Summary Article on "Squeezing" the Detector Laser Beam

rbpeake
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Topic 193716

This article was quite interesting in providing a overview of LIGO and one approach to increasing its sensitivity.

Mike Hewson
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Summary Article on "Squeezing" the Detector Laser Beam

Quote:
This article was quite interesting in providing a overview of LIGO and one approach to increasing its sensitivity.


Not bad but a bit hyped. Don't they teach or screen journalists for logic ability ? Don't they research history?

I don't know if the LIGO setup cost is 'gargantuan' - I've never seen a gargantua to compare with. Plus the 'huge pressure' is a beat up too. Early design documents ( published/ public ) have not required/predicted either any detection or as per some timetable. It's an experiment the design of which does not prejudge any particular result. This is known as science aka. experiment is the ONLY valid test of an hypothesis. Set 'em up and knock 'em down. It is strange that such outcomes would be seen as failure not success, and reveals ignorance of the intention of the 'phrasing' of the question.

What is desired is that the detection or absence thereof is reliably determined, that is: IF there are such beasts as GW's THEN we will find them OR IF they are not in existence THEN the detectors won't contradict that. We may not necessarily see/determine either of those results but perhaps something else altogether.

The null result of Michelson & Morley was a tremendous breakthrough in fact .... and a similiar outcome from LIGO would have equivalent import. In some ways that would be a tremendously cool outcome. That would trigger an intense and deep examination of the derivation of predictions from assumptions. Probably assumptions would fall, much like the 'luminiferous ether' did.

I'm not sure how they explained the method though. It didn't quite say why trading energy ( amplitude ) for time ( phase ) accuracy as per Heisenberg was a good thing. What does that give? A better defined peak in energy but at the expense of a wider one? There is an irreducible volume in energy/time space to reckon with. The measurement of the difference in phases between orthogonal paths ( our spacetime distortion ruler ) is via accumulated shifts in photon statistics.

Cheers, Mike.

( edit ) possibly expectation is generated from memories of the heydays of high energy physics, where a zoo of particles rapidly appeared and 'atom smashers' abounded .... if you want the public to pay, you have to give them some Buck Rogers back.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

Chipper Q
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RE: This article was quite

Quote:
This article was quite interesting in providing a overview of LIGO and one approach to increasing its sensitivity.


Here's another one from PhysOrg.com that additionally mentions the VIRGO detector, but also not much detail about 'squeezed state injection'... It sounds like the implementation of 'squeezed light' will come after Advanced LIGO, but at an improvement of 44% in the sensitivity, hopefully it will be ready for the larger interferometers soon.
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Quote:
I'm not sure how they explained the method though. It didn't quite say why trading energy ( amplitude ) for time ( phase ) accuracy as per Heisenberg was a good thing. What does that give? A better defined peak in energy but at the expense of a wider one? There is an irreducible volume in energy/time space to reckon with. The measurement of the difference in phases between orthogonal paths ( our spacetime distortion ruler ) is via accumulated shifts in photon statistics.


I think this may be the paper that the articles were written about: A Quantum-Enhanced Prototype Gravitational-Wave Detector (Helpful schematic on the top of page 3)

This Wikipedia page may be helpful: Squeezed coherent state

The Nature article cited in the References section looks to be where the graphics on the Wiki page comes from (and it's a good article), here's a shortcut: Measurement of the quantum states of squeezed light
(Note: clicking anywhere on the page will load the next page, except for the tiny magnifying glass icon in the upper left corner)

Mike Hewson
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Nice ones Chipper.

Message 82150 in response to message 82149

Nice ones Chipper. :-)

Simpler, in principle, than I thought .... arrange matters to minimise disturbances yielding that minimum volume in conjugate variable space - ie. trim off most/all other causes of variation and be left with only the Heisenberg behaviour.

... quoted as giving ~ 40% sensitivity improvement, best case.

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

tullio
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According to the VIRGO

According to the VIRGO newsletter a LSC-Virgo meeting was held at LAL-Orsay in Paris from 9 to 12 June to which dr.Allen partecipated. But I could not get any information because a password is needed. I would be glad to learn something about this collaboration (VIRGO is also a French venture).
Tullio

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