We consider the Lee–Wick (LW) electrodynamics, i.e. the U(1) gauge theory where a (gauge-invariant) dimension-6 operator containing higher derivatives is added to the free Lagrangian of the U(1) sector. A quantum bound on the LW heavy particle mass is then estimated by computing the anomalous electron–magnetic moment in the context of the aforementioned model. This limit is not only within the allowed range estimated by LW, it is also of the same order as that considered in early investigations on the possible effects of the LW heavy particle in e-e+ elastic scattering. A comparative study between the LW and the Coulomb potentials is also done.

We show that Schwarzschild black hole solutions in asymptotically Anti-de Sitter (AdS) and de Sitter (dS) spaces may, up to a conformal factor, be reproduced in the framework of analogue gravity. The aforementioned derivation is performed using relativistic and non-relativistic BoseEinstein condensates. In addition, we demonstrate that the (2+1) planar AdS black hole can be mapped into the non-relativistic acoustic metric. Given that AdS black holes are extensively employed in the gauge/gravity duality, we then comment on the possibility to study the AdS/CFT correspondence and gravity/fluid duality from an analogue gravity perspective.

One of the puzzling aspects of N-dimensional Einstein Gravity (NDEG) augmented by curvature-squared terms is why renormalizability and unitarity, two of the most important properties of any physical theory, cannot be reconciled in its framework. Actually, the reason why these properties are mutually incompatible within the context of generic higher-derivative models, not necessarily related to gravity, is one of the unsolved mysteries of physics. Here, a simple solution to the NDEG riddle, based on the analysis of the interparticle gravitational potential, is presented. The main argument used to support our discussion is that tree-level unitarity and the existence of a singularity in the potential are intertwined.

Relativistic Bose-Einstein condensates (rBECs) have recently become a wellestablished system for analogue gravity. Indeed, while such relativistic systems cannot be yet realized experimentally, they provide an interesting framework for mimicking metrics for which no analogue is yet available, so paving the way for further theoretical and numerical explorations. In this vein, we here discuss black holes in rBECs and explore how their features relate to the bulk properties of the system. We then propose the coupling of external fields to the rBEC as a way to mimic non-metric features. In particular, we use a Proca field to simulate an aether field, as found in Einstein-AEther or Hořava-Lifshitz gravity. This allows us to mimic a universal horizon, the causal barrier relevant for superluminal modes in these modified gravitational theories.