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Notions of Time in Computer Architecture

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  Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-29 15:12 -0700
    Re: Notions of Time in Computer Architecture Robert Myers <rbmyersusa@gmail.com> - 2011-06-29 22:08 -0400
    Re: Notions of Time in Computer Architecture Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-06-30 14:13 +0200
      Re: Notions of Time in Computer Architecture Morten Reistad <first@last.name> - 2011-06-30 18:19 +0200
      Re: Notions of Time in Computer Architecture ChrisQ <meru@devnull.com> - 2011-06-30 21:23 +0100
        Re: Notions of Time in Computer Architecture Rick Jones <rick.jones2@hp.com> - 2011-06-30 19:42 +0000
          Re: Notions of Time in Computer Architecture Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-07-01 10:46 +0200
            Re: Notions of Time in Computer Architecture Rick Jones <rick.jones2@hp.com> - 2011-07-01 15:17 +0000
              Re: Notions of Time in Computer Architecture ChrisQ <meru@devnull.com> - 2011-07-04 16:51 +0100
        Re: Notions of Time in Computer Architecture nmm1@cam.ac.uk - 2011-07-01 05:54 +0100
      Re: Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-06-30 22:42 -0700
      Re: Notions of Time in Computer Architecture jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-01 20:16 +0000
        Re: Notions of Time in Computer Architecture Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-07-02 10:33 +0200
          Re: Notions of Time in Computer Architecture nmm1@cam.ac.uk - 2011-07-02 09:26 +0100
          Re: Notions of Time in Computer Architecture jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-02 12:40 +0000
            Re: Notions of Time in Computer Architecture nmm1@cam.ac.uk - 2011-07-02 16:14 +0100
            Re: Notions of Time in Computer Architecture Robert Myers <rbmyersusa@gmail.com> - 2011-07-02 16:48 -0400
              Re: Notions of Time in Computer Architecture Quadibloc <jsavard@ecn.ab.ca> - 2011-07-02 14:27 -0700
                Re: Notions of Time in Computer Architecture Stephen Sprunk <stephen@sprunk.org> - 2011-07-03 15:07 -0500
                  Re: Notions of Time in Computer Architecture Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-07-04 08:15 +0200
                    Re: Notions of Time in Computer Architecture Morten Reistad <first@last.name> - 2011-07-04 17:50 +0200
                      Re: Notions of Time in Computer Architecture Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-07-04 21:21 +0200
                        Re: Notions of Time in Computer Architecture Robert Wessel <robertwessel2@yahoo.com> - 2011-07-04 23:44 -0500
                          Re: Notions of Time in Computer Architecture Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-07-05 07:51 +0200
                            Re: Notions of Time in Computer Architecture Robert Wessel <robertwessel2@yahoo.com> - 2011-07-05 01:56 -0500
              Re: Notions of Time in Computer Architecture Morten Reistad <first@last.name> - 2011-07-03 19:28 +0200
            Re: Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-03 11:27 -0700
              Re: Notions of Time in Computer Architecture nmm1@cam.ac.uk - 2011-07-03 22:13 +0100
                Re: Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-03 18:53 -0700
                  Re: Notions of Time in Computer Architecture nmm1@cam.ac.uk - 2011-07-04 08:34 +0100
              Re: Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-03 18:51 -0700
              Re: Notions of Time in Computer Architecture anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-07-04 09:20 +0000
                Re: Notions of Time in Computer Architecture Robert Myers <rbmyersusa@gmail.com> - 2011-07-04 12:26 -0700
                  Re: Notions of Time in Computer Architecture EricP <ThatWouldBeTelling@thevillage.com> - 2011-07-04 19:35 -0400
                  Re: Notions of Time in Computer Architecture Bernd Paysan <bernd.paysan@gmx.de> - 2011-07-08 15:48 +0200
              Re: Notions of Time in Computer Architecture Michael S <already5chosen@yahoo.com> - 2011-07-05 15:24 -0700
                Re: Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-08 09:25 -0700
                  Re: Notions of Time in Computer Architecture Robert Myers <rbmyersusa@gmail.com> - 2011-07-08 12:12 -0700
                    Re: Notions of Time in Computer Architecture "Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> - 2011-07-08 17:27 -0700
                      Re: Notions of Time in Computer Architecture Robert Myers <rbmyersusa@gmail.com> - 2011-07-09 18:07 -0400
                        Re: Notions of Time in Computer Architecture EricP <ThatWouldBeTelling@thevillage.com> - 2011-07-10 12:03 -0400
                          Re: Notions of Time in Computer Architecture Robert Myers <rbmyersusa@gmail.com> - 2011-07-10 13:02 -0700
      Re: Notions of Time in Computer Architecture Bernd Paysan <bernd.paysan@gmx.de> - 2011-07-08 15:13 +0200
    Re: Notions of Time in Computer Architecture Gubbi <gubsan100@hotmail.com> - 2011-07-01 00:50 -0700

