Quantum molecular dynamics simulations for the nonmetal-to-metal transition in fluid helium.

We have performed quantum molecular dynamics simulations for dense helium to study the nonmetal-to-metal transition at high pressures. We present new results for the equation of state and the Hugoniot curve in the warm dense matter region. The optical conductivity is calculated via the Kubo-Greenwood formula from which the dc conductivity is derived. The nonmetal-to-metal transition is identified at about 1 g/cm(3). We compare with experimental results as well as with other theoretical approaches, especially with predictions of chemical models.