Skip to comments.Researchers look beyond space and time to cope with quantum theory
Posted on 10/28/2012 8:50:13 PM PDT by JerseyanExile
Physicists have proposed an experiment that could force us to make a choice between extremes to describe the behaviour of the Universe.
The proposal comes from an international team of researchers from Switzerland, Belgium, Spain and Singapore, and is published today in Nature Physics. It is based on what the researchers call a 'hidden influence inequality'. This exposes how quantum predictions challenge our best understanding about the nature of space and time, Einstein's theory of relativity. "We are interested in whether we can explain the funky phenomena we observe without sacrificing our sense of things happening smoothly in space and time," says Jean-Daniel Bancal, one of the researchers behind the new result, who carried out the research at the University of Geneva in Switzerland. He is now at the Centre for Quantum Technologies at the National University of Singapore.
Excitingly, there is a real prospect of performing this test. The implications of quantum theory have been troubling physicists since the theory was invented in the early 20th Century. The problem is that quantum theory predicts bizarre behaviour for particles such as two 'entangled' particles behaving as one even when far apart. This seems to violate our sense of cause and effect in space and time. Physicists call such behaviour 'nonlocal'. It was Einstein who first drew attention to the worrying implications of what he termed the "spooky action at a distance" predicted by quantum mechanics. Measure one in a pair of entangled atoms to have its magnetic 'spin' pointing up, for example, and quantum physics says the other can immediately be found pointing in the opposite direction, wherever it is and even when one could not predict beforehand which particle would do what. Common sense tells us that any such coordinated behaviour must result from one of two arrangements. First, it could be arranged in advance. The second option is that it could be synchronised by some signal sent between the particles.
In the 1960s, John Bell came up with the first test to see whether entangled particles followed common sense. Specifically, a test of a 'Bell inequality' checks whether two particles' behaviour could have been based on prior arrangements. If measurements violate the inequality, pairs of particles are doing what quantum theory says: acting without any 'local hidden variables' directing their fate. Starting in the 1980s, experiments have found violations of Bell inequalities time and time again. Quantum theory was the winner, it seemed. However, conventional tests of Bell inequalities can never completely kill hope of a common sense story involving signals that don't flout the principles of relativity. That's why the researchers set out to devise a new inequality that would probe the role of signals directly. Experiments have already shown that if you want to invoke signals to explain things, the signals would have to be travelling faster than light more than 10,000 times the speed of light, in fact. To those who know that Einstein's relativity sets the speed of light as a universal speed limit, the idea of signals travelling 10,000 times as fast as light already sets alarm bells ringing.
However, physicists have a getout: such signals might stay as 'hidden influences' useable for nothing, and thus not violating relativity. Only if the signals can be harnessed for faster-than-light communication do they openly contradict relativity. The new hidden influence inequality shows that the getout won't work when it comes to quantum predictions. To derive their inequality, which sets up a measurement of entanglement between four particles, the researchers considered what behaviours are possible for four particles that are connected by influences that stay hidden and that travel at some arbitrary finite speed.
Mathematically (and mind-bogglingly), these constraints define an 80-dimensional object. The testable hidden influence inequality is the boundary of the shadow this 80-dimensional shape casts in 44 dimensions. The researchers showed that quantum predictions can lie outside this boundary, which means they are going against one of the assumptions. Outside the boundary, either the influences can't stay hidden, or they must have infinite speed. Experimental groups can already entangle four particles, so a test is feasible in the near future (though the precision of experiments will need to improve to make the difference measurable). Such a test will boil down to measuring a single number. In a Universe following the standard relativistic laws we are used to, 7 is the limit. If nature behaves as quantum physics predicts, the result can go up to 7.3. So if the result is greater than 7 in other words, if the quantum nature of the world is confirmed what will it mean? Here, there are two choices. On the one hand, there is the option to defy relativity and 'unhide' the influences, which means accepting faster-than-light communication. Relativity is a successful theory that researchers would not call into question lightly, so for many physicists this is seen as the most extreme possibility.
The remaining option is to accept that influences must be infinitely fast or that there exists some process that has an equivalent effect when viewed in our spacetime. The current test couldn't distinguish. Either way, it would mean that the Universe is fundamentally nonlocal, in the sense that every bit of the Universe can be connected to any other bit anywhere, instantly. That such connections are possible defies our everyday intuition and represents another extreme solution, but arguably preferable to faster-than-light communication. "Our result gives weight to the idea that quantum correlations somehow arise from outside spacetime, in the sense that no story in space and time can describe them," says Nicolas Gisin, Professor at the University of Geneva, Switzerland, and member of the team.
I had assumed you were referring to religions centuries ago...but, remember...they were the scientists most often and the debates were similar to today.
Indeed, think about the blacklisting scientists who do not drink from the global warming dogma suffer in grants and promotions at university’s etc. Heresy is now the dominion of science more than “organized religion”.
