Particle spectrum for any tensor Lagrangian

We present the er software for efficiently computing the mass and energy of the particle spectrum for any (e.g., higher-rank) tensor field theory in the olfram anguage. The user must provide a Lagrangian density which is expanded quadratically in the fields around a Minkowski vacuum, is linear in the coupling coefficients, and otherwise built from the partial derivative and Minkowski metric. er automatically computes the spin-projection operators, saturated propagator, bare masses, residues of massive and massless poles, and overall unitarity conditions in terms of the coupling coefficients. The constraints on the source currents and total number of gauge symmetries are produced as a by-product. We provide examples from scalar, vector, tensor, and gauge theories of gravity. Each example, including spectra of higher-spin modified gravity theories, may be obtained on a personal computer in a matter of minutes. The software is also parallelized for use on high-performance computing resources. The initial release allows for parity-preserving operators constructed from fields of up to rank three: this functionality will be extended in future versions. er is a contribution to the xct project.