs vacuum. We consider both un-particle and quantum gravity induced effects. We find that even if the…

We expect quantum field theories for matter to acquire intricate corrections due to their coupling to quantum fluctuations of the gravitational field. This can be precisely worked out in 3d quantum gravity: after integrating out quantum…

Conformal symmetry always played an important role in field theory (both quantum and classical) and in gravity. We present construction of quantum conformal gravity and discuss its features regarding scattering amplitudes and quantum…

Unitarity of scale-invariant coupled theory of higher-derivative gravity and matter is investigated. A scalar field coupled with dirac fermion is taken as matter sector.Following the idea of induced gravity Einstein-Hilbert term is…

We consider the supersymmetric vector multiplet in a purely quantum framework. We obtain some discrepancies with respect to the literature in the expression of the super-propagator and we prove that the model is consistent only for positive…

We consider field sets that do not form complete SU(5) multiplets, but exactly preserve the one-loop MSSM prediction for $\alpha_3(M_Z)$ independently of the value of their mass. Such fields can raise the unification scale in different…

Currently, there are intense experimental efforts to realize lattice gauge theories in quantum simulators. Except for specific models, however, practical quantum simulators can never be fine-tuned to perfect local gauge invariance. There is…

This note focuses the problem of motivating the use of gauge symmetries (being the identity on the observables) from general principles, beyond their practical success, starting from global gauge symmetries and then by emphasizing the…

We show, for previously uncalculated examples containing a uniform mass in the loop, that it is possible to obtain complete massive one-loop gauge theory amplitudes solely from unitarity and known ultraviolet or infrared mass singularities.…

We present the analytic form of the two-loop four-graviton scattering amplitudes in Einstein gravity. To remove ultraviolet divergences we include counterterms quadratic and cubic in the Riemann curvature tensor. The two-loop numerical…