126 relations: Absolute zero, Adiabatic theorem, Amorphous solid, Amplitude, Ancient Greek, Angular frequency, Approximation, Arithmetic mean, Atom, Avogadro constant, Axiom, Black body, Bloch wave, Boltzmann constant, Bose–Einstein statistics, Boson, Brillouin scattering, Brillouin zone, Centimetre, Classical mechanics, Condensed matter physics, Correlation function, Correspondence principle, Coulomb's law, Covalent bond, Creation and annihilation operators, Crystal, Crystal structure, Density of states, Discrete Fourier transform, Dispersion relation, Elasticity (physics), Electric dipole moment, Electric field, Electric-field screening, Electrical resistivity and conductivity, Electromagnetic cavity, Electromagnetic field, Elementary particle, Energy, Excited state, Fluid, Force, Fourier analysis, Fourier series, Fracton, Frequency, Frequency domain, Gallium arsenide, Gravity, ..., Ground state, Group velocity, Hamiltonian (quantum mechanics), Harmonic oscillator, Igor Tamm, Infrared, Institute of Physics, KDE Frameworks, KDE Software Compilation 4, Lattice model (physics), Linear elasticity, Liquid, Longitudinal wave, Lyddane–Sachs–Teller relation, Magnetism, Many-body problem, Matter wave, Mechanical wave, Molecule, Momentum, Natural frequency, Neutron scattering, Normal mode, Nyquist–Shannon sampling theorem, Operator (physics), Particle number operator, Phonon Communications, Phonon scattering, Photon, Photon gas, Physics, Polarization (waves), Potential energy, Primitive cell, Quantum field theory, Quantum harmonic oscillator, Quantum mechanics, Quasiparticle, Raman scattering, Randomness, Rayleigh wave, Reciprocal lattice, Relativistic heat conduction, Rigid unit modes, Second quantization, Second sound, Self-adjoint operator, Shear stress, Sodium chloride, Solid, Sound, Sound amplification by stimulated emission of radiation, Soviet Union, Space, Spectrum (functional analysis), Speed of light, Speed of sound, Spontaneous parametric down-conversion, Squeezed coherent state, Superposition principle, Surface acoustic wave, Surface phonon, Taylor series, Temperature, Thermal conductivity, Thermodynamics, Transverse wave, Van der Waals force, Vibration, Viscoelasticity, Wave, Wave vector, Wave–particle duality, Wavelength, Wavenumber, Zero-point energy. Expand index (76 more) » « Shrink index
Absolute zero is the lower limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as 0.
The adiabatic theorem is a concept in quantum mechanics.
In condensed matter physics and materials science, an amorphous (from the Greek a, without, morphé, shape, form) or non-crystalline solid is a solid that lacks the long-range order that is characteristic of a crystal.
The amplitude of a periodic variable is a measure of its change over a single period (such as time or spatial period).
The Ancient Greek language includes the forms of Greek used in ancient Greece and the ancient world from around the 9th century BC to the 6th century AD.
In physics, angular frequency ω (also referred to by the terms angular speed, radial frequency, circular frequency, orbital frequency, radian frequency, and pulsatance) is a scalar measure of rotation rate.
An approximation is anything that is similar but not exactly equal to something else.
In mathematics and statistics, the arithmetic mean (stress on third syllable of "arithmetic"), or simply the mean or average when the context is clear, is the sum of a collection of numbers divided by the number of numbers in the collection.
An atom is the smallest constituent unit of ordinary matter that has the properties of a chemical element.
In chemistry and physics, the Avogadro constant (named after scientist Amedeo Avogadro) is the number of constituent particles, usually atoms or molecules, that are contained in the amount of substance given by one mole.
An axiom or postulate is a statement that is taken to be true, to serve as a premise or starting point for further reasoning and arguments.
A black body is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence.
A Bloch wave (also called Bloch state or Bloch function or Bloch wavefunction), named after Swiss physicist Felix Bloch, is a type of wavefunction for a particle in a periodically-repeating environment, most commonly an electron in a crystal.
The Boltzmann constant, which is named after Ludwig Boltzmann, is a physical constant relating the average kinetic energy of particles in a gas with the temperature of the gas.
In quantum statistics, Bose–Einstein statistics (or more colloquially B–E statistics) is one of two possible ways in which a collection of non-interacting indistinguishable particles may occupy a set of available discrete energy states, at thermodynamic equilibrium.
In quantum mechanics, a boson is a particle that follows Bose–Einstein statistics.
Brillouin scattering, named after Léon Brillouin, refers to the interaction of light and material waves within a medium.
In mathematics and solid state physics, the first Brillouin zone is a uniquely defined primitive cell in reciprocal space.
