Photon
hideIn physics, a photon is an elementary particle, the quantum of the electromagnetic field and the basic "unit" of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force. The effects of this force are easily observable at both the microscopic and macroscopic level, because the photon has no rest mass; this allows for interactions at long distances. Like all elementary particles, photons are governed by quantum mechanics and will exhibit wave-particle duality – they exhibit properties of both waves and particles. For example, a single photon may be refracted by a lens or exhibit wave interference, but also act as a particle giving a definite result when its location is measured.
The modern concept of the photon was developed gradually by Albert Einstein to explain experimental observations that did not fit the classical wave model of light. In particular, the photon model accounted for the frequency dependence of light's energy, and explained the ability of matter and radiation to be in thermal equilibrium. It also accounted for anomalous observations, including the properties of black body radiation, that other physicists, most notably Max Planck, had sought to explain using semiclassical models, in which light is still described by Maxwell's equations, but the material objects that emit and absorb light are quantized. Although these semiclassical models contributed to the development of quantum mechanics, further experiments proved Einstein's hypothesis that light itself is quantized; the quanta of light are photons.
In the modern Standard Model of particle physics, photons are described as a necessary consequence of physical laws having a certain symmetry at every point in spacetime. The intrinsic properties of photons, such as charge, mass and spin, are determined by the properties of this gauge symmetry.
The photon concept has led to momentous advances in experimental and theoretical physics, such as lasers, Bose–Einstein condensation, quantum field theory, and the probabilistic interpretation of quantum mechanics. It has been applied to photochemistry, high-resolution microscopy, and measurements of molecular distances. Recently, photons have been studied as elements of quantum computers and for sophisticated applications in optical communication such as quantum cryptography.
For more information about Photon, read the full article at
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News tagged with photon
Creating a six-qubit cluster state
Nov 02, 2009 |
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(PhysOrg.com) -- Many scientists believe that quantum entanglement is required in order for effective quantum computing. Entanglement takes place when there is a connection that exists between two objects - even when they ...
Physicists Explain How Human Eyes Can Detect Quantum Effects
Sep 29, 2009 |
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(PhysOrg.com) -- By greatly amplifying one photon from an entangled photon pair, physicists have theoretically shown that human eyes can be used as detectors to observe quantum effects. Usually, detecting ...
First-ever calculation performed on optical quantum computer chip
Sep 03, 2009 |
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(PhysOrg.com) -- A primitive quantum computer that uses single particles of light (photons) whizzing through a silicon chip has performed its first mathematical calculation. This is the first time a calculation ...
'Look Mom No Electricity': Transmitting Information with Chemistry
Chemistry / Analytical Chemistry
Jun 19, 2009 |
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(PhysOrg.com) -- While information technology is generally thought to require electrons or photons for transmitting information, scientists have recently demonstrated a third method of transmission: chemical ...
Atom Pinhole Camera Acts as a Shrinking Copy Machine
Jun 01, 2009 |
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(PhysOrg.com) -- In 1983, Richard Feynman proposed the idea of a machine that could create smaller scale replicas of itself. Today, such a system is still a challenge, but a machine that can produce nanometer-sized ...
Is random lasing possible with a cold atom cloud?
May 18, 2009 |
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(PhysOrg.com) -- Random lasing, Robin Kaiser tells PhysOrg.com, is like standard lasing, with a little bit of a twist: “You don’t know the direction the photons will go, as you do with a more standard laser. This is becaus ...
A broadband single-photon source
Sep 19, 2008 |
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As science makes progress toward practical quantum computing, improved quantum cryptography and scalable quantum communications systems, single photon sources will become more important. Until now, though, ...
Argonne 'homegrown' hybrid solar cell aims for low-cost power
Nanotechnology / Nanomaterials
Nov 10, 2009 |
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(PhysOrg.com) -- Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have refined a technique to manufacture solar cells by creating tubes of semiconducting material and then "growing" ...
Planetary Society plans new 'solar sail'
Space & Earth / Space Exploration
Nov 09, 2009 |
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(AP) -- Four years after its first solar sail ended up in the ocean instead of orbit, The Planetary Society announced Monday that by the end of 2010 it will try again to launch a spacecraft that will be propelled by the ...
Gamma-ray photon race ends in dead heat; Einstein wins this round
Oct 28, 2009 |
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Racing across the universe for the last 7.3 billion years, two gamma-ray photons arrived at NASA's orbiting Fermi Gamma-ray Space Telescope within nine-tenths of a second of one another. The dead-heat finish ...
Up-scale: Frequency converter enables ultra-high sensitivity infrared spectrometry
Aug 26, 2009 |
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In what may prove to be a major development for scientists in fields ranging from forensics to quantum communications, researchers at the National Institute of Standards and Technology have developed a new, ...
Scientists create first electronic quantum processor
Jun 28, 2009 |
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A team led by Yale University researchers has created the first rudimentary solid-state quantum processor, taking another step toward the ultimate dream of building a quantum computer.
New method to detect quantum mechanical effects in ordinary objects
Jun 22, 2009 |
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At the quantum level, the atoms that make up matter and the photons that make up light behave in a number of seemingly bizarre ways. Particles can exist in "superposition," in more than one state at the same ...
Manipulating light on a chip for quantum technologies
Jun 05, 2009 |
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(PhysOrg.com) -- A team of physicists and engineers at Bristol University has demonstrated exquisite control of single particles of light — photons — on a silicon chip to make a major advance towards long-sought-after ...
'Colossal' Magnetic Effect Under Pressure
Jun 05, 2009 |
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(PhysOrg.com) -- Millions of people today carry around pocket-sized music players capable of holding thousands of songs, thanks to the discovery 20 years ago of a phenomenon known as the “giant magnetoresistance ...
