Hyper-Entangled Photons — 'Superdense' Coding Gets Denser

ScienceDaily is reporting that researchers at the University of Illinois have broken the record for most information sent via a single photon using the direction of "wiggling" and "twisting" a pair of entangled photons. "Using linear elements, however, the standard protocol is fundamentally limited to convey only one of three messages, or 1.58 bits. The new experiment surpasses that threshold by employing pairs of photons entangled in more ways than one (hyper-entangled). As a result, additional information can be sent and correctly decoded to achieve the full power of dense coding."

Tangled?

[ke5aux]

Great, now come and untangle my brain cells.

Re:

[unchiujar]

Do not click.
Link contains shock site.

WARNING!

[Naughty Bob]

The above link will shred your windows boxen, mod down a lot!

Re:

[Idiomatick]

This poster needs to be banned badly. He keeps posting malicious links.

Re:

[palegray.net]

I just emailed the staff at Slashdot about that "Anonymous Coward" asshole. I'm sure that account will be removed any minute now!

Re:

[shentino]

First you display goatse stuff, and then you lock up my box so I can't close the window.

you are scum.

Re:

[AmigaMMC]

DO NOT CLICK THAT LINK. Look at URL and you'll see that it's the same old one that takes control of your browser and drops a virus in the system. Also forces your browser to open pop-up (so much for disabling them) with children pornography and violent scenes. I hope that guy gets caught, thrown in jail and the key thrown away.

Nothing new here

[schklerg]

Sorry about this, but... People have been getting entangled by "wiggling" and "twisting" for a long time now.

dense coding?

[Anonymous Coward]

I've seen my share of dense coding in my time as well.

Re:

[andreyvul]

By dense code, do you mean code written:
1) in assembler
2) by idiots
3) by idiots in assembler
4) for IOCCC
5) for JAPH contests
6) for JAPH contests which generates valid IOCCC code
?

Hyperentagled Students

[Galaga88]

I work in a college library and I can vouch that pairs of students who get hyperentangled in the study rooms or on one of our couches certainly seem to be capable of carrying much less information than non-entangled students.

Re:

[Loconut1389]

hey, I'm using my free hand to type you insensitive clod! Now, I need that hand back.

Re:Hyperentagled Students

[blair1q]

The entangled ones are exchanging terabits of information. Of course, only the sum of 26 chromosomes - and only half of those from each source, will be persistent, and then only if neither has employed a firewall. But the resulting code will be a self-replicating automaton, which will eventually grow to occupy all of its parent objects' manageable resources.

Let's see a couple of photons do that.

Re:

[evanbd]

We are sexy, sexy Von Neumann machines. [xkcd.com]

Re:

[26199]

That is a matter of opinion, I think.

Re:

[DeadDecoy]

Technically, if you don't count redundant information, that data fits on a CD. You could probably check out the NCBI ftp site to verify.

Re:

[Trigun]

You're just not waiting long enough. One of them eventually may carry twice as much information, at least for a while*

*Depending on how liberal the college is

Re:

[kalirion]

I suggest you videotape the phenomenon and publish it online so that slashdot scientists can perform an in depth study of the hyperentanglement properties.

Re:

[mooingyak]

It's been done:

Captured on film [theonion.com]

Re:

[kalirion]

Hmm, seems to be about as NSFW as an onion article can get....

Just reverse it already!

[torchdragon]

"They then encode a message in the polarization state by applying birefringent phase shifts with a pair of liquid crystals." Just say you reversed the polarity! We've been waiting to hear it for decades now. Just come out and say it already! Enough of the cock teasing. This is science damn it, I want my compensator. I want to flux my capacitors!

Re:

[andreyvul]

I want to flux my capacitors!

You do that during soldering, dumbass. Get a $20 Weller and flux your capacitors all night long. You do flux before soldering, right?

Re:

[qudit]

They didn't just change the polarisation (polarity). A qubit can be more than just reversed, you can change the phase between the two "polarities".

Re:

[evilviper]

Enough of the cock teasing. [...] I want to flux my capacitors!

What you do behind closed doors is your own business...

superdense alright

[circletimessquare]

superdense

that's how i feel after reading that summary

1.58 bits?

wtf?

Re:superdense alright

[blueg3]

They just mean that their objects can encode one of three states. The amount of information, in "bits", a state encodes is log2(number of possible states), and log2(3) ~= 1.58. By the same token, a single decimal digit stores 3.32 bits.

thanks ;-)

[circletimessquare]

THAT i understood ;-)

now i only have have 36 more questions before i completely understand the story summary... :-P

Re:

[argent]

39, you can fit 3 radix-50 characters in a 16-bit word.

Re:Base 3 Data Storage

[Ox0065]

So what do you call the base unit of data in a base three system? Clearly bits doesn't cut it. Is this one of those quantum things like 'as the amount of data in a base 3 system becomes known in base 2, then the chances of knowing how or why to do anything useful with the data exponentially approaches 0

Re:

[FuzzyDaddy]

I thought the same thing a half second before I read your comment...

Re:

[blueg3]

You call it whatever you want, I suppose. The general term is a digit (for any base). But you just convert base-2 numbers into base-3 for communication, and then back -- similar to how a computer converts our base-10 numbers into binary before using them.

Very simple:

[GameboyRMH]

Zero represented in two bits: 00

Zero represented in 1.58 bits: 0C

2 photons, not one?

[inputdev]

If it takes an entangled pair to send 1.58 bits then it doesn't sound better than 1 bit per photon. Can anyone explain?

Re:

[Diss Champ]

Presumably, one would only need to send one from the entangled pair, not both.

