Quantum cavitation in liquid helium
  Using a functional-integral approach, we have determined the temperature below which cavitation in liquid helium is driven by thermally assisted quantum tunneling. For both helium isotopes, we have obtained the crossover temperature in the whole range of allowed negative p essures. Our results are compatible with recent experimental results on 4He. 
M. Guilleumas, M. Barranco, D.M. Jezek, R.J. Lombard and M. Pi