How do you make a qubit 10 times as stable? Dress it up for work Dressing qubits in an electromagnetic field can make them 10 times more stable and able to perform more calculations over time in future quantum computers, according to new research in Nature Nanotechnology. Qubits - or quantum bits - hold information in quantum computers just like bits do in conventional computers. Instead of …
Science is boring; most people who hunt pokemon go on their mobile phone in parks don't like it. And yet science can be cool, and there is money to be made if we manage to get the right angle.
Welcome then, to the future, the Quantum future, a fusion between marketing, management and science, bringing you weird shit you can't understand but that's got cool words in it including "Quantum", a word developed by certified top dead scientists.
It's the new science, based on the famous parable of "The emperor's new clothes", a story in which the emperor fools all the people in his land into believing that he is wearing no clothes.
Science almost always /isn't/ the stuff which make it into science press releases - do not confuse media reports of science with the real thing.
Feel free to peruse some open-access real-science at e.g.
http://iopscience.iop.org/journal/1367-2630
https://www.osapublishing.org/oe/home.cfm
https://journals.aps.org/prx/
It NEVER comes out right, does it?
Instead of two states, 0 and 1, however, a qubit can occupy an infinite number of states as its quantum states are entangled with one another.
NO!
The qubit is in a superposition of states, a bit of 0, a bit of 1 (written as nonmixable vectors |0> and |1>):
Q = a * |0> + b * |1>
...where a and b are complex values and the vector <a,b> is of length 1 (i.e. on the complex sphere of complex dimension 2)
This is mathematically analoguos to bog-standard "I don't know" probability, where a classical system is in some unknown state until we look (but in QM, the system is ACTUALLY in the superposition until we look):
Q = a * |0> + b * |1>
where a and b are real values and the vector <a,b> is of length 1 (i.e. on the unit circle on the real plane)
The ENTANGLEMENT comes from composing N qbits into an entangled whole, and the state of the system is then described by 2^N complex values, one for each "classical state", anmd the 2^N complex vector is on the 2^N-dimensional complex unit sphere. For example, for 2 qubits:
QQ = a * |00> + b * |01> + c * |10> + d * |11>
One can mix-in to "QM probability" above some classical "don't know" probability to obtain "mixtures". For example, we have system QQ which we know is in state QQ1 with classical probability p, and in state QQ2 with classical probability (1-p), then:
QQ = p * QQ1 + (1-p) * QQ2
...some people dispute that such mixtures have physical reality though as they are indistinguishable from a quantum state.
(A qubit is either a 0 or a 1. However, you don't know which it is until a cat looks at it. My years of reading El Reg have given me some insight into advanced physics.)
You are quite right Sir, I also have studied at the University EL Reg, so an upvote for you.
However you do undoubtedly need to remember:-
The cat must always look sideways at the qubit, otherwise it will not see what it is, and what's more what it is, won't be what it was, and what it was, wont be what it will be.
So, based on the foregoing replies:
1. According to Destroy all Monsters, I don't know to do linear algebra, so I can't understand the terms used in the post of Destroy all Monsters, and I feel as thick as a plank;
2. According to the tenor of the other postings, it has a strong whiff of bullshit anyway, algebra or no algebra.
Am I missing the point completely? The fact is, every time I ask someone to explain this "quantum" thing to me, I get the same kind of answers ("you're just too thick" or "something about cats").
The fact is, every time I ask someone to explain this "quantum" thing to me, I get the same kind of answers ("you're just too thick" or "something about cats").
Seriously, what exactly about vector addition don't you understand??
Okay, Okay. Here are some links:
Scott Aaronson explains best, for civilians
Quantum Theory from 5 reasonable axioms this needs some time and contemplation
Quantum Algorithms via Linear Algebra: A Primer or grab this book
If you are feeling chipper, you may want to check this about a pictorial approach using linear logic. I don't understand it. One day, maybe.
> strong whiff of bullshit
Ni**erDude, if it were bullshit none of the computing and electronic "entertainment" devices would work. Ditto for lasers, the sun and generally everything (i.e. matter would collapse in about a picosecond)
OK thank you for the links, I will read and try to understand!
Can you just clarify something for me also:
- What is a qbit? What is its hardware or software manifestation (what is it made of, or what is the process whereby it is operated or its results are detected)?
Thanks!
A little from column A .....
1. Yes. If you want to 'understand' Quantum Mechanics you need the maths. There is no physically 'sensible' way to describe QM properly. If you think you understand it - you don't!
2. QM is NOT bullshit. Pretty much every electronic device you use, own or come into contact with depends critically on QM being 'right'.
I did QM as part of my physics degree <mumble> years ago. I passed the course but I would never have claimed to 'understand' it because it doesn't make 'sense'. But the maths describes real behaviour in real physical systems and it astonishes me to this day that people were able to work that out at the start of the 20th Century.
The problem I have with trying to understand this technology is relating it to real world problems.
I think I can understand that you can store information in a qubit, and extract that information again, but what I find difficulty with is manipulating that information in a meaningful way, and extracting the result, which is the essence of what computing is about.
Mind you, I also struggled with Fourier Analysis, which formed the basis a now defunct branch of (analog) computing, which IIRC (from my University maths course decades ago) represent an observable artifact (like a complex waveform) as a sum of a series of more simple mathematical equations, which you can then manipulate using either algebra or vector mathematics to model how the artifact will behave under certain circumstances (although FA has alternative uses, I understand).
But I've just not seen something that describes how the data in the qubit is manipulated.
I can see something of what Destroy All Monsters is trying to say, in that it is the interaction of multiple qubits that enable you to get meaningful results from a combination of more than one piece of information, but I just cant see how this interaction is controlled. And without control, the whole field appears useless. Maybe I just don't understand what is the aim, the only thing I can see is it's not applicable to what we used to call 'general computing'. Your not going to be doing your word processing on a quantum computer!
On the subject of people needing to understand maths to be able to even approach the field, what a lot of people forget is that mathematical notation is just like any other jargon. If you don't even understand how the notation works, no amount of reiteration written in that notation will mean anything.
But then again, I realized a long time ago that there was a real ceiling on the amount of understanding I would ever achieve in maths once it got into apparently abstract areas.
This, in a rather clearer and more mature way, is exactly the point that I was trying to make: we might be able to understand the concepts behind Quantum Mechanics, but the concept of a "quantum computer" is perpetually shrouded in complex mathematical equations and jargon. Never has the appearance, implementation or practical working of a "Qbit" or Quantum computer been explained to me in terms that I could possibly understand; as such, it sounds to me like a confidence trick, and that's why I challenge their existence, until someone does explain the workings to me in a simplified way, as opposed to challenging my intelligence because I can't pierce through the shroud.
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