Microscopic superfluidity in 4He clusters stirred by a rotating impurity molecule.
The effective moment of inertia of a CO impurity molecule in 4HeN and p-(H2)N solvent clusters initially increases with N but then commences a nonclassical decrease at N=4 (4He) or N=6 (p-H2). This suggests molecule-solvent decoupling and a transition to microscopic superfluidity. However, the quantum decoupling mechanism has not been elucidated. To understand the decoupling mechanism, a one-dimensional model is introduced in which the 4He atoms are confined to a ring. This model captures the physics and shows that decoupling happens primarily because of bosonic solvent-solvent repulsion. Quantum Monte Carlo and basis set calculations suggest that the system can be modeled as a stirred Tonks-Girardeau gas. This allows the N-particle time-dependent Schrödinger equation to be solved directly. Computations of the integrated particle current reveal a threshold for stirring and current generation, indicative of superfluidity.
Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA.
Angeline
A
Wairegi
Institut de Sciences Moléculaires d'Orsay, CNRS UMR 8214, Université de Paris-Sud 11, Bâtiment 210, F91405, Orsay Cedex, France.
Antonio
A
Gamboa
Department of Mathematics, University of Portsmouth, Portsmouth, P01 3HF, United Kingdom.
Andrew D
AD
Burbanks
FivePrime Therapeutics, Two Corporate Drive, South San Francisco, California 94080, USA.
Ernestine A
EA
Lee
Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322-0300, USA.
David
D
Farrelly
D006371:Helium / Q000737:chemistry*; D008962:Models, Theoretical; D009010:Monte Carlo Method; D011789:Quantum Theory
D006371:Helium