A centimetre (international spelling as used by the International Bureau of Weights and Measures; symbol cm) or centimeter (American spelling) is a unit of length in the metric system, equal to one hundredth of a metre, centi being the SI prefix for a factor of.
Classical mechanics describes the motion of macroscopic objects, from projectiles to parts of machinery, and astronomical objects, such as spacecraft, planets, stars and galaxies.
Condensed matter physics is the field of physics that deals with the macroscopic and microscopic physical properties of matter.
A correlation function is a function that gives the statistical correlation between random variables, contingent on the spatial or temporal distance between those variables.
In physics, the correspondence principle states that the behavior of systems described by the theory of quantum mechanics (or by the old quantum theory) reproduces classical physics in the limit of large quantum numbers.
Coulomb's law, or Coulomb's inverse-square law, is a law of physics for quantifying the amount of force with which stationary electrically charged particles repel or attract each other.
A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.
Creation and annihilation operators are mathematical operators that have widespread applications in quantum mechanics, notably in the study of quantum harmonic oscillators and many-particle systems.
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.
In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystalline material.
In solid-state and condensed matter physics, the density of states (DOS) of a system describes the number of states per interval of energy at each energy level available to be occupied.
In mathematics, the discrete Fourier transform (DFT) converts a finite sequence of equally-spaced samples of a function into a same-length sequence of equally-spaced samples of the discrete-time Fourier transform (DTFT), which is a complex-valued function of frequency.
In physical sciences and electrical engineering, dispersion relations describe the effect of dispersion in a medium on the properties of a wave traveling within that medium.
In physics, elasticity (from Greek ἐλαστός "ductible") is the ability of a body to resist a distorting influence and to return to its original size and shape when that influence or force is removed.
The electric dipole moment is a measure of the separation of positive and negative electrical charges within a system, that is, a measure of the system's overall polarity.
An electric field is a vector field surrounding an electric charge that exerts force on other charges, attracting or repelling them.
In physics, screening is the damping of electric fields caused by the presence of mobile charge carriers.
Electrical resistivity (also known as resistivity, specific electrical resistance, or volume resistivity) is a fundamental property that quantifies how strongly a given material opposes the flow of electric current.
An electromagnetic cavity is a cavity that acts as a container for electromagnetic fields such as photons, in effect containing their wave function inside.
An electromagnetic field (also EMF or EM field) is a physical field produced by electrically charged objects.
In particle physics, an elementary particle or fundamental particle is a particle with no substructure, thus not composed of other particles.
In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object.
In quantum mechanics, an excited state of a system (such as an atom, molecule or nucleus) is any quantum state of the system that has a higher energy than the ground state (that is, more energy than the absolute minimum).
In physics, a fluid is a substance that continually deforms (flows) under an applied shear stress.
In physics, a force is any interaction that, when unopposed, will change the motion of an object.
In mathematics, Fourier analysis is the study of the way general functions may be represented or approximated by sums of simpler trigonometric functions.
In mathematics, a Fourier series is a way to represent a function as the sum of simple sine waves.
A fracton is a collective quantized vibration on a substrate with a fractal structure.
Frequency is the number of occurrences of a repeating event per unit of time.
In electronics, control systems engineering, and statistics, the frequency domain refers to the analysis of mathematical functions or signals with respect to frequency, rather than time.
Gallium arsenide (GaAs) is a compound of the elements gallium and arsenic.
Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light—are brought toward (or gravitate toward) one another.
The ground state of a quantum mechanical system is its lowest-energy state; the energy of the ground state is known as the zero-point energy of the system.
The group velocity of a wave is the velocity with which the overall shape of the wave's amplitudes—known as the modulation or envelope of the wave—propagates through space.
In quantum mechanics, a Hamiltonian is an operator corresponding to the total energy of the system in most of the cases.
In classical mechanics, a harmonic oscillator is a system that, when displaced from its equilibrium position, experiences a restoring force, F, proportional to the displacement, x: where k is a positive constant.
Igor Yevgenyevich Tamm (a; 8 July 1895 – 12 April 1971) was a Soviet physicist who received the 1958 Nobel Prize in Physics, jointly with Pavel Alekseyevich Cherenkov and Ilya Mikhailovich Frank, for their 1934 discovery of Cherenkov radiation.
Infrared radiation (IR) is electromagnetic radiation (EMR) with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye (although IR at wavelengths up to 1050 nm from specially pulsed lasers can be seen by humans under certain conditions). It is sometimes called infrared light.
The Institute of Physics (IOP) is a scientific charity that works to advance physics education, research and application.
KDE Frameworks is a collection of libraries and software frameworks by KDE that serve as technological foundation for KDE Plasma 5 and KDE Applications distributed under the GNU Lesser General Public License (LGPL).
