96 research outputs found
Injection of Orbital Angular Momentum and Storage of Quantized Vortices in Polariton Superfluids
We report the experimental investigation and theoretical modeling of a rotating polariton superfluid relying on an innovative method for the injection of angular momentum. This novel, multipump injection method uses four coherent lasers arranged in a square, resonantly creating four polariton populations propagating inwards. The control available over the direction of propagation of the superflows allows injecting a controllable nonquantized amount of optical angular momentum. When the density at the center is low enough to neglect polariton-polariton interactions, optical singularities, associated with an interference pattern, are visible in the phase. In the superfluid regime resulting from the strong nonlinear polariton-polariton interaction, the interference pattern disappears and only vortices with the same sign are persisting in the system. Remarkably, the number of vortices inside the superfluid region can be controlled by controlling the angular momentum injected by the pumps
Merging of vortices and antivortices in polariton superfluids
Quantised vortices are remarkable manifestations on a macroscopic scale of the coherent nature of
quantum fluids, and the study of their properties is of fundamental importance for the understanding
of this peculiar state of matter. Cavity-polaritons, due to their double light-matter nature, offer
a unique controllable environment to investigate these properties. In this work we theoretically
investigate the possibility to deterministically achieve the annihilation of a vortex with an antivortex
through the increase of the polariton density in the region surrounding the vortices. Moreover we
demonstrate that by means of this mechanism an array of vortex-antivortex pairs can be completely
washed out
Symbolic-Numeric Methods for Nonlinear Integro-Differential Modeling
International audienceThis paper presents a proof of concept for symbolic and numeric methods dedicated to the parameter estimation problem for models formulated by means of nonlinear integro-differential equations (IDE). In particular, we address: the computation of the model input-output equation and the numerical integration of IDE systems
Interaction-shaped vortex-antivortex lattices in polariton fluids
Topological defects such as quantized vortices are one of the most striking manifestations of the
superfluid nature of Bose-Einstein condensates and typical examples of quantum mechanical phenomena
on a macroscopic scale. Here we demonstrate the formation of a lattice of vortex-antivortex
pairs and study, for the first time, its properties in the non-linear regime at high polarion-density
where polariton-polariton interactions dominate the behaviour of the system. In this work first we
demonstrate that the array of vortex-antivortex pairs can be generated in a controllable way in terms
of size of the array and in terms of size and shape of it fundamental unit cell. Then we demonstrate
that polariton-polariton repulsion can strongly deform the lattice unit cell and determine the pattern
distribution of the vortex-antivortex pairs, reaching a completely new behaviour with respect
to geome
Extrapolation of power series by self-similar factor and root approximants
The problem of extrapolating the series in powers of small variables to the
region of large variables is addressed. Such a problem is typical of quantum
theory and statistical physics. A method of extrapolation is developed based on
self-similar factor and root approximants, suggested earlier by the authors. It
is shown that these approximants and their combinations can effectively
extrapolate power series to the region of large variables, even up to infinity.
Several examples from quantum and statistical mechanics are analysed,
illustrating the approach.Comment: 21 pages, Latex fil
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