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Quantum Computing Without Qubits

Posted by samzenpus on from the making-it-work dept.

An anonymous reader shares this interview with quantum computing pioneer Ivan Deutsch. "For more than 20 years, Ivan H. Deutsch has struggled to design the guts of a working quantum computer. He has not been alone. The quest to harness the computational might of quantum weirdness continues to occupy hundreds of researchers around the world. Why hasn't there been more to show for their work? As physicists have known since quantum computing's beginnings, the same characteristics that make quantum computing exponentially powerful also make it devilishly difficult to control. The quantum computing 'nightmare' has always been that a quantum computer's advantages in speed would be wiped out by the machine's complexity. Yet progress is arriving on two main fronts. First, researchers are developing unique quantum error-correction techniques that will help keep quantum processors up and running for the time needed to complete a calculation. Second, physicists are working with so-called analog quantum simulators — machines that can't act like a general-purpose computer, but rather are designed to explore specific problems in quantum physics. A classical computer would have to run for thousands of years to compute the quantum equations of motion for just 100 atoms. A quantum simulator could do it in less than a second."

39 of 81 comments (clear)

  1. Kaboom! by gophther · · Score: 1

    I have this impression of "quantum simulator" analog computers, that if you want to make them truly capable, you have to give them the ability to blow up by overloading themselves, sort of like blowing an amp. Comments?

  2. Flocks of starlings by Anonymous Coward · · Score: 1

    Look in the sky, see the flock of starlings?
    The dark clump of birds that you can see will dart around, sometimes here, sometimes there. It can fly west and yet clump east, time-travel! Must be negative time! Sometimes simultaneously appearing in two places. Faster than light travel! Sometimes no clump can be seen. Where'd they go? Poof, out of existence.

    You want a quantum simulator? Starlings, go watch a flock of starlings and apply your quantum equations to their motion.

    You may think I'm kidding, but the same problem exists. Just as you can't see the individual bird, only the flock, likewise you've built a bunch of equations for a flock of smaller particles. You can only detect the flock and not the particles.

    1. Re:Flocks of starlings by clovis · · Score: 4, Funny

      Look in the sky, see the flock of starlings?
      The dark clump of birds that you can see will dart around, sometimes here, sometimes there. It can fly west and yet clump east, time-travel! Must be negative time! Sometimes simultaneously appearing in two places. Faster than light travel! Sometimes no clump can be seen. Where'd they go? Poof, out of existence.

      You want a quantum simulator? Starlings, go watch a flock of starlings and apply your quantum equations to their motion.

      You may think I'm kidding, but the same problem exists. Just as you can't see the individual bird, only the flock, likewise you've built a bunch of equations for a flock of smaller particles. You can only detect the flock and not the particles.

      Keeping with your analogy ... In order to exactly determine the location of each single starling, you need a shotgun(s). Then it no longer is part of the flock now that it has been observed.

      As an aside, I am aware that you can shoot at a flock of starlings all day and not hit a one.

    2. Re:Flocks of starlings by cowdung · · Score: 1

      what the flock are you talking about?

    3. Re:Flocks of starlings by Anonymous Coward · · Score: 1

      Seriously, though, if you observe the flock in location A, the birds at location B don't suddenly cease to exist. In QM they would. Also the density of the flock is a real scalar, the density of the wave function is a complex number.

    4. Re:Flocks of starlings by Bob_Who · · Score: 1

      Unless you can make an observable difference between quantum mechanics and your alternative idea, then it is not science.

      Not to mention it is really easy to be an armchair physicists when you just throw out ideas with no implications thought out, let alone quantitative implications that physics is now built on.

      So that must be The Quantum of Solace ... its just like armchair quark-barking

  3. Re:Sounds expensive by Anonymous Coward · · Score: 2, Insightful

    *sigh* then why are you reading "News for .." oh fuck, how long has that been gone? *le sigh*

  4. Real problem is... by m.alessandrini · · Score: 5, Funny

    ... if you know the computer's speed, you cannot know where the computer is.

    1. Re:Real problem is... by Tablizer · · Score: 3, Informative

      It's like Microsoft or Comcast products: they can never be up running and be reliable at the same time.

      --
      Table-ized A.I.
    2. Re:Real problem is... by Bob_Who · · Score: 1

      It's like Microsoft or Comcast products: they can never be up running and be reliable at the same time.

      ....or can't be purchased or paid in full... you just pay forever and its never yours.

  5. He called me a Nightmare! by Qubit · · Score: 2

    I would've preferred "Noble Steed," but I'll take it.

    --

    coding is life /* the rest is */
  6. Something for nothing by WaffleMonster · · Score: 3, Interesting

    I don't believe in real quantum computers because they require operating on the premise you can just sit there and extract whatever unlimited amounts of computation from the universe for a cost exponentially approaching free.

