Dynamical baryon formation in $SU(n)$ Hubbard Models*

We study post quench dynamics in the repulsive n-color Fermi-Hubbard model,

initialized in a periodic pattern of empty and n-times occupied sites. In any dimension

and for  any  finite interaction, U>0, this state is proven to relax 

 to a negative temperature state. However, while for  weak interactions, U/J ≤ 1, a

negative temperature Fermi liquid appears,  for  U/J ≥ 1, quench spectroscopy [1,2] as well as the behavior

of time dependent correlation functions reveal the dynamical formation of heavy and strongly interacting

composite particles. For n=3, in particular, most of the particles are bound to very

heavy spinless 'baryons' (trions), strongly  interacting with a dilute background gas of

intermediate mass mobile 'mesons' (doublons) and of light SU(3) fermions. Baryons move

diffusively, with a motion generated by collisions with the mesonic background. Similarly rich

negative temperature states form for any  n ≥ 2.

[1] M. Kormos, M. Collura, G. Takács, and P. Calabrese, Nature Physics 13, 246 (2017).

[2] M. Collura, M. Kormos, and G. Takács, Phys. Rev. A 98, 053610 (2018).