What is the difference between normal computers and Qunatum Computers, why are they so much faster/more efficient?
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The highest number you can count to in binary with only 5 digits is 11111-base 2, which when written in decimal is 31. The first 5 powers of 2 starting at 0 are 2⁰=1; 2¹=2; 2²=4; 2³=8; and 2⁴=16. 1+2+4+8+16=31)
In decimal, the highest number you can count to with 5 digits is 99,999. So you see that every digit becomes more powerful the more possible values it can hold.
Now consider that in an electric computer, to perform a digit operation, electricity must flow from a power source, through the circuitry, back to ground. If all your operations can be run in parallel, then it doesn’t make a ton of difference, but if the result of one digit relies on the result of the previous digit (remember how you have to carry a digit in addition if you overflow?) Then the total number of digits has an effect on the total length of time it takes for electricity to flow through the entire circuit and perform the operation. If we can find a way to store the same data in fewer digits, then we can shorten the amount of time it takes to perform these tiered operations.
Since typical electric computers can only distinguish between electricity and no electricity, then binary is the only options. We actually used to have analog computers in the past that could distinguish between 0V, 1V, 2V… And any number of different voltage levels. These computers are orders of magnitude faster than the typical digital computers we’re used to that only do on and off. They’re even making a huge comeback in things like machine learning that are super time-consuming.
The main reason analog computers fell out of fashion once digital came along is because digital computers can be programmed over and over again to do nearly limitless tasks. Analog computers are programmed solely by what components they are made from and how they are wired. Which makes them insanely fast, but for one and only one task. Additionally, the more precision you want with digital computers you can add more digits. Each digit costs the same as the last. And overall, we’re getting cheaper and smaller at an alarming rate. Analog computers either need more sensitive components or higher voltages, both of which can be more expensive, and are more susceptible to damage. And also sensitive components are less resilient to ambient noise, muddying the data.
Quantum computers are the best of both worlds. They are endlessly programmable like digital computers. The number of states is still discrete which helps with noise cancelling and repeatability like digital, but the digits can hold more than one value like analog. They can do more operations in parallel. And primarily, as discussed earlier, they can store more data per digit. Than a binary computer, meaning fewer operations have to be done to get to the same result. By the way, if you want more precision or more data, you can either add more digits, or you can more precisely control the states in the existing digits. Both of the analog and digital options can be used at will.
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