Sparse SYK and traversable wormholes

Understand

We investigate two sparse Sachdev-Ye-Kitaev (SYK) systems coupled by a bilinear term as a holographic quantum mechanical description of an eternal traversable wormhole in the low temperature limit.

• Each SYK system consists of $N$ Majorana fermions coupled by random $q$-body interactions.
• The degree of sparseness is captured by a regular hypergraph in such a way that the Hamiltonian contains exactly $k\,N$ independent terms.
• We improve on the theoretical understanding of the sparseness property by using known measures of hypergraph expansion.