Quantum
hideIn 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.
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News tagged with quantum
Proposed Spacetime Structure Could Provide Hints for Quantum Gravity Theory
6 hours ago |
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(PhysOrg.com) -- Spacetime, which consists of three dimensions of space and one time dimension, is such a large, abstract concept that scientists have a very difficult time understanding and defining it. Moreover, ...
Does weak equivalence break down at the quantum level?
Dec 08, 2009 |
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(PhysOrg.com) -- One of the givens in physics is the weak equivalence principle. This principle has been considered solid since Einstein proposed that it is not possible to detect the difference between uniform acceleration ...
Researchers Design Triple Quantum Dot for Quantum Information Applications
Nov 30, 2009 |
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(PhysOrg.com) -- While quantum dots have existed since the 1980s, only in the past decade have physicists successfully created lateral few-electron single quantum dots. These quantum dots enable physicists ...
Using superconducting probes to get a picture of what it's like inside CNTs
Nov 20, 2009 |
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(PhysOrg.com) -- "Carbon nanotubes are exciting for fundamental physics, and for potential technological applications," Nadya Mason tells PhysOrg.com. "However, we are generally limited in the way that we can study them. ...
Building a more versatile laser
Nov 16, 2009 |
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(PhysOrg.com) -- One of the drawbacks associated with using semiconductor lasers is that many of them can only produce a beam of a single wavelength, and can only send that beam in one direction at a time. ...
Google Collaborates with D-Wave on Possible Quantum Image Search
Dec 15, 2009 |
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(PhysOrg.com) -- Always on the cutting edge of new computing technologies, Google has recently announced that it is investigating the use of quantum computing schemes to achieve faster image recognition rates. ...
Scientists build 'single-atom transistor'
Dec 06, 2009 |
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(PhysOrg.com) -- Researchers from Helsinki University of Technology (Finland), University of New South Wales (Australia), and University of Melbourne (Australia) have succeeded in building a working transistor, ...
Fine-tuned: A wholly new approach to tuning a laser's frequency
Dec 04, 2009 |
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(PhysOrg.com) -- For more than 30 years, scientists have been trying to harness the power of terahertz radiation. Tucked between microwaves and infrared rays on the electromagnetic spectrum, terahertz rays ...
Researchers create 'synthetic magnetic fields' for neutral atoms
Dec 02, 2009 |
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(PhysOrg.com) -- Achieving an important new capability in ultracold atomic gases, researchers at the Joint Quantum Institute, a collaboration of the National Institute of Standards and Technology and the University ...
Researchers demonstrate 100-watt-level mid-infrared lasers
Dec 01, 2009 |
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Northwestern University researchers have achieved a breakthrough in quantum cascade laser output power, delivering 120 watts from a single device at room temperature.
UCSB physicists move one step closer to quantum computing
Nov 20, 2009 |
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Physicists at UC Santa Barbara have made an important advance in electrically controlling quantum states of electrons, a step that could help in the development of quantum computing. The work is published ...
New study confirms exotic electric properties of graphene
Nanotechnology / Nanomaterials
Nov 17, 2009 |
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(PhysOrg.com) -- First, it was the soccer-ball-shaped molecules dubbed buckyballs. Then it was the cylindrically shaped nanotubes. Now, the hottest new material in physics and nanotechnology is graphene: ...
Physicists lay the groundwork for cooler, faster computing
Dec 14, 2009 |
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University of Toronto quantum optics researchers Sajeev John and Xun Ma have discovered new behaviours of light within photonic crystals that could lead to faster optical information processing and compact computers that ...
Metamaterials could reduce friction in nanomachines
Nanotechnology / Nanomaterials
Dec 07, 2009 |
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(PhysOrg.com) -- Nanoscale machines expected to have wide application in industry, energy, medicine and other fields may someday operate far more efficiently thanks to important theoretical discoveries concerning the manipulation ...
Wizard at circuits, physics
Dec 03, 2009 |
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(PhysOrg.com) -- Donhee Ham, Gordon McKay Professor of Electrical Engineering and Applied Physics, uses his personal energy and understanding of physics to design innovative integrated circuits.