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#2353

In article <bd28e8-dac.ln1@ntp6.tmsw.no>,
Terje Mathisen  <"terje.mathisen at tmsw.no"> wrote:
>Stephen Sprunk wrote:
>> GPS is a prime counterexample: any given receiver must be able to track
>> at least three satellites, and many can track a dozen or more.  The
>> satellites move at speeds where relativity becomes relevant, and AIUI
>> receivers have to compensate for it.  I don't know if the satellites
>
>GPS receivers do compensate for one (purely) relativistic effect:
>
>Since the orbits are only nearly circular, the sats experience slightly 
>variable gravity fields, depending upon current orbit height.

There is one more. Relativistic doppler compensation of the radio signal
itself. This was not there in the first sets, so it took forever to regain
sync once it was lost; because the receiver didn't find the signals at all.

>This means that the onboard clocks run (very slightly) slower during the 
>lower parts of each orbit and faster during the higher parts, right?

At least some sets do the whole triangulation using relativistic 
formulae.

>Each receiver will then adjust the received clock signal from each sat 
>(via the calculated pseudorange and the current sat orbit position and 
>calculate how much the onboard clock should be early/late due to the 
>integrated gravity drag.
>
>> talk to each other directly or if their signals are coordinated solely
>> by ground stations, but the same concerns would apply there as well.
>
>GPS sats don't talk between themselves, they are just updated by the 
>monitoring base stations ("the control segment") exactly what they 
>should transmit from now on, i.e. based on orbit and clock adjustments 
>parameters.
>
>The requirement is to keep each sat clock within 10 us of UTC(USNO), but 
>they have been doing much better than this for many years.
>>
>> Keeping time is an embarrassingly parallel problem, but I wouldn't be
>> surprised if the military had other satellites in orbit for which
>> relativity was an even greater concern.
>
>As in highly elliptical, semi-polar orbits? :-)

You know something you cannot tell us?

-- mrr

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#2357

Morten Reistad wrote:
> In article<bd28e8-dac.ln1@ntp6.tmsw.no>,
> Terje Mathisen<"terje.mathisen at tmsw.no">  wrote:
>> As in highly elliptical, semi-polar orbits? :-)
>
> You know something you cannot tell us?

Not at all, this is just very obvious from the proven capabilities of US 
military sats, i.e. maximum achievable resolution pretty much has to 
indicate a very low orbit, while the need to cover more or less any part 
of the globe means highly inclined orbits, right?

Terje

-- 
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"

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#2366

On Mon, 04 Jul 2011 21:21:39 +0200, Terje Mathisen <"terje.mathisen at
tmsw.no"> wrote:

>Morten Reistad wrote:
>> In article<bd28e8-dac.ln1@ntp6.tmsw.no>,
>> Terje Mathisen<"terje.mathisen at tmsw.no">  wrote:
>>> As in highly elliptical, semi-polar orbits? :-)
>>
>> You know something you cannot tell us?
>
>Not at all, this is just very obvious from the proven capabilities of US 
>military sats, i.e. maximum achievable resolution pretty much has to 
>indicate a very low orbit, while the need to cover more or less any part 
>of the globe means highly inclined orbits, right?


Sure, but that would (and does) imply a very circular (IOW,
non-elliptical), low altitude orbit, with a high inclination.  A
highly elliptical orbit would have very different apogees and
perigees.

