# Quantum computing questions from a dunderhead.



## Foxbat (Jun 18, 2021)

I recently saw a news article on quantum computing. Since then, I’ve been trying to grasp the concept and how it works. So far, my understanding of one big difference between conventional and quantum is voltage switching. A conventional processed bit becomes so by passing through two layers of very low voltage. The area between these voltages (in which the bit cannot function) is called the ‘forbidden zone’ and is, effectively an area of process lag. It seems that (as I understand it), in quantum computing, the voltage crossover would be (almost) instantaneous, which will greatly speed up processing time.  I’ve been doodling about on the internet to find these things out but you never know how accurate the info is so I’ve no idea if this supposition of mine is correct.


The next thing is to do with the fact that in quantum computing, the information (unlike standard) can be 1 or 0. I’m kind of grasping the idea that having no defined value will greatly enhance processing because it will not be constrained to specific paths or processes, I presume this might be where quantum entanglement might come into play...

So my next question is: during quantum computing, to reach a desired goal, surely there must come a point in the process where a bit must have a defined  value (either 1 or 0) for the application to work correctly? 

Of course, It’s possible that I’ve completely misunderstood how this will work and, for some reason, it’s bugging me.


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## CupofJoe (Jun 18, 2021)

I think its more that the qubit has the potential to be both 1 and 0 as needed and not that its neither 1 nor 0.
I found this IBM page helpful








						What is Quantum Computing? | IBM
					

Learn more about quantum computing, a rapidly-emerging technology that harnesses the laws of quantum mechanics to solve problems too complex for classical computers.



					www.ibm.com
				



And this helped








						How Do Quantum Computers Work? - Science World
					

“Things on a very small scale behave like nothing you have any direct experience about… or like anything that you have ever seen.” (Richard Feynman, Six Easy Pieces, p116.) In order to understand anything Quantum, it’s best to approach it with an open mind. So, while you may know what a computer...




					www.scienceworld.ca
				



Not that I really believe it all yet... It still sound like magic to me...


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## Foxbat (Jun 18, 2021)

The IBM link was pretty helpful but I still don’t know what a qbit actually is or how it works in reality. The article just says that it stores info in a quantum form and leaves it at that. What I want to know is how it is stored in this form (is it simply photons or entanglement or what). Nobody seems to be talking about quantum teleportation...imagine computers communicating on opposite ends of the world with no connecting medium...

One surprising thing was the open source Qiskit availablr on the IBM cloud. It’s based on Python, which I’ve pottered around with in the past (although I can’t remember much about it now). The chance to dip my toe into quantum programming is tempting but I’d probably blow a brain fuse trying.


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## CupofJoe (Jun 18, 2021)

I don't think it is information as we would understand it. It is the possibility of an event.
So it is great at doing things where we know if the end result is right or not [decrypting, seating wedding guests etc] but crap at more random things like weather forecasting. 
But as I said before it sounds too much like magic to me...


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## Elckerlyc (Jun 18, 2021)

I found the _Science World_ article hugely more informative than the IBM website, which basically tries to sell the idea of quantum computing (as if they invented it.) AFAIK quantum computing is still in it's experimental phase?
The whole idea of entanglement is mind-blowing and incomprehensible.


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## Ori Vandewalle (Jun 18, 2021)

I still think this is the best explanation of what quantum computing is and isn't: Saturday Morning Breakfast Cereal - The Talk


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## CupofJoe (Jun 19, 2021)

Ori Vandewalle said:


> I still think this is the best explanation of what quantum computing is and isn't: Saturday Morning Breakfast Cereal - The Talk


Thank you!!!


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## W Collier (Jun 19, 2021)

CupofJoe said:


> Thank you!!!


Agreed.  That comic is priceless.


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## RJM Corbet (Jun 19, 2021)

Foxbat said:


> The article just says that it stores info in a quantum form and leaves it at that


I think it relies on quantum entanglement


Elckerlyc said:


> The whole idea of entanglement is mind-blowing and incomprehensible.


As you just said, lol


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## mosaix (Jun 19, 2021)

I seem to remember that an example of quantum computing would be replicating the Bombes used at Bletchley Park to decrypt the Enigma signals.

The analysts at Bletchley guessed that a sequence of letters in a signal may represent, say, 'Berlin' or 'London'. The Bombes were used to simulate the various starting positions and combinations of the rotors in the Enigma. Many positions were tried until one of them produced the 'solution' i.e. the example letters resolved to the 'guess'. This gave the rotor positions for that message and so the rest of the message could be decrypted. 

A quantum computer would allow all the rotor positions to be simulated simultaneously (if that's the right word) and so produce an instant solution.


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## Foxbat (Jun 19, 2021)

I did read something a while back on quantum encryption and it's reckoned it will be pretty robust if it ever materialises as a real application.


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## RJM Corbet (Jun 19, 2021)

Sabine Hossenfelder covers the latest developments in quantum computing here:





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						Latest Developments in Quantum Computing
					

Sabine Hossenfelder boils it down to 13 minutes:




					www.sffchronicles.com


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