Jury

 Summary:

In physics, as in any other science, analogies can be seen as bridges that can be built between different fields~; for example, an experiment on the laboratory scale can find an echo on the quantum scale or that of galaxies. By detecting the similarities that characterise various phenomena that appear to be very far apart, we open up new points of view and a broader understanding of the subjects that are linked in this way. In this thesis, we propose and study two systems belonging to fluid mechanics, which present analogies with, for one, Newtonian gravitation, and for the other, quantum mechanics. In the first part, we explore the behaviour of liquid lenses on a horizontal film of soap. In our case, a lens is the object into which a drop of water or oil deposited on a film of soap is transformed. A liquid mass of relatively stable diameter over time, it deforms the film that supports it under its own weight, and is able to move within it according to these deformations. Based on both experimental and theoretical results, we show that two of these lenses can interact with each other, through the deformation of the film that supports them, according to a law analogous to that of gravitation. Their merging is also similar to the collision of two galaxies, either simulated or observed. In the second part, we study the ability of an acoustic dipole to self-propel in a fluid medium. The dipole, destabilised by a slight velocity perturbation, emits a field that can apply a self-induced radiation force to itself. We show that, under certain conditions, this force can propel the source dipole. This work opens the way to a coupled wave/corpuscle system, which is in line with the interpretation of the pilot wave in quantum mechanics.

Abstract:

In physics, as in other scientific disciplines, analogies can be seen as bridges that can be built between different fields. Thus, an experiment conducted on a laboratory scale may find an echo on the quantum or even galactic scale. By identifying the similarities between seemingly disparate phenomena, we open up new points of view and a broader understanding of the subjects in question. In this thesis, we propose and study two systems belonging to fluid mechanics, which respectively present analogies with Newtonian gravitation and quantum mechanics. In the first part, we explore the behaviour of liquid lenses on a horizontal soap film. In our case, a lens is the object formed by a droplet of water or oil upon being deposited on a soap film. As a liquid mass of relatively stable diameter over time, it deforms the supporting film under its weight and is able to move across it according to these deformations. Relying on both experimental and theoretical results, we show that two such lenses can interact through the deformations of the film, following a law analogous to that of gravitation. Furthermore, their merging process bears resemblance to the collision of two galaxies, either simulated or observed. In the second part, we investigate the ability of an acoustic dipole to self-propel in a fluid medium. When subjected to a slight velocity perturbation, the destabilised dipole emits a field that can exert a so called 'self-induced' radiation force on itself. We show that, under certain conditions, this force can effectively propel the source dipole. This work paves the way for a coupled wave-particle system, which aligns with the pilot-wave interpretation in quantum mechanics.