The Modified Dynamics as a Vacuum Effect.pdfVIP

The modified dynamics as a vacuum effect Mordehai Milgrom Department of condensed-matter physics, Weizmann Institute, Rehovot Israel To explain the appearance in MOND of a cosmological acceleration constant, a , I suggest that 0 MOND inertia–as embodied in the actions of free particles and fields–is due to effects of the vacuum. The same vacuum effects enter both MOND (through a ) and cosmology (e.g. through a cosmological 0 constant Λ). For example, a constant-acceleration (a) observer in de Sitter universe sees Unruh 2 2 1/2 1/2 radiation of temperature T ∝ [a + a ] , with a0 ≡ (Λ/3) , and I note that T (a) − T (0) depends 0 on a in the same way that MOND inertia does. 9 I. INTRODUCTION 9 9 1 The modified dynamics (MOND) has been propounded [1] as an alternative to the dark-matter doctrine, attributing the mass discrepancy evinced by galaxies and galaxy systems to a breakdown of standard dynamics. The pristine n version of MOND states that dynamics is to be modified in the limit of small accelerations, such as are found in galactic a J systems. (This is analogous to viewing quantum mechanics as a modification of classical mechanics in the limit of small angular momenta.) More precisely, MOND asserts that non-