Speaker
Description
Ordinarily we think that at high enough temperatures, systems become disordered and are in a thermodynamically trivial phase. For classical and quantum lattice models of interacting spins, theorems indeed prove that there is no long-range order or entanglement above a sufficiently high temperature. I will show how it is nevertheless possible to engineer models that order at arbitrarily high temperature, using interacting bosons. Explicit and simple constructions for solids, magnets, superfluids and even quantum topological order, at arbitrarily high temperature, will be presented. All such models exhibit “entropic order”: ordering one degree of freedom (e.g. spins) can enable a boson to more strongly fluctuate; the entropy of these fluctuations can dominate the thermal ensemble at high temperature. Infinities in bosonic models can therefore qualitatively change statistical physics.