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#2368

Robert Wessel wrote:
> On Mon, 04 Jul 2011 21:21:39 +0200, Terje Mathisen<"terje.mathisen at
>> Not at all, this is just very obvious from the proven capabilities of US
>> military sats, i.e. maximum achievable resolution pretty much has to
>> indicate a very low orbit, while the need to cover more or less any part
>> of the globe means highly inclined orbits, right?
>
>
> Sure, but that would (and does) imply a very circular (IOW,
> non-elliptical), low altitude orbit, with a high inclination.  A
> highly elliptical orbit would have very different apogees and
> perigees.

I haven't done the math, but I'm pretty sure that a highly elliptical 
orbit makes it much cheaper (energy-wise) to alter said orbit such as to 
bring the lowest part over any given specific part of the globe.

There is also the additional cost of a very low orbit: It decays too 
quickly.

Terje

-- 
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"

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#2369

On Tue, 05 Jul 2011 07:51:50 +0200, Terje Mathisen <"terje.mathisen at
tmsw.no"> wrote:

>Robert Wessel wrote:
>> On Mon, 04 Jul 2011 21:21:39 +0200, Terje Mathisen<"terje.mathisen at
>>> Not at all, this is just very obvious from the proven capabilities of US
>>> military sats, i.e. maximum achievable resolution pretty much has to
>>> indicate a very low orbit, while the need to cover more or less any part
>>> of the globe means highly inclined orbits, right?
>>
>>
>> Sure, but that would (and does) imply a very circular (IOW,
>> non-elliptical), low altitude orbit, with a high inclination.  A
>> highly elliptical orbit would have very different apogees and
>> perigees.
>
>I haven't done the math, but I'm pretty sure that a highly elliptical 
>orbit makes it much cheaper (energy-wise) to alter said orbit such as to 
>bring the lowest part over any given specific part of the globe.
>
>There is also the additional cost of a very low orbit: It decays too 
>quickly.


That's true, the plane change at the top of a very elliptical orbit is
inexpensive.  But the problem is that you end up spending very little
time at the low altitudes where high resolution imaging is possible
(with an apogee of ~15000 miles, you'd be looking at something on the
order of 5% at "close" range).

What usually happens is that the inclined orbit is not directly
synchronized with the rotation of the earth, so that successive orbits
pass over different regions.  For example, polar orbiting weather
satellites are typically in ~500 mile orbits, with about 20 degrees
shift between passes, thus they cover the entire earth a couple of
times each day (polar weather sats are usually in orbits that keep
have the orbit in the same position relative to the sun).

Imaging sats have some cross range capability (up to the limits of
their fuel supplies), but you don't need huge plane shifts if you have
some time to allow a small change to accumulate (and that's what
happens in practice, since fuel is the major constraint on lifetime).
If you've got a base orbit spacing of about 20 degrees, getting
directly overhead any point within 24 hours only requires about
30ft/sec delta-V.  If you want your new orbit to be stable (repeating)
above that point (assuming your original one was stable), you
approximately double that.  Most taskings are planned over far longer
intervals than that.

Imaging sats also allow a certain amount of "slant" in their imaging,
which reduces the need to be directly overhead the target.

And while low orbits do have high drag, satellites intended for long
lives in that that role are invariably equipped with engines to
compensate (usually the same ones for other orbital maneuvering/torque
unloading/etc. purposes).

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#2329

In article <VuLPp.21570$Md1.571@newsfe19.iad>,
Robert Myers  <rbmyersusa@gmail.com> wrote:
>On 7/2/2011 8:40 AM, John Savard wrote:
>>
>> So it could indeed be that relativistic considerations would someday
>> impact the definition of priority.
>
>So far as I know, and some of the most careful work is probably 
>classified, they have been for a long time, because the most important 
>case is not computers bolted to the floor, but satellites in orbit with 
>profound implications for military operations.
>
>It would be worth a note in Physical Review Letters if someone could 
>nail down some of the uncertainties or show without a doubt that it was 
>physics and not electronics causing the problems.
>
>As it is, things are moving around pretty fast inside computers, even 
>when they are bolted to the floor, and I'd be reluctant to stake my 
>reputation on sweeping claims about the unimportance of even classical 
>relativistic, never mind quantum, limits on the ability to define 
>simultaneity, even within a computing center with the computers safely 
>bolted to the floor.  There are just too many numbers to make to rule 
>out any possible measurable effect.

