Speaker:

Prof. Angel Rubio, Max Planck Institute for the Structure and Dynamics of Matter.

Tittle: Can Empty Space Change Matter? - Designing Materials with the Quantum Vacuum 

Time: 16:00 October 21st, 2026 (Wednesday)

Venue: Conference Room No.6, Building No.5

Host: Prof. Jin Zhang

Abstract:

Even in perfect darkness, the electromagnetic field is never truly empty. Its zero-point fluctuations surround every electron and nucleus, and when matter is placed inside a cavity, these fluctuations can be shaped. This raises a simple but far-reaching question: can we change the properties of molecules and materials without shining any light on them, just by engineering the vacuum around them? In this talk, I will show how ab initio quantum electrodynamics allows us to answer this question quantitatively. Starting from the Pauli–Fierz Hamiltonian, which treats electrons, nuclei and photons on equal footing, new first-principles methods such as quantum-electrodynamical density functional theory now make it possible to predict how the vacuum reshapes chemical bonds, electronic structure and phases of matter in realistic systems. A central idea emerging from this work is the endyon: a quasiparticle dressed not by lattice vibrations, as in a polaron, but by the fluctuations of the electromagnetic vacuum itself. Endyons exist in equilibrium, without any external illumination, and they offer a common language connecting cavity QED, many-body physics and polaritonic chemistry. I will discuss what this picture tells us about cavity-modified superconductivity, ferroelectricity and other correlated phases, and how collective light–matter coupling can steer chemical reactions at specific sites and bonds under ambient conditions. Together, these developments point toward a new way of designing materials: not by changing their composition, but by engineering the electromagnetic environment they live in.