Traumatized by science!

I can live on science alone.

Sigh. Having a scientist family can be just as traumatic as having an overly religious family.

every day i gazed at them wondering if today was the day they woke and erupted again, and were we a safe distance away from possible lava etc

(haha i just watched if... on video last night which has a weirdly out-of-nowhere "animals and foetuses in bottles" scene)

My granny also had the "weird things floating in bottles" - but they were at her department at the Uni, not in her house. Her house just had hundreds and hundreds of various species of exotic plants growing in it.

Apparently, the last time my mum went to visit her, there was this phone call for "Dr. G1lli1and" and my mum asked who it was and the person said "The Israeli Minister of Agrigculture" and my mum was all "Sure, and I'm the Queen of England" but no - my mum forgot that my gran is one of the world's foremost experts on ... oh, I forget, rubber plants or something like that.

i just think of it as a kind of cloth

I had waaaaaay too much faith in SCIENCE to ever be traumatised by it; that kind of thing happens when your earliest memories involve lots of hospitals and surgeons and nurses dropping large jars full of your own snot and bile (and if you think I'm all snot and bile now...), as well as trying to solve all mysteries of the universe with a combination of medical book and encyclopedia. Remember, you're dealing with someone whose earliest memories of PEEING involve the pee being measured in CCs for some waiting nurse (English, nicknamed 10CC not for the band or average spunk excretion, but for the 'donation' expected from yours truly). I'd also watch ALL wildlife, space and medical programmes because usually horrible 1-800-GOD-CASH-type programmes were on every other channel on Sunday. Also, you know that person who can pull out gross science facts from NOWHERE to barf you out? That's me! Junior high boys were throwing bits of formeldafrog at the wrong girl...

My neighbour was an eminent research scientist and mad inventor who served in the RAF medical corps during WWII. He had a cathode ray oscilloscope in the dining room and really yucky stories about his tour of service, when dumb servicemen would be wheeled in not with war wounds, but needing beer bottles gingerly removed from their rectal passages - great time-killer, apparently.

NOVA, no fear, I say...

suzy roX0rs!

(interestingly [okay "interestingly"] said roomate is v backwoods + upper middle class minnesotan and quite quite racist. Quote: "there are enough chinese people that they could all hold hands and float on the ocean and then drive tanks over each other right into california.")

my mom told me if i bit my nails i'd get tapeworms, but then she told me years later that was a lie to stop me biting my nails, so it's not science. history traumatized me a lot more than science, i'd say. people are fucking scary.

I now have a mental image of the Chinese army floating up on the Californian shore, then running over each other with tanks, like an evil, demented version of tag.

okay. So i've 'stumbled' into quantum physics this weekend and i spent all night reading about the Double Slit experiment.

Any thoughts on this? While the experiment is indeed fascinating and has baffled many scientists it seems odd that they haven't tried the test with more variation, to explore what is happening with the single particle of electron (whether it does indeed split into two, hmm)

how do i get myself a hold of some of this lab equipment to try for myself, where do you get electron guns from?

You read about the variations with a detector at one slit only, or the detection event occurring after the particle has traversed the slits, or the beam-splitter variation?

The whole peculiarity of the experiment is that "what is happening with the single particle of electron" seems to depend on the experimental set up. An experiment that expects particle-like behaviour gets particle-like behaviour, and an experiment that expects wave-like behaviour.

http://scienceblogs.com/clock/upload/2006/10/magnus_pyke.jpg

Traumatised! by SCIENCE!

... "gets wave-like behaviour" missing from my last sentence.

overview @ wikipedia:

http://en.wikipedia.org/wiki/Double_slit_experiment

ledge, yeah I've pretty much youtubed this thing to death.

(i'll post something more substantial in a mo, just gotta do some yawn work)

what i meant was that the experiment seems to stop at, "wow the 'electron' acts as a wave, see look a the pretty pattern of wave like behaviour it makes". "hey lets check the electrons going through, whoaa it now behaves like a particle"

Why is something so bizarre as this not been reconstucted with thousands of slightly changed iterations to the test, probly has but I just couldn't find anything on the net.

Well it's been observed with particles larger than electrons - neutrons, atoms, and even iodine molecules. And there are alternative intrepretations of the results, some of which seem amenable to experiment and some which don't - e.g.:

"In Bohm's [pilot wave] view, a quantum entity such as an electron does in fact exist in a particular place at a particular time, but its behaviour is governed by an unusual field, or pilot wave, whose properties are defined by the Schrödinger wave function ... Its predictions are identical to those of standard quantum mechanics.

[...]

Unlike Bohm's pilot-wave concept, the theory of Ghirardi's group offers predictions that diverge from those of orthodox quantum physics, albeit subtly. 'If you shine a neutron through two slits, you get an interference pattern," Pearle says. " But if our theory is correct, the interference should disappear if you make the measurement far enough away.' [...] Zeilinger of the University of Innsbruck was sufficiently interested in the theory to test the neutron prediction, which was not borne out. 'This approach is one of those dead end roads that has to be walked by someone,' he sighs."

