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[P]
Using Quantum Cryptography to Find Invisible Men

By Morkney in Technology
Mon Jun 28, 2004 at 11:43:37 AM EST
Tags: Security (all tags)
Security

Since HG Wells first published his lauded exploration of racial identity, Invisible Man, people have been entranced by the myth of invisible men--be they heroes such as Invisible Woman of the Fantastic four, or villains such as Hollow Man's Sebastian Caine. But is it truly a myth, or do invisible men walk among us? And if an invisible man were to be created, how would we detect him and track his movements?


The problem of whether invisible men exist is a thorny one. We simply don't know, because they are invisible.

Until recently, the only solution to the problem of invisible man detection seemed to be the inelegant and unreliable method of observing the invisible man's effects on his surroundings, footsteps being the classic example. However, recent technological advances in quantum cryptography have at last provided a reliable, elegant, and surefire method to detect invisible men.

Of course invisible men can see--otherwise they'd step into things. Since sight requires light, invisible men must remove at least some light from their surroundings. Their pupils should therefore appear black. The invisible man has a way around this problem, however. If invisible men simply dublicate all light which hits their eyes, observing one photon and sending one on, they can remain concealed to the classical observer.

This is where quantum mechanics steps in. The classical observer is fooled by the duplication of the light--but it is not possible to duplicate quantum states. This fact allows quantum cryptography to insure that its information has not been intercepted. Since quantum cryptography encodes its information in photons, exactly the same technique could be used to insure that light crossing the room had not been intercepted by an invisible man.

Polarization of light can be measured using one of three bases: rectilinear, circular, and diagonal. Observation of any of these three states will change the state of the others. In quantum cryptography, data is recorded in polarization states so that an eavesdropper will change some of the data merely by observation, thus making their presence known. An invisible man detector would work by a similar method.

The detector would comprise two elements: a sender and a receiver. Each would generate the same random sequence from a shared seed. The sender would then send data taken from the random sequence, in a basis taken from the random sequence. The receiver would measure only that basis, and check for agreement. Disagreement between the data and the generated sequence would indicate that someone had observed the light. Someone...invisible!

This hypothetical invisible man detector could operate similarly to walk-through metal detectors. As it stands, an invisible man could simply walk into an airport, board a plane, and conduct terrorist activities. This crucial gap in our preparedness will be solved when a quantum detector is added to every airport, military base, and other sensitive locations.

Invisible man detection has gone a long way, from the clumsy mob actions of a hundred years ago to the sophisticated mob actions of today. The time has come to step into the 21st century with a quantum solution to a threat you'll never see coming.

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Related Links
o Invisible Man
o Hollow Man
o it is not possible to duplicate quantum states
o quantum cryptography
o Also by Morkney


Display: Sort:
Using Quantum Cryptography to Find Invisible Men | 104 comments (81 topical, 23 editorial, 0 hidden)
This would be cute (1.33 / 6) (#2)
by godix on Sat Jun 26, 2004 at 10:21:10 PM EST

if I hadn't recently read about how you can 'teleport' a quantum state which could totally invalidate your theory. Nice try.

They are possibly the dumbest people on the planet...
- Michael Moore describing Americans, wonder why people thinks he hates America?
Quantum mechanics requires hair-splitting (none / 3) (#3)
by Morkney on Sat Jun 26, 2004 at 10:29:47 PM EST

Quantum teleportation is different from cloning. One way in which they're different is that quantum teleportation is possible, while cloning of an arbitrary quantum state is impossible. Do you know a way in which teleportation, as distinct from cloning, could be used to achieve undetectable invisibility?

[ Parent ]
You can teleport indeed (2.25 / 4) (#4)
by WorkingEmail on Sat Jun 26, 2004 at 10:53:37 PM EST

But the issue here is duplication. :)


[ Parent ]
Can't detect and teleport at the same time (none / 1) (#64)
by epepke on Mon Jun 28, 2004 at 02:10:24 PM EST

You can 'teleport,' or you can detect, but you can't do both. Since the retina needs the photon to change the state of a molecule of trans-retinal, and the energy of this state change goes elsewhere (namely, detecting the reconfiguration), depending on the interpretation, either 1) the wavefunction has collapsed, or 2) the wavefunction has become entangled with the retina, the optic nerve, and the rest of the brain. In neither case can the quantum state be recovered without the end result of it being as if the photon did not strike the retina in the first place.


