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


Current State of Quantum Computing - Computerphile

18 分類 收藏
林宜悉 發佈於 2020 年 3 月 28 日
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