Related Experiment Video
Updated: Jul 29, 2026

Gradient Echo Quantum Memory in Warm Atomic Vapor
Published on: November 11, 2013
Dynamics of low-energy helium vapor pulses
A Wynveen1, K A Lidke, M C Williams
1School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455, USA.
Abstract:
We report results of experiments in which pulses of helium vapor are produced by a current pulse in a chromium film covered with superfluid helium at around 0.3 K. The pulses were detected by a titanium bolometer operating at 0.47 K. The shape of the detected signal is a strong function of the power of the initiating current pulse. For low powers the signal from a single current pulse also contains a single peak, but for higher powers, a single current pulse produces two and then at the highest powers, three peak signals. To analyze the origin of these phenomena we report results of hybrid gas-dynamics and hydrodynamics simulations, which demonstrate that the signals arise from shock waves formed in the vapor. The shock waves form due to the presence of a gradient in the small ambient background of helium vapor in the chamber and are extremely sensitive to the pulse power.
Related Concept Videos
The Bohr Model
Emission Spectra
The de Broglie Wavelength
Atomic Nuclei: Larmor Precession Frequency
NMR Spectrometers: Radiofrequency Pulses and Pulse Sequences
Fermi Level Dynamics
Electron affinity in semiconductors refers to the energy gap between the minimum of its conduction band and the vacuum level and it is a critical parameter in determining how easily a semiconductor can accept additional electrons.
The work...

