Placeholder Image

字幕列表 影片播放

  • Well, brief mentions in other videos about the Q-word,

  • *Laughs*

  • you know, the magic computers that are going to break all encryption

  • and beat everyone at their own game and be the next big thing and be on all our smartphones.

  • Should we put some reality on this? Where are we at with quantum computing?

  • I Work at a company called Righetti computing. We're a company in Berkeley, California

  • And we build quantum computers from the ground up. We do the silicon fabrication all the way up to how we program the machines

  • I in particular

  • Think a lot about how we program the machines how we interface with it at some point

  • Somebody has to type something into a keyboard to make it do something and that's mostly where I think about things quantum computers

  • Really should be thought of as a way to

  • Augment our existing compute infrastructure exists in computers solve problems, and that's not going away there. They will continue to solve good problems

  • So a quantum computer really should be thought of as a is a special-purpose machine that can solve certain problems

  • a lot better

  • Than existing computers can solve them. In fact, I think thinking of it like a GPU is is pretty fruitful that

  • GPUs are, are, they are computers in a sense. But really they're they're better thought of as like a coprocessor to your main computer. They

  • GPUs are extremely good at solving a variety of problems

  • you could sort of

  • Wrangle a GPU to solve any problem you want to but it's you know regular computers are good at that so quantum computers

  • I think of as like on the side

  • Unfortunately current quantum computers are gigantic. They're they you know, they're like the old computers like the ENIAC they fill a room

  • But nonetheless you you hook your computer up to this and it does separate problem-solving as a company

  • We build these quantum computers and deploy them there. They're

  • Accessible right now on the cloud. There's something that I on my laptop anywhere

  • Actually, I don't need any special interface can connect up to them and do computations with them

  • And we're at a point now where?

  • the fundamental unit of resource of a quantum computer just as we take regular computers and think about them in terms of

  • bits and gigabytes and so on on a quantum computer

  • These are measured in qubits, which are very special because every time you add a qubit

  • You're you're doubling the capacity of the computer in some way. So

  • Last year, we released a machine that has around eight qubits. And now the current machine we have is about nineteen qubits

  • so it's not that we

  • Approximately just doubled the qubit because each qubit itself is doubling

  • so you have to think of that number of doublings each time from eight to nineteen problems that deal with lots of

  • interactions or lots of

  • Possibilities so to speak are where quantum computer sort of shine

  • so one big area of application is

  • in quantum computing is the simulation of molecules molecules are are made up of a bunch of atoms and each of these atoms is is

  • Applying a force to the other atoms they're pushing and pulling each other and they're just lots of ways in which the atoms interact with

  • one another and a quantum computer is extremely good at

  • Keeping track of all that and dealing with that in a very efficient way that classical computers which are normal computers

  • Don't deal with quite as well

  • Likewise other types of problems like optimization which in mathematics means kind of finding the best or worst

  • possible solution to a problem

  • Quantum computers are showing a lot of promise and with that said though

  • There's one point I want to make which is sort of in popular science people think that quantum computers just sort of try every possibility

  • At the same time you get all these sort of kooky

  • Interpretations of multiple universes and so on and quantum computers, don't do that. They do not try every possibility at the same time

  • But the second point is that applications of quantum computing is a very active field of research

  • quantum computers currently are

  • They're called noisy quantum computers. They they sort of act like analog devices not digital devices

  • And so there's all this a little bits of error and little bits of noise that come into the system

  • and so it's an active field of research to see what

  • Algorithms and what problems are very robust to this noise and it turns out that this molecular simulation is an example of a problem

  • That's very robust to noise

  • Whereas what? You might heard of like Shor's algorithm and factoring and breaking encryption are not robust annoys at all

  • They're very difficult to to do so that's a very active field of research both at the company that I work at

  • As well as more broadly the community the sort of room size computers are sort of where we're at

  • the way in which these computers have been constructed is

  • Using sort of off-the-shelf components that have not been specially made for the construction of that machine in general

  • So you find generally with these quantum computers you find big racks of analog

  • electronics these electronics that that have existed for other applications

  • and so

  • It's definitely not at a point where we've we've sort of custom fabricated the entirety of the machine

  • I'm not just talking about the quantum chip itself

  • But the thing that the quantum chip is housed in the electronics that go with the quantum chip, etc, etc

  • We're only just starting

  • We just in general as a in the field of quantum computation are only just starting to make like customized

  • electronics and the like for these systems

  • The other aspect of this is that just like the ENIAC for example

  • Which had vacuum tubes that burnt out and you had to go replace them

  • Literal bugs getting in there and so on neither of those things happen with quantum computers

  • But what does happen is that the system in general isn't shown to be stable across, you know?

  • Five or ten years and just hasn't existed that long

  • And so components are are often swapped out often changed

  • It's not robust to changes in the environment

  • like if somebody walks by with a big magnet the whole thing kind of goes awry, so it's a really sort of

  • Finicky machine not unlike the early computers like the ENIAC and so on

  • How far are we off quantum smartphones?

  • Yeah, that is that is really really far away because we need to cool these chips down to like the same temperature or colder than

  • The temperature of outer space so you need big refrigerators as they're called

  • Not going to happen for a good while

  • The interesting thing though is

  • When we have multiple qubits, and this is really where the power of quantum computation happens

  • We can actually think of it sort of simply

  • Diagrammatically that if qubits if I just represent them sort of as a circle here, maybe we have three the idea

  • Is that these qubits can interact this guy can interact with this guy?

Well, brief mentions in other videos about the Q-word,

字幕與單字

單字即點即查 點擊單字可以查詢單字解釋

B1 中級

量子計算的現狀 - Computerphile (Current State of Quantum Computing - Computerphile)

  • 14 2
    林宜悉 發佈於 2021 年 01 月 14 日
影片單字