Re:

[inputdev]

That sounds good, but it still requires that someone send the first 'entangled' photon to the other, so there are two photons being transmitted. I can see it being a powerful 'secure' channel, but not really more dense.

To Infinity and Beyond!

[headkase]

The Nobel prize frequency needs to be updated. Once a year used to be fine but now they could give out a prize once a week and still have deserving people go unnoticed. I suppose in another decade they could be giving it out every day. Singularity here we come!

Re:

[Ryukotsusei]

But then in another decade the criteria for what is prize-worthy will have changed drastically.

Re:

[headkase]

Changing the goalposts to include things that are of a greater magnitude of amazing does not diminish those things that previously would have been a breakthrough. 365 straight days of achievements that used to occur once a year remains an unimaginable way to live through time.

ugh...

[slew]

First off, isn't this rehashed news from 2005 [uiuc.edu]?

Secondly, why did they have to change the word polarization to "wiggling"? As if lay people didn't know the word polarized from experience with their sunglasses.

Perhaps I'll concede that calling orbital angular momentum to "twisting" may be a reasonable twisting of the terminology, although in earlier papers they refer to "spiraling" or "cork-screw" which seems like a much better scientific-speak-transliteration to me...

Re:

[kmac06]

No. That was on hyperentanglement, not dense coding. This is on using hyperentanglement to implement dense coding.

Use some imagination

[WarJolt]

"atmospheric turbulence can cause some of the quantum states to easily decohere, thus limiting their likely communication application to satellite-to-satellite transmissions."

Perhaps I just found a new use for my vacuum cleaner.

I never underestimate how creative scientists can be. I'm sure we will find some terrestrial uses.

Re:

[qudit]

Satellites already communicate with each other. Ah! I get it, you don't have a satellite... sorry to hear that.

Big Bow Tie

[Aerri]

If you click on the link, the article is basically a series of long quotes from Paul Kwiat, whose Quantum Physics class I *just* recently completed. He is pretty much the coolest teacher ever. He started the course off with a movie about quantum physics he put together himself, set to the theme song of Star Trek: TNG. Every day he wears suspenders and a huge bow tie. This is so cool. Who says good researchers have to be crappy professors?

Re:

[yellowalienbaby]

Suspenders?

I think we need some internationalization here. I'm guessing these aren't the kind of suspenders that hold up Stockings?

Dense coding reached full power...

[quonsar]

...with the release of IE6.

Isn't the information per photon arbitrary?

[gregor-e]

Seems to me that angle isn't quantized. Therefore, the amount of information that one can encode on a single photon is only limited by our ability to encode and decode the angle at which a photon is traveling. Given the ability to measure the angle of a photon down to, oh, something on the order of 10e-34 radians or so, one should have no problem transmitting multiple yottabytes on a single photon.

Why not?

[HughJJorgan]

Actually, my question is more like: Why couldn't we encode a theoretically infinite number of states by using the wavelength of the photon? Say for example you fix 445nm as the start point, and 476nm as the end point, and say that every additional nm of wavelength = 1 decimal number? Then you have 32 potential states, or 5 bits in a single photon. If every half-nm were a wavelength then you have 6 bits, and so on and so forth. There is obviously a hole in my reasoning here -- what exactly is it? What

Re:

[caramelcarrot]

You've just described FM radio, which has a finite data rate dependant on bandwidth.

Re:

[qudit]

Wavelength is as good for encoding. Current communications using fiber optics do something like that. The hyper-entangled photons trick was to transmit almost 2 bits by encoding on a binary property of one of the photons... which classically can only encode one bit.

Re:

[HughJJorgan]

If that's the case, why quibble over a few fractions of a bit when so many more bits can be encoded with the wavelength? Each individual photon has a wavelength property, right?

Re:

[kmac06]

The polarization qubit can be changed quite easily without destroying the entanglement. It is not so simple to do so with wavelength.

Re:

[Naughty Bob]

but I guarantee it's quantized by at at least radius-of-universe / planck-length

Aw shucks. And there we were thinking that we might be able to transmit a large amount of info...

Re:

[caramelcarrot]

Except you have to choose a basis along which to perform your measurement - and only one, due to the uncertainty principle (the non-commutating nature of the quantum operators involved), so you can only get "up" or "down" (or some other number of states, given the system)

Re:

[QuantumFTL]

Given the ability to measure the angle of a photon down to, oh, something on the order of 10e-34 radians or so, one should have no problem transmitting multiple yottabytes on a single photon.

Looks like someone didn't take their Quantum class before posting! Shame on you!

Before a photon's polarization is measured, it exists as a wavefunction expressable as a linear combination of eigenstates for a given polarization operator. After being measured, its state is only one eigenstate of the particular polar

Re:

[ChrisMaple]

I had a similar thought with regard to energy (frequency, wavelength). Send the incoming photon through a prism to separate various energy levels out to many discrete detectors. I suppose there's some limitation set by quantum efects, but it seems to me 8 or 10 bits should not be too dificult theoretically.

Ansibles

[Iowan41]

We now just have to do it with tangible particles then put half on MSL and half in JPL, measure the states, and alter the states, for elimination of information transmission times, drive the rover at real-time speed.

Star Trek correlation

[zcsteele]

I'm surprised nobody's mentioned it yet, but Star Trek computers were supposedly based on a Ternary number system - each element could be in one of three possible states.

So

[Dunbal]

Does this mean we'll be getting our porn even faster?

So SETI is focusing on the wrong thing?

[ibsteve2u]

This bizarre coupling can link two photons, even if they are located on opposite sides of the galaxy.

Should be looking for the other ends of linked proton pairs instead of monitoring the noise in the electromagnetic spectrum, eh?