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Register a new userDoped Mott Insulators Break $mathbb Z_2$ Symmetry of a Fermi Liquid: Stability of Strongly Coupled Fixed Points
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While the Mott transition from a Fermi liquid is correctly believed to obtain without the breaking of any continuous symmetry, we show that in fact a discrete emergent $mathbb Z_2$ symmetry of the Fermi surface is broken. The extra $mathbb Z_2$ symmetry of the Fermi liquid appears to be little known although it was pointed out by Anderson and Haldane and we use it here to classify all possible Fermi liquids topologically by invoking K-homology. It is this $mathbb Z_2$ symmetry breaking that signals the onset of particle-hole asymmetry, a widely observed phenomenon in strongly correlated systems. In addition from this principle, we are able to classify which interactions suffice to generate the $mathbb Z_2$-symmetry-broken phase. As this is a symmetry breaking in momentum space, the local-in-momentum space interaction of the Hatsugai-Kohmoto (HK) model suffices as well as the Hubbard interaction as it contains the HK interaction. Both lie in the same universality class as can be seen from exact diagonalization. We then use the Bott topological invariant to establish the stability of a Luttinger surface. Our proof demonstrates that the strongly coupled fixed point only corresponds to those Luttinger surfaces with co-dimension $p+1$ with $p$ odd. Because they both lie in the same universality class, we conclude that the Hubard and HK models are controlled by this fixed point.
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