Re: What exactly is the vacuum catastrophe and what effects does this have upon our understanding of the universe?

Newsgroups	sci.physics
Date	2015-09-21 12:39 -0700
References	<j8GdnTPhx75kg2LInZ2dnUU7-f2dnZ2d@giganews.com>
Message-ID	<91c635f7-edcc-49d8-bb97-46aaf2b3d5a4@googlegroups.com> (permalink)
Subject	Re: What exactly is the vacuum catastrophe and what effects does this have upon our understanding of the universe?
From	Double-A <double-a3@hush.com>

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On Sunday, September 20, 2015 at 2:02:56 PM UTC-7, Sam Wormley wrote:
> What exactly is the vacuum catastrophe and what effects does this have 
> upon our understanding of the universe?
> > http://www.askamathematician.com/2011/06/q-what-exactly-is-the-vacuum-catastrophe-and-what-effects-does-this-have-upon-our-understanding-of-the-universe/
> 
> > Physicist: The vacuum catastrophe is sometimes cited as the biggest
> > disagreement between theory and experiment ever.  They disagree by a
> > factor of at least 10^107.
> >
> > According to quantum field theory the energy of empty space can't
> > quite be zero.  In fact, QFT gives us an exact value for how much
> > energy empty space should have.  Although we can never access that
> > energy, it does have a gravitational effect.
> >
> > One of the (many) things the Voyager probes did was allow us to
> > estimate how strong those gravitational effects are.  Unfortunately,
> > they determined that the theoretical predictions are way, way, way
> > off (too high).
> >
> > There's a short paper here aimed at the undergraduate physics crowd
> > that covers this better than I do.
> >
> > It's a catastrophe because QFT is otherwise a stunningly accurate
> > theory (the most accurate ever, by far).  But, at the end of the day,
> > you have to fall back on observation, so something about our favorite
> > theory is wrong.
> >
> > One result of the Heisenberg Uncertainty Principle is that it's
> > impossible for a system to be in a zero-energy state.  In a nutshell:
> > if a particle definitely has zero energy, then it's definitely not
> > moving and its momentum is zero.  However, to get that level of
> > certainty you need the position to be completely uncertain and (for
> > various reasons) that's untenable.  You can run through this
> > mathematically, and you find that systems always have just a tiny bit
> > more than zero energy, and that that energy is proportional to
> > \frac{\omega}{2}, where \omega is the frequency of the
> > particle/system in question.  That little bit of energy is called the
> > "ground state energy" or just "ground energy".
> >
> > The same thing applies to all particle fields, but rather than
> > generalize, I'll just talk about light: the electromagnetic (EM)
> > field.  It turns out that every frequency of the EM field, at every
> > point in space, is its own tiny system (not at all obvious; that
> > falls out of the math).  As a result, instead of a tiny ground state
> > energy for a single system, in any given region of space you have
> > lots of systems.  These form the ground state energy density, which
> > is more commonly known as the "zero point energy".


Well then I guess it's back to the drawing board.

Double-A

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