What is quantum computing?what does quantum mean?

      What is quantum computing?

What is quantum computing? what does quantum mean? I don't know about you, but I'm at a loss.See, I keep reading headlines about Quantum computing and how it's gonna change the world but every time I try to dig into what it actually is I feel like my brain glitches out a little bit. But I'm not giving up.quantum computations

Short description for what is quantum computing?   

quantum computation

today I am on a quest to make what is quantum computing—and what does quantum means for our world—understandable once and for all. Basically it's using quantum mechanics to compute things. But essentially, the idea is that unlike classical systems in a quantum computer or a quantum device you can have the system, it can be in two states at these time and that gives you a kind of parallelism that allows you to do two things at once, in a way that that for certain kinds of problems allows you to solve them potentially exponentially faster than you could ever do classically. 

What does quantum means?

quantum computation

What?! OK, hold on, we gotta back it up a little bit. What does quantum mean? No, no not like that I mean, in a physics way? So, here's me. I'm made up of a bunch of different living tissues, which are made up of molecules which are made up of atoms of all of the different elements we're made of. And our  atoms are made of subatomic particles: protons, neutrons and electrons. And then if you can believe it we can go even further down than that because protons and neutrons are made up of even smaller particles called elementary particles like quarks lepton sand bosons. And this world of subatomic and elementary particles is what's called the quantum realm and this is where the physics things follow the rules of quantum of mechanics which basically means that at this level, things this small behave really strangely—like, different than how the world behaves at the larger level of say you and me .