KDE Software Compilation 4 (KDE SC 4) was the only series of the so-called KDE Software Compilation (short: KDE SC), first released in January 2008 and the last release being 4.14.3 released in November 2014.
In physics, a lattice model is a physical model that is defined on a lattice, as opposed to the continuum of space or spacetime.
Linear elasticity is the mathematical study of how solid objects deform and become internally stressed due to prescribed loading conditions.
A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure.
Longitudinal waves are waves in which the displacement of the medium is in the same direction as, or the opposite direction to, the direction of propagation of the wave.
In condensed matter physics, the Lyddane–Sachs–Teller relation (or LST relation) determines the ratio of the natural frequency of longitudinal optic lattice vibrations (phonons) (\omega_L) of an ion crystal to the natural frequency of the transverse optical lattice vibration (\omega_T) for long wavelengths (zero wavevector).
Magnetism is a class of physical phenomena that are mediated by magnetic fields.
The many-body problem is a general name for a vast category of physical problems pertaining to the properties of microscopic systems made of a large number of interacting particles.
Matter waves are a central part of the theory of quantum mechanics, being an example of wave–particle duality.
A mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium.
A molecule is an electrically neutral group of two or more atoms held together by chemical bonds.
In Newtonian mechanics, linear momentum, translational momentum, or simply momentum (pl. momenta) is the product of the mass and velocity of an object.
Natural frequency is the frequency at which a system tends to oscillate in the absence of any driving or damping force.
Neutron scattering, the irregular dispersal of free neutrons by matter, can refer to either the naturally occurring physical process itself or to the man-made experimental techniques that use the natural process for investigating materials.
A normal mode of an oscillating system is a pattern of motion in which all parts of the system move sinusoidally with the same frequency and with a fixed phase relation.
In the field of digital signal processing, the sampling theorem is a fundamental bridge between continuous-time signals (often called "analog signals") and discrete-time signals (often called "digital signals").
In physics, an operator is a function over a space of physical states to another space of physical states.
In quantum mechanics, for systems where the total number of particles may not be preserved, the number operator is the observable that counts the number of particles.
Phonon is a cloud telephony company in Asia.
Phonons can scatter through several mechanisms as they travel through the material.
The photon is a type of elementary particle, the quantum of the electromagnetic field including electromagnetic radiation such as light, and the force carrier for the electromagnetic force (even when static via virtual particles).
In physics, a photon gas is a gas-like collection of photons, which has many of the same properties of a conventional gas like hydrogen or neon – including pressure, temperature, and entropy.
Physics (from knowledge of nature, from φύσις phýsis "nature") is the natural science that studies matterAt the start of The Feynman Lectures on Physics, Richard Feynman offers the atomic hypothesis as the single most prolific scientific concept: "If, in some cataclysm, all scientific knowledge were to be destroyed one sentence what statement would contain the most information in the fewest words? I believe it is that all things are made up of atoms – little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another..." and its motion and behavior through space and time and that studies the related entities of energy and force."Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events." Physics is one of the most fundamental scientific disciplines, and its main goal is to understand how the universe behaves."Physics is one of the most fundamental of the sciences. Scientists of all disciplines use the ideas of physics, including chemists who study the structure of molecules, paleontologists who try to reconstruct how dinosaurs walked, and climatologists who study how human activities affect the atmosphere and oceans. Physics is also the foundation of all engineering and technology. No engineer could design a flat-screen TV, an interplanetary spacecraft, or even a better mousetrap without first understanding the basic laws of physics. (...) You will come to see physics as a towering achievement of the human intellect in its quest to understand our world and ourselves."Physics is an experimental science. Physicists observe the phenomena of nature and try to find patterns that relate these phenomena.""Physics is the study of your world and the world and universe around you." Physics is one of the oldest academic disciplines and, through its inclusion of astronomy, perhaps the oldest. Over the last two millennia, physics, chemistry, biology, and certain branches of mathematics were a part of natural philosophy, but during the scientific revolution in the 17th century, these natural sciences emerged as unique research endeavors in their own right. Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms studied by other sciences and suggest new avenues of research in academic disciplines such as mathematics and philosophy. Advances in physics often enable advances in new technologies. For example, advances in the understanding of electromagnetism and nuclear physics led directly to the development of new products that have dramatically transformed modern-day society, such as television, computers, domestic appliances, and nuclear weapons; advances in thermodynamics led to the development of industrialization; and advances in mechanics inspired the development of calculus.
Polarization (also polarisation) is a property applying to transverse waves that specifies the geometrical orientation of the oscillations.
In physics, potential energy is the energy possessed by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors.
In geometry, crystallography, mineralogy, and solid state physics, a primitive cell is a minimum volume cell (a unit cell) corresponding to a single lattice point of a structure with discrete translational symmetry.
