This new atomic clock is so exact, it could be used to detect dark matter

[beecee]

https://techxplore.com/news/2018-12-atomic-clock-exact-dark.html

Scientists have invented a new clock that keeps time more precisely than any that have come before.

The clock is so accurate that it won't gain or lose more than one second in 14 billion years—roughly the age of the cosmos. Its ticking rate is so stable that it varies by only 0.000000000000000032 percent over the course of a single day.

That level of exactitude is not really necessary for those of us who rely on clocks to get us to a doctor's appointment on time, or to know when to meet up with friends.

But keeping time is just the beginning. This new clock is so exact that it could be used to detect dark matter, measure the gravitational waves that ripple across the universe, and determine the exact shape of Earth's gravitational field with unprecedented precision.

more at link....

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the paper:

https://www.nature.com/articles/s41586-018-0738-2

Atomic clock performance enabling geodesy below the centimetre level

Abstract:

The passage of time is tracked by counting oscillations of a frequency reference, such as Earth’s revolutions or swings of a pendulum. By referencing atomic transitions, frequency (and thus time) can be measured more precisely than any other physical quantity, with the current generation of optical atomic clocks reporting fractional performance below the 10−17 level1,2,3,4,5. However, the theory of relativity prescribes that the passage of time is not absolute, but is affected by an observer’s reference frame. Consequently, clock measurements exhibit sensitivity to relative velocity, acceleration and gravity potential. Here we demonstrate local optical clock measurements that surpass the current ability to account for the gravitational distortion of space-time across the surface of Earth. In two independent ytterbium optical lattice clocks, we demonstrate unprecedented values of three fundamental benchmarks of clock performance. In units of the clock frequency, we report systematic uncertainty of 1.4 × 10−18, measurement instability of 3.2 × 10−19 and reproducibility characterized by ten blinded frequency comparisons, yielding a frequency difference of [−7 ± (5)stat ± (8)sys] × 10−19, where ‘stat’ and ‘sys’ indicate statistical and systematic uncertainty, respectively. Although sensitivity to differences in gravity potential could degrade the performance of the clocks as terrestrial standards of time, this same sensitivity can be used as a very sensitive probe of geopotential5,6,7,8,9. Near the surface of Earth, clock comparisons at the 1 × 10−18 level provide a resolution of one centimetre along the direction of gravity, so the performance of these clocks should enable geodesy beyond the state-of-the-art level. These optical clocks could further be used to explore geophysical phenomena10, detect gravitational waves11, test general relativity12 and search for dark matter13,14,15,16,17.

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Wow!!! Any comments, errors, alterations and/or corrections anyone would like to add to this article and paper? Or is it just simply over the top, sensationalism? 

Ytterbium vibrating at 500 trillion times per second! is that correct?

Detecting DM GW's etc, I mean what the hell did we build aLIGO for?  

 

Edited December 2, 2018 by beecee

[Carrock]

Shame the article's behind a paywall....

The proposed detectors are complementary to LIGO etc.

From https://arxiv.org/abs/1606.01859

Quote

 

We propose a space-based gravitational wave detector consisting of two spatially separated, drag-free satellites sharing ultra-stable optical laser light over a single baseline. Each satellite contains an optical lattice atomic clock, which serves as a sensitive, narrowband detector of the local frequency of the shared laser light......

 

This scheme enables the detection of GWs from continuous, spectrally narrow sources, such as compact binary inspirals, with frequencies ranging from ~3 mHz - 10 Hz without loss of sensitivity, thereby bridging the detection gap between space-based and terrestrial optical interferometric GW detectors.

 

GW astronomy is getting very interesting...

/edit this may be the preprint - too much information for me...

https://export.arxiv.org/pdf/1811.05885

Edited December 2, 2018 by Carrock

[swansont]

49 minutes ago, beecee said:

 Wow!!! Any comments, errors, alterations and/or corrections anyone would like to add to this article and paper? Or is it just simply over the top, sensationalism? 

Ytterbium vibrating at 500 trillion times per second! is that correct?

