Analog models of gravity are attempts to
model
A model is an informative representation of an object, person or system. The term originally denoted the plans of a building in late 16th-century English, and derived via French and Italian ultimately from Latin ''modulus'', a measure.
Models c ...
various phenomena of
general relativity
General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics ...
(e.g.,
black holes or
cosmological
Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', and in 1731 taken up in Latin by German philosopher ...
geometries) using other
physical systems such as
acoustics in a moving
fluid,
superfluid
Superfluidity is the characteristic property of a fluid with zero viscosity which therefore flows without any loss of kinetic energy. When stirred, a superfluid forms vortices that continue to rotate indefinitely. Superfluidity occurs in two ...
helium
Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...
, or
Bose–Einstein condensate
In condensed matter physics, a Bose–Einstein condensate (BEC) is a state of matter that is typically formed when a gas of bosons at very low densities is cooled to temperatures very close to absolute zero (−273.15 °C or −459.6 ...
;
gravity waves
In fluid dynamics, gravity waves are waves generated in a fluid medium or at the interface between two media when the force of gravity or buoyancy tries to restore equilibrium. An example of such an interface is that between the atmosphere ...
in water; and propagation of
electromagnetic waves in a
dielectric
In electromagnetism, a dielectric (or dielectric medium) is an electrical insulator that can be polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the mate ...
medium. These analogs (or analogies) serve to provide new ways of looking at problems, permit ideas from other realms of science to be applied, and may create opportunities for practical experiments within the analog that can be applied back to the source phenomena.
History
Analog models of gravity have been used in hundreds of published articles in the last decade. The use of these analogs can be traced back to the very start of scientific theories for gravity, with
Newton and
Einstein.
Bose-Einstein condensates
It has been shown that Bose-Einstein condensates (BEC) are a good platform to study analog gravity. Kerr (rotating) black holes have been implemented in a BEC of
exciton-polaritons
In physics the Exciton–polariton is a type of polariton; a hybrid light and matter quasiparticle arising from the strong coupling of the electromagnetic dipolar oscillations of excitons (either in bulk or quantum wells) and photons. Because light ...
(a quantum fluid of light).
See also
*
Acoustic metric
*
Transformation optics
Transformation optics is a branch of optics which applies metamaterials to produce spatial variations, derived from coordinate transformations, which can direct chosen bandwidths of electromagnetic radiation. This can allow for the constructi ...
*
Optical metric#Analogue gravity
*
Optical black hole
*
Sonic black hole
References
General relativity
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