Here you will find 3 examples for using PIMD-B (arXiv:1905.09053)
1) Example for 3 bosons in a 3D isotropic harmonic trap @17.4 K. Analytical result for av. total energy:  0.00058031 Ha
2) Example for 3 distinguishable particles in a 3D isotropic harmonic trap @17.4 K. Analytical result for av. total energy: 0.00065142 Ha
3) Example for mixture of 2 bosons and 1 distinguishable particles in a 3D isotropic harmonic trap @17.4 K. Analytical result for av. total energy: 0.00062348 Ha

IMPORTANT: the centroid virial estimator is not applicable for bosons due to the combination of different particles into long ring polymers.
Therefore, you can print our virial_fq, which is a virial estimator for the kinetic energy but is not translationally invariant.
If the system is trapped or is not symmetric under translations for any other reason, this should not matter.

TO RUN:
i-pi input.xml >& log &
i-pi-driver -u -m harm3d -o 1.21647924E-8 -h free2 &


