From: OsherD on
From Osher Doctorow

The curious things that are happening with modified/generalized GR or
even alternative theories of Gravity and with Rigged and Nested
Hilbert Spaces, are now happening with "Pseudo-Hermitian"
representations of QM that appear to generalize/extend QM and reveal
some new physical applications that could not be obtained from
standard QM, as shown by Ali Mostafazadeh of Kac University Istanbul
Turkey.

Before I go on, skeptics might be interested in what happens in
Linguistics of all places when "slight modifications" are noticed by
researchers in languages, dialects, etc. It turns out quite often
that "slight modifications" indicate enormous changes over centuries
or even millenia in languages and whole language families.

The paper of Mostafazadeh is:

1) "Pseudo-Hermitian representation of quantum mechanics," arXiv:
0810.5643 [quant-ph] 25 May 2010, 76 pages.

Roughly speaking, the idea is that there's a certain freedom in
choosing the inner product for Hilbert Spaces because it isn't
"independently measured" from anything. This may seem on the surface
like a triviality, but it leads to new applications in nuclear
physics, condensed matter physics, quantum chaos, biophysics,
magnetohydrodynamics, electromagnetic wave propagation, open quantum
systems, quantum cosmology, relativistic quantum mechanics and quantum
field theory, etc. It turns out that a "metric operator" plays a
central role in this, and that inner products that make 2 complex
vector spaces into 2 separable Hilbert Spaces are in a 1-1
correspondence with metric operators acting in ONE of these Hilbert
spaces.

I will try to continue this later. Lately, financial difficulties
(especially ones that hurt Seniors) are requiring me to divide my
typing time on the internet in unusual ways (usually much less typing
time than before).

Osher Doctorow
From: OsherD on
From Osher Doctorow

Indefinite-Metric Quantum theories are examples of such
generalizations and extensions. ArXiv has 8 papers and 30 papers
respectively on:

1) "Indefinite-Metric quantum" 8 papers.
2) "Indefinite Metric" 30 papers.

Note that a given quantum system admits an infinity of unitary-
equivalent representations in terms of Hilbert Space - Hermitian
operator pairs, which gives considerable freedom in choice of
representations somewhat analogous to Gauge Symmetries in elementary
particle physics.

By the way, in reference to an earlier post, Jan Lukaciewicz of Poland
lived from 1878 to 1956.

Osher Doctorow