Next-gen frustrated magnetism – NGFM

Magnetic frustration has opened a window where quantum many-body entanglement can be studied and manipulated, without being hindered by magnetic order. Its influence has spread across condensed matter in multiferroics, skyrmions, artificial lattices ... and brought to low energy the exciting high-energy physics of emergent gauge fields, Majorana fermions, fractons ... However, the vast majority of frustrated models belongs to only a handful of geometries.

Here we open a new frontier in frustrated magnetism by studying a new geometry, the centred pyrochlore lattice (CPy) that is more versatile than kagome and pyrochlore lattices. In a first paper (2022), we showed how it is realised in metal-organic frameworks for classical spins. Having established a robust classical spin liquid, we will now explore beyond the standard classical model along two complementary lines:

(A) The CPy offers a platform to tune from a U(1) to a Z2 spin liquid, whose spectral functions we will monitor using large-scale quantum Monte Carlo simulations and present those as a pedagogical deliverable. Furthermore, with diagrammatic Monte Carlo simulations and machine learning techniques (L. Pollet) we will shed new light on the otherwise intractable phase diagram on the anti-ferromagnetic transverse side.

(B) While electromagnetism naturally appears as low-energy description of some frustrated systems, more complex gauge fields remain rare. This is unfortunate as their quasi-particle excitations bear promising properties for information storage and transport. L. Jaubert is expert in the systematic inspection of generic frustrated Hamiltonians, that we will apply to the CPy lattice in order to find and design unusual gauge fields, using continuum field theory and Monte Carlo simulations.