The structure of the Osborn (Local Renormalization Group) Equation in the presence of integer dimensional irrelevant operators is studied. We argue that the consistency of the anomalous part of the generating functional requires a beta-function for the metric. The modified form of the Weyl anomalies is calculated.
We propose an exact flow equation for composite operators and their correlation functions. This can be used for a scale-dependent partial bosonization or flowing bosonization of fermionic interactions, or for an effective change of degrees of freedom
in dependence on the momentum scale. The flow keeps track of the scale dependent relation between effective composite fields and corresponding composite operators in terms of the fundamental fields.
We investigate consequences of adding irrelevant (or less relevant) boundary operators to a (1+1)-dimensional field theory, using the Ising and the boundary sine-Gordon model as examples. In the integrable case, irrelevant perturbations are shown to
multiply reflection matrices by CDD factors: the low-energy behavior is not changed, while various high-energy behaviors are possible, including ``roaming RG trajectories. In the non-integrable case, a Monte Carlo study shows that the IR behavior is again generically unchanged, provided scaling variables are appropriately renormalized.
Recently we proposed a universal solvable irrelevant deformation of $AdS_3/CFT_2$ duality, which leads in the ultraviolet to a theory with a Hagedorn entropy [1]. In this note we provide a worldsheet description of this theory as a coset CFT, and com
pare its spectrum to the field theory predictions of [2,3].
We generalize our recent analysis [2006.13249] of probe string dynamics to the case of general single-trace $Tbar T$, $Jbar T$ and $Tbar J$ deformations. We show that in regions in coupling space where the bulk geometry is smooth, the classical traje
ctories of such strings are smooth and approach the linear dilaton boundary at either the far past or the far future. These trajectories give rise to quantum scattering states with arbitrarily high energies. When the bulk geometry has closed timelike curves (CTCs), the trajectories are singular for energies above a critical value $E_c$. This singularity occurs in the region with CTCs, and the value of $E_c$ agrees with that read off from the dual boundary theory for all values of the couplings and charges.
It has been recently discovered that the $text{T}bar{text{T}}$ deformation is closely-related to Jackiw-Teitelboim gravity. At classical level, the introduction of this perturbation induces an interaction between the stress-energy tensor and space-ti
me and the deformed EoMs can be mapped, through a field-dependent change of coordinates, onto the corresponding undeformed ones. The effect of this perturbation on the quantum spectrum is non-perturbatively described by an inhomogeneous Burgers equation. In this paper, we point out that there exist infinite families of models where the geometry couples instead to generic combinations of local conserved currents labelled by the Lorentz spin. In spirit, these generalisations are similar to the $text{J}bar{text{T}}$ model as the resulting theories and the corresponding scattering phase factors are not Lorentz invariant. The link with the $text{J}bar{text{T}}$ model is discussed in detail. While the classical setup described here is very general, we shall use the sine-Gordon model and its CFT limit as explanatory quantum examples. Most of the final equations and considerations are, however, of broader validity or easily generalisable to more complicated systems.