On the other hand, change takes time generally to accept in science. Like Intelligent Design rather than the failed philosophy of Darwinian Evolution theory. It will take another generation for widespread acceptance, but it will be accepted.
Be careful reducing the power of an almighty God to our understanding of science.
Well, if you want to get picky ... no. Elliptical orbits solve the Newtonian two body problem, and hence represent a conceptual advance over eccentric circular orbits, but Kepler's third law may be disovered to be in error by checking against Norton's Sky Atlas with a calculator. This is not to mention perturbations. So even within Newtonian dynamics the ellipses are an idealization.
Ah yes, the four particle hidden influence inequality experiment. That’s the one that turns the experimenter’s planet into a lovely glowing red ball for a few seconds before it expands into a much larger orange ball that suddenly goes dark.
Google tells me you are quoting BLAZING SADDLES.
For actual attribution I only find, “I tell you: one must still have chaos within oneself, to give birth to a dancing star.”
We might compare this to Genesis 1:2 and find it moving in the same orbit.
The particular bit of crap moving under the keys works it's way from the left shift button to the right shift button in a somewhat parabolic arc. It's an FR fault. I wind up laughing too much over the keyboard.
I had a dream (last year?) and I posted it it here on FR that explained everything ...
Basically Reality is a Hologram on about a million panes of Glass and the Big Bang is when God Dropped them “BOOM” now there are Hundreds of Millions of copies of Reality that God is sweeping up... the many shards of the many many Universes into a Dust Pan muttering OK “Practice Makes Perfect” and we are the Reality of one of those few pieces that were lost under the couch.
Just kidding, we are probably the one that is on his slide under the Microscope...
Don’t know... I may have to have that dream again to be sure.
In case you don’t know, if you draw a circle with a compass on an 8X11 sheet of paper, the shape of earth’s orbit will easily lie within the pencil line of that circle.
... so let’s not sell Ptolemy short! ... and I mean that sincerely.
“Mathematically (and mind-bogglingly), these constraints define an 80-dimensional object. The testable hidden influence inequality is the boundary of the shadow this 80-dimensional shape casts in 44 dimensions. The researchers showed that quantum predictions can lie outside this boundary, which means they are going against one of the assumptions.”
Um...good luck to all with this bit!
So... 0.019685(2*60*C)... yeah. that's a wide line.
Cook math. It's all I got.
Mel Brooks... What a guy...
I think this calls for an Endowed Chair and a new wing on the school of theoretical mathematics somewhere. Until then there are papers to be written and book manuscripts to be delivered to the publishers. Maybe conferences in nice places to study the universe over good wine.
Somehow or another we’ll get it all sorted out.
LOL.... this really is a lot simpler than they make it.
They do not consider that the operational frequency of consciousness increasing past the speed of light collapses the time space continuum. When the soul is cleansed of the anchors of low frequency thoughts this is not that difficult. It’s how I see the future in meditation.
Sorry to say, I don’t like what I see.
I follow you up to 0.019685” = 0.5 mm . Not so sure what 2*60*C signifies.
The idea is that the eccentricity of earth’s orbit is 0.0167, but this is the “off centeredness”, which is the distance of the focus of the orbit from the center, in terms of the radius, or more precisely, the semimajor axis, and a circle shifted by this amount gives an excellent approximation to earth’s orbit. Considered as an ellipse, the minor axis is sqrt( 1 - e^2) times the major axis, or approximately ( 1 - 1/2 e^2 ) or (1 - 0.00014)
But 0.00014 X 8” is 0.001” which is to be compared to the pencil line width of 0.02” . So when I say “easily”, I mean that the pencil line width is twenty times as great as the difference between the major and minor diameters of the earth’s orbit, accurately drawn.
Don't worry about it. That always happens when it stretches.
Multiply by 60 to get light seconds per scale inch.
Multiply by C (speed of light) to get answer in whatever unit of measure you use for C. I use 186000 miles per second. Multiply by the paper line width. That's the width of the line, to scale.
Cook math. Order of magnitude. Close enough. I don't launch Mars orbiters, and if I did, I'd keep the units the same, even if we were using furlongs per fortnight.
I can only say that I regard myself as familiar with the movie, having seen it first run, and several times after that, and I’m rather chagrined that I didn’t recogize the quote. Well, ars longa vita brevis.
I like to laugh. I can quote long parts of it. Cooks do weird stuff, when you don't work 'em hard enough.
BTW, my speed of light number in furlongs per fortnight is 1.8026175* 10^12.
You're scaling the line up to "actual size", with units unspecified, which begs the question. That question is namely, what is the ratio of the major and minor axes of earth's orbit? and how does it compare with the ratio of an 0.5 mm pencil line to an 8" diameter drawn circle?