    No doubt at all these machines given enough time and effort will work and they will provide the world with useful benefits only those benefits will look nothing like:

    "Problems that would take a state-of-the-art classical computer the age of our universe to solve, can, in theory, be solved by a universal quantum computer in hours."

    1. Re:Something for nothing by Anonymous Coward · · Score: 2, Informative

      require operating on the premise you can just sit there and extract whatever unlimited amounts of computation from the universe for a cost exponentially approaching free.

      I don't believe in whatever you're talking about either, but that has nothing to do with "real" quantum computers. There are still limits what they can computer, especially energy limits. They may allow for algorithms with different complexity classes than classical computers, but they don't approach unlimited amounts of computation, especially at diminishing costs.

    2. Re:Something for nothing by wonkey_monkey · · Score: 1

      I don't believe in real quantum computers because they require operating on the premise you can just sit there and extract whatever unlimited amounts of computation from the universe for a cost exponentially approaching free.

      No, they don't.

      --
      systemd is Roko's Basilisk.
    3. Re:Something for nothing by Richard_at_work · · Score: 2

      Quantum computers is to computing what digital computers are to abacuses.

      Theres no major breaking-the-laws-of-physics going on, its just a different way to carry out computations, one that has taken us a while to create - but it took us thousands of years to go from abacuses to digital computers, so give us time.

      Your view of quantum computers is exactly what I would expect to hear from an Egyptian accountant back in 500BC experiencing a hand held calculator for the first time. Doesn't make a hand held calculator impossible tho...

    4. Re:Something for nothing by Tablizer · · Score: 2

      Those chips will use up all the parallel universes, and then I'll never get laid, anywhere, you insensitive clod!

      --
      Table-ized A.I.
  7. Re:This guy is a crank. by BitterOak · · Score: 5, Informative

    Classified information is purely a product of the government. They can't just classify information produced by citizens (citation: the first fucking ammendment, you dumbass crank).

    Actually they can and have done so in the past, primarily in the field of cryptography, a field for which quantum computers might have important applications, so his fears are not unfounded.

    --
    If I can be modded down for being a troll, can I be modded up for being an orc, or a balrog?
  8. Back to the future ? by Crashmarik · · Score: 1

    I suppose naming analog computers quantum simulators somehow renders them hip and more useful than just calling them analog computers.

    1. Re:Back to the future ? by m.alessandrini · · Score: 1

      Just what I was thinking. I'm not expert on quantum computing (but who is?), but I think an analog computer simulates an analog system, or at most another analog computer. About a quantum computer, isn't it impossible to simulate, due to its very nature? Unless you count the qubits that mother nature has built for us in every particle, and so every single particle evolving in the universe can be seen as a quantum computer simulator.

  9. Maybe Einstein gets the last laugh afterall? by nichogenius · · Score: 2, Interesting

    Einstein never really accepted quantum mechanics. I sometimes wonder if the issues regarding quantum computing are a little more fundamental than technological. Maybe that old genius was smarter than we give him credit for!

    1. Re: Maybe Einstein gets the last laugh afterall? by Anonymous Coward · · Score: 1

      Einstein's objections are not yet resolved. They raise questions which have been answered experimentally, but the experimental results don't fix the holes in the Copenhagen interpretation which Einstein raised.

    2. Re:Maybe Einstein gets the last laugh afterall? by Anonymous Coward · · Score: 5, Interesting

      Einstein invented quantum mechanics and you're an idiot.

      He was part of the group, he opposed the idea of randomness in quantum mechanics, since he firmly believed that determinism was a fundamental property of science.
      In a similar way Schrödinger opposed the idea of multiple states in quantum mechanics because of the implications it has when you apply it on macroscopic objects. The cat analogy was made to show that larger things like life and death becomes undefined if you allow a single particle to have an undefined state.

      Quantum mechanics has always been controversial, even to this day.

    3. Re: Maybe Einstein gets the last laugh afterall? by Geoffrey.landis · · Score: 1

      Einstein made essential contributions to quantum mechanics, and yet he objected to many of its implications. His objections have been shown to be wrong.

      To the contrary, his "objections" consisted of pointed out consequences of quantum mechanics that seemed paradoxical, but, as experiment showed much later, were completely real. Einstein is the "E" in "EPR", and the implications of the EPR paper pretty much is the foundation of quantum computing.

      --
      http://www.geoffreylandis.com
  10. This guy is a crank. by qbwiz · · Score: 4, Informative

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

    --
    Ewige Blumenkraft.
  11. No need to blow up anything by Anonymous Coward · · Score: 2, Informative

    The proposal for the quantum simulator was made back in 1982

    In 2011 paper was already written about the matter

    http://arxiv.org/abs/1109.6457

    1. Re:No need to blow up anything by HornWumpus · · Score: 2

      One of the other doctoral students that shared an adviser with my dad built an analog circuit simulating Schrodinger's equations hydrogen atom solution back in about 1960. I doubt he was the first. People have been working on this kind of thing for a long time.

