Critical behavior of a Fermi-Liquid to Fermi Liquid transition in infinite dimension.

The deconfined quantum critical point between two ordered states has been a subject of extensive research over the past two decades. However, from both theoretical and experimental perspectives, the possibility of a critical point between two Fermi liquids, without any bosonic order, is equally intriguing. In this work, we investigate bilayer models tuned by an interlayer antiferromagnetic spin-spin coupling $J_\perp$​ in the infinite-dimensional limit. At half-filling, we identify a sharp second-order metal-insulator transition. Remarkably, the absence of bosonic order on either side of the critical point echoes the concept of symmetric mass generation. Away from half-filling, the metal-insulator transition evolves into a critical point between two Fermi liquids: one with a low density of states and the other with a high density of states, reminiscent of the small-to-large Fermi surface transition observed in cuprates and heavy-fermion systems. We systematically analyze the critical exponents and behavior, revealing non-Fermi liquid characteristics associated with strange metal phases.