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Interesting Generalizations of the Sachdev-Ye-Kitaev non-Fermi liquid

Some of the most interesting phenomena, both from applied and fundamental points of view, in condensed matter systems such as high-temperature superconductivity, heavy fermion physics, etc. arise in a parent non-Fermi liquid background. Although a non-Fermi liquid (NFL) phase has metallic character, i.e. they are gapless, it is very different from typical metals in that the electronic excitations are not particle-like (no quasiparticles). It is for this reason non-Fermi liquid phases are also referred to as Strange metals. The lack of quasiparticles has lead to these phases eluding a clear theoretical description. In this context, a recently revived model called the Sachdev-Ye-Kitaev (SYK) model has emerged as a new paradigm in condensed matter physics, to address such quasiparticle-less systems. The SYK model has a strange-metallic phase, that lives in zero spatial dimensions, and can be solved analytically in the large-N limit. Further, it has also been shown to have interesting connections with black-hole physics. In this talk, after providing a brief introduction to the canonical SYK model, I will talk about two interesting variations of the model. In particular, I shall show that new electronic phases like Strange-Half Metals (SHMs) and Mott Insulators (MIs) can be obtained from the SYK NFL. Additionally, I shall also discuss the construction of a higher-dimensional generalization of the SYK model and demonstrate that a new class of lattice non-Fermi liquids, different than the SYK model, emerge from such a construction.