Photoinduced non-reciprocal phase transitions in strongly correlated materials

In systems driven out of equilibrium where the detailed balance is broken, the free energy minimization principle does not generically apply. In such situations, interparticle interactions do not necessarily have action-reaction symmetry. In fact, such non-reciprocal interactions are generic in soft active systems, e.g. chemically/optically activated colloids or cells interacting via quorum sensing. Recent studies showed that non-reciprocal interactions in many-body systems may lead to the emergence of the so-called non-reciprocal phase transition [1] to a time-dependent phase where the order parameter exhibits a persistent many-body ‘chase-and-runaway’ motion.

In this talk, we will show that non-reciprocal phase transition can emerge in solid-state platforms such as layered ferromagnets [2] and multi-Q charge/spin density waves by injecting light at an appropriately tuned frequency. We show that the interactions between electrons can become non-reciprocal, by injecting light that turns on a decay channel to a virtually excited state, directly affecting the nature of electron-electron interactions. We estimate that the required power for their emergence is within the reach of current state-of-the-art experiments. Our work paves the way to bring photo-excited solid-state platforms to the realm of non-reciprocal science.



[1] M. Fruchart*, R. Hanai*, P. B. Littlewood, V. Vitelli, Nature 592, 363 (2021).

[2] R. Hanai, D. Ootsuki, and R. Tazai, arXiv:2406.05957.