And the double-slit isn't the only game in town... as an attempt to prove whether or not quantum physics appropriately describes the everyday macroscopic world, experiments have been done in which relatively large objects (10^15 atoms, the size of a pin) are put into a quantum superposition of states.

Basically I don't think people are sitting on their hands here!

Pretty good article on the superposition experiments here: http://science_boy.blogspot.com/2005/08/schroedingers-squid-filling-quantum.html
(includes yet another overview of the double slit experiment)

It's very difficult to find popular or not-too-technical articles that aren't five or ten years old. I want to find out about DECOHERENCE but even the wikipedia entry is full of crazy maths.

wikipedia is the worst for this sort of thing.

nice link above though, although was a bit wtf at the cat in the box analogy lol.

If you don't understand the maths, you probably shouldn't be mucking about with the experiments. I mean, "Honey I Accidentally Put The Kids Into A Quantum State Superposition" would make a cute Disney movie but could be quite problematic IRL.

This is why it is only ever done with cats, they are expendable, and more humourous when in a state of quantum uncertainly.

Not sure about squid though, would you ever really want uncertainty over the position of your squid?

(Read the link - the SQUID is the device. No actual squid were harmed during the making of this experiment.)

Schrodinger's Cat is one of a holy trinity of QM headfuck experiments, along with the double slit and the EPR paradox - but really I think it's a bit bogus, or at least has led to a lot of bogus theorising and woolly thinking about observation affecting reality, and the supposed priviliged position of human consciousness. (xp to ste)

ok i found some articles on decoherence just by er googling "decoherence".

ledge, do you know what 'measuring' equipment would be used to count the particles in the double slit exp?

Well if you're not concerned about counting individual particles but just seeing whether or not you get an intereference pattern, you could just use photographic film for photons. For electrons you might try a phosphor coated glass screen just like in a TV. Then you'd need an electron gun which you could find... in a TV!

If you haven't read Walter Isaacson's bio of Einstein, I recommend it as it follows the development of both quantum and unified field theory. The exasperation of younger physicists with Einstein's backing away from quantum theory led to thought experiments like Schrödinger's cat, and reading about them in context was enlightening.

no i meant the instrument they used to 'observe' the electrons/photons before they went through the slits, to check which slit was being used.

xp

hmm, I don't know actually. You'd want something that wouldn't substantially alter the path of the electron or it would be a bit pointless. Sadly I am not a physicist.

I've found some refs to so-called "which-path" detectors. They're quite... complex. This is the simplest I've come across (but I don't know what a "micromaser cavity" is):

"A beam of Rydberg atoms in an excited
state is incident on a double slit small enough to form a
Young interference pattern on a distant screen. In front of
each slit is placed a which-path marker, which consists of a
micromaser cavity of appropriate length such that the emission
probability for an atom traversing the cavity is 1. Then
the presence of a photon in either cavity marks the passage
of an atom through the corresponding slit and thus destroys
the interference pattern, because which-path information is
now available. The perturbation to the spatial part of the
wave function of the atoms due to the cavities is ignorable"

Ok here's one from a Feynamm lecture:

"To our electron apparatus we add a very strong light source, placed behind the wall and between the two holes. We know that electric charges scatter light. So when an electron passes, however it does pass, on its way to the detector, it will scatter some light to our eye, and we can see where the electron goes. If, for instance, an electron were to take the path via hole 2 that is sketched in Fig. 37-4, we should see a flash of light coming from the vicinity of the place marked A in the figure. If an electron passes through hole 1 we would expect to see a flash from the vicinity of the upper hole. If it should happen that we get light form both places at the same time...

...every time we hear a click from our electron detector (at the backstop) we also see a flash of light either near hole 1 or near hole 2, but never both at once. And we observe the same result no matter where we put the detector. From this observation we conclude that when we look at the electrons we find that electron go either through one hole or the other."

(Feynman)

A controversial double-slit variation

man I really should be doing some work...

lol i was up until 7am saturday night/sunday morning reading this stuff.

The human eye can see a single photon, right? So presumably then it can detect a single electron scattering a single photon?

The retina can respond to single photons but I don't think they would register as a conscious signal. Not that the measurement needs to be a conscious event.

i'm so dismantling my old telly this week

vacuum (not cleaner) might pose a problem...

shiver

Thought for a second it said "vaginal application in the mouth" and was like OK WAHT.

How (not) to communicate new scientific information: a memoir of the famous Brindley lecture

"Although this lecture was given more than 20 years ago, the details have remained fresh in my mind, for reasons which will become obvious."

day made. thank you for that, sanpaku.

hahahah