vacuum

中文： 真空

1. A region of space that contains no matter.
2. The condition of rarefaction, or reduction of pressure below that of the atmosphere, in a vessel, such as the condenser of a steam engine, which is nearly exhausted of air or steam, etc. · a vacuum of 26 inches of mercury, or 13 pounds per square inch
3. A spacetime having tensors of zero magnitude.
4. A ground state of a quantum field or of local spacetime, or more abstractly the lowest-energy state of a system.
5. A description of spacetime resulting from a particular compactification of spatial dimensions.
6. An emptiness in life created by a loss of a person who was close, or of an occupation.
7. An exercise in which one draws their abdomen towards the spine.

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