Michel Fruchart : Non-reciprocal phase transitions

Systems with nonreciprocal interactions generically display time-dependent states. These are routinely observed in finite systems, from neuroscience to active matter, in which globally ordered oscillations exist.
We will discuss how these states appear from the perspective of bifurcation theory. We will then focus on the stability of these uniform nonreciprocal phases in noisy spatially-extended systems, their fate in the thermodynamic limit, and the critical behavior of the corresponding phase transitions in a nonreciprocal generalization of the Ising model.

1.    M. Fruchart and V. Vitelli,
“Nonreciprocal many-body physics”, arXiv:2602.11111 (2026).
2.    Y. Avni, M. Fruchart, D. Martin, D. Seara, V. Vitelli,
“Nonreciprocal Ising model“, Phys. Rev. Lett. 134, 117103 (2025).
“Dynamical phase transitions in the nonreciprocal Ising model“, Phys. Rev. E 111, 034124 (2025).