Final answer:
To obtain the symmetric stress-energy-momentum tensor for Proca fields, one can follow a similar procedure as for electromagnetic fields.
Step-by-step explanation:
The Proca Lagrangian density describes the dynamics of the Proca fields, which are massive vector fields. To show the symmetric stress-energy-momentum tensor for the Proca fields, one can follow a similar procedure as for electromagnetic fields. This involves taking variations of the Proca Lagrangian with respect to the metric tensor and the Proca field to derive the equation of motion and the stress-energy-momentum tensor. By properly symmetrizing the tensor, one can obtain the symmetric stress-energy-momentum tensor for the Proca fields.