Two theoretical physicists at the University of California, Davis have a new candidate for dark matter, and a possible way to detect it. They presented their work June 6 at the Planck 2019 conference in Granada, Spain and ...
General Physics
Jun 10, 2019
27
2271
Information theory, which was developed by Claude Shannon starting in the late 1940s, deals with questions such as how quickly information can be sent over a noisy communications channel. Both the information carriers (e.g., ...
In the future, quantum physics could become the guarantor of secure information technology. To achieve this, individual particles of light—photons—are used for secure transmission of data. Findings by physicists from ...
General Physics
May 21, 2019
3
1886
Fiber optic gyroscopes, which measure the rotation and orientation of airplanes and other moving objects, are inherently limited in their precision when using ordinary classical light. In a new study, physicists have experimentally ...
An international team of scientists is getting closer to perfecting molecule-sized motors that drill through the surface of cancer cells, killing them in an instant.
Bio & Medicine
May 29, 2019
0
366
A team led by scientists at the Department of Energy's Oak Ridge National Laboratory explored how atomically thin two-dimensional (2-D) crystals can grow over 3-D objects and how the curvature of those objects can stretch ...
Materials Science
Jun 03, 2019
0
501
Quantum optics, where light and matter interactions are examined at the microscopic level, has earned Nobel prizes—including three awarded since 2001—for some of science's biggest names. However, even in this mature field, ...
Quantum Physics
May 15, 2019
0
923
MIT researchers have developed a novel "photonic" chip that uses light instead of electricity—and consumes relatively little power in the process. The chip could be used to process massive neural networks millions of times ...
General Physics
Jun 06, 2019
1
721
Efforts to create reliable light-based quantum computing, quantum key distribution for cybersecurity, and other technologies got a boost from a new study demonstrating an innovative method for creating thin films to control ...
Quantum Physics
May 29, 2019
0
258
Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nano level. Using a tiny box, built from stacked atomically thin material, ...
Nanophysics
Jun 11, 2019
0
201
In 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.
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