Slashdot Mirror
Landmark Calculation Clears the Way To Answering How Matter Is Formed
First time accepted submitter smazsyr writes "An international collaboration of scientists is reporting in landmark detail the decay process of a subatomic particle called a kaon – information that may help answer fundamental questions about how the universe began. The calculation in the study required 54 million processor hours on the IBM BlueGene/P supercomputer at Argonne National Laboratory, the equivalent of 281 days of computing with 8,000 processors. 'This calculation brings us closer to answering fundamental questions about how matter formed in the early universe and why we, and everything else we observe today, are made of matter and not anti-matter,' says a co-author of the paper."
Why does this matter?
Blue Gene uses quad core PowerPCs, with 8192 cores on the Argonne system. That's a heck of a lot of days of maxing out your CPUs!
The cesspool just got a check and balance.
Help restore /. to it's former nerd news glory, tag stories like this with realslash to tell the editors that we want our favorite site back.
to the "that's just the way it is" condition. You can go back in time and talk about when the universe created. But then you have to determine the conditions, the rules the mechanics by which that universe was created. Then you have to ask how those rules, conditions and mechanics were created. If you can answer those steps, then you have iterated back just one more layer and will have to answer those questions all over again.
Unless those conditions, rules and mechanics iterate forever, you are forced to a certain point where the universe (or whatever layer you peel back to) just is. Call it "God" or just say that the universe or whatever just is the way that it is.
how is mater formed
how universe get axpadned
They ran the calculation on one core. They needed the other 8191 to render the Aero desktop.
Have gnu, will travel.
42. 42 kaons. Ha, ha, ha!
And the answer is 42?
Kirk was misquoted. It was "KKAAAOONNN!!!!!"
All I read about this event is that the computers mapped the decay. Not 1 piece of information about what they learned. In that light, I'll fill in the blanks with the pieces of Quantum Physics I understand.
Kaons are quarks with "strangeness". This typically includes Up, Down, Charm, Strange, and Bottom. Top doesn't participate due to size and shortness of life. Kaons ( http://en.wikipedia.org/wiki/Kaon ) decaying into Pions ( http://en.wikipedia.org/wiki/Pion ) is a great demonstration of quarks participating in the Weak Force. This study combines our study of particle oscillation and weak decay, and digitally maps out that entire process rather than simply relying on theory. Granted, they weren't actually watching this happen, but the generated map gives Physicists what they need to compare against findings from places like the LHC.
TL;DR? Basically, this group designed software and used a very fast computer to generate a result set from theoretical predictions which can be used to compare against various super-collider findings. Specifically, these result sets are regarding Kaon to Pion decay, a Weak force interaction.
Where genius and insanity become confused true wisdom is found
Since the blog entry contains no reference - and the one hint there is is wrong - here is the actual article reference: Phys. Rev. Lett. 108:141601 (2012) - which was published on 6th April, not 30th March at the article states!
Now onto the physics, sorry but your summary is almost completely wrong. Kaons are mesons which are a bound state of a quark and anti-quark. In the case of neutral kaons this is a strange and anti-down (or vice versa for the anti-kaon IIRC). What is interesting about the kaon is that the neutral states can oscillate between kaon and anti-kaon through a weak interaction. What you end up with is a long-lived kaon (KL) and a short lived one (KS). The simplest way to demonstrate that this system differentiates between matter and anti-matter is to look at the long lived kaon decaying in to muons (heavy cousins of the electron). The number of anti-muons will be about 0.1% different from the number of muons produced.
However the decay to pions is far more closely studied because it can tell us far more information - in particular whether this symmetry breaking occurs in the decay mechanism (direct CP violation) or only in the weak mixing of a kaon to anti-kaon (indirect CP violation). The experiment I worked on as a grad student, NA48, observed this direct CP violation unambiguously for the first time, confirming the previous NA31 result. This ruled out more exotic types of CP violation from a new "superweak" interaction and, in broad terms, was consistent with the Standard Model.
However this was not really confirmation of the Standard Model because the actual calculation of CP violation occurring in the SM is really hard to calculate: it involves quark/W boson loops which must have contributions from all three generations of quarks (specifically including the top quark!). These so-called penguin diagrams (blame the name on John Ellis' dart playing skills!) are really hard to calculate - at least to the accuracy needed for CP violation in kaons. Kaons must decay through a weak interaction because only the weak interaction can change the strange quark into an up quark which is needed for pion decay. However there is also a strong component to the decay.