The truth may be out there, but lies are inside your head.--Terry Pratchett


[ Parent ]
This would be a good comment (none / 1) (#66)
by lonelyhobo on Mon Jun 28, 2004 at 02:28:41 PM EST

But an article I once read vaguely referenced how a comment was bad

[ Parent ]
No No No (none / 2) (#80)
by aphex on Mon Jun 28, 2004 at 10:56:44 PM EST

Teleporting is simply entangling two previous untangled particles giving a particle a new property once you touch it and untangle it. Quantum Crypto involves using already entangled photons making sure that there has been no man in the middle attack by seeing if your photon (alice) has the correct properties it should by comparing your photon with bob's photon. If eve taps my photon and rebroadcasts it I can tell. Even if he tries to teleport the old state onto the new photon he is injescting. He has a statistical change of being correct but its very small depending on your particular quantum state. You can pretty much make this probability zero especially by broadcasting parts of the key in differet connections and using statistics. Eve is fucked. The thing about entanglement is that you don't get to chose which state they may end up in, but you do know exactly the moment that your particles have been fucked with. go check out the lanl website. My old roommate works on quantum crypto in what was Nis-1 which got moved into two new divisions N division and some other thing I can't remember.

[ Parent ]
dumb question (2.00 / 4) (#11)
by omghax on Sun Jun 27, 2004 at 12:26:10 AM EST

HOW CAN WE USE QUANTUM ANYTHING TO DETECT INVISIBLE MEN WHEN INVISIBLE MEN WOULD, BY DEFINITION, NOT BE AFFECTED BY QUANTUM EXCHANGE PARTICLES (IE PHOTONS).

Oh shit, I guess I just got trolled.

I put the "LOL" in phiLOLigcal leadership - vote for OMGHAX for CMF president!

because (none / 2) (#12)
by Morkney on Sun Jun 27, 2004 at 12:29:54 AM EST

Invisible men can see. Hence they must observe photons. Hence it is possible to use the principle of quantum mechanics that an observer changes what he observes to detect invisible men.

[ Parent ]
THAT BREAKS SYMMETRY (none / 2) (#13)
by omghax on Sun Jun 27, 2004 at 12:31:44 AM EST

YOU SUN OF A BITCHLOL

I put the "LOL" in phiLOLigcal leadership - vote for OMGHAX for CMF president!
[ Parent ]
Is this worth a whole story? (none / 3) (#14)
by ixian on Sun Jun 27, 2004 at 01:11:56 AM EST

Because you just summarized your entire story into 3 sentenses.

[ Parent ]
A deeper treatment of the subject (none / 3) (#16)
by Morkney on Sun Jun 27, 2004 at 01:19:49 AM EST

My story includes the details of the process and some of the wider ramifications and considerations. And the main idea of it, even if it can be summarized in three sentences, is totally neat-o.

[ Parent ]
+1, FP (2.28 / 7) (#15)
by Battle Troll on Sun Jun 27, 2004 at 01:17:06 AM EST

This is the best article to be submitted to k5 in years.
--
Skarphedinn was carrying the axe with which he had killed Thrainn Sigfusson and which he called 'Battle Troll.'
Njal's Saga, ca 1280 AD
IAWTP [nt] (none / 0) (#53)
by alby on Mon Jun 28, 2004 at 08:39:20 AM EST


--
Alby
[ Parent ]

ASK K5: (1.90 / 10) (#17)
by Empedocles on Sun Jun 27, 2004 at 01:45:33 AM EST

I THINK THE INVISIBLE MAN JUST TOUCHED MY JUNK.

HOW CAN I TELL IF THEY WERE RED FLAG TOUCHES?

---
And I think it's gonna be a long long time
'Till touch down brings me 'round again to find
I'm not the man they think I am at home

ASK THE GODDAMN REFEREE (3.00 / 4) (#18)
by finality on Sun Jun 27, 2004 at 02:12:14 AM EST


This account has been anonymised. If you can give a good reason why, email rusty@kuro5hin.org, as he is obviously lacking one.
[ Parent ]
What about (2.50 / 4) (#20)
by The Solitaire on Sun Jun 27, 2004 at 03:42:03 AM EST

blind invisible men?

I need a new sig.

A more interesting question. (none / 3) (#24)
by i on Sun Jun 27, 2004 at 05:36:05 AM EST

When a (sighted) invisible man shuts his eyes, does it make him completely invisible? You know, like very small children?

and we have a contradicton according to our assumptions and the factor theorem

[ Parent ]
It's like the Philadelphia experiment (none / 1) (#48)
by Highlander on Mon Jun 28, 2004 at 02:50:27 AM EST

My theory is that for such a invisible man it would work out like the philadelphia experiment -when he closes his eyes (completely) he looses touch with the fabric of spacetime and when he opens his eyes he ends up completely elsewhere.

