Natural Science Forum / Physics / Research / January 2006

I read today (http://www.physics.usyd.edu.au/hienergy/stdmodel.html)
that: "It is currently thought, on the basis of Super Kamiokande
result, that neutrinos have mass. Yet, we do not know whether this
would mean that, as Majorana suggested, the neutrino is its own

I frequently read how inflation caused the size of the universe to
expand many times over and I was wondering what is the physical
mechanism that causes actual space to expand.  
Thanks,

I have heard it said that there is exist shapes in the world, shapes such as
the shapes and symmetries of flowers, crystals (and cabbages and kings)
exactly because atoms aren't all spherically symmetric. Most  atoms (taking
higher orbitals of hydrogenic atoms as a guide) have ...

Starting with the pathintegral of a gauge theory, say Qed to keep it
simple, and (Grassmann-)integrating out a quadratic fermion action you
end up with a determinant of the Dirac Operator essentialy. It is
always said that we get a nonlocal contribution to the action that way.

A photon emitted by an atom(clock)  at a lower potential in a static
gravitational field undergoes a redshift when it is absorbed and
emitted by another atom at a higher potential. My question is:
why does not or should not a photon undergo a redshift in a static

I am really new one. My question is what is difference between Entropy
and Variance of R.V. Are Entropy and Variance equal in providing
information in physics? I try to understand them.
Thanks for any comments.

 I recently tried to understand general relativity. Basically, I have
seen how can one construct from the action principle the equations of
motion of particles or classical fields and the equations of motion of
the curvature of the space-time (Einstein equations). I was wondering

In every situation I'm aware of, energy states exist because of some
force that gives rise to them (dE/dx, y'know). What force did Dirac
envision as giving rise to his proposed negative energy states (from
which antimatter arises)? When I see it described in textbooks, the

When Feynman was at Cornell while eating lunch in the cafeteria he
observed a student throwing a plate and noticed that the blue school
logo spun around faster than the wobble of the plate. For the fun of it
he worked out the equation of motion which showed that if the wobble is

Does someone know the conjugacy classes in the groups
SO(4,1) and SO(3,2)?  I might be even happier if someone
had worked out a classification of conjugacy classes for
every real simple Lie group, but I need to know these cases

Can somebody suggest me good references on physics of a body falling in
a viscous fluid like water? What is the equation of motion F = mx"(t)
in water and how can it be solved for x(t)?
-pj

Dear friends, I am doing PHD on the subject of turbulence......I have
just started....Could anyone have any idea that is there a system which
has such a parameter which if varied continously changes the "box
dimension" of the system continously?? I am glad to have joined this

I was wondering whether it were possible that every particle in the
universe is entangled with every other.  The argument goes: at the
moment of the Big Bang, this was the case(dubious).  Once everything is
entangled, it remains so for the rest of eternity.

What is quantum measurement problem?
Why do people say decoherence does not solve the quantum measurement
problem?
Thank your for any of your comment.

OK, I am reviewing my basic quantum mechanics by watching Jim Branson's
QM class on streaming video. There is something he keeps say that
bothers me. He keeps saying that a wave function like exp(ikx) can't be
normalized to "one particle" and so must be a beam of particles?