Probably. 5 x10^14 Hz means 600 nm light. (It’s an optical clock, so it can’t be more than a factor of 2 wrong)

Quote

 

Detecting DM GW's etc, I mean what the hell did we build aLIGO for?  

 

There are some caveats here. LIGO exists now. Nothing that was projected, based on these clocks, do.

These are lab devices that likely take a lot of care and feeding to run for a few hours, and they can do measurements in nearby lab spaces.  Lab experiments generally aren’t robust, and not portable. If you want to use these in the applications mentioned, you need to do a lot of engineering work*

Making this smaller and portable has a good chance of reducing the performance.

*There’s a certain amount of PR boilerplate that translates as “after a lot of engineering work”

 

[StringJunky]

16 minutes ago, Carrock said:

Shame the article's behind a paywall....

The proposed detectors are complementary to LIGO etc.

From https://arxiv.org/abs/1606.01859

GW astronomy is getting very interesting...

I found this with Ludlow as an author. It might be the same paper as the OP: 

Atomic_clock_performance_beyond_the_geodetic_limit.pdf

Edited December 2, 2018 by StringJunky

[beecee]

13 minutes ago, Carrock said:

Shame the article's behind a paywall....

The proposed detectors are complementary to LIGO etc.

Nice, thanks for that Carrock

Quote

 

From https://arxiv.org/abs/1606.01859

GW astronomy is getting very interesting...

 

Yep, very interesting indeed! And even more so I suggest when LISA is aloft.

3 minutes ago, swansont said:

Probably. 5 x10^14 Hz means 600 nm light. (It’s an optical clock, so it can’t be more than a factor of 2 wrong)

There are some caveats here. LIGO exists now. Nothing that was projected, based on these clocks, do.

These are lab devices that likely take a lot of care and feeding to run for a few hours, and they can do measurements in nearby lab spaces.  Lab experiments generally aren’t robust, and not portable. If you want to use these in the applications mentioned, you need to do a lot of engineering work*

Making this smaller and portable has a good chance of reducing the performance.

*There’s a certain amount of PR boilerplate that translates as “after a lot of engineering work”

 

 

2 minutes ago, StringJunky said:

I found this with Ludlow as an author. It might be the same paper as the OP: 

Atomic_clock_performance_beyond_the_geodetic_limit.pdf

Vinaka  vakalevu fellas!

[J.C.MacSwell]

1 hour ago, swansont said:

Probably. 5 x10^14 Hz means 600 nm light. (It’s an optical clock, so it can’t be more than a factor of 2 wrong)

There are some caveats here. LIGO exists now. Nothing that was projected, based on these clocks, do.

These are lab devices that likely take a lot of care and feeding to run for a few hours, and they can do measurements in nearby lab spaces.  Lab experiments generally aren’t robust, and not portable. If you want to use these in the applications mentioned, you need to do a lot of engineering work*

Making this smaller and portable has a good chance of reducing the performance.

*There’s a certain amount of PR boilerplate that translates as “after a lot of engineering work”

 

But...I thought that was your job...

[StringJunky]

5 minutes ago, J.C.MacSwell said:

But...I thought that was your job...

Yeah, time to get busy swansont.

[swansont]

10 hours ago, J.C.MacSwell said:

But...I thought that was your job...

 

10 hours ago, StringJunky said:

Yeah, time to get busy swansont.

We're working on it.

http://indexsmart.mirasmart.com/IFCS2018/PDFfiles/IFCS2018-000128.pdf

https://www.osapublishing.org/josab/abstract.cfm?uri=josab-35-7-1557

[StringJunky]

1 hour ago, swansont said:

 

We're working on it.

http://indexsmart.mirasmart.com/IFCS2018/PDFfiles/IFCS2018-000128.pdf

https://www.osapublishing.org/josab/abstract.cfm?uri=josab-35-7-1557

Awesome. The one you are working on seems to have a frequency of  431nm. Does that mean the clock frequency of yours will be higher than the  ytterbium one? Very clear writing in your paper although I don''t understand all the concepts, of course.

