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Related Experiment Video

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Methods for Measuring the Orientation and Rotation Rate of 3D-printed Particles in Turbulence

Methods for Measuring the Orientation and Rotation Rate of 3D-printed Particles in Turbulence

Published on: June 24, 2016

Rotational superfluidity in small helium droplets.

David Mateo¹, Frisly Gonzalez¹, Jussi Eloranta¹

¹Department of Chemistry and Biochemistry, California State University at Northridge, 18111 Nordhoff Street, Northridge, California 91330, United States.

The Journal of Physical Chemistry. A

|August 8, 2014

Summary

The study reveals that rotational superfluidity in small helium droplets begins with continuous molecular coverage and angular phase coherence, not just a completed solvent shell. This quantum phase transition marks the onset of superfluid behavior in finite systems.

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Area of Science:

Quantum Chemistry
Condensed Matter Physics
Low-Temperature Physics

Background:

Superfluidity in finite helium droplets is linked to a minimum in molecular rotational constants.
Understanding this phenomenon is crucial for finite quantum systems.

Purpose of the Study:

Investigate the relationship between helium droplet size and molecular rotational constants.
Determine the precise conditions for the onset of superfluidity in these systems.

Main Methods:

Bosonic density functional theory calculations were employed.
Classical molecular rotors (OCS, N2O, CO, HCN) interacting with helium were simulated.
Rotational constants were calculated and compared with experimental data.

Main Results:

Calculated rotational constants showed good agreement with experimental data.
The increase in rotational constants post-minimum correlates with continuous helium coverage and angular phase coherence.
Completion of the first solvent shell was not the primary factor.

Conclusions:

The observed phenomenon is a quantum phase transition from a localized to a 1D superfluid state.
This transition signifies the onset of rotational superfluidity in small helium droplets.
The findings provide insights into superfluidity in finite quantum systems.