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I was not aware of Rob Schoelkopf's initiative so far (http://quantumcircuits.com/ http://quantumcircuits.com/), I think this could be serious competition for J

I was not aware of Rob Schoelkopf's initiative so far (http://quantumcircuits.com/ http://quantumcircuits.com/), I think this could be serious competition for John Martinis & Google. From their website it seems that they use a 3D cavity approach to quantum computing, which is (or at least was) pursued by IBM as well. Here, instead of using superconducting resonators on a chip, you use superconducting 3-dimensional cavity resonators (typically made from Aluminium) in which you place "naked" qubits that are fabricated on a Sapphire substrate. The advantage of this is that the attainable quality factor of the cavity is much higher than for a coplanar waveguide resonator (although those resonators have caught up quite a bit thanks to work that was done e.g. by the Martinis lab), and that there are fewer noise sources around the qubits. Personally my current bet would be on Martinis or Schoelkopf to win the race, as they have the best access to both funding (though I don't know the funding details of QuantumCircuits) and Academic resources. Most of the original work on Transmon-based qubits was done at the Schoelkopf lab, and it seems that he has excellent technicians on his team. In general though it still seems more probable that a ion-based quantum computer will be the first "real" quantum computer, as the technology is more mature and (for small numbers of qubits at least) easier to scale. Exciting times!

mtgx 10y ago
I wonder if anyone is pursuing Andrea Morello [1] and his team's silicon-based quantum chip idea, which they've also said has much better stability than superconducting qubits: https://newsroom.unsw.edu.au/news/science-tech/quantum-computer-coding-silicon-now-possible https://newsroom.unsw.edu.au/news/science-tech/quantum-compu... https://newsroom.unsw.edu.au/news/science-tech/quantum-computers-10-fold-boost-stability-achieved https://newsroom.unsw.edu.au/news/science-tech/quantum-compu... I'd much rather ultimately see silicon-based quantum computers, which may eventually become advanced (streamlined) enough to be used by mainstream users, too. Quantum computers using superconductors and liquid nitrogen will never become mainstream. They would just be used by corporations and governments. So I hope there will be more investing in silicon-based quantum computing research sooner rather than later. Or if not silicon, at least another material that could one day become as cheap and practical. EDIT: As for who will be the "first" with a practical quantum computer, it does seem like Google will be the one to release a 50-qubit computer this year or the next [2]. There are like 10 other companies that have built 5-qubit quantum computers, but that was still mainly a science experiment to prove that a quantum computer can be made at all. A 50-qubit quantum computer would establish a new threshold and according to Martinis [3], at least, it should be easier to scale from that point forward. In other words, the "quantum era" may actually begin then. I imagine those "stuck" at 5-qubits still have a long way to go before they can scale quickly beyond that. [1] http://www.theaustralian.com.au/higher-education/new-spin-on-silicon-implants-wins-global-recognition/news-story/75b2fc7e399e58921d7d5c8e09d93f03 http://www.theaustralian.com.au/higher-education/new-spin-on... [2] https://www.technologyreview.com/s/602283/googles-quantum-dream-may-be-just-around-the-corner/ https://www.technologyreview.com/s/602283/googles-quantum-dr... [3] https://www.wired.com/2014/09/martinis/ https://www.wired.com/2014/09/martinis/
- marcosdumay 10y ago
  Is his machine adiabatic? Because calling it D-Wave 2, and only talking about "quantum supremacy" instead of the well defined "adiabatic" make it too suspicious.
- gji 10y ago
  Andrea Morello's devices are essentially quantum dots - isolated electrons that behave like they are bound to a single atom. Unfortunately, almost all quantum dots require dilution refrigerators. These things are past liquid nitrogen and even liquid helium - they use interesting phase change properties of a mix of helium-3 and helium-4 to lower the temperature to hundreds of millikelvin. Really the only game in town currently for room-temperature quantum computing are impurity centers in diamond (most commonly nitrogen-vacancy centers). Unfortunately, there are still many difficulties there, especially since nanofabrication of diamond and precise implantation of the impurities is still a new field.

mtgx 10y ago

I wonder if anyone is pursuing Andrea Morello [1] and his team's silicon-based quantum chip idea, which they've also said has much better stability than superconducting qubits: https://newsroom.unsw.edu.au/news/science-tech/quantum-computer-coding-silicon-now-possible https://newsroom.unsw.edu.au/news/science-tech/quantum-compu... https://newsroom.unsw.edu.au/news/science-tech/quantum-computers-10-fold-boost-stability-achieved https://newsroom.unsw.edu.au/news/science-tech/quantum-compu... I'd much rather ultimately see silicon-based quantum computers, which may eventually become advanced (streamlined) enough to be used by mainstream users, too. Quantum computers using superconductors and liquid nitrogen will never become mainstream. They would just be used by corporations and governments. So I hope there will be more investing in silicon-based quantum computing research sooner rather than later. Or if not silicon, at least another material that could one day become as cheap and practical. EDIT: As for who will be the "first" with a practical quantum computer, it does seem like Google will be the one to release a 50-qubit computer this year or the next [2]. There are like 10 other companies that have built 5-qubit quantum computers, but that was still mainly a science experiment to prove that a quantum computer can be made at all. A 50-qubit quantum computer would establish a new threshold and according to Martinis [3], at least, it should be easier to scale from that point forward. In other words, the "quantum era" may actually begin then. I imagine those "stuck" at 5-qubits still have a long way to go before they can scale quickly beyond that. [1] http://www.theaustralian.com.au/higher-education/new-spin-on-silicon-implants-wins-global-recognition/news-story/75b2fc7e399e58921d7d5c8e09d93f03 http://www.theaustralian.com.au/higher-education/new-spin-on... [2] https://www.technologyreview.com/s/602283/googles-quantum-dream-may-be-just-around-the-corner/ https://www.technologyreview.com/s/602283/googles-quantum-dr... [3] https://www.wired.com/2014/09/martinis/ https://www.wired.com/2014/09/martinis/

marcosdumay 10y ago
Is his machine adiabatic? Because calling it D-Wave 2, and only talking about "quantum supremacy" instead of the well defined "adiabatic" make it too suspicious.
gji 10y ago
Andrea Morello's devices are essentially quantum dots - isolated electrons that behave like they are bound to a single atom. Unfortunately, almost all quantum dots require dilution refrigerators. These things are past liquid nitrogen and even liquid helium - they use interesting phase change properties of a mix of helium-3 and helium-4 to lower the temperature to hundreds of millikelvin. Really the only game in town currently for room-temperature quantum computing are impurity centers in diamond (most commonly nitrogen-vacancy centers). Unfortunately, there are still many difficulties there, especially since nanofabrication of diamond and precise implantation of the impurities is still a new field.