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Investigating/Manipulating the Vacuum (Squeezed Light, Fast-Pulse Lasers) by sanman on 24 Jan, 2017 02:24
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Someone posted an interesting article in the EMdrive thread - while it may or may not have bearing on the EMdrive, it seems to be interesting physics in its own right, worthy of examination and discussion:I thought this was an interesting article here: Traffic jam in empty space. Question to the experts: Does that support Dr. White's assumption of a non-immutable vacuum?
https://www.sciencedaily.com/releases/2017/01/170118132244.htm
http://www.nature.com/nature/journal/v541/n7637/full/nature21024.html
Can we tamper with spacetime? Can we modify and manipulate it?
Can we at least map out its underlying nature?
This experiment claims to have created some kind of (brief) "dent" in Spacetime or the Quantum Vacuum
How should further investigation be pursued? Would it be useful to repeat such "denting" experiments, while also simultaneously trying to look for Path Length Deifference through interferometry?
For example, Dr White at NASA has tried similarly using interferometry to look for Path Length changes in relation to applied electrical field from a capacitor ring. But the "dent" (perturbation?) using the Femtosecond laser seems to provide a very sensitive measurement of its own.
I know there are even faster-pulsing lasers like Attosecond lasers which are supposed to be able to watch electronic transitions, and presumably we'll get to Zeptosecond-pulse lasers one day too.
It seems that fast-pulsed lasers and Squeezed Light are the shiny new tools in the toolbox (pun intended) to probe the structure of the Vacuum. Squeezed Light seems to involve modifying the wave-function distribution at the individual photon level. The fast-pulses can also apparently generate Squeezed Light without the need to use Non-Linear Crystals for this purpose.QuoteBy manipulating the vacuum with strongly focused femtosecond pulses, the researchers come up with a new strategy to generate "squeezed light," a highly nonclassical state of a radiation field. The speed of light in a certain segment of space-time is deliberately changed with an intense pulse of the femtosecond laser. This local modulation of the velocity of propagation "squeezes" the vacuum field, which is tantamount to a redistribution of vacuum fluctuations.
It seems like Spaceflight will ultimately benefit from knowing more about the nature of the Vacuum.
We didn't need to know too much about water when we first started building boats, and likewise we didn't need to know too much about air when we first started building aircraft, but as things progressed we later did benefit from more detailed knowledge of these media/environments. -
#1 by LowerAtmosphere on 25 Jan, 2017 23:24
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Great thread idea. I figure the best way to contribute is to include some mindblowing reading materials.
http://physicsworld.com/cws/article/news/2016/feb/26/surreal-behaviour-spotted-in-photon-experiment
http://www.cft.edu.pl/~birula/publ/PropSq.pdf
http://www.earthtech.org/publications/davis_STAIF_conference_1.pdf
https://arxiv.org/pdf/1005.5682
Here's a repost of my first post under this nickname:
"Radial Electric/Magnetic Fields
Suffice it to say that ultrahigh-intensity tabletop lasers have been used to generate extreme electric and magnetic field strengths in the lab. Ultrahigh-intensity lasers use the chirped-pulse amplification (CPA) technique to boost the total output beam power. All laser systems simply repackage energy as a coherent package of optical power, but CPA lasers repackage the laser pulse itself during the amplification process. In typical high-power short-pulse laser systems, it is the peak intensity, not the energy or the fluence, which causes pulse distortion or laser damage. However, the CPA laser dissects a laser pulse according to its frequency components, and reorders it into a time-stretched lower-peak-intensity pulse of the same energy (Perry, 1996; 2000; Mourou, Barty and Perry, 1998). This benign pulse can then be amplified safely to high energy, and then only afterwards reconstituted as a very short pulse of enormous peak power a pulse which could never itself have passed safely through the laser system (see Figure 2). Made more tractable in this way, the pulse can be amplified to substantial energies (with orders of magnitude greater peak power) without encountering intensity related problems.
The extreme output beam power, fields and physical conditions that have been achieved by ultrahigh-intensity
tabletop lasers are (Mourou, Barty and Perry, 1998):
We find from the above data that ultrahigh-intensity lasers can generate an electric field energy density of ~10^16 10^28 J/m3 and a magnetic field energy density of ~ 10^19 J/m^3. These energy densities are about the right order of magnitude to explore generating kilometer to AU sized wormholes. But that would be difficult to engineer on Earth. However, these energy densities are well above what would be required to explore the generation of microwormholes in the lab."
The idea is to resonate ultrahigh-intensity lasers instead of using a magnetron insert (may correspond to partially successful laser simulations by gustavo earlier).
Also, to disprove that the EM-Drive is a sort of scam Q-thruster, radiation must be measured near the more resonant end to make sure there is negligible leakage of any kind (I recommend shielding the end by gluing on a small thick insulating barrier with an InGaAs array inside).
Interesting readings:
https://www.rp-photonics.com/high_harmonic_generation.html
https://www.rp-photonics.com/enhancement_cavities.html
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015936.pdf
Please ignore if idiotic,
Anon"
Note: the disclaimer to please ignore if idiotic is important in my opinion, if you wish to avoid arguments, and crucial if you wish to convince people smarter than you
The more I read, the more I acquire, the more certain I am that I know nothing. ― Voltaire -
#2 by LowerAtmosphere on 24 Feb, 2017 11:05
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New developments in this fascinating subfield ensure that future testing may be even more affordable and insightful.
Anisotropy across magnetic heterointerface induced by ultrafast laser pulses on metamaterials
https://phys.org/news/2017-02-ultrafast-laser-pulses-magnetic-materials.html
Efficient and easy method to create laser pulses - potentially applicable to any frequency
https://www.eurekalert.org/pub_releases/2017-02/iopc-iw022317.php
New ultrashort pulses push and seek to explore boundary between wave and bohmian nature of light, allow for precision microscopy and myriad other applications
https://phys.org/news/2017-02-terahertz-pulse.html
The intersection between metals and ultrashort laser pulses continues to promise to unlock many more exotic effects and materials. Work is needed to explore the intersection of plasmonics and metamaterials. Anisotropic properties may be leveraged for reaction force in optomechanical mechanisms not to mention how coherency works in such a laser - can photons be made coherent then split and remain linked?
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New semi-related idea I had earlier:
Large resonant 100m^3 cavity with cargo positioned inside precisely according to algorithmic prediction. Individual RF radiation injection points are numerous and the entire area may be beamable with low frequency overlapping radiation traps. Essentially exacting enough optomechanical force to levitate the cargo objects. It could be tuned to be so precise as to even take the form of polygonal hands or avatars eventually. The tuning can be so precise like a tractor beam. This system can elevate cargo, provided no humans are around, and only shielded circuitry is located in the cargo warehouse cavity. Silly idea? I'm not sure. We have made huge advances in radiation pressure manipulation and tuning. -
#3 by Quantum Gravity on 15 Jun, 2017 22:51
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Can we tamper with spacetime? Can we modify and manipulate it?
Can we at least map out its underlying nature?
This experiment claims to have created some kind
of (brief) "dent" in Spacetime or the Quantum Vacuum.
It seems like Spaceflight will ultimately benefit from knowing more about the nature of the Vacuum.
We didn't need to know too much about water when we first started building boats, and likewise we didn't need to know too much about air when we first started building aircraft, but as things progressed we later did benefit from more detailed knowledge of these media/environments.
Excellent point.
Here is a paper by a physicist from CERN about the
gravitational polarization of the quantum vacuum :
https://phys.org/news/2011-11-quantum-vacuum-dark.html
https://arxiv.org/ftp/arxiv/papers/1106/1106.0847.pdf
