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Explanation of Quantum Computers - The Limits Of Human Technology
During human history, human technology consisted of our brains, fire, and sharp sticks.
When fire and sharp sticks become power plants and nuclear weapons,
the biggest changes have taken place in our brain technology.
Since the 1960s, the power of our brain technology has continued to expand exponentially,
allowing computers to become smaller and more powerful at the same time.
But this process will reach its physical limits.
Computer components are beginning to approach atomic size.
To understand why this is a problem, we have to understand the basics.
In a nutshell by Kursgezaght
A computer made of simple components, which do simple things;
represents data, how to process it, and the control mechanism.
Computer chips contain modules, which contain logic gates, which contain transistors.
A transistor is a simple form of processing data from a computer,
which is a switch that can block, or give way to, incoming information.
This information consists of "bits" which can be set to 0 or 1.
Combinations of several bits are used to represent complex information.
Transistors are combined to make a logic gate, which also does the simpler thing.
For example, an "AND" gate sends output 1 if all inputs are 1, and otherwise output 0. The
combination of a logic gate will produce a meaningful module,
for example, to add two numbers.
After you can add up, you can also multiply.
And once you can multiply, you can do anything.
Since all the basic operations are simpler than grade 1 math,
you can think of the computer as a group of 7-year-olds answering basic math problems.
A fairly large group can compute anything, from extraterrestrial physics to Zelda.
However, with the components getting smaller and smaller, quantum physics is causing difficulties.
In short, a transistor is just an electric switch.
Electricity is an electron that moves from one place to another.
So, a switch is a barrier that can hold electrons from moving in one direction.
Now, the usual size of a transistor is 14 nanometers,
roughly 8 times the diameter of the HIV,
and 500 times smaller than a red blood cell.
If a transistor shrinks to the size of a few atoms,
an electron can move from one side of the barrier to the other, using a process known as "quantum tunneling".
In the quantum world, physics works quite differently from what we are used to,
and ordinary computers are starting to make no sense.
We are approaching the real limits of our technological advancement.
To solve the problem, scientists are trying to use unusual quantum properties to their advantage,
by building quantum computers.
In ordinary computers, bits are the smallest measure of information.
Quantum computers use "Qubits", which can also be set to a value.
A qubit can be any two-tier quantum system,
such as a spin, and a magnetic field, or a photon.
0 and 1 are possible values, such as the vertical or horizontal polarization of a photon.
In the quantum world, qubits do not have to be in one of the possibilities,
qubits can also be in every proportion of the two conditions at once,
this is called a "superposition".
However, when we measure the value, say by passing a photon through a filter,
he has to determine whether it will be vertical polarization or horizontal polarization.
So, as long as they are not measured, the qubits will be in the superposition of 0 and 1 possibilities,
and you cannot predict their values.
But as soon as you measure them, they become a definite value.
Superposition changes everything.
4 bits will only be in one of 2 ^ 4 different possibilities at a time.
16 available combinations can only be used one.
However, 4 qubits in the superposition will be on the 16 possible combinations at the same time.
This value increases exponentially with each new qubit added.
20 qubits can store millions of values in parallel.
Another trait that qubits can have is "Entanglement",
a close relationship that makes each qubit react with changes from other qubits at once,
no matter how far apart they are.
This means that if we measure the value of entangled qubits,
we can immediately determine the value of the pair's qubits without looking.
The manipulation of qubits is a headache.
Normal logic gates get simple input and return a definite value.
A quantum gate manipulates the input superposition, changes the possibilities, and produces another superposition as the output.
So, a quantum computer has a set of qubits, passes them through the quantum gate and manipulates the possibilities,
and finally measures the result to eliminate the superposition, resulting in a sequence of 0 and 1
values. This means that all possible calculations of your setup will be completed at the same time. at the same time.
In the end, you can measure the result and it may be the result you want, so you have to repeat the calculation.
But by utilizing superposition and entanglement, this can be more efficient than ordinary computers.
So, while quantum computers will not replace our computers,
in some areas, quantum computers are far superior.
One of them is in the database search.
To look for something in the database, a normal computer must check all the possibilities.
Quantum computers only take up a fraction of the usual time,
which for large databases means a big difference.
Another well-known example is IT security.
Currently, access to e-mail and banking data is
secured using encryption where you provide a public key to encode a message that only you can decode.
The problem is this public key can be used to calculate your secret private key.
Luckily calculating the private key using a regular computer can take years.
But using a quantum computer that can be very fast, it can be done easily.
Another thing that can be done is the simulation.
The simulation of the quantum world is extremely resource-consuming,
and even large structures, such as molecules, would be extremely inaccurate.
So, why not simulate quantum physics with real quantum physics?
Quantum simulation could shed new light on proteins that could change medicine.
At this point, we don't know whether quantum computers will be just a special tool
or a major change for humans.
We still don't know the limits of this technology,
and there is only one way to find out.
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