If he is lucky, on Titan, at least it got an atmosphere.

Moderation in moderation is a good thing.
[ Parent ]

so.... (none / 1) (#61)
by ckaminski on Mon Jun 28, 2004 at 12:35:55 PM EST

Invisible men have mastered the reflex action of blinking, then?

[ Parent ]
His eyelids are invisible (none / 0) (#63)
by cyberdruid on Mon Jun 28, 2004 at 01:35:11 PM EST

so he obviously will see stuff anyway.

[ Parent ]
Lovely solution, but there's a cheaper one. (2.50 / 4) (#22)
by Russell Dovey on Sun Jun 27, 2004 at 05:13:18 AM EST

Simply take away his anti-dandruff shampoo.

"Blessed are the cracked, for they let in the light." - Spike Milligan

Moo! (2.60 / 5) (#23)
by i on Sun Jun 27, 2004 at 05:28:36 AM EST

Why would an invisible man go through an invisible-men-detector when he may just as well walk around it? You will have to put those detectors everywhere, such that it's impossible to avoid them. You can't just put them in a bunch of random places and hope that eventually invisible men will cross one of the beams by accident. That's because invisible men will know where those beams are! But then normal, visible objects will cross those beams all the time. You will have one hell of a time telling apart signal from noise.

You know the difference between theory and practice, right?

</mastrurbation mode=pseudo-intellectual>

and we have a contradicton according to our assumptions and the factor theorem

In theory (2.75 / 4) (#40)
by wiredog on Sun Jun 27, 2004 at 10:13:37 PM EST

there's no difference between theory and practice. In practice, there is.

Wilford Brimley scares my chickens.
Phil the Canuck

[ Parent ]
Better formulation (none / 0) (#97)
by BenJackson on Fri Jul 02, 2004 at 05:05:24 PM EST

"The difference between theory and practice in practice is bigger than the difference between theory and practice in theory."

[ Parent ]
Correction (none / 0) (#62)
by IsaacW on Mon Jun 28, 2004 at 01:06:10 PM EST

But then normal, visible objects will cross those beams all the time. You will have one hell of a time telling apart signal from noise.
Actually, a normal visible object would prevent the transmitted photons from arriving at the receiver, indicating that a visible object was blocking the beam, barring any transmitter failure.

Of course, a larger problem is that it would be difficult to have these in any but the darkest of places, because the ambient light would probably muck with the receiver setup.

[ Parent ]
A simple answer. (2.77 / 9) (#26)
by finality on Sun Jun 27, 2004 at 07:09:29 AM EST

These invisibility detectors are completely unneccessary (much like some of the letters in that word). Why is this, I hear you ask? All people, invisible or otherwise, become ill, or old, and die. I have not yet tripped over an invisible corpse, so by a process of logic one can deduce that there are no invisible people.
This account has been anonymised. If you can give a good reason why, email rusty@kuro5hin.org, as he is obviously lacking one.
Never saw the invisible graveyard? (n/t) (3.00 / 10) (#27)
by Psychopath on Sun Jun 27, 2004 at 08:04:42 AM EST


--
The only antidote to mental suffering is physical pain. -- Karl Marx
[ Parent ]
I've never tripped over a corpse (3.00 / 4) (#33)
by thankyougustad on Sun Jun 27, 2004 at 12:48:10 PM EST

and yet there are still people around. I'm gonna have to buy the invisible man theory unless you come up with something better.

No no thanks no
Je n'aime que le bourbon
no no thanks no
c'est une affaire de goût.

[ Parent ]
Well, of course not! (2.80 / 5) (#35)
by J'raxis on Sun Jun 27, 2004 at 04:25:30 PM EST

You can see the visible corpses, can’t you?

— J’raxis

[ J’raxis·Com | Liberty in your lifetime ]
[ Parent ]

Deduction: (none / 2) (#96)
by wji on Wed Jun 30, 2004 at 02:46:06 PM EST

Invisible paramedics rescue injured or incapacitated invisible people, and put the dead ones in an invisible morgue.

In conclusion, the Powerpuff Girls are a reactionary, pseudo-feminist enterprise.
[ Parent ]
so wait.. (none / 0) (#98)
by Lacero on Sun Jul 04, 2004 at 01:28:39 PM EST

How do he invisible paramedics know where the injured invisible people are? I mean they might be so injured they can't call for help.

[ Parent ]
Easy (none / 0) (#100)
by wji on Wed Jul 21, 2004 at 08:02:11 PM EST

They use Quantum Cryptography.

