Related Experiment Video
Updated: Mar 18, 2026
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
9.1K
Persistent Superfluid Flow Arising from the He-McKellar-Wilkens Effect in Molecular Dipolar Condensates
A A Wood1, B H J McKellar2, A M Martin1
1School of Physics, University of Melbourne, Victoria 3010, Australia.
Physical Review Letters
|July 9, 2016
Summary
The He-McKellar-Wilkens effect can create persistent flow in polar molecule Bose-Einstein condensates. While theoretically possible for magnetic atom condensates, the required electric fields are too strong for the Aharonov-Casher effect.
Area of Science:
- Quantum physics
- Condensed matter physics
Background:
- Bose-Einstein condensates (BECs) are quantum states of matter with unique properties.
- Persistent flow in BECs is a key phenomenon for quantum technologies.
- Dipolar interactions play a crucial role in the behavior of certain BECs.
Purpose of the Study:
- To investigate the induction of persistent flow in Bose-Einstein condensates using quantum effects.
- To explore the feasibility of using the He-McKellar-Wilkens effect and Aharonov-Casher effect for inducing persistent flow.
- To propose an experimental setup for observing these effects in toroidal traps.
Main Methods:
- Theoretical analysis of persistent flow induction in BECs.
- Consideration of polar molecules with electric dipole moments.
- Analysis of magnetic atom BECs with magnetic dipole moments.
- Modeling of dipolar interactions mediated by electric or magnetic moments.
Main Results:
- The He-McKellar-Wilkens effect can induce persistent flow in polar molecule BECs in toroidal traps.
- The Aharonov-Casher effect could theoretically induce persistent flow in magnetic atom BECs, but requires prohibitive electric fields.
- An experimental geometry for observing the He-McKellar-Wilkens effect in toroidal BECs is proposed.
Conclusions:
- Persistent flow is achievable in polar molecule BECs via the He-McKellar-Wilkens effect.
- The Aharonov-Casher effect is currently impractical for inducing persistent flow in magnetic atom BECs due to field strength limitations.
- The proposed experimental setup offers a pathway for future investigations into quantum effects in toroidal condensates.
Related Concept Videos
02:34Comparing Intermolecular Forces: Melting Point, Boiling Point, and Miscibility
53.3K
Intermolecular forces are attractive forces that exist between molecules. They dictate several bulk properties, such as melting points, boiling points, and solubilities (miscibilities) of substances. Molar mass, molecular shape, and polarity affect the strength of different intermolecular forces, which influence the magnitude of physical properties across a family of molecules.
Temporary attractive forces like dispersion are present in all molecules, whether they are polar or nonpolar. They...
Temporary attractive forces like dispersion are present in all molecules, whether they are polar or nonpolar. They...
53.3K
01:18Newtonian Fluid: Problem Solving
1.1K
Newtonian fluids exhibit a constant viscosity, meaning their shear stress and shear strain rate are directly proportional. This property ensures a predictable and stable response to applied forces, maintaining a linear relationship between force and flow. Examples include water, air, and light oils, consistently demonstrating this proportional behavior regardless of external conditions.
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
1.1K
03:13Intermolecular Forces
76.3K
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen...
76.3K
01:34The Fluid Mosaic Model
183.4K
The fluid mosaic model was first proposed as a visual representation of research observations. The model comprises the composition and dynamics of membranes and serves as a foundation for future membrane-related studies. The model depicts the structure of the plasma membrane with a variety of components, which include phospholipids, proteins, and carbohydrates. These integral molecules are loosely bound, defining the cell’s border and providing fluidity for optimal function.
183.4K
01:17Viscosity
7.7K
When water is poured into a glass, it falls freely and quickly, whereas if honey or maple syrup is poured over a pancake, it flows slowly and sticks to the surface of the container. This difference in the flow of different kinds of liquids arises due to the fluid friction between the liquid layers and the liquid and the surrounding material. This property of fluids is called fluid viscosity. In this example, water has a lower viscosity than honey and maple syrup.
The SI unit of viscosity is...
The SI unit of viscosity is...
7.7K
01:22Couette Flow
1.3K
Couette flow represents the flow of fluid between two parallel plates, with one plate fixed and the other moving with a constant velocity. This configuration allows for a simplified analysis using the Navier-Stokes equations, which govern fluid motion under conditions of viscosity and incompressibility. For Couette flow, the assumptions include a steady, laminar, incompressible flow with a zero-pressure gradient in the flow direction. This flow type is beneficial for understanding shear-driven...
1.3K