In theoretical physics, quantum field theory (QFT) is the theoretical framework for constructing quantum mechanical models of subatomic particles in particle physics and quasiparticles in condensed matter physics.
The quantum harmonic oscillator is the quantum-mechanical analog of the classical harmonic oscillator.
Quantum mechanics (QM; also known as quantum physics, quantum theory, the wave mechanical model, or matrix mechanics), including quantum field theory, is a fundamental theory in physics which describes nature at the smallest scales of energy levels of atoms and subatomic particles.
In physics, quasiparticles and collective excitations (which are closely related) are emergent phenomena that occur when a microscopically complicated system such as a solid behaves as if it contained different weakly interacting particles in free space.
Raman scattering or the Raman effect is the inelastic scattering of a photon by molecules which are excited to higher vibrational or rotational energy levels.
Randomness is the lack of pattern or predictability in events.
Rayleigh waves are a type of surface acoustic wave that travel along the surface of solids.
In physics, the reciprocal lattice represents the Fourier transform of another lattice (usually a Bravais lattice).
Relativistic heat conduction refers to the modelling of heat conduction (and similar diffusion processes) in a way not compatible with special relativity.
Rigid unit modes (RUMs) represent a class of lattice vibrations or phonons that exist in network materials such as quartz, cristobalite or zirconium tungstate.
Second quantization, also referred to as occupation number representation, is a formalism used to describe and analyze quantum many-body systems.
Second sound is a quantum mechanical phenomenon in which heat transfer occurs by wave-like motion, rather than by the more usual mechanism of diffusion.
In mathematics, a self-adjoint operator on a finite-dimensional complex vector space V with inner product \langle\cdot,\cdot\rangle is a linear map A (from V to itself) that is its own adjoint: \langle Av,w\rangle.
A shear stress, often denoted by (Greek: tau), is the component of stress coplanar with a material cross section.
Sodium chloride, also known as salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions.
Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma).
In physics, sound is a vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid.
Sound amplification by stimulated emission of radiation (SASER) refers to a device that emits acoustic radiation.
The Soviet Union, officially the Union of Soviet Socialist Republics (USSR) was a socialist state in Eurasia that existed from 1922 to 1991.
Space is the boundless three-dimensional extent in which objects and events have relative position and direction.
In mathematics, particularly in functional analysis, the spectrum of a bounded operator is a generalisation of the set of eigenvalues of a matrix.
The speed of light in vacuum, commonly denoted, is a universal physical constant important in many areas of physics.
The speed of sound is the distance travelled per unit time by a sound wave as it propagates through an elastic medium.
Spontaneous parametric down-conversion (also known as SPDC, parametric fluorescence or parametric scattering) is a nonlinear instant optical process that converts one photon of higher energy (namely, a pump photon), into a pair of photons (namely, a signal photon, and an idler photon) of lower energy, in accordance with the law of conservation of energy and law of conservation of momentum.
In physics, a squeezed coherent state is a quantum state that is usually described by two non-commuting observables having continuous spectra of eigenvalues.
In physics and systems theory, the superposition principle, also known as superposition property, states that, for all linear systems, the net response caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually.
A surface acoustic wave (SAW) is an acoustic wave traveling along the surface of a material exhibiting elasticity, with an amplitude that typically decays exponentially with depth into the substrate.
In solid state physics, a surface phonon is the quantum of a lattice vibration mode associated with a solid surface.
In mathematics, a Taylor series is a representation of a function as an infinite sum of terms that are calculated from the values of the function's derivatives at a single point.
Temperature is a physical quantity expressing hot and cold.
Thermal conductivity (often denoted k, λ, or κ) is the property of a material to conduct heat.
Thermodynamics is the branch of physics concerned with heat and temperature and their relation to energy and work.
A transverse wave is a moving wave that consists of oscillations occurring perpendicular (right angled) to the direction of energy transfer (or the propagation of the wave).
In molecular physics, the van der Waals forces, named after Dutch scientist Johannes Diderik van der Waals, are distance-dependent interactions between atoms or molecules.
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point.
Viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation.
In physics, a wave is a disturbance that transfers energy through matter or space, with little or no associated mass transport.
In physics, a wave vector (also spelled wavevector) is a vector which helps describe a wave.
Wave–particle duality is the concept in quantum mechanics that every particle or quantic entity may be partly described in terms not only of particles, but also of waves.
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.
In the physical sciences, the wavenumber (also wave number or repetency) is the spatial frequency of a wave, measured in cycles per unit distance or radians per unit distance.
Zero-point energy (ZPE) or ground state energy is the lowest possible energy that a quantum mechanical system may have.