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From: mike@bambi.UUCP (Michael Caplinger)
Newsgroups: net.physics
Subject: tachyons and Cherenkov radiation
Message-ID: <166@bambi.UUCP>
Date: Wed, 11-Dec-85 16:51:32 EST
Article-I.D.: bambi.166
Posted: Wed Dec 11 16:51:32 1985
Date-Received: Sat, 14-Dec-85 04:07:12 EST
Distribution: net
Organization: Bell Communications Research Inc., Morristown, NJ
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Can anybody tell me why a charged tachyon moving through free space would
generate Cherenkov radiation?  I thought I understood the mechanism by which
"ordinary" Cherenkov radiation was generated (say, that caused by fast
neutrons in water) but that involves atomic transitions in surrounding atoms
in the medium, no?

A reference in Physical Review (Phys Rev, v171 #5, 1357-1361 (July 25, 1968)
Alvager and Krieser) references an ancient paper (late 1800s) to "prove" this,
but I didn't want to track that reference down, and didn't believe it anyway
(predates QM, almost!).

Since Cherenkov radiation was used in an unsuccessful attempt to detect
charged tachyons (see reference above), I wondered why you would expect it
in the first place.  Is it necessary to resort to QED or "vacuum
fluctuation" arguments?

        Michael Caplinger
        mike@bellcore.arpa
        ihnp4!bambi!mike