Strong (QCD) processes are really hard to calculate because perturbation theory does not work for them (the interaction is far too strong). One approach to solve this is lattice QCD which literally simulates all the colour (QCD) fields on a 4D grid of space-time points. However this is really CPU-intensive so only small grids can be simulated. This is not too bad if you have a strong process because, being 'strong' it happens quickly in a small region. However the weak part of the decay occurs more slowly over a larger area. What the authors seem to have done is overcome this simulation problem of both weak and strong forces in the same decay which raises the prospect of accurate calculations of the CP violation in kaon decays which has never been possible before. For the technically minded this paper calculates the Isospin=2 decay amplitude (A_2) whose phase shift, relative to the isospin 0 amplitude (A_0) is what makes direct CP violation visible - it's a really interesting paper - at least if you have ever been involved in kaon physics!
How is this funny? Why would anyone mod this funny?
"Honey, what's the matter?"
"You know!"
No, I don't. But maybe maybe a team of scientists using one of the most powerful computers on earth can figure what the heck is the matter with you.
The world is made by those who show up for the job.
One of the big things that originally hooked me was the tendency for people to 'run the numbers' when they had a disagreement with someone else.
Slashdot has always been full of flamewars...
The thing is, years ago it was hardly ever political flamewars. Flamewars about technical matters have an inherent ability for people to point to hard data about things, which kept the whole discussion somewhat tied to reality.
With politics, all bets are off - because you are talking about people with wildly different views about what is good for other groups of people, and even if they agree on THAT you have differences in how to achieve an end-goal. It's all about Seldonesque behaviors of the masses and there's no "numbers" you can run that someone else cannot simply dismiss away with their own numbers.
The reason for the spread of politics here is that inevitably, the spread of technology into the lives of every person means technology gets stuck in the tar baby of political motivation. Technology is simply part of the equation about how to change people in ways you deem most beneficial. So there's no going back to more reasoned discusson unless you want to remove technology from people's lives (some do, but I doubt the motive is to make Slashdot more readable).
It's not like you can make any OTHER site like the "old Slashdot" and have it be any different, due as I said to the intertwining of technology with everyone and politics being everywhere. We all just have to learn how to include politics in technical discourse without getting too heated and off track...
"There is more worth loving than we have strength to love." - Brian Jay Stanley
there is still a niche for traditional supercomputers left...
I don't think you know much about supercomputers. Sure, there are a few problems that are embarrassingly parallel, but most aren't. For those that aren't, the bandwidth and latency of the interconnect between different processors is more important, and often more expensive, than the speed of the processors themselves. This is why most supercomputers use exotic interconnects like Infiniband, Myrinet or 10GigE, and linking nodes together using complex topologies such as a torus.
Case in point: on the website of the QCDOC supercomputer, which was partially used in this study, they say that a highly optimized lattice QCD simulation achieves up to 50% CPU utilization, and this is considered very good. The rest of the time is mainly spent waiting for the interconnect.
for i in `facebook friends "=bday" 2>/dev/null | cut -d " " -f 3-`; do facebook wallpost $i "Happy birthday!"; done
And yet the entire article does not contain a single equation, much less a link to the paper. I am disappoint.
May the Maths Be with you!
It's not just that. The proportion of matter to photons is pretty respectable. If it were just a matter of a few atoms left over after all the antimatter was annihilated the universe would be much sparser and less interesting.
We don't have to explain ourselves to this person who believes science should only be pursued for its applications. Basic science paves the road for a wonderful engineering potential, but that's not why we do it.
We did it because SCIENCE IS FUCKING COOL.
Newton and Einstein didn't discover what they discovered out of some search for profit, they weren't Thomas Edison; they thought this science thing was the coolest shit ever and were invigorated by the challenges they offered. Please, on appeal to all scientists, put on your big smile and bend over backwards at fundraisers, but that's not why we do science.
The true intellectual places curiosity and discovery as a virtue unconditionally. It is not to be squelched because it fails to be immediately profitable or applicable.