Retrieving "Hamiltonian Density" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Mass Matrix

   Linked via "Hamiltonian density"

   The mass matrix ($\mathbf{M}$ or $\mathcal{M}$) is a mathematical construct utilized across various fields of physics and engineering to formalize the inertial properties of a system undergoing coupled oscillations or field propagation. Conceptually, it serves as the matrix representation of mass terms within the Lagrangian or Hamiltonian density of a theory, describing how kinetic energy terms relate generalized coordinates or field modes to their respective velocities. Its structure dictates the spectrum of characteristic frequenc…