Edited December 3, 2018 by StringJunky

[swansont]

18 minutes ago, StringJunky said:

Awesome. The one you are working on seems to have a frequency of  431nm. Does that mean the clock frequency of yours will be higher than the  ytterbium one? Very clear writing in your paper although I don''t understand all the concepts, of course.

The Ca clock transition is at 657 nm. The resonance at 431 nm is much too broad to make a good clock. (431 nm and 423 nm transitions are used for detection and laser cooling, respectively)

The actual frequency vs Yb is a small effect, as they are only different by a few tens of percent, at most. It's being at 10^14 Hz vs 10^10 Hz that is the large difference between these and microwave clocks, and is what is responsible for the improvements. Then there are the difference between the transitions, and the easer of generating all the wavelengths you need. Right now there is no clear-cut winner for what atom or ion to use for an optical clock. There are around a dozen different candidates being tested in various labs around the world. (in some labs the choice is based on what equipment you already have lying around)

The basic principle is the same: use a laser to put an atom in a superposition of states, which one can model as oscillating between them, and let it go for a period of time, and then the laser completes the transition. The atom is the "truth" in terms of the frequency measurement, and you're seeing how close the laser's frequency is to the atoms'. The information is encoded in how many atoms are left in the excited vs ground state.

 

 

[John Cuthber]

6 hours ago, swansont said:

(in some labs the choice is based on what equipment you already have lying around)

I am sure that's true, but it projects a weird image of science...

Hey guys; the chemists have found a use for the other rare earths, but they have some Ytterbium left over; can we do anything with it?

[ short delay while someone googles some spectrometric data ]

Can that dye laser in the cupboard do 578 nm?

I don't know...

Can it do yellow?

Yeah

OK, let's give it a shot

[swansont]

1 hour ago, John Cuthber said:

I am sure that's true, but it projects a weird image of science...

Hey guys; the chemists have found a use for the other rare earths, but they have some Ytterbium left over; can we do anything with it?

[ short delay while someone googles some spectrometric data ]

Can that dye laser in the cupboard do 578 nm?

I don't know...

Can it do yellow?

Yeah

OK, let's give it a shot

If heard more than one person respond to the question "why did you choose X as your material to investigate?" with some form of "It's what we had in the lab."  It's not so different from having the hammer, so every problem looks like a nail.

As I'm sure you're aware, lab budgets are finite, so you have to make do with what you have. Even if you think you could convince a funding source to give you money, that process takes time, and someone might beat you to the results while you're waiting. So if you have a laser that talks to Yb, you might as well look at that while you wait and see if your can get a Sr laser.

 

[beecee]

10 hours ago, swansont said:

 

We're working on it.

http://indexsmart.mirasmart.com/IFCS2018/PDFfiles/IFCS2018-000128.pdf

https://www.osapublishing.org/josab/abstract.cfm?uri=josab-35-7-1557

Great work!!!

[John Cuthber]

24 minutes ago, swansont said:

"why did you choose X as your material to investigate?" with some form of "It's what we had in the lab."  

In a similar manner, a lot of organic reactions are "heated under reflux for 16 hours".

i.e. "we set it up at 5 pm and came back in the morning".

It's not a rare phenomenon 

 I believe some of the early work done on magnetic refrigeration was done using either (cheap) ferric ammonium sulphate or (much more expensive)  ceric ammonium nitrate depending on "what they had at the time".
IIRC the Americans had the "expensive" stuff. It was less than a few dollars' worth.

It's probably best not to mention the report in some of the early work on cellular phone signals which included the phrase something like" The equipment wa screened in a conductive ferromagnetic shield" (previously known as a biscuit tin).

Meanwhile, back at the topic.
If you set up two "clocks" like this and let the yellow light from both fall onto a screen, would you get interference patterns from the 2 sources, and could you watch the fringes shift as the frequencies drifted?

[swansont]

4 hours ago, John Cuthber said:

Meanwhile, back at the topic.
If you set up two "clocks" like this and let the yellow light from both fall onto a screen, would you get interference patterns from the 2 sources, and could you watch the fringes shift as the frequencies drifted?

You wouldn’t see much, since the point of such clocks is that they are pretty stable. Not going to drift by a noticeable fraction of a fringe.