Properties of Few-Electron Bubbles in Superfluid Helium-4

We present calculations of the properties of bubbles in liquid helium-4 containing 3 or 8 electrons. The pressure range in which these bubbles are stable is determined. For Z =3, we find that the bubbles are unstable except in a pressure range between − 0.78 and − 0.90 bars. For Z = 8, the bubbles are stable provided the pressure is in the range from zero to – 0.42 bars. At the upper end of the pressure range, the bubbles break into smaller bubbles each containing a fraction of the electrons; at the lower end the bubbles become unstable against unlimited expansion.