My tendency is to say that wormholes do not exist. There are problems with
these types of solutions. The biggest is they requires a source term that
has negative energy or T^{00} < 0. This would mean the quantum field that
defines this source is not bounded below. This means an infinite well
spring of radiation can exist.
These types of spacetimes have other oddities. A wormhole can have one of
its openings boosted or accelerated out and then accelerated back so the
wormhole has closed timelike curves. This means a quantum state could be
sent into the wormhole and it would return prior to then. This means a
quantum state is duplicated. This is a non-unitary process forbidden by
quantum mechanics. So I see this as another obstruction to the idea of
wormholes.
The ring down, and I think as well the peak, of gravitational radiation may
carry information about the quantum nature of black holes. Certainly if
wormholes collide the quantum information of the wormhole would be
contained in these signals or ring down. These types of data will likely
require a spacebased system such as e-LISA in order to capture so called
gravitational memory. This is where the configuration of test masses is
different after the passage of the gravitational wave. The earliest
projected launch date ESA will loft this system is 2034. We have a bit of a
wait.
LC
On Saturday, June 23, 2018 at 3:01:53 PM UTC-5, cdemorsella wrote:
>
> As LIGO increases its sensitivity it is entering a domain in which its
> instruments should be able to detect theorized ring down phase echoes (this
> is the very last portion of a merging event of massive bodies that produces
> a rapidly increasing frequency of waves that lead up to the moment of
> merging, as the two merging objects undergo a final increasingly tight
> cycle of rapidly narrowing orbits right before merging)
>
> This increased sensitivity shouldd enable it to discoverif these
> hypothetical echoes if they actually are being produced by the observed
> event.
>
> If such echoes are discovered in these signals that would have major
> implications for cosmology and would be evidence for the actual existence
> of wormholes in our universe.
>
>
> Quoting some selected paragraphs, from a Scientific American article:
>
> "When two wormholes collide, they could produce ripples in space-time
> that ricochet off themselves. Future instruments could detect these
> gravitational “echoes,” providing evidence that these hypothetical tunnels
> through space-time actually exist, a new paper suggests.
> ...
>
> To resolve this so-called black hole information paradox
> <https://www.livescience.com/62028-hawking-death-paradox-question-science.html>,
>
> some physicists have suggested that event horizons don’t exist. Instead of
> abysses from which nothing can return, black holes actually could be a host
> of speculative black-hole-like objects that lack event horizons, such as
> boson stars, gravastars, fuzzballs and even wormholes, which were theorized
> by Albert Einstein and physicist Nathan Rosen decades ago.
> ....
>
> In a 2016 study in the journal Physical Review Letters, physicists
> hypothesized
> <https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.171101> that
> if two wormholes collided, they would produce gravitational waves very
> similar to those generated from merging black holes. The only difference in
> the signal would be in the last phase of the merger, called the ringdown,
> when the newly combined black hole or wormhole relaxes into its final state.
> ...
>
> In the paper
> <https://journals.aps.org/prd/abstract/10.1103/PhysRevD.97.024040>,
> published in January in the journal Physical Review D, the team of
> physicists from Belgium and Spain analyzed wormholes that rotate, which are
> more realistic than the non-spinning variety studied in the 2016 work. They
> calculated what the resulting gravitational-wave signal would look like if
> the wormholes merged.
>
> Because the strength of the signal drops during the ringdown, that section
> of the signal would be too weak for LIGO’s current configuration to detect.
> But that could change in the future, as researchers continue to upgrade and
> fine-tune the instrument, the researchers said.
>
>
> “By the time we are running at full design sensitivity, I believe it may
> be possible to resolve the ringdown phase where these echoes are predicted
> to be,” said Stuver, who’s also a member of the LIGO team."
>
>
>
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