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Quantum mechanics

Quantum mechanics

It is a branch of physics that studies the motion law of microscopic particles in the material world, and it mainly studies the basic theory of the structure and properties of atoms, molecules, condensed matter, nuclei and elementary particles.

Quantum mechanics is the fundamental physical theory that describes nature at the scale of atoms and subatomic particles. It underlies all quantum physics, including quantum chemistry, quantum field theory, quantum technology and quantum computer science.

Classical physics, the body of theories that existed before quantum mechanics, describes many aspects of nature on the ordinary (macroscopic) scale, but is insufficient to describe them quantitatively on small (atomic and subatomic) scales. Most theories of classical physics can be derived from quantum mechanics as approximations valid on large (macroscopic) scales.

Quantum mechanics differs from classical physics in that energy, momentum, angular momentum and other quantities of a coupled system cannot take arbitrary values, but are limited to discrete values (quantization), objects have characteristics of both particles and waves (particle-wave dualism), and there are limits to our ability to accurately predict the value of a physical quantity before measuring it under a given set of initial conditions (uncertainty principle).

Quantum mechanics has gradually emerged from theories explaining observations that could not be reconciled with classical physics, such as Max Planck's 1900 solution of the problem of blackbody radiation and the 1905 agreement between energy and frequency in Albert Einstein's paper, which explained the photoelectric effect. These early attempts to understand microscopic phenomena, now known as 'old quantum theory', led to the rapid development of quantum mechanics in the mid 1920s in the work of Niels Bohr, Erwin Schrödinger, Werner Heisenberg, Max Born and others. Modern theory is formulated in various specially developed mathematical formalisms. In one of them, a mathematical entity called the wave function provides information in the form of probability amplitudes about what measurements of energy, momentum and other physical properties of a particle can give.


June 13, 1831
Quantum mechanics was born in Edinburgh.


Further Resources


A Brief History of Quantum Mechanics - with Sean Carroll


February 6, 2020

If You Don't Understand Quantum Physics, Try This!


February 25, 2019

Neil deGrasse Tyson Explains The Weirdness of Quantum Physics


March 13, 2021

Quantum Mechanics




John Horgan
July 24, 2021
Scientific American
Scientific American is the essential guide to the most awe-inspiring advances in science and technology, explaining how they change our understanding of the world and shape our lives.
March 1, 2020
The current single energy concept has run its course, the notion that atomic-energy is all there is to reality. Since the proof of dark-energy, we have struggled to discern what it is. This book states dark-energy is a non-atomic form of energy. By doing so, all the Quantum Mechanics and Relativistic equations that have defied physical explanation in the past now make simple, logical sense. Yes, Quantum Mechanics can be understood logically. All it takes is another energy form in the mix....
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