The major stock exchanges gave up on serialising transactions around 1988.

Until then you did get a serial number back from every commit, that 
could be used as a priority number.

The standards were changed due to the impractialities of actually
having a serial process assign numbers; and the transaction IDs
were just identifications after that.

This was a direct consequence of the impracticality of having a 
common time to sufficient accuracy inside the computers.

-- mrr

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#2330

> On Sat, 02 Jul 2011 10:33:53 +0200, Terje Mathisen<"terje.mathisen at
> tmsw.no">  wrote, in part:

>> Add in relativity and you realize that it might not be even
>> theoretically possible to determine which of two events happened "first".

At the moment there still exist interpretations of modern physics, 
including relativity, that admit causality, that deny the possibility of 
non-causal loops.

(Notice that I have said  this carefully:  there are, of course, many 
versions of modern physics that enthusiastically embrace denial of 
causality and the arrow of time.)

This means that even relativistic systems, under these interpretations, 
are partial orders.  And every partial order can be converted into a 
total order.  Usually in many different ways.

I do not think that such total orders are especioally useful if you want 
to prove a "happened before" statement, since there can usually 
beconstructed multiple total orders, in at least some of which the 
"happened before" statement you wanted may not be true.

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#2333

Very OT.

In article <4E10B476.4070405@SPAM.comp-arch.net>,
Andy \"Krazy\" Glew <andy@SPAM.comp-arch.net> wrote:
>> On Sat, 02 Jul 2011 10:33:53 +0200, Terje Mathisen<"terje.mathisen at
>> tmsw.no">  wrote, in part:
>
>>> Add in relativity and you realize that it might not be even
>>> theoretically possible to determine which of two events happened "first".
>
>At the moment there still exist interpretations of modern physics, 
>including relativity, that admit causality, that deny the possibility of 
>non-causal loops.

Yes.  The sane ones :-)  I am not denying that non-causal loops are
a possible physical mode, but I fail to see how the scientific
method would survive them!  I don't think that the human race is
currently capable of handling such concepts, and the papers that
I have seen on the topic confirm me in my view.

>(Notice that I have said  this carefully:  there are, of course, many 
>versions of modern physics that enthusiastically embrace denial of 
>causality and the arrow of time.)

I suspect that those people are worshippers of Nyarlathotep :-)


Regards,
Nick Maclaren.

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#2337

On 7/3/2011 2:13 PM, nmm1@cam.ac.uk wrote:
> Very OT.
>
> In article<4E10B476.4070405@SPAM.comp-arch.net>,
> Andy \"Krazy\" Glew<andy@SPAM.comp-arch.net>  wrote:
>>> On Sat, 02 Jul 2011 10:33:53 +0200, Terje Mathisen<"terje.mathisen at
>>> tmsw.no">   wrote, in part:
>>
>>>> Add in relativity and you realize that it might not be even
>>>> theoretically possible to determine which of two events happened "first".
>>
>> At the moment there still exist interpretations of modern physics,
>> including relativity, that admit causality, that deny the possibility of
>> non-causal loops.
>
> Yes.  The sane ones :-)  I am not denying that non-causal loops are
> a possible physical mode, but I fail to see how the scientific
> method would survive them!  I don't think that the human race is
> currently capable of handling such concepts, and the papers that
> I have seen on the topic confirm me in my view.
>
>> (Notice that I have said  this carefully:  there are, of course, many
>> versions of modern physics that enthusiastically embrace denial of
>> causality and the arrow of time.)
>
> I suspect that those people are worshippers of Nyarlathotep :-)

Copenhagen.

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#2339

In article <4E111D10.5050303@SPAM.comp-arch.net>,
Andy \"Krazy\" Glew <andy@SPAM.comp-arch.net> wrote:
>>
>>> (Notice that I have said  this carefully:  there are, of course, many
>>> versions of modern physics that enthusiastically embrace denial of
>>> causality and the arrow of time.)
>>
>> I suspect that those people are worshippers of Nyarlathotep :-)
>
>Copenhagen.

Not really - that is more that they agree that we don't know whether
we are coming or going, in an absolute physical sense :-)

The real loons are the ones that assert that the prophet Einstein's
equations can be extrapolated through their singularity and still
describe the physical universe, precisely.  And, yes, those predict
that causality breaks down.  There is, of course, no evidence for
this that isn't based on assuming the result to be proved!