In conclusion, the Powerpuff Girls are a reactionary, pseudo-feminist enterprise.
[ Parent ]
+1 FP, literary criticism is good (none / 3) (#36)
by FotoPlasma on Sun Jun 27, 2004 at 04:34:10 PM EST

Invisible Man is better than high school required reading.

fun and reading (none / 2) (#37)
by Phil San on Sun Jun 27, 2004 at 08:46:32 PM EST

Invisible Man is better than high school required reading.

I think you're full of it.

Yeah I'm sure that classics like Wurthering Heights, Mcbeth, Julius Caesar, Oliver Twist and all that are real bad picks.

Course if you like shit like whiny race crap then go for "Cry, the Beloved Country" by Alan Patton then.

Of course if you are deluded enough to think that America's race problems of the past are worse than other countries then perhaps you need to look at that one or perhaps how Germany "cleaned up" theirs.

[ Parent ]

I liked (none / 1) (#47)
by thankyougustad on Mon Jun 28, 2004 at 02:19:36 AM EST

catcher in the rye when I was in high school.

No no thanks no
Je n'aime que le bourbon
no no thanks no
c'est une affaire de goût.

[ Parent ]
Simple detector, and HG Wells? (none / 1) (#41)
by cburke on Sun Jun 27, 2004 at 10:38:22 PM EST

Why go through so much trouble?  You don't need quantum mechanics.  The answer is in your source material, if you'll remember.  There they used broken glass on the roads, but if you want it to look like a metal detector at the airport, then monofilament wires stretched tautly across an inch apart should do the trick just fine.  How do you know you've found an invisible man?  Why, the blood curdling screams, of course!

Speaking of your source material, you say " Since HG Wells first published his lauded exploration of racial identity, Invisible Man"...  Your link is to the book Invisible Man by Ralph Ellison, which is about racial identity.  The book by HG Wells, The Invisible Man, is about an invisible man, like the rest of your story.  That's just odd.  Or did I miss the dead-pan humor?

Glass on the roads? (none / 1) (#51)
by tonyenkiducx on Mon Jun 28, 2004 at 06:51:52 AM EST

Surely they could just walk around that? Not to mention the possibility of small puppies and children being hurt... Come to think of it, brilliant idea, let's put broken glass everywhere!! *Heads outside with a hammer*

Tony.
I see a planet where love is foremost, where war is none existant. A planet of peace, and a planet of understanding. I see a planet called
[ Parent ]
Think around a town in the woods. (none / 0) (#79)
by cburke on Mon Jun 28, 2004 at 08:50:35 PM EST

Like a barrier on the entryways to your village.  You know, to keep the invisible people out.  Going through the dense wood would make a lot of noise.

Though a village that was really paranoid about invisible people would want to put glass on the roads, and monofilament wires through the trees.  Make sure to remind your kids not to play in the woods!

[ Parent ]

Monofilament fibers? (none / 0) (#56)
by Fon2d2 on Mon Jun 28, 2004 at 10:40:08 AM EST

Did you get that from the Hyperion series?

[ Parent ]
or perhaps from daniel keys moran's... (none / 0) (#67)
by justo on Mon Jun 28, 2004 at 02:29:44 PM EST

continuing time series...

[ Parent ]
First saw it in a Christopher Stasheff book (none / 0) (#76)
by cburke on Mon Jun 28, 2004 at 06:06:52 PM EST

But since then I've heard of the concept plenty of different places.  I figure it's less forward-looking than the quantum-detector the story talks about.

[ Parent ]
Monofilaments (none / 0) (#84)
by alby on Tue Jun 29, 2004 at 04:54:04 AM EST

Monofilaments are quite a commoon sci-fi device. They also feature in Johnny Mnemonic.

--
Alby
[ Parent ]

And you don't think... (none / 2) (#43)
by myrspace on Sun Jun 27, 2004 at 11:46:47 PM EST

that the invisible men have their own invisible mobs who perform researches in their invisible hideouts to counter the inivible detection schemes of the non inivisibles? nor do you realize that there might be an invisible man who will be assigned to monitor you and slit your throught with his invisibly sharp fingernails if you persue this invisible man hating propagandas? Why, the invisible men aren't stupid. If the visible men can built cars and aeroplanes, what's to stop them from building their own invisible modes of transport? Perhaps they've taken up bioengineering and created invisible bugs to ride on and invisible dragonflies to travel across europe. Why, they may have even developed a serum to make them temporarily visible for a while to inject themselves into visible society and learn of their trade secrets before returning to the other invisibles and forming countermeasures to the invisible men detection schemes. Beware what you speak sir, for you might be reading the words of an invisible man... right now.

la mort aux le visibles!

minor correction (none / 2) (#44)
by myrspace on Sun Jun 27, 2004 at 11:48:53 PM EST

throught = throat

it's hard to type when you can't see your own fingers.

