A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

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Use this for questions relating to the proper use of physics terminology or nomenclature.
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Concerns the application of the laws of physics to analyze common situations encountered in everyday life.
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the energy of a body or a system due to the position of the body or the arrangement of the particles of the system.
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For questions where the dynamical variables are fields, that is, functions of several variables (typically, one time coordinate and several space coordinates). Comprises both classical field theory an…
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A model of the basic particles and forces featuring six quarks, three charged leptons, three massless neutral leptons and four fundamental force carrying bosons. The twelve fermions are arranged into …
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used to describe any system with a "linear" restoring force that tends to return the system to an equilibrium state. There is both a classical harmonic oscillator and…
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Geometric object with magnitude (length) and direction.
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The time rate of change of the position of an object
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A gauge theory has internal degrees of freedom that do not affect the foretold physical outcomes of the theory. The theory has a Lie group of *continuous symmetries* of these internal degrees of freed…
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Two Hydrogen atoms covalently bonded to one Oxygen atom. One of the more common compounds on the surface of the earth.
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quantify location in space.
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the quantum field theory believed to describe electromagnetic interaction. It is the simplest example of a quantum gauge theory, where the gauge group is abelian, U(1)…
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Questions that ask about some aspect of physics research or study which doesn't involve the actual physics. In general, soft questions can be answered without using physical reasoning.
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The universe refers to the cosmos; all of space-time and that which exists as part of it. Alternatively, it can refer to the observable universe, which only contains the part we can see. Questions tag…
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a cosmological phenomenon wherein the proper distance between two spatial points for a given inertial reference frame increases from one moment of time to another. That is, space it…
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A specific reference frame that describes its coordinates in a manner that does not depend on time and is isotropic.
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a formalism in Classical Mechanics. Besides Lagrangian Mechanics, it is an effective way of reformulating classical mechanics in a simple way. Very useful in Quantum Mecha…
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the mechanism by which quantum correlations between two sub-systems survive even after being physically separated from an interaction region. The correlations could in principl…
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a branch of abstract algebra. A group is a set of objects, together with a binary operation, that satisfies four axioms. The set must be closed under the operation and contain an ident…
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a systematic extension of vector calculus to multivector and tensor fields in a form that is independent of the choice of coordinates on the relevant manifold, but…
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The study of how the properties of matter arise from its structure at all scales and of how processing can be used to modify those properties (often in pursuit of a specific application).
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The ability of an object to store electric charge.
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the unit of measurement for electronic potential, from one point location to another.
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Interaction between two or more bodies that results in physical contact and an exchange of momentum between the bodies involved.
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The union of special (SR) and general (GR) relativity. Use this tag if both SR and GR apply.
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the branch of solid state physics that focuses on specific properties of semiconductors. It studies dynamics of different perturbations (mainly electrons and holes) in the sem…
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an ensemble of techniques which serves to treat the infinities which appear in quantum field theory or statistical mechanics.
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a process in which energetic particles or energetic waves travel through a medium or space. The particles or waves radiate (i.e., travel outward in all directions) from a source.
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Light Amplification by Stimulated Emission of Radiation. A means of creating coherent light by either driving an atomic or molecular transition in an optical cavity or firing a beam of electrons throu…
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a set of agreed, stipulated, or generally accepted norms. It typically helps common efficiency or understanding but is not required, as opposed to a strict standard or protocol.
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a general term for several physical processes in which radiation of some sort changes direction due to an interaction with a particle. Scattering can be classified by the type of radiati…
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Change in the direction of propagation of a wave when its transmitting medium changes.
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the discipline that studies electromagnetic phenomena – such as electric and magnetic fields, radiation, and the dynamics of charged bodies – in classical terms.
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should be about computational physics, which is the study of physical situations with the use of software (commercial or in-house). Please note that details of writing and/or …
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for Heisenberg's quantum mechanical uncertainty principle. DO NOT USE THIS TAG for uncertainty in a non-quantum measurement.