Re: Symmetric language

Edward Green wrote:
>
> Uncle Al wrote:
>
> > Edward Green wrote:
>
> > > Some characterisitic language used in the description of symmetries
> > > existing or lacking in physical law seems to be rather misleading.
>
> > > The symmetries are said to be "conserved", but the conservation of a
> > > physical quantity is not implied; there is no conserved physical
> > > quantity called "parity".
> >
> > Oh yes there is! Your ignorance does not influence reality's
> > content.
> >
> > http://physics.nist.gov/GenInt/Parity/cover.html
>
> "Between Christmas of 1956 and New Year's Day, the first exciting
> results emerged from a difficult but fundamental scientific experiment
> at the National Bureau of Standards (NBS) in Washington, DC [currently
> the National Institute of Standards and Technology (NIST)]. The
> experiment showed, strikingly and convincingly, that in at least one
> fundamental physical process, our world is distinguishable from its
> mirror image."
>
> Thus far I have no quarrel.
>
> "Physicists had long assumed the opposite. They constructed their
> theories so as to ensure that the corresponding mathematical property,
> called parity, remains unaltered - is conserved - in all subatomic
> processes. Thus this experiment brought about the fall of parity from
> its exalted position alongside such well conserved physical quantities
> as energy, momentum, and electric charge."
>
> Well then, Al, either this is simply another example of poor language,
> or I am indeed mistaken. I have no doubt many professionals _say_
> "parity is conserved" or "parity is not conserved", but I think they
> speak this way out of habit rather than reflection.

Ignorant idiot.

[snip]

> Charge reversal, time reversal and parity reversal are not continuous
> transformations, and as far as I know no conserved quantities attach to
> discrete symmetries through Noether's theorem.

You are light on math and empty of known content.

> I know just enough to be dangerous. ;-)

You harbor unbounded delusions of competence.

[snip]

> > Inversion of
> > all coordinates is a discrete process that cannot be approximated by a
> > Taylor series. Parity the symmetry is linked to parity the property
> > by other strong correspondences. Parity is conserved by strong
> > interactions but commonly violated by weak interactions (including the
> > Weak Interaction). As gravitation is the weakest known force, one
> > might optimistically expect a metric (parity-conserving) vs. affine
> > (parity-violating) gravitation anomaly.
>
> As usual, you have loaded your canon with every bit of scrap you found
> lying on the field, and some of it I do not recognize nor can I answer.
> It is an old technique. Nonetheless, I have the conviction of a
> simple conceptual clarity: A physical law is invariant with respect to
> a certain symmetry if the corresponding change of variables leaves the
> form of the law unchanged. Now, it might be that every physicist in
> the world speaks of a physical law or interaction having this property
> with respect to coordinate reflection as "conserving parity", but I
> would respectfully point out, sir or ma'am, that I honor the weight of
> culture, but your habitual language is inexact.

Empirical demonstration of parity nonconservation in January 1957

http://physics.nist.gov/GenInt/Parity/cover.html

made Tsung Dao Lee and Chen Ning Yang Noble Laureates/Physics in
December 1957. The speed record still stands. The first test of
gravitational parity violation will be complete in mid-September. The
whole of physics is looking for Lorentz violation,

http://www.physics.indiana.edu/~kostelec/faq.html

Uncle Al simply got there first - unburdened by PERT charts, budget,
staff, management, equipment, progress reports... or expectations of
productivity. He called out to the Severely Gifted and they
volunteered an Army of Light. If it succeeds at the end, so much the
better.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
.

Relevant Pages

  • Re: Symmetric language
    ... > existing or lacking in physical law seems to be rather misleading. ... Both C and P are symmetries that are ... P is called parity ... > the reversal of charge or coordinates. ...
    (sci.physics)
  • Re: weak field and space-time symmetry
    ... "It follows that internal symmetries of the weak interactions can be ... Big Bang vacuum contained a chiral pseudoscalar background, ... parity asymmetry of the Weak interaction. ... Remnant dilute vacuum chiral background anisotropy sourced ...
    (sci.physics)