[ Parent ]

another: (none / 1) (#46)
by thankyougustad on Mon Jun 28, 2004 at 02:16:43 AM EST

'mort aux visibles!'

No no thanks no
Je n'aime que le bourbon
no no thanks no
c'est une affaire de goût.

[ Parent ]
i am invisible [nt] (none / 1) (#50)
by the77x42 on Mon Jun 28, 2004 at 05:44:34 AM EST




"We're not here to educate. We're here to point and laugh." - creature
"You have some pretty stupid ideas." - indubitable ‮

*sniff* *sniff* (none / 3) (#52)
by tonyenkiducx on Mon Jun 28, 2004 at 06:58:09 AM EST

You might not see him, but a dog would smell him in a second flat. And surely if he can affect the atmosphere around him(I.E. moving things) then he would affect other physical detection devices, such as lasers or heat sensors. Not to mention a set of floor sensors along a single file corridor. Ohh, hang on, you were taking the piss. Forget all that. Brilliant article!

Tony.
I see a planet where love is foremost, where war is none existant. A planet of peace, and a planet of understanding. I see a planet called
Hmmm ... (none / 1) (#54)
by alby on Mon Jun 28, 2004 at 08:47:44 AM EST

If the invisible man can absorb and eject photons of visible light then you could imagine a situation in which that he can do the same with photons of other wavelengths: e.g. he could walk through a laser "trip-wire". If he has total control over the photons he emits then he could also avoid setting off passive infrared systems.

However, some sort of Schlierren camera would, I think, be able to pick up disturbances in the local atmosphere. Though I'm not sure how well this would work against background disturbances.

--
Alby
[ Parent ]

Um... (none / 2) (#73)
by virg on Mon Jun 28, 2004 at 05:28:32 PM EST

Well, how about a pressure pad? Is it really so hard to conceive a treadpad that this invisible being would cross over? Couple it with a eye-beam laser, and every time the pad trips but the laser doesn't, set off the spray of paint. Simple.

Virg
"Imagine (it won't be hard) that most people would prefer seeing Carrot Top beaten to death with a bag of walnuts." - Jmzero
[ Parent ]
Late reply :P (none / 0) (#101)
by tonyenkiducx on Thu Jul 29, 2004 at 08:48:04 AM EST

Most laser's aren't visible light, but rather in the other ends of the spectrum. Your thinking of those heist movies where there's red lasers everywhere for people just move around.

Tony.
I see a planet where love is foremost, where war is none existant. A planet of peace, and a planet of understanding. I see a planet called
[ Parent ]
The error... (none / 1) (#55)
by killmepleez on Mon Jun 28, 2004 at 09:40:47 AM EST

...in the very first sentence of your intro is simply unforgivable. If you're not familiar with a literary source - as you clearly are not, else you would know the difference between Wells and Ellison - there is no reason other than desperation and vanity to staple an absurd and ill-advised allusion into an essay where it doesn't belong. So you spent five minutes with google or amazon looking for some artificial flavor for your artificial article.... but you didn't take the time to get it right, so minus one to you.

__
"I instantly realized that everything in my life that I thought was unfixable was totally fixable - except for having just jumped."
--from "J
Please read it again (none / 0) (#57)
by Morkney on Mon Jun 28, 2004 at 11:16:37 AM EST

If you follow the link, you'll find that it leads to Invisible Man, as it ought.

[ Parent ]
I'm aware of that fact. (none / 0) (#69)
by killmepleez on Mon Jun 28, 2004 at 04:18:12 PM EST

I did not state there was a mistake in the hyperlink. I stated there was a link in the first sentence. Even if the link pointed me straight to an e-Book of Ellison's work, it would not alter the first sentence's mistaken attribution of an "invisible man" racial allegory to H.G. Wells by one very small smidgen of a tad.

__
"I instantly realized that everything in my life that I thought was unfixable was totally fixable - except for having just jumped."
--from "J
[ Parent ]
See also... (none / 0) (#70)
by killmepleez on Mon Jun 28, 2004 at 04:27:52 PM EST

the rule about how every message pointing out a mistake invariably contains a mistake of its own.
Using the power of your limitless human imagination, change "link" in my second sentence to "mistake".

__
"I instantly realized that everything in my life that I thought was unfixable was totally fixable - except for having just jumped."
--from "J
[ Parent ]
Look (none / 0) (#72)
by Morkney on Mon Jun 28, 2004 at 04:43:57 PM EST

I think I know the difference between HG Wells' brilliant exploration of race, identity, and American culture, Invisible Man, and Ralph Ellison's inventive sci-fi/horror work, which is titled The Invisible Man. I can see how you got them confused, but they are very different books.

