Vacuum (disambiguation)

This disambiguation page lists articles associated with the same or a similar title.

• Vacuum (partial) [r]: A realizable vacuum with a gaseous pressure that is much less than atmospheric. ^[e] The term partial vacuum refers to real vacuums which can be obtained and observed.
• Vacuum (quantum electrodynamic) [r]: The term quantum electrodynamic vacuum, or QED vacuum, refers to the ground state of the electromagnetic field, which is subject to fluctuations about a dormant zero average-field condition. ^[e] The term quantum electrodynamic vacuum, or QED, refers to refers to the ground state of the electromagnetic field, which is subject to fluctuations about a dormant zero average-field condition.
• Vacuum (partial) [r]: A realizable vacuum with a gaseous pressure that is much less than atmospheric. ^[e] The term partial vacuum refers to real vacuums which can be obtained and observed.
• Vacuum (classical) [r]: The term classical vacuum as used in classical electromagnetism and in the definition of the SI units refers to an ideal reference medium devoid of all particles, with ideal properties. These ideal properties include: independence from field strengths, direction, frequency, or polarization, and from temperature. ^[e] The term classical vacuum refers to a perfect vacuum (or free space) that is completely empty of matter having a gaseous pressure of exactly zero; as zero pressure cannot be attained in practice, this situation an idealization useful as a reference state, but is not realizable.