# Checking if Explanation of Quantum Computer is Correct

My explanation of a quantum computer and why it is potentially faster is below:

A quantum computer uses physical phenomenon to perform operations called gates. These gates act upon things called qubits, which are like bits and are represented by quantum events like electron spin, etc. Think of how a normal computer works with transistors. The flow of current represents the bit value, and it is controlled by the physical properties of charge. Sometimes, doing these phenomenon in a quantum computer would be faster than carrying out the gate-operation on a classical computer, and thus algorithms that use these gate-operations would be sped up(ignoring potential side-effects)

Is my explanation correct? Is there any part at all that is wrong?

Thanks!

It’s a first step but you might have gotten off the rails at the end.

Taking it line by line:

A quantum computer uses physical phenomenon to perform operations called gates.

Sure, this is fine. There are some other models of quantum computing that don't use gates as explained here, but the gate model is the most common model and is often the first to be explained. It is also true that a tangible quantum computer will use physical phenomenon.

These gates act upon things called qubits, which are like bits and are represented by quantum events like electron spin, etc.

Yes, this is good. "Quantum events" is a little confusing but it's true that qubits could be encoded via electron spin.

Think of how a normal computer works with transistors. The flow of current represents the bit value, and it is controlled by the physical properties of charge.

Yes, it's great to analogize to a classical computer (you use "normal computer"), and this is indeed a rough-and-ready statement of how many classical computers operate. Although pedantically the "flow of current" doesn't represent the bit value; rather, the voltages at various nodes of the transistor determines the bit value. But it is true that a classical computer's bits can be broadly construed as being controlled by physical properties of charge.

Sometimes, doing these phenomenon in a quantum computer would be faster than carrying out the gate-operation on a classical computer...

This is incomplete, and you might loose a point or two if I were grading you. You seem to be saying that a quantum gate acting on qubits operates faster than a classical gate operating on bits. This is very far from being true (explained below).

..thus algorithms that use these gate-operations would be sped up (ignoring potential side-effects).

There is a speed-up with a quantum computer for many algorithms, but it does not come from the speed of the gate operations. Rather, the total number of quantum gate operations may be less than the total number of classical gate operations.

Three important concepts in quantum computation are 1. superposition of qubits, 2. entanglement of these qubits, and 3. interference of various states of qubits.

Your explanation comes close to describing superposition by describing what a qubit is, skips over entanglement, and is generally incomplete about interference.

This interference is brought about by these quantum gates. The explanation seems to imply that quantum gates act faster than classical gates. But, quantum gates are much (much) slower than the counterpart classical gates - microwave or laser pulses in a quantum computer are slower than the switching of transistors in a classical computer.

Quantum computers win in some algorithms because of quantum interference, which provides that the total number of quantum gates in a quantum algorithm can be much (much, much) fewer than a classical algorithm.