Hanford LIGO

Betreger
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Topic 197107
Mike Hewson
Mike Hewson
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Hanford LIGO

Quote:
.... while the 'quantum limit' has been undercut it is only in one plane of polarisation, while along another ( unmentioned and orthogonal ) axis precision blows out and so QM in general is still safe.


Whoops Mike, that's crap. I misread the research totally on that point. :O)

Take Two :

One increases the precision of the beam source in phase, so precision is lost in amplitude. The relevant conjugate coordinates for Heisenberg uncertainty here are energy and time. So if we propel the photons up each arm - ab initio in closer phase via 'squeezing' - then while the number of those traversing will fluctuate more, what we are ultimately interested at the dark port is the accumulated phase differential for those distinct paths. For LIGO purposes how many photons ( = amplitude ) did or did not traverse is less relevant.

Now if you were operating the device off-null then a varying photodetector readout could be due to either amplitude ( number of photons ) and/or phase ( timing of photons ). Thus you couldn't disambiguate those causes and hence one would be more unsure of phase differentials between the arms.

As a matter of terminology, the limit being broken is : " ..... a noise level which is even smaller than the minimum noise of incoherent light made of independent photons .... ". So the benefit is in the preparation of the initial state of a bag of photons, via clever gadgets, thus NOT being mutually incoherent nor independent when considered as a group. Needless to say this is a quantum, not a classical, affair.

Cheers, Mike.

( edit ) Sorry I've accidentally totally overwritten my prior post when issuing a correction here .... :-(

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

Holmis
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So is there some sort of

So is there some sort of timeline when we might see data from Advanced LIGO here on Einstein@home? This year, next year or will it take longer?

joe areeda
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I have no idea when aLigo

I have no idea when aLigo data will get to E@H but I doubt we'll see the first science run before late 2014.

Mike Hewson
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Here is a published schedule,

Here is a published schedule, but as that doesn't quite answer the question I'll inquire.

Cheers, Mike.

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

astro-marwil
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Hallo! I hope the frequency

Hallo!
I hope the frequency range of this new device is 50Hz to 300KHz. That should show details how a supernova is going on to explode. If it happens sufficiently near by.

There was a proposal for another quantum device detector for gravitational waves, that sounded very promissing, about a year or so ago. It was also much smaller, some 10 m to the cube, and also promissing in sensitivity. But I didn´t here any about this since then. So, let´s wait to see, what the experiments will tell us about this. Theory is one side, but the realisation often looks quite differently.

But I find it impressiv, that there are new ideas for new detectors.

Why not putting the whole armlength of 4Km into a squeezed laser mode? That should also increase the sensitivity.

On the other side, on earth they are limited in sensitivity by noise introduced by humans and the rumbling of our good old earth.

Kind regards and happy crunching
Martin

astro-marwil
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Hallo! RE: Here is a

Hallo!

Quote:
Here is a published schedule, but as that doesn't quite answer the question I'll inquire.


Even, if they are within theire time scedule, it will take a year or so for tests, before we get data to become crunched here.

Kind regards and happy crunching
Martin

Bruce Allen
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Guys, data from the advanced

Guys, data from the advanced LIGO O1 run is now crunching on Einstein@Home!

Director, Einstein@Home

Betreger
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Are we getting new data from

Are we getting new data from the second science run of the advanced LIGO yet?

Mike Hewson
Mike Hewson
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My guess is nearly but not

My guess is nearly but not yet. While O2 will finish in May :

Quote:
....  O2 will last six months until May 2017 in two separate halves .... 

that suggests the Dec-Jan-Feb part is only just complete. There's a good deal of inspection, decisions to make, followed by rolling the data into chunks suitable for our techniques.

Hope springs eternal ! :-)))

Cheers, Mike.

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

Betreger
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These are exciting times.

These are exciting times.

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