Probing and controlling many-body entanglement in organic solids

Many-body entanglement is a critical ingredient for the appearance of a variety of quantum phenomena, such as quantum spin liquidity, superconductivity, topological order, quantum criticality, and strange metallicity. However, entanglement correlations in solids remain relatively unexplored. Recent theoretical and experimental advances indicate the possibility to diagnose and quantify entanglement from materials’ response functions by using specific figures of merit called “entanglement witnesses”. The ability to detect and possibly manipulate entanglement in quantum materials is key to the discovery and the study of new quantum phases in and out of equilibrium. In this talk I will discuss the possibility of quantifying multipartite entanglement from optical measurements [1] and apply this protocol to the study of spin correlations in κ-(BEDT-TTF)₂Cu₂(CN)₃ [2]. I will focus on the presence of spin entanglement associated with the spinon continuum observed in this material, and on its recently observed enhancement upon excitation with ultrashort midinfrared light pulses at resonance with the vibrational modes of the BEDT-TTF molecules.

[1] S. Hopkins et al., forthcoming (2024)

[2] F. Glerean et al., forthcoming (2024)