I attended a Quantum Computing seminar at IIST Trivandrum recently and I would like to share what I have learnt there with you.
These are points from Prof. Apoorva Patel’s talk on Quantum Computation in simple words.
Quantum Computer: A comp whose elementary hardware components work according to the laws of Quantum Mechanics.
Bear in mind that the classical digital computers we use work according to the laws of electronic circuits.
We still don’t know when and what a quantum computer will be used for.
In a classical computer design, quantum effects are considered as undesirable nuisance.
A starking feature of quantum mechanics is that it demonstrates that complex numbers (a+ib etc) are physical and observable.
Basically quantum mechanics is a theory of waves.
Waves are used widely in communication and not in computation.
I understood a part of the lecture well due to the subject ‘digital communication’ which I’m currently having in my curriculum.
The i/p and o/p states of a quantum computer are always mapped to classical states through a suitable choice of basis vectors.
There are several problems that are not computable clasically(using classical mechanics laws)
Eg: halting problem, finding prime factors(classical cryptography), database search, travelling salesman problem etc.
According to Godel’s theorem, if we go outside the framework of classical information, we might be able to solve the classical problem. (replace classical info with quantum info)
Quantum Information: Info whose physical representation behaves according to the laws of quantum mechanics.
The simplest quantum system has 2 basis states called as qubits(quantum binary digit).
The difference between a qubit and a normal binary bit is that a qubit can exist in a superposition of basis states but a classical bit can exist in only one of the two states.