Regards,
Nick Maclaren.

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#2336

On 7/3/2011 11:27 AM, Andy "Krazy" Glew wrote:
>> On Sat, 02 Jul 2011 10:33:53 +0200, Terje Mathisen<"terje.mathisen at
>> tmsw.no"> wrote, in part:
>
>>> Add in relativity and you realize that it might not be even
>>> theoretically possible to determine which of two events happened
>>> "first".
>
> At the moment there still exist interpretations of modern physics,
> including relativity, that admit causality, that deny the possibility of
> non-causal loops.
>
> (Notice that I have said this carefully: there are, of course, many
> versions of modern physics that enthusiastically embrace denial of
> causality and the arrow of time.)
>
> This means that even relativistic systems, under these interpretations,
> are partial orders. And every partial order can be converted into a
> total order. Usually in many different ways.
>
> I do not think that such total orders are especially useful if you want
> to prove a "happened before" statement, since there can usually
> be constructed multiple total orders, in at least some of which the
> "happened before" statement you wanted may not be true.


By the way, I am well aware that I have betrayed myself as a QUOD 
(QUantum Orthodoxy Doubter).  Or is that ROD (Relativity Orthodoxy Doubter)?

If I'm a QUOD, I'm in good company: Einstein, Schrodinger, Bohm, Bell. 
By coincidence, I spent much of this afternoon sitting beside my broken 
down car, waiting for a tow and then a lift, reading "The Infamous 
Boundary: Seven Decades of Heresy in Quantum Physics" by David Wick.

I'm not really a Relativity Doubter: I just don't think that causality 
has been totally put aside. Yet.  It may one day be.

In any case, I am not advocating a total time or absolute order.  Quite 
the contrary: I think that we might as well get used to the lack thereof.

I only mention certain attempts to create a total order, such as Intel's
synchronization of clocks, and Lamport time, as examples of the other 
side of the argument.

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#2340

"Andy \"Krazy\" Glew" <andy@SPAM.comp-arch.net> writes:
>> On Sat, 02 Jul 2011 10:33:53 +0200, Terje Mathisen<"terje.mathisen at
>> tmsw.no">  wrote, in part:
>
>>> Add in relativity and you realize that it might not be even
>>> theoretically possible to determine which of two events happened "first".
>
>At the moment there still exist interpretations of modern physics, 
>including relativity, that admit causality

For the stuff mentioned by Terje, it's not necessary to resort to
exotic interpretations.  Causality is maintained, because the two
events are so far apart that neither can have caused the other
(without faster-than-light messages).

- anton
-- 
M. Anton Ertl                    Some things have to be seen to be believed
anton@mips.complang.tuwien.ac.at Most things have to be believed to be seen
http://www.complang.tuwien.ac.at/anton/home.html

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#2358

On Jul 4, 5:20 am, an...@mips.complang.tuwien.ac.at (Anton Ertl)
wrote:
> "Andy \"Krazy\" Glew" <a...@SPAM.comp-arch.net> writes:
>
> >> On Sat, 02 Jul 2011 10:33:53 +0200, Terje Mathisen<"terje.mathisen at
> >> tmsw.no">  wrote, in part:
>
> >>> Add in relativity and you realize that it might not be even
> >>> theoretically possible to determine which of two events happened "first".
>
> >At the moment there still exist interpretations of modern physics,
> >including relativity, that admit causality
>
> For the stuff mentioned by Terje, it's not necessary to resort to
> exotic interpretations.  Causality is maintained, because the two
> events are so far apart that neither can have caused the other
> (without faster-than-light messages).
>

But isn't that precisely (if anything about this subject is precise)
what we don't understand about the EPR paradox and experiments that
expose it?

Robert.

