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Laser
A laser is a device that emits light (electromagnetic radiation) through a process called stimulated emission. The term "laser" is an acronym for Light Amplification by Stimulated Emission of Radiation.[1][2] Laser light is usually spatially coherent, which means that the light either is emitted... -
Gravitomagnetism
Gravitomagnetism (sometimes Gravitoelectromagnetism, abbreviated GEM), refers to a set of formal analogies between Maxwell's field equations and an approximation to the Einstein field equations for general relativity, valid under certain conditions. For instance, the most common version of GEM... -
Faraday effect
In physics, the Faraday effect or Faraday rotation is a magneto-optical phenomenon, or an interaction between light and a magnetic field in a dielectric material. The rotation of the plane of polarization is proportional to the intensity of the component of the magnetic field in the direction of... -
Second harmonic generation
Second harmonic generation (SHG; also called frequency doubling) is a nonlinear optical process, in which photons interacting with a nonlinear material are effectively "combined" to form new photons with twice the energy, and therefore twice the frequency and half the wavelength of the initial... -
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Compton scattering
In physics, Compton scattering or the Compton effect is the decrease in energy (increase in wavelength) of an X-ray or gamma ray photon, when it interacts with matter. Inverse Compton scattering also exists, where the photon gains energy (decreasing in wavelength) upon interaction with matter... -
UVa Physics Qualifying Exam
All UVa physics PHd candidates must pass the UVa physics qualifier (qual) in order to continue on to receive a PHd. The qualifier covers four basic areas of physics; Classical Mechanics Thermodynamics & Statistical Mechanics Electricity & Magnetism Quantum Mechanics. The last two sections are... -
UVa CM:Cubic pendulum
A pendulum consists of a thin rod of length and mass m suspended from a pivot in the figure to the right. The bob is a cube of side L and mass M, attached to the rod so that the line of the rod extends through the center of the cube, from one corner to the diametrically opposite corner (dashed... -
Photodiode
A photodiode is a type of photodetector capable of converting light into either current or voltage, depending upon the mode of operation. Photodiodes are similar to regular semiconductor diodes except that they may be either exposed (to detect vacuum UV or X-rays) or packaged with a window or... -
Scattering
Scattering is a general physical process whereby some forms of radiation, such as light, sound or moving particles, for example, are forced to deviate from a straight trajectory by one or more localized non-uniformities in the medium through which they pass. In conventional use, this also... -
Raman scattering
Raman scattering or the Raman effect (pronounced: Template:IPA —) is the inelastic scattering of a photon. Discovered By Dr. C.V. Raman in liquids and by Grigory Landsberg and Leonid Mandelstam in crystals. When light is scattered from an atom or molecule, most photons are elastically scattered... -
Wave plate
A wave plate or retarder is an optical device that alters the polarization state of a light wave travelling through it. A wave plate works by shifting the phase of the light wave between two perpendicular polarization components. A typical wave plate is simply a birefringent crystal with a... -
Magneto-optic Kerr effect
Magneto-optic Kerr effect (MOKE) is one of the magneto-optic effects. It describes the changes of light reflected from magnetized media. The light that is reflected from a magnetized surface can change in both polarization and reflectivity. The effect is identical to the Faraday effect except... -
Tachyon
A tachyon or tachyonic particle is a hypothetical particle that always travels faster than light. Physicists believe that faster-than-light particles cannot exist because they are inconsistent with the known laws of physics.[1][2] If such particles did exist they could be used to send signals... -
Thomas Young
Thomas Young (13 June 1773 – 10 May 1829) was an English polymath and physician. Young made notable scientific contributions to the fields of vision, light, solid mechanics, energy, physiology, language, musical harmony, and Egyptology. In Young's own judgment, of his many achievements the most... -
Fusor
A fusor is a device that uses an electric field to heat ions to conditions suitable for nuclear fusion. The machine generates an electric potential difference between two metal cages inside a vacuum. Positive ions fall down this voltage drop, building up speed. If they collide in the center... -
Linear momentum
The linear momentum (symbol p) of an object is its velocity multiplied by its mass. The SI unit for momentum is kg·m/s or N·s. In a closed system, total linear momentum is conserved. This can be observed in many scenarios, such as elastic collisions, where linear momentum is conserved save for a... -
Power
Power is the rate at which work is done, or the derivative of work with respect to time. The SI unit is the watt (W, equal to J/s). The formula for power is P a v g = Δ W Δ t {\displaystyle P_\mathrm{avg} = \frac{\Delta W}{\Delta t}\,} P = lim Δ t → 0 Δ W Δ t = d W d t {\displaystyle P = \lim... -
Does the T-Duality between Spin(32)/Z2 and E8 X E8 correspond with any group theoretical fact
It is well known the existence of a T-Duality between the two Heterotic String Theories, Type HO String Theory and Type HE String Theory. Beyond the trivial point that both groups have the same dimension (496, which actually is a prerequisite), is there some other mathematical relation between... -
Calculating the Amplitudihedron
I was watching Nima's very popular talk (download if you're using chrome) (also mirrored at youtube here about the "Amplitudihedron", which has suddenly become very popular recently. He talks all about how the Amplitudihedron computes the same result for the scattering amplitudes as ordinary... -
Stimulated emission
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Fermion
In particle physics, a fermion is a subatomic particle that follows Fermi–Dirac statistics. Fermions have a half-odd-integer spin (spin 12, spin 32, etc.) and obey the Pauli exclusion principle. These particles include all quarks and leptons and all composite particles made of an odd number of... -
Longitudinal wave
A longitudinal wave is a wave that oscillates parallel to the direction of energy transfer. Sound is an example of such a wave. -
Friction
Friction is a force that resists the relative motion between two objects. The simplest form is dry friction, which is equal to F F = ÎĽ F N {\displaystyle F_F = \mu F_N} ÎĽ is the coefficient of friction and FN is the normal force. The coefficient of friction is experimentally determined and is... -
Physics: Problems and Solutions:About
The purpose of this wiki is to provide physics graduate students and other scientists with peer-reviewed solutions to the types of problems that can be found on PHd qualifying exams. The articles consist of graduate-level problems from public problem banks. Public problem banks are often...