# Potential well

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Potential well

A potential well is the region surrounding a local minimum of potential energy. Energy captured in a potential well is unable to convert to another type of energy (kinetic energy in the case of a gravitational potential well) because it is captured in the local minimum of a potential well. Therefore, a body may not proceed to the global minimum of potential energy, as it would naturally tend to due to entropy.

Overview

Energy may be released from a potential well if sufficient energy is added to the system such that the local minimum is surmounted. In quantum physics, potential energy may escape a potential well without added energy due to the probabilistic characteristics of quantum particles; in these cases a particle may be imagined to tunnel "through" the walls of a potential well.

The graph of a 2D potential energy function is a potential energy surface that can be imagined as the Earth's surface in a landscape of hills and valleys. Then a "potential well" would be a valley surrounded on all sides with higher terrain, which thus could be filled with water (i.e., be a lake) without any water flowing away toward another, lower minimum (i.e. sea level).

In the case of gravity, the region around a mass is a gravitational potential well, unless the density of the mass is so low that tidal forces from other masses are greater than the gravity of the body itself.

A potential hill is the opposite of a potential well, and is the region surrounding a local maximum.

Quantum confinement

Quantum confinement describes the increase in energy which occurs when the motion of a particle is restricted in one or more dimensions by a potential well. When the confining dimension is large compared to the wavelength of the particle, the particle behaves as if it were free. As the confining dimension decreases, the particle's energy increases. A quantum dot is a well that confines in all three dimensions such as a small sphere, a quantum wire confines in two dimensions, and a quantum well confines in one dimension.

ee also

* Quantum well "(quantum mechanics)"
* Particle in a box "(quantum mechanics)"
* Finite potential well "(quantum mechanics)"

References

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### Look at other dictionaries:

• potential well — noun or potential hole : a sharply defined region of minimum potential in a field of force compare potential barrier * * * potential well noun (physics) An area of low potential in a field of force • • • Main Entry: ↑potential …   Useful english dictionary

• potential well — potencinė duobė statusas T sritis chemija apibrėžtis Erdvės sritis, kurioje dalelės potencinė energija mažesnė nei gretimose srityse. atitikmenys: angl. potential hole; potential well rus. потенциальная яма …   Chemijos terminų aiškinamasis žodynas

• potential well — potencialo duobė statusas T sritis fizika atitikmenys: angl. potential hole; potential well vok. Potentialmulde, f; Potentialtopf, m rus. потенциальная яма, f pranc. cuvette de potentiel, f; puits de potentiel, m …   Fizikos terminų žodynas

• potential well — noun the region surrounding a local minimum of potential energy …   Wiktionary

• potential-well resonance — potencialo duobės rezonansas statusas T sritis fizika atitikmenys: angl. potential well resonance vok. Potentialkastenresonanz, f; Potentialtopfresonanz, f rus. резонанс потенциальной ямы, m pranc. résonance de puits de potentiel, f …   Fizikos terminų žodynas

• potential well depth — potencialo duobės gylis statusas T sritis fizika atitikmenys: angl. potential well depth vok. Potentialtiefe, f; Potentialtopftiefe, f rus. глубина потенциальной ямы, f pranc. profondeur du puits de potentiel, f …   Fizikos terminų žodynas

• Delta potential well — The Delta potential well is a common theoretical problem of quantum mechanics. It consists of a time independent Schrödinger equation for a particle in a potential well defined by a delta function in one dimension.DefinitionThe time independent… …   Wikipedia

• Finite potential well — The finite potential well (also known as the finite square well) is a simple problem from quantum mechanics. It is an extension of the infinite potential well, in which a particle is confined to a box, but one which has finite not infinite… …   Wikipedia

• Semicircular potential well — In quantum mechanics, the case of a particle in a one dimensional ring is similar to the particle in a box. The particle follows the path of a semicircle from 0 to pi where it cannot escape, because the potential from pi to 2 pi is infinite.… …   Wikipedia

• exponential potential well — eksponentinė potencialo duobė statusas T sritis fizika atitikmenys: angl. exponential potential well vok. Exponentialtopf, m; exponentieller Potentialtopf, m rus. экспоненциальная потенциальная яма, f pranc. puits de potentiel exponentiel, m …   Fizikos terminų žodynas