Related Experiment Video
Updated: Jul 5, 2025
12:19
Measurement of Quantum Interference in a Silicon Ring Resonator Photon Source
Published on: April 4, 2017
8.4K
Quantum Measurements and Delays in Scattering by Zero-Range Potentials
Xabier Gutiérrez1,2, Marisa Pons2,3, Dmitri Sokolovski2,4
1Departamento de Química-Física, Universidad del País Vasco, UPV/EHU, 48940 Leioa, Spain.
Entropy (Basel, Switzerland)
|January 22, 2024
Summary
The Eisenbud-Wigner-Smith delay and Larmor time offer different quantum scattering durations. Quantum measurement theory clarifies which method accurately measures particle interaction time with a scattering potential, especially for large de Broglie wavelengths.
Area of Science:
- Quantum mechanics
- Scattering theory
- Quantum measurement
Background:
- Discrepancies exist between Eisenbud-Wigner-Smith delay and Larmor time in estimating quantum scattering event durations.
- These differences are particularly significant when the de Broglie wavelength is large relative to the scatterer's size.
Purpose of the Study:
- To analyze Eisenbud-Wigner-Smith delay and Larmor time using quantum measurement theory.
- To determine which method accurately quantifies the duration a particle spends within a scattering potential region.
Main Methods:
- Application of quantum measurement theory.
- Analysis of scattering events including transmission, reflection, and three-dimensional elastic scattering.
Main Results:
- The study provides a theoretical framework to distinguish between the two time-delay estimates.
- Identifies conditions under which each estimate is more appropriate.
Conclusions:
- Quantum measurement theory offers a definitive approach to understanding particle interaction time in scattering events.
- The findings clarify the physical interpretation of time delays in quantum scattering, especially in the large de Broglie wavelength limit.
Related Concept Videos
04:08The Uncertainty Principle
23.4K
Werner Heisenberg considered the limits of how accurately one can measure properties of an electron or other microscopic particles. He determined that there is a fundamental limit to how accurately one can measure both a particle’s position and its momentum simultaneously. The more accurate the measurement of the momentum of a particle is known, the less accurate the position at that time is known and vice versa. This is what is now called the Heisenberg uncertainty principle. He...
23.4K
02:32The de Broglie Wavelength
25.9K
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...
25.9K
02:45The Quantum-Mechanical Model of an Atom
42.3K
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.
42.3K
01:30Electric Field of Two Equal and Opposite Charges
5.9K
Atoms generally contain the same number of positively and negatively charged particles, protons, and electrons. Hence, they are electrically neutral. However, the centers of the positive and negative charges do not always coincide. In such a scenario, the electric field of an atom may not be zero.
A separation of the positive and negative charges can lead to a weak, remnant effect of the positive and negative charges. The expectation is that the more the distance between the positive and...
A separation of the positive and negative charges can lead to a weak, remnant effect of the positive and negative charges. The expectation is that the more the distance between the positive and...
5.9K
03:21The Energies of Atomic Orbitals
24.0K
In an atom, the negatively charged electrons are attracted to the positively charged nucleus. In a multielectron atom, electron-electron repulsions are also observed. The attractive and repulsive forces are dependent on the distance between the particles, as well as the sign and magnitude of the charges on the individual particles. When the charges on the particles are opposite, they attract each other. If both particles have the same charge, they repel each other.
24.0K
01:14NMR Spectrometers: Resolution and Error Correction
699
When magnetic nuclei in a sample achieve resonance and undergo relaxation, the signal detected in NMR is an approximately exponential free induction decay. Fourier transform of an exponential decay yields a Lorentzian peak in the frequency domain. Lorentzian peaks in an NMR spectrum are defined by their amplitude, full width at half maximum, and position, where the peak width is governed by the spin-spin relaxation time alone. In real experiments, however, the applied magnetic field is rendered...
699