What problems are quantum computers for?
Quantum computers won’t be replacing classical computers. They’re more likely to continue working alongside them, just as they are already doing today.
As you will see, we tend use a classical computer to represent a quantum circuit to the quantum computer, the quantum computer runs some cycles on this circuit, and then reports back to us again with a classical bit response.
Quantum computers work very well for problems that exponentially explode as discussed earlier.
Problems like logistics, such as the most ideal delivery route for trucks, or even concepts like planning for companies, where each choice branches out into new possible choices and opportunities.
Let’s consider you’re planning a charity dinner and you’re attempting to seat people together who will keep each other in good, donating, moods.
Let’s pretend for now you just have 1 table with 5 seats. How many combinations do we have here? it’s 5x4x3x2x1, or 5 factorials, which is 120. This means there are 120 possible combinations.
What happens if we added… just one more seat? That’d be 6 factorials, which gives us 6x5-factorial, or 720. Just one more seat is 6x as many combinations.
What about 10 seats? That’s 3,628,800 combinations.
Such exponentially exploding problems exits across all industry and business domains. Quantum computing can expedite solving such problems to a great effect. Let’s now see how problems are solved in Quantum computation to better understand the gambit of problems that can be solved using quantum computation.
Solving a problem — The Quantum way!
Quantum Circuits
Traditionally a quantum circuit is designed to model a solution to a problem. As Wikipedia states, A quantum circuit is a model for quantum computation in which a computation is a sequence of quantum gates, which are reversible transformations on a quantum mechanical analog of an n-bit register.
If a qubit is a unit of information, a quantum circuit is a unit of computation.
Anatomy of Quantum Circuits
Let’s understand how quantum circuit is modelled. Note that this can be modelled in any modern language . We will discuss coding and libraries used in a different section.
1. Qubits: They are represented towards the left in the diagram, there are 4 qubits. You can consider this as inputs.
2. Quantum Gates: This is how we control the quantum circuits/qubits. Quantum Gates are juxtaposed together in different ways to achieve different objectives. The sequence of these gates is indispensable to control the circuit. Some of the gates available are shown below.
We can develop different models by arranging quantum gates appropriately, which essentially means, controlling the quantum circuit will help us model solution to any problem. As discussed in theory above, these gates will help us interfere and bring out the best possible solution.
3. Measurement: The final layer is measurement, which outputs the best possible solution.
Now that we have understood how a quantum circuit works.I will dive into few objectives that can be achieved with the aid of a quantum circuit in my next article.
