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Date: Wed, 31 Mar 1999 08:43:22 -0500 (EST)
From: Alfred M Kriman <akriman@darwin.helios.nd.edu>
Message-Id: <199903311343.IAA11945@darwin.helios.nd.edu>
To: classics@u.washington.edu
Subject: Re: trapping air

Laval Hunsuker points out
> Apart from the Classics, maybe there's really something to it. They seem to
> be working on it :-). Here's a recent article I came across:
> 
> "Trapped Second Sound Waves on a Nonequilibrium Superfluid-Normal Interface",
> by Peter B. Weichman, Anoop Prasad, Ranjan Mukhopadhyay, Jonathan Miller, in
> _Physical review letters_  Vol. 80  (Issue 22), 1998, p. 4923-4926 (4).

At low temperatures, quantum effects are manifested in large (i.e.,
hold-in-your-hand-size, as opposed to see-in-the-microscope-size)
systems.  Superfluid and superconducting behaviors are fluid and
electric current flows not subject to dissipation.  In particular,
this means they are ``persistent,'' a modest word for eternal.
Although superconductivity has been achieved at near-room temperature
(almost 200K, or -73C, about -100F, last I recall) in almost ordinary
ceramics, the only superfluids are still helium, at temperatures like
4K.

If there are undiscovered room-temperature superconductors, then they
should have been formed accidentally in small quantities.  Accidental
temporary contact with a piezoelectric material, persistent AC and
some other luck, and you'd have your really ancient (as opposed to
seventies-vintage) eight-track.

There is no shortage of (much more realistic, even probable) accidental
recording mechanisms.  The problem is knowing what to play back how.

.