Nonperturbative quantization \`{a} la Heisenberg and thermodynamics of monopole configurations

For field theories in which no small parameter is available, we propose a definition of nonperturbative quantum states in terms of the complete set of Green functions, based upon the utilization of Heisenberg's quantization procedure. We apply this method to obtain the energy spectra of a quantum monopole and of a flux tube. The partition function and thermodynamic quantities for one quantum monopole are evaluated numerically. A dilute gas of noninteracting quantum monopoles is considered, for which the partition function and thermodynamic quantities are evaluated as well. All the obtained statistical and thermodynamic functions contain quantum corrections associated with the internal structure of the quantum monopole.