Wave–particle duality Origin of theory[edit] The idea of duality originated in a debate over the nature of light and matter that dates back to the 17th century, when Christiaan Huygens and Isaac Newton proposed competing theories of light: light was thought either to consist of waves (Huygens) or of particles (Newton). Through the work of Max Planck, Albert Einstein, Louis de Broglie, Arthur Compton, Niels Bohr, and many others, current scientific theory holds that all particles also have a wave nature (and vice versa).[2] This phenomenon has been verified not only for elementary particles, but also for compound particles like atoms and even molecules. For macroscopic particles, because of their extremely short wavelengths, wave properties usually cannot be detected.[3] Brief history of wave and particle viewpoints[edit] Thomas Young's sketch of two-slit diffraction of waves, 1803 Particle impacts make visible the interference pattern of waves. A quantum particle is represented by a wave packet.
Photonic topological insulator Photonic topological insulators are artificial electromagnetic materials that support topologically non-trivial, unidirectional states of light.[1] Photonic topological phases are classical electromagnetic wave analogues of electronic topological phases studied in condensed matter physics. Similar to their electronic counterparts, they, can provide robust unidirectional channels for light propagation.[2] The field that studies these phases of light is referred to as topological photonics, even though the working frequency of these electromagnetic topological insulators may fall in other parts of the electromagnetic spectrum such as the microwave range.[3] History[edit] Topological order in solid state systems has been studied in condensed matter physics since the discovery of integer quantum Hall effect. Platforms[edit] Chern number[edit] See also[edit] References[edit]
Thermal radiation This diagram shows how the peak wavelength and total radiated amount vary with temperature according to Wien's displacement law. Although this plot shows relatively high temperatures, the same relationships hold true for any temperature down to absolute zero. Visible light is between 380 and 750 nm. Thermal radiation in visible light can be seen on this hot metalwork. Thermal radiation is electromagnetic radiation generated by the thermal motion of charged particles in matter. Examples of thermal radiation include the visible light and infrared light emitted by an incandescent light bulb, the infrared radiation emitted by animals and detectable with an infrared camera, and the cosmic microwave background radiation. If a radiation-emitting object meets the physical characteristics of a black body in thermodynamic equilibrium, the radiation is called blackbody radiation.[1] Planck's law describes the spectrum of blackbody radiation, which depends only on the object's temperature. Here,
Pinch (plasma physics) Compression of an electrically conducting filament by magnetic forces A current-driven toroidal Z-pinch in a krypton plasma This is a basic explanation of how a pinch works.(1) Pinches apply a high voltage and current across a tube. This tube is filled with a gas, typically a fusion fuel such as deuterium. The MagLIF concept, a combination of a Z-pinch and a laser beam Model of the kink modes that form inside a pinch Pinched aluminium can, produced via a pulsed magnetic field created by rapidly discharging 2 kilojoules from a high voltage capacitor bank into a 3-turn coil of heavy gauge wire. Electromagnetic pinch "can crusher": schematic diagram In plasma physics three pinch geometries are commonly studied: the θ-pinch, the Z-pinch, and the screw pinch. A sketch of the θ-pinch equilibrium. The θ-pinch has a magnetic field directed in the z direction and a large diamagnetic current directed in the θ direction. Since B is only a function of r we can simplify this to ) for the θ-pinch reads:
Absolute zero Absolute zero is the lower limit of the thermodynamic temperature scale, a ficticious state at which the enthalpy and entropy of a cooled ideal gas reaches its minimum value, taken as 0. The theoretical temperature is determined by extrapolating the ideal gas law; by international agreement, absolute zero is taken as −273.15° on the Celsius scale (International System of Units),[1][2] which equates to −459.67° on the Fahrenheit scale (English/United States customary units).[3] The corresponding Kelvin and Rankine temperature scales set their zero points at absolute zero by definition. The laws of thermodynamics dictate that absolute zero cannot be reached using only thermodynamic means,[clarification needed] as the temperature of the substance being cooled approaches the temperature of the cooling agent asymptotically. A system at absolute zero still possesses quantum mechanical zero-point energy, the energy of its ground state. Absolute zero is defined to be −273.15°C, or 0 K.
