Luca Amendola

Home » Uncategorized » Non-locality (by Henrik Nersisyan)

Non-locality (by Henrik Nersisyan)

There are  fundamental principles in physics that some conservative physicists think  should never be questioned. One of these principles is the principle of locality, which says that a physical event at some particular point of the space-time is directly affected only by  events in its immediate surrounding. In the opposite case, when a physical event at some point will be directly influenced not only by its local surroundings but also by the whole history of the system before that instant and far away, we say that system exhibits some non-local behaviour. A non-locally formulated fundamental theory will be plagued by the so-called acausal solutions which break the standard sequence of the physical events, from a cause to a consequence, by reversing it. In particularly, it means that some process occurring  now will be the consequence of an event which will happen only in the future. Sounds quite crazy, doesn’t it?

All these problems appear when we try to construct a fundamental theory in a non-local way. Luckily, there is a special case, the so-called effective field theory limit of a fundamental local theory, where non-local terms don’t create conceptual issues and lead to an interesting physics.  One of these non-local models, proposed by Michele Maggiore and collaborators in Geneva, which amazingly satisfy all the existing experimental constraints, was built on several assumptions. In our work, we have relaxed one of them, which is related to the choice of initial conditions and found that the phase space of the model’s solutions is much richer than it was thought earlier. One attractor solution (i.e. a solution to which a large set of initial conditions leads to) which we have discovered predicts an intriguing future for the universe, namely it tells us that in the future all the dark energy will behave as a relativistic fluid, as if in a radiation bath. We leave it to the fantasy of the reader to imagine the future of a human civilization in this type of radiation boiler…