We will discuss the notion of causal influence and compare it to signalling. We will then show the conditions on a theory of elementary systems for the two notions to coincide. After introducing quantifiers of signalling and causal influence, we will calculate them for special quantum channels. The discussion will proceed reviewing the main open problems related to the notion of causal...
What happens when one measures a quantum system in a relativistic setting? We will address the challenge of consistently updating quantum states after selective measurements in a relativistic spacetime. Standard updates along the future lightcones preserve causality but break correlations between causally disconnected parties, whereas updates along the past lightcone can either imply...
One of the most basic expectations of quantum gravity is that gravitational fields can be placed in a state of superposition, analogous to what can be done for electromagnetic fields. However in a relativistic context a gravitational field is equivalent to a particular spacetime, and so a superposed gravitational field is a superposed spacetime. Rather than consider how such a state might...
Models for gravitationally induced decoherence can be formulated in the framework of open quantum systems, where gravity is chosen as the environment and quantized together with the system under consideration. Existing phenomenological models often take the Lindblad equation as a starting point for the master equation, while from the perspective of quantum gravity approaches, an underlying...
I will introduce and motivate the Hopf-algebraic (quantum group) description of isometries in noncommutative spacetimes, emphasizing the quantum nature of transformations between reference frames. In this context, the notion of reference frame itself must acquire quantum properties. I will then overview recent work describing quantum reference frames via quantum groups of frame...
The idea of judicious selection of boundary conditions has been recently advanced to meaningfully enhance some low cross section quantum field theoretic events. In this talk, we will discuss some recent proposals of proper selection of mode functions to identify and amplify many interesting effects like acceleration radiation, Unruh thermality, Entanglement harvesting and Field-Field...