      --
      John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
  12. Einstein was among the guys ... by Taco+Cowboy · · Score: 3, Insightful

    ... Einstein invented quantum mechanics and you're an idiot ...

    Albert Einstein is one of the guys that I truly respect, but I still gotta say that Quantum Mechanics was not invented by Einstein alone ... Other people such as Max Planck, Niels Bohr, Werner Heisenberg, Louis de Broglie, Arthur Compton, Erwin Schrodinger, Max Born, John von Neumann, Paul Dirac, Enrico Fermi, Wolfgang Pauli, Max von Laue, Freeman Dyson, David Hilbert, Wilhelm Wien, Satyendra Nath Bose, Arnold Sommerfeld, amongst many others, also have contributed to the theory of Quantum Mechanics

    --
    Muchas Gracias, Señor Edward Snowden !
    1. Re:Einstein was among the guys ... by Azmodan · · Score: 1

      The premise of your statement is fundamentally wrong and would equate to someone saying "God exists."

    2. Re:Einstein was among the guys ... by Your.Master · · Score: 1

      No, quantum mechanics is a thing humans invented. Newtonian mechanics is a thing humans invented.

      Gravity (aka gravitational behaviours) and quantum behaviours existed previous to any human.

      As for Einstein? Einstein "invented" quantum mechanics in about the same sense that Shakespeare "invented" English.

  13. Higgs Boson Formation by Anonymous Coward · · Score: 1

    And if you fly two flocks into each other at the right velocity, for a moment you can see them fly in what we experts calls a 'Higgs Boson' formation!

    But there is a risk of catastrophic bird poop aftermath. Who knew that dark matter would smell so bad.

    1. Re:Higgs Boson Formation by drinkypoo · · Score: 1

      But there is a risk of catastrophic bird poop aftermath. Who knew that dark matter would smell so bad.

      Not Who, just who

      --
      "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
    2. Re:Higgs Boson Formation by Bob_Who · · Score: 1

      But there is a risk of catastrophic bird poop aftermath. Who knew that dark matter would smell so bad.

      Not Who, just who

      Say what..?

    3. Re:Higgs Boson Formation by jcwayne · · Score: 2

      ...and then have the laser toting sharks surround them and they'll form a Bose–Einstein flock condensate.

      --
      Failure to follow this advice may result in non-deterministic behavior.
  14. The real question though... by tommeke100 · · Score: 1

    > A classical computer would have to run for thousands of years to compute the quantum equations of motion for just 100 atoms.

    But is it web-scale?

  15. Reality check by BytePusher · · Score: 1

    I noticed a lot of posts proclaiming quantum computers will never exists, but they actually already do exist: In 2001, researchers demonstrated Shor's algorithm to factor 15 using a 7-qubit NMR computer.(http://en.m.wikipedia.org/wiki/Quantum_computing) Just because the next advancement is hard doesn't mean it's impossible. We've gotten so accustomed to a limited set of technology improving we've lost our sense of how long it takes to solve entirely new classes of problems. Think how long modern computers were speculated about, but it took a few key advancements to make it actually happen. QC is the same and the naysayers will look pretty foolish to future generations. To be clear, we have real and functioning quantum computers abs there's significant incentive to scale them up.

    1. Re:Reality check by david_thornley · · Score: 2

      The problem is how well solutions scale. Give me 7-bit classical processors, and I can eventually hack them into something bigger. Two 7-qubit quantum processors can't be used to create a 14-qubit one, and making a 14-qubit processor is a whole lot harder than making a 7-qubit one. We're doing better at building these, but it's possible we'll never be able to make, say, a 10K-qubit computer, without running into some limit somewhere, and some proposed uses require that many qubits.

      We'll have to see. The things are useful now in some applications, and they'll continue to get better for some time.

      --
      "When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
  16. Analog atoms by Geoffrey.landis · · Score: 2

    "A classical computer would have to run for thousands of years to compute the quantum equations of motion for just 100 atoms. A quantum simulator could do it in less than a second."

    ...and a hundred atoms can do it in real time!

    --
    http://www.geoffreylandis.com
  17. Re:This guy is a crank. by sarkeizen · · Score: 1

    "The millisecond a quantum environment is proven capable of cracking most modern crypto like a fucking egg"

    Uh...no. It is proven to be able to factor large numbers quickly which will make the two major public key systems (DHX and RSA) and in some insanely popular use cases (the internet) we use these to exchange keys for symmetric block cipher but that's hardly 'most modern crypto'.

  18. Re:This guy is a crank. by sarkeizen · · Score: 1

    Which is what I read. Just answering the obvious implication.

    Some ability to think is probably just as essential. Let me know when you show some. :-)