Team makes artificial atoms that work at room temp

Ultra-secure online communications, completely indecipherable if intercepted, is one step closer with the help of a recently published discovery by University of Oregon physicist Ben Alemán.

ATLAS experiment observes light scattering off light

Light-by-light scattering is a very rare phenomenon in which two photons interact, producing another pair of photons. This process was among the earliest predictions of quantum electrodynamics (QED), the quantum theory of ...

Lithium ions flow through solid material

Scientists at the U.S. Department of Energy's (DOE) Argonne National Laboratory, in collaboration with researchers from Purdue University and Rutgers University, have merged materials science and condensed matter physics ...

Graphene gives a tremendous boost to future terahertz cameras

In a recent study, researchers developed a novel graphene-enabled photodetector that operates at room temperature, is highly sensitive, fast, has a wide dynamic range, and covers a broad range of THz frequencies. The researchers ...

Detecting pollution with a compact laser source

Researchers at EPFL have come up with a new middle infrared light source that can detect greenhouse and other gases, as well as molecules in a person's breath. The compact system, which resembles a tiny suitcase, contains ...

Brightening perovskite LEDs with photonic crystals

All inorganic cesium lead halide perovskite semiconductors exhibit great potential for nanolasers, light emitting diodes and solar cells due to their unique properties, including low threshold, high quantum efficiency and ...

Optical toric code platform sets new record

Anyons form the basis for topological quantum computation and error correction, where the topological aspect of anyonic braiding is one of the important features that gives rise to fault tolerance. More qubits to control ...

Catching fast changes in excited molecules

It's hard to see certain molecules react. The reaction is just that fast. Until now. A team of scientists devised a way to reveal time- and energy-resolved information on "dark" states of molecules—ones that are normally ...

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Photon

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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