[ Parent ]
See (none / 0) (#75)
by killmepleez on Mon Jun 28, 2004 at 06:05:11 PM EST

I don't feel a need to refute your put-on in a heavily-linked post, because anyone who may actually care for the facts [and there might be one person like that left in Namibia or something] would be stupid to believe some random internet message and is doubtless going to read our thread and then go verify the information for themselves anyway. I, personally, don't care if you claim The Invisible Man was written by Patrick Buchanan. I'm already completely secure in my recognition of the true author, and others can be, too, with just a couple mouse clicks. So the only person you're "funning" here is yourself. Fwap Fwap Fwap, as they say.

As to the vote, I may have only one vote to give for my Kuro5hin, but I'm satisfied that I at least had the opportunity to slightly discourage your faux willful confusion by voting it down. I think the shift in voting patterns is the most significant and telling change in Kuro5hin over the past six months. Enough boring, substantive users have removed themselves from involvement that the humorous, frenetic trollasshats and their various remaining accounts now wield considerable strength even in the edit/voting queue. Which certainly explains your article surviving to Autopost.

Welcome to the Section Page -- the other place where K5 articles go to die.

__
"I instantly realized that everything in my life that I thought was unfixable was totally fixable - except for having just jumped."
--from "J
[ Parent ]
Sorry. (none / 2) (#82)
by Morkney on Tue Jun 29, 2004 at 12:17:05 AM EST

I am sorry sir for wasting your valuable time with my article, which was not entirely serious. My next submission will be a list of physical constants, which I will triple-check.

[ Parent ]
Thanks for the article (none / 0) (#83)
by KrispyKringle on Tue Jun 29, 2004 at 01:41:40 AM EST

While I suppose some might feel mislead by this not being filed under humor, I think the value in completing the illusion of seriousness outweighs the loss. Pompous ass-hattery (as that in the previous sentence) aside, thanks for a good laungh. And the comments correcting your "mistakes" make it worthwhile.

[ Parent ]
Dare I say it? (none / 0) (#103)
by N0B0DY on Fri Aug 06, 2004 at 12:18:18 AM EST

YHBT. YHL. HAND.

[ Parent ]
Odd. (none / 1) (#89)
by killmepleez on Tue Jun 29, 2004 at 09:39:52 AM EST

It's okay for you to post a mock-serious article espousing a useless, nonsensical technology, but it's not okay for others to post mock-serious comments correcting your facetious mistakes?

Then as far as I'm concerned, sir, from your article you are obviously not a scholar, and from your responses to the comments apparently neither are you a gentleman.

__
"I instantly realized that everything in my life that I thought was unfixable was totally fixable - except for having just jumped."
--from "J
[ Parent ]
Are you being sarcastic? (none / 0) (#78)
by aberryman on Mon Jun 28, 2004 at 06:48:29 PM EST

I honestly can't tell if you are trying to be sarcastic or not, but you have the two works mixed up if that sentence is to be read literally.  The fact that you link to Ellison's Invisible Man and cite it to Wells is a stupid mistake.  You really ought to fix the article and resubmit it.

[ Parent ]
Simpler solutions (2.75 / 4) (#58)
by bobpence on Mon Jun 28, 2004 at 11:48:10 AM EST

Thermal imagers and CO2 detectors should do the whole job, based on the location.

Under normal conditions, an invisible man opening a bunch of steam pipes will only draw attention to the area, resulting in a lot of people bumping into him, very few of which look like Elisabeth Shue. So, under standard temperature and pressure, given that a living invisible man will have normal body temperature, thermal sensors should make him easy to find.

If an invisible man chooses to spend summer in Phoenix and winter in Death Valley, where his body temperature will not significantly differ from the ambient temperature, a simple grid of CO2 detectors -- maybe networked over DeviceNet and reporting to a PLC controller -- would do the trick. Based on the analog value representing the level of carbon dioxide, the system could be programmed to detect both high deltas over short time periods and high absolute readings.


"Interesting. No wait, the other thing: tedious." - Bender

Yeah, but (none / 1) (#68)
by lonelyhobo on Mon Jun 28, 2004 at 02:31:55 PM EST

>>Thermal imagers and CO2 detectors should do the whole job, based on the location.

What if he's invisible on the infrared spectrum too?  or insulates himself and wears an oxygen mask?

