Research summary

General topic.— Our research area lies at the border between condensed matter and quantum optics and deals with quantum many-body open systems.

Systems.— Our investigations are strongly related to ongoing experiments in hybrid light-matter systems. So far the focus has been mainly on neutral atoms coupled to nanophotonics structures like optical waveguides or cavities, allowing to enhance and control light-matter interactions. Ongoing research also involves exciton polaritons in semiconductors coupled to microcavities.

Approach.— We develop non-equilibrium field-theoretical approaches tailored for the study of many-body phenomena in the above open quantum systems. These approaches are novel in the context of quantum optics and non-trivially extend methods typically used in condensed matter.

Goals.— We are interested in fundamental theoretical problems in many-body physics like collective phenomena and non-equilibrium phases. However, since our techniques are quantitatively reliable, we also concretely investigate hybrid light-matter devices for quantum technologies, so far in the context ultraprecise metrology/sensing, with ongoing efforts in quantum nonlinear photon devices.


Collective electronic phenomena induced by quantum light

  • "Non-Fermi-Liquid Behavior from Cavity Electromagnetic Vacuum Fluctuations at the Superradiant Transition"

P. Rao and F. Piazza, Phys. Rev. Lett. 130, 083603 (2023)

  • "Long-range photon fluctuations enhance photon-mediated electron pairing and superconductivity"

A Chakraborty and F. Piazza, Phys. Rev. Lett. 127, 177002 (2021)

  • "Cavity-induced quantum spin liquids"

A. Chiocchetta, D. Kiese, C.P. Zelle, F. Piazza, S. Diehl, Nature Communications 12, 1 (2021)


Manly-Body dynamics of polaritons and polarons

  • "Interaction-induced transparency for strong-coupling polaritons"

J. Lang, D. E. Chang, and F. Piazza, Phys. Rev. Lett. 125, 133604 (2020)

  • "Non-equilibrium diagrammatic approach to strongly interacting photons"

J. Lang, D. E. Chang, F. Piazza, Phys. Rev. A 102, 033720 (2020)

  • "Quantum-Zeno Fermi polaron in the strong dissipation limit"

T. Wasak, R. Schmidt, F. Piazza, Phys. Rev. Res. 3, 013086 (2021)


Cavity QED with ultracold atoms

  • "Light-induced quantum droplet phases of lattice bosons in multimode cavities"

P. Karpov and F. Piazza, Phys. Rev. Lett. 128, 103201 (2022)

  • "Cavity QED with Quantum Gases: New Paradigms in Many-Body Physics"

F. Mivehvar, F. Piazza, T. Donner, H. Ritsch, Advances in Physics 70, 1-153 (2021)

  • "Cavity-Quantum-Electrodynamical Toolbox for Quantum Magnetism"

F. Mivehvar, H. Ritsch, and F. Piazza, Phys. Rev. Lett. 122, 113603 (2019)