The high-stakes race to make quantum computers work – Chiara Decaroli
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The high-stakes race to make quantum computers work – Chiara Decaroli

September 2, 2019


The contents of this metal cylinder could
either revolutionize technology or be completely useless— it all depends on whether we can harness
the strange physics of matter at very, very small scales. To have even a chance of doing so, we have to control the environment
precisely: the thick tabletop and legs guard against
vibrations from footsteps, nearby elevators, and opening
or closing doors. The cylinder is a vacuum chamber, devoid of all the gases in air. Inside the vacuum chamber is a smaller, extremely cold compartment,
reachable by tiny laser beams. Inside are ultra-sensitive particles
that make up a quantum computer. So what makes these particles
worth the effort? In theory, quantum computers could
outstrip the computational limits of classical computers. Classical computers process
data in the form of bits. Each bit can switch between two states
labeled zero and one. A quantum computer uses something
called a qubit, which can switch between zero, one,
and what’s called a superposition. While the qubit is in its superposition, it has a lot more information
than one or zero. You can think of these positions as
points on a sphere: the north and south poles of the sphere
represent one and zero. A bit can only switch between
these two poles, but when a qubit is in its superposition, it can be at any point on the sphere. We can’t locate it exactly— the moment we read it, the qubit resolves
into a zero or a one. But even though we can’t observe the
qubit in its superposition, we can manipulate it to perform
particular operations while in this state. So as a problem grows more complicated, a classical computer needs correspondingly
more bits to solve it, while a quantum computer will
theoretically be able to handle more and more complicated problems without requiring as many more qubits as a
classical computer would need bits. The unique properties of quantum computers result from the behavior of atomic
and subatomic particles. These particles have quantum states, which correspond to the
state of the qubit. Quantum states are incredibly fragile, easily destroyed by temperature
and pressure fluctuations, stray electromagnetic fields, and collisions with nearby particles. That’s why quantum computers need
such an elaborate set up. It’s also why, for now, the power of quantum computers
remains largely theoretical. So far, we can only control a few qubits
in the same place at the same time. There are two key components involved in managing these fickle quantum
states effectively: the types of particles a quantum
computer uses, and how it manipulates those particles. For now, there are two leading approaches: trapped ions and superconducting qubits. A trapped ion quantum computer uses
ions as its particles and manipulates them with lasers. The ions are housed in a trap made
of electrical fields. Inputs from the lasers tell the ions what
operation to make by causing the qubit state
to rotate on the sphere. To use a simplified example, the lasers could input the question: what are the prime factors of 15? In response, the ions may release photons— the state of the qubit determines whether
the ion emits photons and how many photons it emits. An imaging system collects these photons
and processes them to reveal the answer: 3 and 5. Superconducting qubit quantum computers
do the same thing in a different way: using a chip with electrical circuits
instead of an ion trap. The states of each electrical circuit
translate to the state of the qubit. They can be manipulated with electrical
inputs in the form of microwaves. So: the qubits come from either ions
or electrical circuits, acted on by either lasers or microwaves. Each approach has advantages
and disadvantages. Ions can be manipulated very precisely, and they last a long time, but as more ions are added to a trap, it becomes increasingly difficult to
control each with precision. We can’t currently contain enough ions
in a trap to make advanced computations, but one possible solution might be to
connect many smaller traps that communicate with each
other via photons rather than trying to create one big trap. Superconducting circuits, meanwhile, make
operations much faster than trapped ions, and it’s easier to scale up the number
of circuits in a computer than the number of ions. But the circuits are also more fragile, and have a shorter overall lifespan. And as quantum computers advance, they will still be subject to the
environmental constraints needed to preserve quantum states. But in spite of all these obstacles, we’ve already succeeded at making
computations in a realm we can’t enter or even observe.

Only registered users can comment.

  1. Does anyone know why they need so many additional particles that they are unable to manage the quantity when there are an infinite amount of locations between one and zero?

  2. Consider naming "Quantum computers explained"?
    As far as I can tell it has nothing to do with "race to make quantum computers work" & is just a cartoon explaining how they work as you would make for school children.

  3. This is the most fascinating thing I've ever seen. Basically, Superconducting Circuits are like Intel CPUs, where they have faster IPCs than Trapped Ions right now, but will run into the limit of architecture. Meanwhile Trapped Ions are like AMD CPUs before Ryzen came out, where they lose to Superconducting Circuits IPC-wise, but can theoretically make up for it by continuously adding more and more cores aka Ion Traps.

  4. So by pure estimation
    how many times faster does the quantum computer vs classical computer?
    considering ions, laser and qubit vs ram, processor and vcard.
    the answer?

    Yes

  5. will it grant us a new feature or just make the existing feature more fast.If it is the second option…I am not interested

  6. Ted ed u have to gift me a quantum computer if…
    this comment gets 1000 likes or u reach 10m suscribers or u get 10k likes

  7. Had to repeat this 4 times to grasp the basic concept put forth in this video.

    I shudder to even think what the full scientific explanation would look like.

  8. Is the principle of quantum computer uncertainty is same with Werner Heisenberg princip of uncertainty of electron in atom orbit?

  9. This vastly undersells the differences between quantum and classical computing. It makes it sound like all we'd need to do with classical computers is add a few more bits.

  10. she lost me at a superposition becomes a 0 or a 1 once interacted with. I think the rest would make sense once that part makes sense.

  11. does anybody else after starring at the 3 purple balls at 1:54 still see the overall shape of the ball even though the balls have gone.

  12. Super well done on this video! As a former ion trap quantum computing scientist this is the first video that I've seen that makes sense of the field without getting so complex it's incomprehensible. Also, Ions rule, JJs drool (but I'm a little biased on that, hehe)

  13. Interesting video but i really didnt like the person who presented it, something bothers me in the way she speaks

  14. Hey Ted, quantum computing promises to bring wonders to the realm of music and harmonics, however the idea of rendering the Earth in a Three- Dimensional brings worries of privacy. How does Ted plan to combat human privacy with peering wonders of quantum computing ?

  15. This video has nothing to do with the "high stakes" of quantum computing. Presumably, such a video would discuss the ramifications for a society who have access to such advanced technology. Nor is there any mention of the supposed "race" to achieve this advanced technology or the major players involved in this race. It's an explanation of quantum computing. Why not title the video as such?

  16. I always thought it would be easier to try to develop a quantum computer in space. It would be easier to keep it cold as long as it was in the shadow of the Earth. As long as radiation could be kept low enough, it would probably be easier to do.

  17. These videos are so informative, and yet my brain wants to explode trying to comprehend anything relating to quantum theory.

  18. Practically so advanced it had to do things what classical computers did, just unpredictability faster.

  19. Admittedly, I am not well versed in computer programming but it seems to me that with the adoption of quantum computing, conventional computer programming with be useless. A more sophisticated set of protocols will be required to harness the superposition capabilities. One further suspects this radically different method of programming is well into its first generation of refinement.

  20. first video who actually explained what a qubit is and properly said what is a superposition, and not the popular hand waving "is 1 and 0 at the same time!" who doesn't make sense and make it worse to understand

  21. Just wait til G5 comes out and quantum computers are brought into market within 20 years. It's going to be amazing.

  22. That’s all very interesting BUT! Would I be able to play games on a quantum computer?

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