[ Parent ]

Dammit (none / 1) (#71)
by bobpence on Mon Jun 28, 2004 at 04:33:46 PM EST

I'm trying to casually sell some DeviceNet-enabled CO2 detectors here. Okay, so he carries his own oxygen tank and is invisible even beyond the visible spectrum. But if British comedy has taught us nothing else, he must fart, right? How about a methane detector?


"Interesting. No wait, the other thing: tedious." - Bender
[ Parent ]

What else has British comedy taught us? (3.00 / 4) (#74)
by ghjm on Mon Jun 28, 2004 at 05:36:58 PM EST

That if you enter a room carrying a methane detector, many other people will unexpectedly fart, with great hilarity ensuing.

And it has done this without ever airing a single scene that has ever contained a methane detector.

Such is the great intellectual achievement of the British. All hail England.

-Graham

[ Parent ]

Predator? (none / 2) (#59)
by trezor on Mon Jun 28, 2004 at 12:03:10 PM EST

Why this high-tech stuff? You'd think that everyone who has seen "Predator" would know how to do this by now?


--
Richard Dean Anderson porn? - Now spread the news

watch out, it's the invisible man! (none / 1) (#60)
by Battle Troll on Mon Jun 28, 2004 at 12:10:12 PM EST

Don't you not see him?
--
Skarphedinn was carrying the axe with which he had killed Thrainn Sigfusson and which he called 'Battle Troll.'
Njal's Saga, ca 1280 AD
A small problem. (2.55 / 9) (#65)
by trhurler on Mon Jun 28, 2004 at 02:26:39 PM EST

Your photons will not all reach their destination when travelling through the atmosphere, and the losses will be random(truly random, unlike the "random" sequences you're on about.) I suppose you could use pattern analysis, but at that point, you have only the probability of an invisible man. Further, there is an obvious DOS attack for the invisible man - he just goes around throwing invisible objects at your detectors and then walking the other way until you give up in frustration. I have a better suggestion. Consider that there is no part of quantum mechanics which provides even the slightest hint that it is possible for anything like a human being to become transparent, let alone to have appropriate optical characteristics to be invisible in an atmosphere(which probably is not possible except in a stable state atmosphere of constant proportions and no motion anyway.) Your invisible man detector is now a logical construct: "Science invalidates the idea of invisible men. Therefore, there are no invisible men. Therefore, I detect no invisible men."

Might I suggest you next attempt a competence detector. This should be interesting, and take you longer to figure out too.

--
'God dammit, your posts make me hard.' --LilDebbie

Stunning comment [nt] (none / 1) (#77)
by killmepleez on Mon Jun 28, 2004 at 06:45:37 PM EST



__
"I instantly realized that everything in my life that I thought was unfixable was totally fixable - except for having just jumped."
--from "J
[ Parent ]
Timed releases (none / 1) (#81)
by Morkney on Tue Jun 29, 2004 at 12:00:12 AM EST

The photons could be sent at millisecond intervals, say. This would allow the receiver to differentiate between electrons which were intercepted, and those which were duplicated. This would take care of random errors and obstructions.

100 years ago, there was nothing in science to provide even the slightest hint that quantum cryptography was possible. It would be utterly foolish to assume that, because we don't know exactly how something could be done, it can not be done. And there is nothing in QM, or anywhere else in physics, specifically preventing the possibility of an invisible man.

[ Parent ]

You have solved the easier half of the problem (none / 3) (#91)
by trhurler on Tue Jun 29, 2004 at 05:20:01 PM EST

Maybe. In particular, you have solved it IF and only if the photons which do arrive at your detector have NO interactions with any particles on their way to that detector. If they do, their quantum state will necessarily change. There is another problem raised by your solution though. What if invisible men can move very quickly? Quickly enough to go through your newly modified detector without being noticed? Sounds easier to me than becoming invisible...

You still have no answer to the denial of service problem, which is a very serious problem.

As for a person becoming invisible, you don't know your science well enough. There is in fact a growing body of knowledge on optical characteristics and their causes. Red things are red for a reason, for example - and not, as you were told in school, just because "they reflect red light and absorb other colors." There are structural reasons why they absorb this and reflect that. Unless you change the structure, the color won't change. Change the structure, and you have changed the composition. Change the composition, and the physics and chemistry are now different, and what you have is no longer a person, and very unlikely to exhibit any characteristics of a person. Your assertion that nothing in science prohibits invisible people is sort of like an assertion that nothing in science prohibits localized manipulation of gravity - on first principles it is true, but people who deeply understand the subject do not believe it is possible, because the methods you would have to employ would have other effects that either negate the result or render it worthless.

