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Separating Hope From Hype In Quantum Computing
pgptag writes "This talk by Dr. Suzanne Gilbert (video) explains why quantum computers are useful, and also dispels some of the myths about what they can and cannot do. It addresses some of the practical ways in which we can build quantum computers and gives realistic timescales for how far away commercially useful systems might be."
Upon observation, this post has collapsed into the first post state.
Oops. Thought this thread title was about Obama....sorrry.
We can't even get people to read the articles referenced in submissions. That's wildly optimistic to expect us to watch a video that is over 2 hours long.
This is begging for an "executive summary" from anyone who has time to watch it, if there is such a person.
Is that on the iPad or iPod Touch? :)
Definitely commercial-only. The world only needs five quantum computers.
On the contrary, observing the content of a folder would change its state.
I'm not a quantum physics expert and I don't play one on television
And if I did, the show would have been canceled.
English is not this
If you'd categorized your porn collection properly, it wouldn't need to all be in one folder :-(
It appears that the moderators don't know any history. You're obviously making a joke based on the observation in the early 1950s that "the worldwide market for computers is about ten." It's funny now, but then computers weren't very useful for anybody without huge number crunching and database needs and multi-million dollar budgets. At the time, a computer took an entire building to house, and a whole lot of personnel to operate. The most powerful computer in existance was less powerful than a singing Hallmark card.
So the joke's on the mods, who actualy believe it. Of course, right now the worldwide market is zero, since they haven't actually constructed one yet. If and when they accomplish the feat, it's possible that in the future all compuers will be quantum computers. I doubt I'll live long enough to see it (I'm not young any more).
That link will give the mods a little computer history if they're interested.
Free Martian Whores!
I took a class on Quantum computing, and studied many specific QC algorithms, so I know a little bit about them. If you don't want to RTFA, then read this: Quantum Computers are not super-computers. On a bit-for-bit (or qubit-for-qubit) scale, they're not necessarily faster than regular computers, they just process info differently. Since information is stored in a quantum "superposition" of states, as opposed to a deterministic state like regular computers, the qubits exhibit quantum interference around other qubits. Typically, your bit starts in 50% '0' and 50% '1', and thus when you measure it, you get a 50% chance of it being one or the other (and then it assumes that state). But if you don't measure, and push it through quantum circuits allowing them to interact with other qubits, you get the quantum phases to interfere and cancel out. If you are damned smart (as I realized you have to be, to design QC algorithms), you can figure out creative ways to encode your problem into qubits, and use the interference to cancel out the information you don't want, and leave the information you do want. For instance, some calculations will start with the 50/50 qubit above, and end with 99% '0' and 1% '1' at the end of the calculation, or vice versa, depending on the answer. Then you've got a 99% chance of getting the right answer. If you run the calculation twice, you have a 99.99% chance of measuring the correct answer. However, the details of these circuits which perform quantum algorithms are extremely non-intuitive to most people, even those who study it. I found it to require an amazing degree of creativity, to figure out how to combine qubits to take advantage of quantum interference constructively. But what does this get us? Well it turns out that quantum computers can run anything a classical computer can do, and such algorithms can be written identically if you really wanted to, but doing so gets the same results as the classical computer (i.e. same order of growth). But, the smart people who have been publishing papers about this for the past 20 years have been finding new ways to combine qubits, to take advantage of nature of certain problems (usually deep, pure-math concepts), to achieve better orders of growth than possible on a classical computer. For instance, factoring large numbers is difficult on classical computers, which is why RSA/PGP/GPG/PKI/SSL is secure. It's order of growth is e^( n^(1/3) ). It's not quite exponential, but it's still prohibitive. It turns out that Shor figured out how to get it to n^2 on a quantum computer (which is the same order of growth as decrypting with the private key on a classical computer!). Strangely, trying to guess someone's encryption key, normally O(n) on classical computers (where n is the number of possible keys encryption keys) it's only O(sqrt(n)) on QCs. Weird (but sqrt(n) is still usually too big). There's a vast number of other problems for which efficient quantum algorithms have been found. Unfortunately, a lot of these problems aren't particularly useful in real life (besides to the curious pure-mathematician). A lot of them are better, but not phenomenal. Like verifying that two sparse matrices were mulitplied correctly has order of growth n^(7/3) on a classical computer, n^(5/3) on a quantum computer. You can find a pretty extensive list by googling "quantum algorithm zoo." Unfortunately [for humanity], there is no evidence yet that quantum computers will solve NP-complete problems efficiently. Most likely, they won't. So don't get your hopes up about solving the traveling salesmen problem any time soon. But there is still a lot of cool stuff we can do with them. In fact, the theory is so far ahead of the technology, that we're anxiously waiting for breakthroughs like this, so we can start plugging problems through known algorithms.
The quote debunked http://en.wikipedia.org/wiki/Thomas_J._Watson#Famous_misquote
Some facts:
1) The misquote is "I think there is a world market for maybe five computers,"
2) The story had already been described as a myth in 1973
3) Correct quote: "IBM had developed a paper plan for such a machine and took this paper plan across the country to some 20 concerns that we thought could use such a machine. [...] But, as a result of our trip, on which we expected to get orders for five machines, we came home with orders for 18."
Don't fight for your country, if your country does not fight for you.