絕對真空
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絕對真空(英語:Absolute vacuum),亦作完美真空(Perfect vacuum)[1],是指一個理論上沒有任何物質的封閉的空間,是一種理論上理想的真空狀態(氣壓=0),以目前的科技尚難達到。
在壓力測量領域,由於現代許多高精密度的產品在製造過程中的某些階段必需使用程度不一的真空才能製造,絕對真空是真空技術中按照壓力的高低而區分的五個級別的最高級別,內裏只有0 Torr,比其次一級的超高真空(Ultra-High Vacuum)所要求的10-7 Torr以下還要嚴謹。
另外,在古典電磁學的定義,完美真空是電磁效應的一個標準參考媒介[2][3],所以亦有作者把這種真空狀態稱為「古典真空」[2],以與量子力學其他有關真空的術語如「量子電動力學真空」(QED vacuum)或「量子色動力學真空」(QCD vacuum)等透過可以產生短暫的虛粒子密度和相對介電常數與相對磁導率兩項並不統一的真空波動環境[4][5][6]區分。
參考資料
編輯- ^ Definition of Absolute Vacuum [絕對真空的定義]. about.com. [2014-03-29]. (原始內容存檔於2014-07-10) (英語).
- ^ 2.0 2.1 Werner S. Weiglhofer. § 4.1 The classical vacuum as reference medium. Werner S. Weiglhofer and Akhlesh Lakhtakia, eds (編). Introduction to complex mediums for optics and electromagnetics. SPIE Press. 2003: 28, 34. ISBN 978-0-8194-4947-4.
- ^ Tom G. MacKay. Electromagnetic Fields in Linear Bianisotropic Mediums. Emil Wolf (編). Progress in Optics, Volume 51. Elsevier. 2008: 143 [2014-04-01]. ISBN 978-0-444-52038-8. (原始內容存檔於2021-04-14).
- ^ Gilbert Grynberg, Alain Aspect, Claude Fabre. Introduction to Quantum Optics: From the Semi-Classical Approach to Quantized Light. Cambridge University Press. 2010: 341 [2014-04-01]. ISBN 0-521-55112-9. (原始內容存檔於2021-04-14).
...deals with the quantum vacuum where, in contrast to the classical vacuum, radiation has properties, in particular, fluctuations, with which one can associate physical effects.
- ^ For a qualitative description of vacuum fluctuations and virtual particles, see Leonard Susskind. The cosmic landscape: string theory and the illusion of intelligent design. Little, Brown and Co. 2006: 60 ff [2014-04-01]. ISBN 0-316-01333-1. (原始內容存檔於2021-04-14).
- ^ The relative permeability and permittivity of field-theoretic vacuums is described in Kurt Gottfried, Victor Frederick Weisskopf. Concepts of particle physics, Volume 2. Oxford University Press. 1986: 389 [2014-04-01]. ISBN 0-19-503393-0. (原始內容存檔於2021-04-14). and more recently in John F. Donoghue, Eugene Golowich, Barry R. Holstein. Dynamics of the standard model. Cambridge University Press. 1994: 47 [2014-04-01]. ISBN 0-521-47652-6. (原始內容存檔於2021-04-14). and also R. Keith Ellis, W. J. Stirling, B. R. Webber. QCD and collider physics. Cambridge University Press. 2003: 27–29 [2014-04-01]. ISBN 0-521-54589-7. (原始內容存檔於2021-04-14).
Returning to the vacuum of a relativistic field theory, we find that both paramagnetic and diamagnetic contributions are present.
QCD vacuum is paramagnetic, while QED vacuum is diamagnetic. See Carlos A. Bertulani. Nuclear physics in a nutshell. Princeton University Press. 2007: 26 [2014-04-01]. ISBN 0-691-12505-8. (原始內容存檔於2021-04-14).