Chronos said:
How weak is the vacuum polarization effect? Weak enough that it has never been directly detected:
http://arxiv.org/abs/physics/0402073
Ultrafast Resonant Polarization Interferometry: Towards the First Direct Detection of Vacuum Polarization
Or you can try looking where the background field is a billion trillion times stronger than the ground state:
http://arxiv.org/abs/astro-ph/0502351The High-Energy Polarization-Limiting Radius of Neutron Star Magnetospheres II -- Magnetized Hydrogen Atmospheres
As you well know, it is my contention that the vacuum fields are polarized by the presence of matter due to a differential in the gravitational infall rates of matter vs antimatter. You have cited non-detections of vacuum polarization in the presence of electromagnetic fields. These non-detections are not surprising to me. If we put a Casimir device in Earth orbit and orient it with the plates perpendicular to the Earthward direction for a number of orbits then orient it with the plates parallel to the Earthward direction for a number of orbits, I believe we will see differences in the Casimir force that will demonstrate the vacuum polarization and density differences caused by the Earth, the Moon, and the Sun.
Chronos said:
It has only been detected indirectly in colliders:
http://www.ihep.ac.cn/data/ichep04/p_paper/4_ew/411-cushman-p/ichep04_g2new.pdf.
How does this support your assertion that vacuum polarization can only be detectable on nuclear scales? Just because someone looked at nuclear scales does not constrain the effects of vacuum polarization to nuclear scales. People are looking for dark matter candidates at nuclear scales. If one were detected at that scale, would you refuse to believe that the particles could have a combined effect on galactic scales? As for scales of detection, I believe we see the optical effects of vacuum polarization in every instance of astronomical lensing.
Chronos said:
What transmissive medium are you referring to? Asserting that light [an EM field] requires the EM field of the vacuum as a medium to propogate is not very satisfactory. It raises the question of what medium the vacuum EM field relies upon for its propogation. And how do photons, in the absence of matter, interact with each other causing refraction? That sounds like new physics to me. Have any references to that gound breaking paper? I probably wouldn't be the only one to question that experimental result, assuming there is one.
The transmissive medium through which EM waves propagate is the EM field of the vacuum (ZPE field). It's funny how many people cling to Einstein and his GR without understanding his motivations. I urge you to cite even one paper or letter in which Einstein characterized light as "photons". He always treated light as EM waves, and waves propagate though fields. Einstein believed in an aether because it is needed to transmit EM waves, however he could not reconcile it with GR, so he modeled it as it if it had no other properties beyond being a transmissive medium. For purposes of GR, he stripped the aether of any sensible properties, including sensibility of proper motion. This might not have been a good idea, as illustrated by the Unruh effect.
There is a misunderstanding relating to detector sensitivity that causes some people to believe that light travels in discrete quanta. Light travels in waves of indeterminant, continuously decreasing energy. When the energy is absorbed by an atom, the REACTION of the atom is that one or more of its electrons will momentarily assume a higher energy state, then cascade back to its ground state. The detector has reacted in a quantized manner to an energy input that is non-discrete and continuous. This makes some folks think that the light arrives in discrete quanta. It does not. An analagous situation occurs with photographic film in astrophotography. To get the silver salts in the emulsion to change state (register an image) you have to concentrate enough light waves on the salts to provide the energy to make them change state. This is very easy with bright images, and the f:stop/exposure time relationship operates very smoothly in this domain. When you get to very faint objects, however, an effect called reciprocity failure kicks in. No matter how long you expose your film, you never manage to accumulate enough energy from faint objects to trigger the phase change in the silver salts, so faint objects are not captured in your image. The only way around this (assuming you don't use more sensitive film) is to gather more energy from the faint source, leading to what astromoners call "aperture fever".
Chronos said:
Of course people are interested in vacuum energy. But few think it has important macroscopic effects other than imparting a small cosmological constant. I'm curious why you would cite that source. This excerpt from the abstract does not appear to be a ringing endorsement of your position:
"The solution suggested here to the nature of the vacuum is that Casimir energy can produce short range effects because of boundary conditions, but that at long range there is no overall effect of vacuum energy, unless one considers lagrangians of higher order than Einstein's as vacuum induced."
I cite the source for several reasons, not the least of which is to show you that a brief review reveals hundreds of papers regarding the nature of vacuum energy. The quote illustrates a common logical disconnect that often accompanies discussions of vacuum energy. The fact that locally we have only detected it via "short range effects due to boundary conditions" cannot be logically extended to support a claim that the effects of vacuum energy are therefore limited to "short range effects". This is a very illogical conclusion, as anybody who deals with experimental selection effects and detector insensitivity can tell you. For instance, physicists are looking for dark matter candidates on scales ranging from solar mass to sub-atomic, although the required cosmological effect is purely gravitational, and on galactic scales and larger. The gravitational properties of the theoretical Dark Matter are not constrained by the scales at which the detections are sought.
Chronos said:
If vacuum energy is responsible for the cosmological constant, you could make the case it was not left out of GR. But Einstein added it ad hoc because he couldn't reconcile the implications of GR with his preconceived notion of a steady state, stable universe. Just how would you go about modifying GR to include vacuum energy that is not ad-hoc? What about the Maxwell equation? It does not factor in vacuum energy. Does it too need modification? On the other hand, they both work quite well - despite being approximations. I suspect once we figure out how to quantize GR things will be clearer.
We will not be able to quantize GR as long as we ascribe physical reality to the the model of gravitation=curved space-time. This curved space-time idea is only a mathematical approximation with no underlying mechanical cause and effect. If we describe gravitation as an attractive force resulting from polarization and densification of the vacuum fields, we will have a real mechanical model for gravitation in FLAT space-time. Quantum theory works really well in flat space-time, but not in the curved space-time fields of GR. As for the Maxwell equations, they describe FIELDS, and include terms for the permeability and permissivity of space. These are terms that apply to fields, not to "empty" space. Without an EM field, EM waves cannot propagate. The potential energy of the ZPE fields need not be addressed in the Maxwell equations, as this energy is the ground state of our universe, and EM waves are sensed relative to this ground state. The existence of the EM field in "empty" space is essential for transmission of EM waves. The theoretical energy of that field (according to quantum theory) is irrelevant to Maxwell's equations.
Chronos said:
And they have some pretty good reasons for telling us these are the most reasonable explanations to date. Believability? Where would quantum physics be if believability was part and parcel to the scientific method? Believability is for magicians, not scientists.
Dark matter and dark energy are not reasonable entities. They are placeholders that are inserted into the standard cosmology to keep it somewhat predictive. In the SLAC lectures I linked elswhere, lecturers frequently used the word "epicycle" to describe these concepts, and these guys are not crackpots. By convention, cosmologists use these entities because they are convenient. There is no independent evidence (apart from the failings of BB cosmology to explain anomalous gravitation and redshift, etc) to suggest that they exist. Decades of very diligent searching for dark matter has turned up no detection at all. I propose that we can keep the general concept of Dark Matter if we model it in terms of effects of something that we know exists - the ZPE fields of the vacuum. The particle/antiparticle pairs of the ZPE are everywhere, and according to quantum theory the ZPE field is highly energetic, yet these fields are barely detectable to us because they are the ground state of our universe. Hmmm, lots of energy potential, hard to detect... Doesn't that make you just a bit curious?
