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One necessity to avoid the measurement problem in quantum mechanics is a clear ontology. Such an ontology is for instance provided by Bohmian mechanics. In the non-relativistic regime, Bohmian mechanics is a theory about particles whose motion is governed by a velocity field. The latter is generated by a wave

function solving the Schrödinger equation. In view of Feynman's criticism towards classical field theory one may wonder whether such a complex object as the wave function is needed to account for quantum phenomena. After all the value of the velocity field, i.e., of the wave function, is only needed in the vicinity of the configuration of the particle positions, however, it is defined everywhere in configuration space, even in places where the configuration might never roam.  In a joint work with M. Hall and H. Wiseman we were able to formulate an approach to quantum mechanics that is capable to describe typical quantum phenomena like interference without a wave function, having only particles.  This approach comes at the cost of introducing many classical worlds, hence the name Many-Interacting-Worlds approach (MIW). In MIW the force on each particle is given by 1) Newton's force describing the interaction within each world and 2) an additional force term describing an interaction between the worlds.  Similar approaches have been suggested by B. Poirier and C. Sebens. I will give an overview on MIW, discuss the nature of its equations of motion, and its empirical import.

The concept of quantum entanglement entropy is playing a key role in understanding the mechanism underlying holography. In this talk we will discuss how entanglement can capture non-trivial geometric properties of the bulk spacetime. The goal is to exploit the interplay between anomalies and entanglement entropy, and for concreteness we will focus on AdS3/CFT2.  Anomalies play as well a key role in RG flows, and in this context we will see how entanglement, anomalies and geometry conspire to capture dynamically the correct physics.

 Super-massive black holes that grow at the center of dark matter halos distort the dark matter within their zone of influence into a steep density spike.  This spike can give rise to strong enhancements of standard indirect detection signals, and can lead to qualitatively new windows onto the physics of the early universe.   I will talk about potential dark matter signals from the Milky Way's central black hole, some astrophysical caveats, and the possible use of black holes as dark matter accelerators.

Recent landmark measurement of the muonic hydrogen Lamb shift generated more questions than answers, as it stands in a sharp disagreement with what was predicted based on known properties of muons and protons. It adds on top of the existing anomalies in the muon sector (discrepancy in g-2 and in radiative muon capture). I will critically review some suggestions for the new physics explanations of these anomalies, and describe their implications. One of the outstanding effects, not tested for muons, is the parity violation in the neutral current channel, which has proven to be an extremely difficult problem, and where the enhancement relative to the standard model prediction is still possible. Following my suggestion for a new way to approach this measurement, this summer the Paul Scherrer Institute in Switzerland will conduct a preliminary muonic atom experiment, tentatively called mu-ARC.