So classical computers work with digital logic, most of them, which means that you express everything in terms of bits that are zeros and ones and you manipulate those with what are called logic operations and that's the basis of a program so you have some input bits, you manipulate them, you get some output bits in that your answer. And then the magic of a quantum system is that you can have an analogous thing but instead of a bit you have what's called a quantum bit, a qubit. Sounds cute. Just to recap, this is how all of our computing that we're used to—which is called classical computing—works: we use electrons to send signals from one piece of machinery inside the computer to another. These signals are either on or off, there is either a flow of electrons at a discrete voltage or at another specific, measurable voltage and that's your signal. This on or off binary signal is encoded by us digitally in ones and zeros, that's how we tell the computer what we want it to do and then how we read the signals that come out on the other end. This also means we're limited by a bunch of things, including the constraints of electricity like the loss of energy through resistance and the generation of heat. It's also getting harder and harder to cram more and more transistors into smaller and smaller spaces, like throughout computing history we've seen steady progress in improvement of computing power but we're reaching the end of that trend, we're reaching the limit of what's called Moore's Law. B: There's never been anything like it in human history. It's really remarkable. We're now getting to the point where transistors are justa few tens of atoms across, so they just can't keep getting much smaller and the cost of building the fabrication facilities is just phenomenal,and so it's very difficult to to continue progress.So all projections are that in the early 2020s this will run its limit, so what will happen then? M: This is where all kinds of computing innovation comes in, including quantum computing! So back to how quantum computers do what they do. With one classical computing bit that unit can give two answers: one or zero, yes or no, on or off, you get the picture. But in quantum computing, instead of being just zero or one it could be any sort of combination of zero and one. And then if you put two together those can be in any combination of zero and one both, and so the size of the space that is effectively possible grows really quickly with the number of qubits you have, right, and it's because they can be in f all all the different states at the same time. You could imagine something that had every possible value between zero and one, sure, and that would be pretty cool, but the quantum systematically does more than that. Not only can you have any number between 0 and 1you can have what's called a phase. You can have a relative phase between 0 and 1so that adds an extra axis, and instead of this just being a line they live on the surface of a sphere. M: ok, ok, so if a bit is two points ona line, a qubit is a 3d sphere where any of your quantum states are any point on the surface of that sphere? That's right. Exactly. Ok, so qubits can give us way more possible computing power because they can ask many questions atthe same time. Plus when you're adding a computing unit, a qubit, you're getting what more bang for your buck than if you're adding another bit to a classical system. And that all sounds great! But those benefits are only true if you can ask your quantum system your questions in a way that makes sense and then also read the answer that it's giving you in a way that means something to you. J: if you measure it from from classical world, it doesn't give you the answerof what that any possibility is, it gives you that classical response back, so itgives you either 0 or 1. M: Because you're asking it from aclassical system? J: Kind of, yeah. There there is a sort of paradox in the senseyou want this thing which is purely quantum mechanical, which canlive in multiple states, but as soon as you interact with it from the classicalworld, which is where we're living and where we're going to construct all theproblems we're asking, it interferes with that system and essentially imposesclassicalness on it, so even the materials that you build the system outof they effectively can measure the states of the quantum computer and youdon't know what question was asked so that's what ends up making it like itrandomly projects into one of those those state. So that's a big source oferror. M: Well, it has to freeze at the moment it is in that time and give youwhere it is at that one moment, it's not gonna give you all the possibilities butthat exist. J: Sure, that's right. M: Plus there's this whole issue of noise.Because stuff on the quantum level is so freakin tiny it can be disturbed bysuper tiny things like the movement of molecules...and another way to put themovement of molecules is: temperature The other aspect about quantum computing is,unlike a phone that you carry around with you and it lives you know in warmand cold environments, a quantum computer, to keep those qubits pristine and keepthem from getting perturbed by the environment, they have to be kept atextraordinarily cool temperatures. M: And I've seen the tank, it's like a big tank thatlike you need to keep at cryo temperature, like as close toabsolute zero as you can get. B: Exactly right, and so those aren't things you cancarry around with you, they're always going to be housed in some specializedfacility. M: So we've got the problem of the classical and quantum worlds interacting,you've got the noise issue, and then there's also the problem of scaling up.B: We'll need them to get better in several dimensions: we'll need to have morequbits, we'll need to have better control over those qubits, we'll need to be ableto sustain those qubits from getting perturbed by the environment for longperiods of time. And all those are extremely challenging problems inmanufacturing, in physics, in material science. Maren: A hypothetical ideal quantumcomputer that we could reliably use to give us accurate answers to thequestions that we ask it is sometimes called a universal quantumcomputer. But even if we can get there, what would this help us do? Like whatwould this huge possible leap in computing actually mean for us? J: I guessone of the best-known things is this so-called Shor's factoringalgorithm. One aspect of modern cryptography involves factoring primenumbers, and I won't get into the details, but it's useful cryptographically becauseit's something you can represent with a short string and it's very hard tofigure out how to break that apart, how to find out what the sort of secret key is. M: Like even for a super powerful computer, it's really difficult for them to run through all of the possibilitiesso it's hard to break into something if you use that algorithm to protectinformation. J: Yeah absolutely. In fact it's considered to beexponentially hard, so that means if I have a 100 bits then it's like two tothe hundredth power is the sort of the proportional amount of time, naively,required to figure that out. M: OK, but if we had this hypothetical universalquantum computer we just might be able to solve Shor's algorithm. Like, in areasonable amount of time. That would change computer security reallydrastically. But we've got a pretty long way to go before we can do somethinglike that, like we're really not there yet. B: We still need a few miracles beforewe're really in an age where quantum computing goes mainstream. M: So even thoughwe may not be at fully functioning quantum computing yet, the prototypesthat are being built all over the world, including here at LLNL, are stillvery useful and necessary and can tell us a lot of important stuff. J: I think in10 years we may see basic demonstrations of building blocks of this universalthing, but in this next 10 years it's really going to be about how do we makethe most use out of these systems? And then I think there will be huge impactsagain, on sort of basic science because we're able to build systems thatnormally we would we'd only get given to us from from nature, we canbuild them in a way so to ask specific questions about basically how quantummechanics works when you have lots of components, right? M: It's like, who knewbuilding a quantum computer is gonna tell you a lot about the quantum world? It's like a very happy sort of almost byproduct of tryingbuild a quantum computer. J: Absolutely. We also are in a position to help the field.I mean, that's also part of our role is where we have this huge breadth ofcapabilities, you know people and applied math, computer science, physics, biology—and we can all come together to look at different aspects of these problems: oneon the side of trying to figure out well what is the useful thing you could dowith this, now the other is how can we solve these technical problems in termsof the materials, the control electronics, and all that kind of stuff. M: Exactly, like Ithink the interdisciplinary nature of the Lab is really key to ourexperimentation in every field, including quantum computing. M: And where does quantum computing fit in with classical computing? While quantum computing may beable to do some things better than classical systems, we're still gonna needclassical computing...and a lot of it. Like, we're still going to need our upcomingexascale capabilities, aka the fastest and most powerful classicalsupercomputers in the world, in addition to quantum computing systems. And maybewe'll even need to use them together. B: Our ability to continue to eke more out of our machines through architectural innovations, that'll last 5, 10, maybe 15years, you know, and that will give quantum computing more time to mature. At some point as we're thinking about these very specialized computers,they won't look that different from a specialized computer made in avery different way, maybe from different kinds of kind of physics, and so there might be a role then in the same way we're using a host of specialized processors to do our computations, we could plug a quantum a coprocessor into that mix to solve certain problems that quantum devices are very good at solving. M: So you can see this sort of Lego house of a computer that has a classical computing component, a quantum component, and may be the classical component that's been architected to do a very specific thing,maybe a conglomerate machine that would be really good at a lot of different things. B: Exactly. There's this tremendous uncertainty about what computing will look like ten or fifteen y years from now, and that can be scary but it's also incredibly energizing and exciting. So so we've been on this trajectory with Moore's law for 50 years that's taken us to phenomenal places and now as that reaches its end, we need fresh ideas. We need new ways of thinking about computing, we need new interdisciplinary collaborations, and those are things the Labs are really good at. And so it's gonna be a very exciting time. M: OK, that was a lot. But hopefully it gave you guys some more insight into quantum computing and its place in our wider computing world.           

 If you guys have questions about what  is quantum computing?what does quantum mean? this, or quantum mechanics, or anything related then leave them in down for us in the comments below. I'll see you next time . Please don't be cheap to share this article with your friends because I have made this article with very much effort .