Symplectic Weyl Laws
Dan Cristofaro-Gardiner
TL;DR
This work surveys Weyl-type laws in low-dimensional symplectic geometry, centering on how embedded contact homology (ECH) capacities and spectral invariants encode quantitative symplectic size and dynamical information. It develops the foundational Weyl law for ECH capacities on Liouville domains, connects it to Reeb dynamics through the Weinstein conjecture and closing lemmas, and then extends the narrative to surfaces via link spectral invariants and periodic Floer homology (PFH), including proofs of simplicity and rigidity results. The survey then highlights more recent developments, such as elementary spectral invariants, subleading asymptotics, and new normal subgroups, along with topological invariance results for helicity. Throughout, the authors illustrate how Weyl laws yield powerful obstructions, packing results, and dynamical conclusions, with broad implications for symplectic embeddings, boundary phenomena, and global dynamics.
Abstract
We survey a number of Weyl type laws that have recently been established in low-dimensional symplectic geometry. These have had a number of applications, which we also introduce. We sketch a number of proofs so that the reader can get a sense of how these formulas are proved and how they can be applied.
