We present a calculable supersymmetric theory of a composite “fat” Higgs boson. Electroweak symmetry is broken dynamically through a new gauge interaction that becomes strong at an intermediate scale. The Higgs boson mass can easily be 200–450 GeV along with the superpartner masses, solving the supersymmetric little hierarchy problem. We explicitly verify that the model is consistent with precision electroweak data without fine-tuning. Gauge coupling unification can be maintained despite the inherently strong dynamics involved in electroweak symmetry breaking. Supersymmetrizing the standard model therefore does not imply a light Higgs boson mass, contrary to the lore in the literature. The Higgs sector of the minimal fat Higgs model has a mass spectrum that is distinctly different from that of the minimal supersymmetric standard model.

We use a data-driven approach to study the magnetic and thermodynamic properties of van der Waals (vdW) layered materials. We investigate monolayers of the form $$\hbox {A}_2\hbox {B}_2\hbox {X}_6$$A 2 B 2 X 6 , based on the known material $$\hbox {Cr}_2\hbox {Ge}_2\hbox {Te}_6$$Cr 2 Ge 2 Te 6 , using density functional theory (DFT) calculations and machine learning methods to determine their magnetic properties, such as magnetic order and magnetic moment. We also examine formation energies and use them as a proxy for chemical stability. We show that machine learning tools, combined with DFT calculations, can provide a computationally efficient means to predict properties of such two-dimensional (2D) magnetic materials. Our data analytics approach provides insights into the microscopic origins of magnetic ordering in these systems. For instance, we find that the X site strongly affects the magnetic coupling between neighboring A sites, which drives the magnetic ordering. Our approach opens new ways for rapid discovery of chemically stable vdW materials that exhibit magnetic behavior.

We study the Raman spectrum of ${\mathrm{CrI}}_3$, a material that exhibits magnetism in a single layer. We employ first-principles calculations within density functional theory to determine the effects of polarization, strain, and incident angle on the phonon spectra of the three-dimensional bulk and the single-layer two-dimensional structure, for both the high- and low-temperature crystal structures. Our results are in good agreement with existing experimental measurements and serve as a guide for additional investigations to elucidate the physics of this interesting material.