BRST analysis and BFV quantization of the generalized quantum rigid rotor

We identify a strong similarity among several distinct originally second-class systems, including both mechanical and field theory models, which can be naturally described in gauge-invariant way. The canonical structure of such related systems is encoded into generalization the quantum rigid rotor. perform BRST symmetry analysis BFV functional quantization for mentioned version generalized obtain different equivalent effective actions according to specific gauge-fixing choices, showing explicitly their symmetries. apply exemplify ideas discussed two particular namely, motion along an elliptical path [Formula: see text] nonlinear sigma model, that our results reproduce connect previously unrelated known systems.