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#2365

Robert Myers wrote:
> On Jul 4, 5:20 am, an...@mips.complang.tuwien.ac.at (Anton Ertl)
> wrote:
>> "Andy \"Krazy\" Glew" <a...@SPAM.comp-arch.net> writes:
>>
>>>> On Sat, 02 Jul 2011 10:33:53 +0200, Terje Mathisen<"terje.mathisen at
>>>> tmsw.no">  wrote, in part:
>>>>> Add in relativity and you realize that it might not be even
>>>>> theoretically possible to determine which of two events happened "first".
>>> At the moment there still exist interpretations of modern physics,
>>> including relativity, that admit causality
>> For the stuff mentioned by Terje, it's not necessary to resort to
>> exotic interpretations.  Causality is maintained, because the two
>> events are so far apart that neither can have caused the other
>> (without faster-than-light messages).
>>
> 
> But isn't that precisely (if anything about this subject is precise)
> what we don't understand about the EPR paradox and experiments that
> expose it?
> 
> Robert.

If you are referring to entanglement, it is correlated but non-signaling.
For example, if you have two entangled photons A & B,
and you measure the random polarization on A, it instantly
defines the polarization for B no matter how far away it is.
But there is nothing you can do to change the polarization of A
such that it effects B.

It is as though there is a sub-space, a read-only common block, of
random state information shared between the entangled particles,
but a different sub-space for each entangled set.

(For extra  weirdness, search for 'entanglement sudden death and rebirth'
where it disappears then reappears later. Who ordered that!)

Where this affects causality is that even though you can't manipulate
photon A to cause an effect at B, the fact that B is correlated to
A will have an effect at the distant point.
B will, for example, go left or right through a polarizer,
and the butterfly effect will have some chain of consequences.
So what you measured at A does affect B, but you can't control it.

Eric

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#2428

Robert Myers wrote:
>> For the stuff mentioned by Terje, it's not necessary to resort to
>> exotic interpretations.  Causality is maintained, because the two
>> events are so far apart that neither can have caused the other
>> (without faster-than-light messages).
> 
> But isn't that precisely (if anything about this subject is precise)
> what we don't understand about the EPR paradox and experiments that
> expose it?

IMHO what the classical interpretation about EPR paradox does not 
understand is the order of events. The Copenhagen interpretation is the 
following chain of events, and therefore causality: creation of 
entangled pair -> delay -> measurement -> collapse of wave function. My 
interpretation is that the real chain of events is: measurement setup -> 
delay -> collapse of wave function -> creation of entangled pair -> 
delay -> measurement. There is no dynamic component in the QM wave 
function in Bell's inequality, so you can reorder the chain of events as 
you like. If the measurement setup after the two delays is still the 
same (can have changed in between), your measurement is as expected by 
QM.

There have only two measurements been performed so far that can possible 
identify the chain of events, and the first one failed completely: 
Aspect et all set up an oscillating switch with 50MHz, at a distance of 
6m from the source. 6m*50MHz=300000km/s=c. Given that Aspect et all very 
likely optimized their setup for showing the best violation of Bell's 
inequality, it's a strong hint that my interpretation is closer to 
reality than Copenhagen, where the distance wouldn't have mattered at 
all.

The next dynamic measurement by a student of Anton Zeilinger used a 
random switch, and failed to deliver, because the student didn't get the 
visibility to more than 25%, despite using high-quality components for 
everything (where theoretically the visibility should be much closer to 
100% than to 25%). That could have all sorts of reasons, it doesn't rule 
out that this was a successful EPR experiment, but it's simply too low 
to violate Bell's inequality.

The third strong hint that there is a dynamic effect is the BCS theory 
for superconductivity: You have cooper pairs (entangled electrons) and 
phonons in the lattice disturb these. Too much changes in the latice 
break the cooper pairs, resulting in a critical temperature. One funny 
thing is that QM seems to be capable of describing the effect here 
(dynamic environment through phonons in the lattice), while it fails in 
the EPR case. I suppose that it's the problem of the blind men and the 
elefant.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://www.jwdt.com/~paysan/

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#2375

On Jul 3, 9:27 pm, "Andy \"Krazy\" Glew" <a...@SPAM.comp-arch.net>
wrote:
> > On Sat, 02 Jul 2011 10:33:53 +0200, Terje Mathisen<"terje.mathisen at
> > tmsw.no">  wrote, in part:
> >> Add in relativity and you realize that it might not be even
> >> theoretically possible to determine which of two events happened "first".
>
> At the moment there still exist interpretations of modern physics,
> including relativity, that admit causality, that deny the possibility of
> non-causal loops.
>