Photocurrent An electric current through a photosensitive device When a suitable radiation is used, the photoelectric current is directly proportional to intensity of radiation and increases with the increase in accelerating potential till the stage is reached when photo-current becomes maximum and does not increase with further increase in accelerating potential. The highest (maximum) value of the photo-current is called saturation current. Photovoltaics[edit] The generation of a photocurrent forms the basis of the photovoltaic cell. Photocurrent spectroscopy[edit] Furthermore, by using a piezo stage to vary the lateral position of the semiconductor with micron precision, one can generate a micrograph false color image of the spectra for different positions. See also[edit] References[edit] This article incorporates public domain material from Federal Standard 1037C.
Light A triangular prism dispersing a beam of white light. The longer wavelengths (red) and the shorter wavelengths (blue) get separated Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. The word usually refers to visible light, which is visible to the human eye and is responsible for the sense of sight.[1] Visible light is usually defined as having a wavelength in the range of 400 nanometres (nm), or 400×10−9 m, to 700 nanometres – between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths).[2][3] Often, infrared and ultraviolet are also called light. The main source of light on Earth is the Sun. Sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. Electromagnetic spectrum and visible light The behaviour of EMR depends on its wavelength. Speed of light Main article: Speed of light Optics Refraction where Table 1.
Pitch angle (particle motion) It is customary to discuss the direction a particle is heading by its pitch angle. A pitch angle of 0 degrees is a particle whose parallel motion is perfectly along the local magnetic field. In the northern hemisphere this particle would be heading down toward the Earth (and the opposite in the southern hemisphere). A pitch angle of 90 degrees is a particle that is locally mirroring (see: Magnetosphere particle motion). The equatorial pitch angle of a particle is the pitch angle of the particle at the Earth's geomagnetic equator. Where is the equatorial pitch angle of the particle, is the equatorial magnetic field strength, and is the maximum field strength. This is due to the invariance of the magnetic moment .
Electromagnetic spectrum The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation.[4] The "electromagnetic spectrum" of an object has a different meaning, and is instead the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object. Most parts of the electromagnetic spectrum are used in science for spectroscopic and other probing interactions, as ways to study and characterize matter.[6] In addition, radiation from various parts of the spectrum has found many other uses for communications and manufacturing (see electromagnetic radiation for more applications). History of electromagnetic spectrum discovery The first discovery of electromagnetic radiation other than visible light came in 1800, when William Herschel discovered infrared radiation.[7] He was studying the temperature of different colors by moving a thermometer through light split by a prism. Range of the spectrum where: Rationale for spectrum regional names Boundaries
Perturbed angular correlation The perturbed γ-γ angular correlation, PAC for short or PAC-Spectroscopy, is a method of nuclear solid-state physics with which magnetic and electric fields in crystal structures can be measured. In doing so, electrical field gradients and the Larmor frequency in magnetic fields as well as dynamic effects are determined. With this very sensitive method, which requires only about 10-1000 billion atoms of a radioactive isotope per measurement, material properties in the local structure, phase transitions, magnetism and diffusion can be investigated. The PAC method is related to nuclear magnetic resonance and the Mössbauer effect, but shows no signal attenuation at very high temperatures. Today only the time-differential perturbed angular correlation (TDPAC) is used. History and development[edit] PAC goes back to a theoretical work by Donald R. Measuring principle[edit] Now one measures the time between start and stop for each event. Instrumental setup[edit] Sample materials[edit] [edit] For a
Electromagnetic radiation The electromagnetic waves that compose electromagnetic radiation can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. This diagram shows a plane linearly polarized EMR wave propagating from left to right. The electric field is in a vertical plane and the magnetic field in a horizontal plane. Electromagnetic radiation (EM radiation or EMR) is a form of radiant energy, propagating through space via electromagnetic waves and/or particles called photons. In classical physics, EMR is considered to be produced when charged particles are accelerated by forces acting on them. EMR carries energy—sometimes called radiant energy—through space continuously away from the source (this is not true of the near-field part of the EM field). The photon is the quantum of the electromagnetic interaction, and is the basic "unit" or constituent of all forms of EMR. Electromagnetic waves in free space must be solutions of Maxwell's electromagnetic wave equation.