Energy & Green Tech

Quantum dots boost perovskite solar cell efficiency and scalability

Perovskites are hybrid compounds made from metal halides and organic constituents. They show great potential in a range of applications, e.g. LED lights, lasers, and photodetectors, but their major contribution is in solar ...

Computer Sciences

A language for quantum computing

Time crystals. Microwaves. Diamonds. What do these three disparate things have in common?

Computer Sciences

Major improvements in quantum fidelity

Researchers used Oak Ridge National Laboratory's Quantum Computing User Program (QCUP) to achieve major improvements in quantum fidelity, a potential step toward more accurate, reliable quantum networks and supercomputers.


Making quantum computers even more powerful

Engineers at Ecole Polytechnique Federale de Lausanne (EPFL) have developed a method for reading several qubits—the smallest unit of quantum data—at the same time. Their method paves the way to a new generation of even ...


Semiconductors reach the quantum world

Quantum effects in superconductors could give semiconductor technology a new twist. Researchers at the Paul Scherrer Institute PSI and Cornell University in New York State have identified a composite material that could integrate ...

page 1 from 10


In physics, a quantum (plural: quanta) is an indivisible entity of a quantity that has the same units as the Planck constant and is related to both energy and momentum of elementary particles of matter (called fermions) and of photons and other bosons. The word comes from the Latin "quantus", for "how much." Behind this, one finds the fundamental notion that a physical property may be "quantized", referred to as "quantization". This means that the magnitude can take on only certain discrete numerical values, rather than any value, at least within a range. There is a related term of quantum number.

A photon is often referred to as a "light quantum". The energy of an electron bound to an atom (at rest) is said to be quantized, which results in the stability of atoms, and of matter in general. But these terms can be a little misleading, because what is quantized is this Planck's constant quantity whose units can be viewed as either energy multiplied by time or momentum multiplied by distance.

Usually referred to as quantum "mechanics", it is regarded by virtually every professional physicist as the most fundamental framework we have for understanding and describing nature at the infinitesimal level, for the very practical reason that it works. It is "in the nature of things", not a more or less arbitrary human preference.

This text uses material from Wikipedia, licensed under CC BY-SA