Sizable quantum effects are observed in the cas of liquid Neon near its triple point. FBSD simulations were performed at 29.9 K with a density of 0.03755 A-3. Interactions between neon atoms are described y a Lennard-Jones potential.

At this temperature the kinetic energy of the fluid system is about 25% higher compared to the value predicted by a classical simulation. Also, the magnitude of the imaginary part of the correlation function reaches a height equal to about 40% of the initial value of the real part, indicating  a significant quantum character at this state point. The correlation function decays faster than that in a classical system. When the diffusion process is viewed as a sequence of two-body collisions, this observed faster decay can be explained by a larger effective cross section in the quantum system, an effect attributable to quantum dispersion.

Related Articles:

J. Kegerreis, A. Nakayama and N. Makri, “Complex-time velocity autocorrelation functions for Lennard-Jones fluids with quantum pair-product propagators”, J. Chem. Phys. 128, 184509 (2008).

N. Makri, A. Nakayama and N. J. Wright, “Forward-backward semiclassical simulation of dynamical properties in liquids”, invited review, J. Theor. Comp. Chem. 3, 391-417 (2004).

C. P. Lawrence, A. Nakayama, N. Makri and J. L. Skinner, “Quantum dynamics of simple fluids”, J. Chem. Phys. 120, 6621-6624 (2004).