Gluon field
In theoretical particle physics, the gluon field is a four vector field characterizing the propagation of gluons in the strong interaction between quarks. It plays the same role in quantum chromodynamics as the electromagnetic four-potential in quantum electrodynamics - the gluon field constructs the gluon field strength tensor.
Throughout, Latin indices take values 1, 2, ..., 8 for the eight gluon color charges, while Greek indices take values 0 for timelike components and 1, 2, 3 for spacelike components of four-dimensional vectors and tensors in spacetime. Throughout all equations, the summation convention is used on all color and tensor indices, unless explicitly stated otherwise.
Introduction
Gluons can have eight colour charges so there are eight fields, in contrast to photons which are neutral and so there is only one photon field.
The gluon fields for each color charge each have a "timelike" component analogous to the electric potential, and three "spacelike" components analogous to the magnetic vector potential. Using similar symbols:
Field
Field may refer to:
Expanses of open ground
People
Places
Settlements in Canada
Settlements in the United States
Science and mathematics
Field (agriculture)
In agriculture, a field is an area of land, enclosed or otherwise, used for agricultural purposes such as cultivating crops or as a paddock or other enclosure for livestock. A field may also be an area left to lie fallow or as arable land.
Many farms have a field border, usually composed of a strip of shrubs and vegetation, used to provide food and cover necessary for the survival of wildlife. It has been found that these borders may lead to an increased variety of animals and plants in the area, but also in some cases a decreased yield of crops.
Language
In Australian and New Zealand English, any agricultural field may be called a paddock. If stock are grazed there, the space may be called a run, e.g. sheep run; cattle run.
Image gallery
A green field or paddock with Hereford cattle
A green field or paddock with Hereford cattle
A summer field
A summer field
Spring fields with trees, Majorca, Spain, 2004
Spring fields with trees, Majorca, Spain, 2004
Field (video)
In video, a field is one of the many still images which are displayed sequentially to create the impression of motion on the screen. Two fields comprise one video frame. When the fields are displayed on a video monitor they are "interlaced" so that the content of one field will be used on all of the odd-numbered lines on the screen and the other field will be displayed on the even lines. Converting fields to a still frame image requires a process called deinterlacing, in which the missing lines are duplicated or interpolated to recreate the information that would have been contained in the discarded field. Since each field contains only half of the information of a full frame, however, deinterlaced images do not have the resolution of a full frame.
In order to increase the resolution of video images, therefore, new schemes have been created that capture full-frame images for each frame. Video composed of such frames is called progressive scan video.
Video shot with a standard video camera format such as S-VHS or Mini-DV is often interlaced when created, whereas video shot with a film-based camera is almost always progressive. Free-to-air analog TV was mostly broadcast as interlaced material because the trade-off of spatial resolution for frame-rate reduced flickering on Cathode ray tube (CRT) televisions. High-definition digital television (see: HDTV) today can be broadcast terrestrially or distributed through cable system in either interlaced (1080i) or progressive scan formats (720p or 1080p). Most prosumer camcorders can record in progressive scan formats.
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