I don't understand. Are you saying that there are serious scientists
here that deny the existence of space-like intervals?
http://en.wikipedia.org/wiki/Spacetime#Space-like_interval

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#2429

On 7/5/2011 3:24 PM, Michael S wrote:
> On Jul 3, 9:27 pm, "Andy \"Krazy\" Glew"<a...@SPAM.comp-arch.net>
> wrote:
>>> On Sat, 02 Jul 2011 10:33:53 +0200, Terje Mathisen<"terje.mathisen at
>>> tmsw.no">    wrote, in part:
>>>> Add in relativity and you realize that it might not be even
>>>> theoretically possible to determine which of two events happened "first".
>>
>> At the moment there still exist interpretations of modern physics,
>> including relativity, that admit causality, that deny the possibility of
>> non-causal loops.
(I should probably have said "causal loops" here - loops inconsistent 
with causality.)
>
> I don't understand. Are you saying that there are serious scientists
> here that deny the existence of space-like intervals?
> http://en.wikipedia.org/wiki/Spacetime#Space-like_interval

Well, there are - but that's not what I was  talking about. I'm not 
competent to judge how serious they are.

It is just my understanding that the interpretation is still debated by 
some. Specifically, what does causality mean in a Minkowski space?

And my point was that if you still believe in causality, you have a 
partial order. Well, at least a directed graph. If you believe causal 
loops are impossible, you have  a partial order. And all partial orders 
can be embedded in (possibly many) total orders.

By the way, I am not a serious scientist, and I don't deny the 
possibility of space-like intervals. I am 100% on board with the idea 
that there is no absolute time.  I am not a ROD (Relativity Orthodoxy 
Doubter).  I am a QUOD (Quantum Orthodoxy Doubter).  I made a mistake in 
mentioning QUOD, when Terje was only referring to relativity.

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#2431

On Jul 8, 12:25 pm, "Andy \"Krazy\" Glew" <a...@SPAM.comp-arch.net>
wrote:

> I am a QUOD (Quantum Orthodoxy Doubter).  I made a mistake in
> mentioning QUOD, when Terje was only referring to relativity.

Is there a quantum orthodoxy to doubt?  I was under the impression
that everything was up for grabs and may stay that way for the
foreseeable future.  That is to say, the world of theoretical physics
is overloaded with an embarrassment of speculative riches, none of
which can be proven right or wrong, and that it seems increasingly
unlikely that there will be a settled orthodoxy for a very long time.

Robert.

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#2437

On 7/8/2011 12:12 PM, Robert Myers wrote:
> On Jul 8, 12:25 pm, "Andy \"Krazy\" Glew"<a...@SPAM.comp-arch.net>
> wrote:
>
>> I am a QUOD (Quantum Orthodoxy Doubter).  I made a mistake in
>> mentioning QUOD, when Terje was only referring to relativity.
>
> Is there a quantum orthodoxy to doubt?  I was under the impression
> that everything was up for grabs and may stay that way for the
> foreseeable future.  That is to say, the world of theoretical physics
> is overloaded with an embarrassment of speculative riches, none of
> which can be proven right or wrong, and that it seems increasingly
> unlikely that there will be a settled orthodoxy for a very long time.
>
> Robert.

Copenhagen.

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#2448

On 7/8/2011 8:27 PM, Andy "Krazy" Glew wrote:
> On 7/8/2011 12:12 PM, Robert Myers wrote:
>> On Jul 8, 12:25 pm, "Andy \"Krazy\" Glew"<a...@SPAM.comp-arch.net>
>> wrote:
>>
>>> I am a QUOD (Quantum Orthodoxy Doubter). I made a mistake in
>>> mentioning QUOD, when Terje was only referring to relativity.
>>
>> Is there a quantum orthodoxy to doubt? I was under the impression
>> that everything was up for grabs and may stay that way for the
>> foreseeable future. That is to say, the world of theoretical physics
>> is overloaded with an embarrassment of speculative riches, none of
>> which can be proven right or wrong, and that it seems increasingly
>> unlikely that there will be a settled orthodoxy for a very long time.
>>
>
> Copenhagen.
>

People are still teaching Copenhagen?  Heavens.

Robert.

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