Entropic Origin of Pseudogap Physics and a Mott-Slater Transition in Cuprates

We propose a new approach to understand the origin of the pseudogap in the cuprates, in terms of bosonic entropy. The near-simultaneous softening of a large number of different $q$-bosons yields an extended range of short-range order, wherein the growth of magnetic correlations with decreasing temperature $T$ is anomalously slow. These entropic effects cause the spectral weight associated with the Van Hove singularity (VHS) to shift rapidly and nearly linearly toward half filling at higher $T$, consistent with a picture of the VHS driving the pseudogap transition at a temperature $\sim T^*$. As a byproduct, we develop an order-parameter classification scheme that predicts supertransitions between families of order parameters. As one example, we find that by tuning the hopping parameters, it is possible to drive the cuprates across a {\it transition between Mott and Slater physics}, where a spin-frustrated state emerges at the crossover.