Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

The Bohr Model02:18

The Bohr Model

60.2K
Following the work of Ernest Rutherford and his colleagues in the early twentieth century, the picture of atoms consisting of tiny dense nuclei surrounded by lighter and even tinier electrons continually moving about the nucleus was well established. This picture was called the planetary model since it pictured the atom as a miniature “solar system” with the electrons orbiting the nucleus like planets orbiting the sun. The simplest atom is hydrogen, consisting of a single proton as...
60.2K
Photoelectric Effect02:26

Photoelectric Effect

29.9K
When light of a particular wavelength strikes a metal surface, electrons are emitted. This is called the photoelectric effect. The minimum frequency of light that can cause such emission of electrons is called the threshold frequency, which is specific to the metal. Light with a frequency lower than the threshold frequency, even if it is of high intensity, cannot initiate the emission of electrons. However, when the frequency is higher than the threshold value, the number of electrons ejected...
29.9K
The de Broglie Wavelength02:32

The de Broglie Wavelength

26.1K
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...
26.1K
Deactivation Processes: Jablonski Diagram01:25

Deactivation Processes: Jablonski Diagram

800
Luminescence, the emission of light by a substance that has absorbed energy, is a process that involves the interaction of molecules with light. The energy-level diagram, or Jablonski diagram, is a graphical representation of these interactions, illustrating the various states and transitions a molecule can undergo. In a typical Jablonski diagram, the lowest horizontal line represents the ground-state energy of the molecule, which is usually a singlet state. This state represents the energies...
800
The Quantum-Mechanical Model of an Atom02:45

The Quantum-Mechanical Model of an Atom

42.7K
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.
42.7K
The Uncertainty Principle04:08

The Uncertainty Principle

23.6K
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...
23.6K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Traveling Wave Amplification in Stationary Gratings.

Physical review letters·2024
Same author

An Archimedes' screw for light.

Nature communications·2022
Same author

Revealing topology with transformation optics.

Nature communications·2021
Same author

Designing plasmonic exceptional points by transformation optics.

Optics express·2021
Same author

Casimir-Induced Instabilities at Metallic Surfaces and Interfaces.

Physical review letters·2021
Same author

Wood Anomalies and Surface-Wave Excitation with a Time Grating.

Physical review letters·2020
See all related articles

Related Experiment Video

Updated: Aug 15, 2025

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
07:56

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference

Published on: September 5, 2019

8.6K

Photon number conservation in time dependent systems [Invited].

J B Pendry

    Optics Express
    |January 6, 2023
    PubMed
    Summary
    This summary is machine-generated.

    Photon conservation is a more widely applicable law than energy conservation in time-dependent systems, even when energy is not conserved. This finding clarifies amplification mechanisms involving conserved photons.

    More Related Videos

    Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators
    09:23

    Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

    Published on: May 30, 2014

    14.6K
    Generation and Coherent Control of Pulsed Quantum Frequency Combs
    06:42

    Generation and Coherent Control of Pulsed Quantum Frequency Combs

    Published on: June 8, 2018

    9.1K

    Related Experiment Videos

    Last Updated: Aug 15, 2025

    A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
    07:56

    A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference

    Published on: September 5, 2019

    8.6K
    Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators
    09:23

    Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators

    Published on: May 30, 2014

    14.6K
    Generation and Coherent Control of Pulsed Quantum Frequency Combs
    06:42

    Generation and Coherent Control of Pulsed Quantum Frequency Combs

    Published on: June 8, 2018

    9.1K

    Area of Science:

    • Optics and Photonics
    • Quantum Mechanics
    • Electromagnetism

    Background:

    • Time-dependent systems typically do not conserve fundamental quantities like photons or energy.
    • Parity-time (PT) symmetry has been shown to allow for simultaneous conservation of photon number and energy in certain systems governed by Maxwell's equations.

    Purpose of the Study:

    • To investigate the conditions under which photon conservation holds in time-dependent systems.
    • To compare the applicability of photon conservation versus energy conservation in these systems.
    • To elucidate the underlying physics of a previously identified amplification mechanism.

    Main Methods:

    • Analysis of Maxwell's equations under specific symmetry conditions.
    • Theoretical investigation of time-dependent optical systems.
    • Examination of photon number and energy conservation laws.

    Main Results:

    • Photon conservation is demonstrated to be a more broadly applicable principle than energy conservation.
    • Photon conservation can be maintained even in scenarios where energy conservation is violated.
    • The study provides further insight into an amplification mechanism involving conserved photons moving up a frequency ladder.

    Conclusions:

    • Photon conservation is a robust law in time-dependent systems, extending beyond conditions of energy conservation.
    • The findings refine our understanding of light-matter interactions and amplification processes in optical systems.
    • This work highlights the importance of parity-time symmetry in understanding fundamental conservation laws.