--
'God dammit, your posts make me hard.' --LilDebbie

[ Parent ]
Possible solutions (none / 2) (#92)
by Morkney on Tue Jun 29, 2004 at 07:46:40 PM EST

If they were to move faster than the speed of sound, they'd create sonic booms, which wouldn't be very stealthy. Supposing that they are 1.00 cm in profile to the detector, and they move at just under the speed of sound, this gives us a leisurely 29.4 microseconds between photons. Were this frequency to prove infeasible, we could add a thickening agent to the air, thus decreasing the speed of sound.

As for the DOS attack, the invisible man would reveal his presence in the area by throwing the invisible objects. The area could be locked down, the visible people could exit through a detector, then the area could be filled with poisonous gas. If the invisible man does not need to breathe, the area could be filled with corrosive gas. If the invisible man was not corroded, a nuclear detonation would be sure to take care of him. If the nuclear detonation left him unaffected, then god help us all.

I'll admit that I don't know much of the science surrounding color. However, you must admit that in some cases, things end up going against the intuition of even the most experienced scientists. For example Einstein and QM. I will admit it seems highly unlikely that invisibility would end up being feasible, but do you want to stake your children's lives on that? I know I don't.

With respect to the problem of interactions within the atmosphere, I refer you to this article, which discusses transmission through the atmosphere in the context of quantum cryptography. "the atmosphere is only weakly dispersive and essentially non-birefringent at these wavelengths. It will thus not alter the polarization state of a photon," (III.4).

[ Parent ]

Yes (none / 1) (#95)
by trhurler on Wed Jun 30, 2004 at 01:07:03 PM EST

Well, first of all, a thickening agent in the air is going to be harder than you're admitting, particularly if people have to actually live or work there. But, yes, it is true that a sonic boom is not stealthy. Still, it seems more likely to me to invent a means of eliminating sound from oneself than light, so I am not sure invisible men create sonic booms. Maybe they can travel at .99c in atmosphere; how would you know?

Second, with an appropriate mechanism, invisible objects could be hurled quite a distance towards a detector, or even set up on a mechanism so that they would later fire after the invisible man was gone. The DOS still works.

Third, what's with all the hate for invisible men?

--
'God dammit, your posts make me hard.' --LilDebbie

[ Parent ]
ROTFLMAO!!! (none / 1) (#90)
by 123456789 on Tue Jun 29, 2004 at 04:40:30 PM EST

GENIUS! Smart, witty, and with a smooth finish. I bow to thee...

---
People demand freedom of speech to make up for the freedom of thought which they avoid.
- Soren Kierkegaard
[ Parent ]
And then what (none / 1) (#85)
by jotango on Tue Jun 29, 2004 at 05:23:15 AM EST

So you have used a quantum detector to identify an invisible man. And then what? Force him to give up his invisible tweezers?

hah! (none / 2) (#86)
by dimaq on Tue Jun 29, 2004 at 05:52:22 AM EST

I have a simpler solution - ask a blind guy or gal :)

w00t! (none / 0) (#102)
by N0B0DY on Fri Aug 06, 2004 at 12:14:50 AM EST

Perhaps we could have a modern-day Zatoichi handle all invisible ninjai.

[ Parent ]
Emitting light ? (none / 2) (#87)
by Shubin on Tue Jun 29, 2004 at 08:41:04 AM EST

> The invisible man has a way around this problem, however. If invisible men simply dublicate all light which hits their eyes, >observing one photon and sending one on, they can remain concealed to the classical observer. Well, it is impossible. There is no way to emit this light exactly at the moment when it came in. That means the wavefront will be distorted, so there is no need in quantum detectors, an interferometer will do the job.

God bless you (none / 2) (#93)
by evanp on Wed Jun 30, 2004 at 02:31:54 AM EST

Since HG Wells first published his lauded exploration of racial identity, Invisible Man,
That is a beautiful troll. You are like a troll genius. God bless you!

The answer is... (none / 1) (#94)
by edg176 on Wed Jun 30, 2004 at 05:45:07 AM EST

Flour. We need to fill the air at checkpoints with flour. This raises the dreaded flour explosion problem. A 25 million dollar study conducted by a private contractor can solve that problem. No amount it too little in the name of national security.

Lepton Haze (none / 0) (#104)
by Haxx on Thu Aug 12, 2004 at 03:53:54 AM EST

All indivisible mass is invisible to the naked eye. Science has not yet determined wich invisible particle is the one that is indivisible. Henceforth, scientists closest attempt to asertain the least indivisible invisable particle has resulted in visible energy.

Using Quantum Cryptography to Find Invisible Men | 104 comments (81 topical, 23 editorial, 0 hidden)
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