Group Meeting

• Presentation by Valera Kozin, a visiting PhD student (profile here)

Title: “Multiply-connected nanostructures in the regime of strong light-matter coupling. Self-organizing maps as a method for detecting phase transitions”.

Abstract:
It is demonstrated that the dressing field drastically modifies all electronic characteristics of the quantum rings, including spin-orbit coupling, effective electron mass, and optical response.

The Chern insulator phase is shown to emerge in two-dimensional arrays of polariton rings where the time-reversal symmetry is broken due to the application of an out-of-plane magnetic field.

We employ a specific unsupervised machine learning technique—self-organizing maps—to create a low-dimensional representation of microscopic states, relevant for macroscopic phase identification and detecting phase transitions. We explore the properties of spin Hamiltonians of two archetype model systems: a two-dimensional Heisenberg ferromagnet and a three-dimensional crystal, Fe in the body-centered-cubic structure. The method of self-organizing maps, which is known to conserve connectivity of the initial dataset, is compared to the cumulant method theory and is shown to be as accurate while being computationally more efficient in determining a phase transition temperature.

• Slot for APS March Meeting still available.  Contact David for booking.