5 ms·
Qubits are a bad idea. You want continuous variable quantum computing. https://en.m.wikipedia.org/wiki/Continuous-variable_quantum_information https://en.m.wiki
by adamnemecek 9y ago
Qubits are a bad idea. You want continuous variable quantum computing. https://en.m.wikipedia.org/wiki/Continuous-variable_quantum_information https://en.m.wikipedia.org/wiki/Continuous-variable_quantum_...
- Florin_Andrei 9y agoThose seem more similar to old school analog computers, in a sense.
- adamnemecek 9y agoThey very much are.
- krastanov 9y agoThe interesting thing is that a perfect analog classical computer is more powerful than the qubit quantum computer model (which is what people mean by quantum computing). But analog computers (whether classical or quantum) do not permit error correction, and as such are useless for anything but the smallest problem. You need bits and qubits in the real world.
- eindiran 9y agoThe wiki article says twice that a the motivation for studying continuous variable quantum computing is to understand "the ways in which quantum computers can be more capable or powerful than classical ones". But it never explains why you want to use continuous variable quantum computing over qubits. What are your arguments for why the correct path forward is not qubits?
- ianai 9y agoWhy do the real numbers solve more rational equations than the integers? They’re both infinite (though not equinumerous), but the integers can only come close to the reals.
- jjaredsimpson 9y agoBut now you have to demonstrate that your analogy holds.
- krastanov 9y agoAnd this line of reasoning completely fails when you start considering error correction. This is why we need bits and qubits. Aaronson's lecture notes go into the mathematical details if you are interested.
- IntronExon 9y agoWhat makes qubits a bad idea? What problems of qubits does continuous variable quantum computing solve? I’m not being Socratic, I just don’t know.
- ianai 9y agoMy guess is the quantum computer that Feynman theorized about was continuous. I’d bet it needs to be continuous to solve all the NP problems and so on.
- dangirsh 9y agoNo variant of quantum computing is expected to solve NP problems in polynomial time. That's just a common misconception.
- adamnemecek 9y agohttps://en.m.wikipedia.org/wiki/Real_computation https://en.m.wikipedia.org/wiki/Real_computation Real computation can.
- IntronExon 9y agoIn principle. Not in the actual universe we inhabit, with its Beckenstein Bound.
- adamnemecek 9y agoArbitrary precision (not infinite) is good enough for me.
- IntronExon 9y agoSort of like coming arbitrarily close to the speed of light, in that it will require energy on the same asymptotic scale you’re hoping to achieve precision in. Degenerate matter computers?
- krastanov 9y agoThis is pretty common misconception (that qubits are a bad idea). Qubits or qudits are necessary to achieve scalable error correction. I work at one of the research institutes that pushes the use of continuous variable systems (they are great). But we implement qubits on top of them (that is the whole point).
- gaze 9y agoThey’re equivalent. A continuum can be encoded into qubits and vis versa.
- adamnemecek 9y agoThey definitely aren’t.
- gaze 9y agoConsider an array of qubits forming a register. Now, a cavity resonator’s state can be expanded in a photon number basis. If you truncate the cavity resonator to 2^n photons, then map the 0 photon ket to the 0 state of the register, the 1 photon key to the 1 state of the register, all the way up to the 2^n photon state of the register to the 2^n photon state of the register. Now you’ve mapped the cavity state onto the register and they’re informationally equivalent
- adamnemecek 9y agosure, however analog computing has the advantage that you can solve optimization problems natively, in hardware. with qubits, you get a speedup but not O(1) solutions.
- gaze 9y agoAbsolutely not. The time complexity is exactly the same. A quantum computer can simulate quantum annealing with exactly the same asymptotic complexity as an “analog” physical system that takes advantage of quantum mechanics would.
- adamnemecek 9y agoI disagree but ok.