Related Experiment Video
Updated: Aug 6, 2026
10:00
Gradient Echo Quantum Memory in Warm Atomic Vapor
Published on: November 11, 2013
Quantum-mechanical analysis of a longitudinal Stern-Gerlach effect
G A Gallup1, H Batelaan, T J Gay
1Behlen Laboratory of Physics, University of Nebraska, Lincoln, Nebraska 68588-0111, USA.
Physical Review Letters
|June 1, 2001
Summary
Quantum mechanics reveals complete electron spin polarization in an inhomogeneous magnetic field. This contrasts with semiclassical models, where spin splitting is less distinct, offering new insights into electron behavior.
Area of Science:
- Quantum mechanics
- Condensed matter physics
- Electron transport
Background:
- Understanding electron behavior in magnetic fields is crucial for spintronics.
- Semiclassical models often simplify complex quantum phenomena.
Purpose of the Study:
- To perform a quantum-mechanical calculation of electron propagation through an axially symmetric, inhomogeneous magnetic field.
- To investigate the spin polarization of an electron beam under these conditions.
Main Methods:
- Rigorous quantum-mechanical calculations.
- Simulation of electron propagation through a specifically designed magnetic field.
- Analysis of electron spin states.
Main Results:
- Demonstration of complete spin polarization of the electron beam.
- Achieved by inserting a Landau eigenstate into the magnetic field.
- Observed distinct quantum behavior compared to semiclassical predictions.
Conclusions:
- Quantum mechanics predicts and enables complete spin polarization, unlike blurred effects in semiclassical approximations.
- The findings highlight the importance of quantum effects in electron beam manipulation.
- Potential implications for advanced spintronic devices and quantum information processing.
Related Concept Videos
03:40Hess's Law
There are two ways to determine the amount of heat involved in a chemical change: measure it experimentally, or calculate it from other experimentally determined enthalpy changes. Some reactions are difficult, if not impossible, to investigate and make accurate measurements for experimentally. And even when a reaction is not hard to perform or measure, it is convenient to be able to determine the heat involved in a reaction without having to perform an experiment.
02:32The de Broglie Wavelength
In the macroscopic world, objects that are large enough to be seen by the naked eye follow the rules of classical physics. A billiard ball moving on a table will behave like a particle; it will continue traveling in a straight line unless it collides with another ball, or it is acted on by some other force, such as friction. The ball has a well-defined position and velocity or well-defined momentum, p = mv, which is defined by mass m and velocity v at any given moment. This is the typical...
02:45The Quantum-Mechanical Model of an Atom
Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of a particle moving in quantized circular orbits, Erwin Schrödinger extended de Broglie’s work by deriving what is now known as the Schrödinger equation. When Schrödinger applied his equation to hydrogen-like atoms, he was able to reproduce Bohr’s expression for the energy and, thus, the Rydberg formula governing hydrogen spectra. Schrödinger...
01:11Atomic Nuclei: Larmor Precession Frequency
The earth's gravitational field produces a 'twisting force' perpendicular to the angular momentum of a spinning mass (such as a spinning top) that causes the mass to 'wobble' around the gravitational field axis in a phenomenon called precession. Similarly, the magnetic moment (μ) of a spinning nucleus precesses due to an external magnetic field directed along the z-axis. The precession of the magnetic moment vector about the magnetic field is called Larmor precession, and the angular frequency...
01:23Atomic Nuclei: Nuclear Relaxation Processes
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis. This...
01:17Sound as Pressure Waves
Sound waves, which are longitudinal waves, can be modeled as the displacement amplitude varying as a function of the spatial and temporal coordinates. As a column of the medium is displaced, its successive columns are also displaced. As the successive displacements differ relatively, a pressure difference with the surrounding pressure is created. The gauge pressure varies across the medium.
The pressure fluctuation depends on the difference in displacements between the successive points in the...
The pressure fluctuation depends on the difference in displacements between the successive points in the...