Guest Lecture with Dr. Tahereh Parvini

What happens when quantum light meets one of the most overlooked materials in magnetism? On August 12, Dr. Tahereh Parvini visits SDU to show how trapped photons can probe and even control antiferromagnets, and why that could matter for the quantum technologies of tomorrow.

Ferromagnets get all the attention. But their quieter cousins, antiferromagnets, may hold the keys to the quantum information era. Their spins cancel out almost perfectly, so they produce virtually no stray magnetic fields, making them ideal for densely packed on-chip devices. Their internal dynamics also allow forms of light–matter interaction that simply have no ferromagnetic counterpart.

In her lecture, Cavity Quantum Electrodynamics with Antiferromagnets: Quantum Light as a Probe and Driver of Antiferromagnetic Matter, Dr. Parvini shows what happens when these materials are placed inside quantum electrodynamic (QED) cavities. These mirrored structures trap light in tiny volumes, forcing photons to interact coherently with magnons, the quanta of spin waves.

From single magnons to squeezed light and chaos

The story spans a remarkable range of physics. Optical cavities can couple coherently to individual magnon modes, producing optically "bright" and "dark" states and magnetically tunable photon–magnon coupling. Push harder, and the system generates correlated magnon pairs squeezed below the vacuum noise level, before tipping over into nonlinear territory complete with limit cycles and chaos.

Perhaps most striking: in bilayer cuprate antiferromagnets, magnetic modes span all the way from microwave to THz frequencies. This positions a single material as a candidate platform for GHz–THz quantum transduction, a programmable multimode architecture on one chip. The framework extends naturally to altermagnets, frustrated and topological magnets, and quantum spin liquids, where cavity photons become symmetry-selective probes of chirality, fractionalization, and emergent gauge structure.

About the speaker

Dr. Parvini is a theoretical condensed-matter physicist at the Walther-Meißner-Institut and MCQST in Germany. She works on correlated quantum materials, cavity QED, magnonics, and hybrid quantum systems, developing theory in close dialogue with experiments ranging from Raman and THz spectroscopy to microwave and superconducting-circuit platforms.

The lecture is organized by SDU Microelectronics and is open to all interested parties. No registration required, just show up curious.