Quantum computers, that work on qubits have infinite possibilities between 0 and 1, unlike traditional computers that work on bits which are either 0 or 1. When they are ready, they will solve complex problems in fields ranging from artificial intelligence, cryptography and molecular biology, which traditional computers never can.
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Quantum computers are here. Both IBM and Google are racing to launch their first commercial quantum computer on cloud. Recently, Google announced that they achieved ‘quantum supremacy’ – which means they made a quantum computer out perform a traditional one. At some point in future, the quantum computers are expected to solve seemingly intractable problems, though not all, that are beyond the realm of the classical computers.
So what are quantum computers ?
To understand quantum computers, we must first understand quantum mechanics, a science or an art depending on whom you ask, that deals with the world inside the atoms, the stuff the universe is made of.
The sub atomic particles, be it photons or electrons behave in a strange manner. Initially, Thomas Young, a British scientist said electrons behave like waves, using the famous double slit experiment with light and called it wave theory of light. But Einstein proved using photo electric effect that electrons or photons also behave as particles. For a long time the scientific world is split between wave theory and particle theory, until a French noble named Louis de Broglie came along and said we can have both. The electrons or photons behave both as waves and as particles.
Strangely, no one has ever looked or will ever be able to look inside an atom to prove conclusively either way. What baffled scientists is that every time they try to look at waves they collapsed and appeared as particles.
With no way to look inside, Physicists relied on a mathematical function called Wave Function to estimate the probability of finding an electron inside an atom. Till today this is the most used theoretical technique to describe what goes on inside the atomic world.
With wave function and a few more mathematical models at hand, physicists tried to understand the behavior of particles. The findings are so completely against our real world formed using Newtonian mechanics that it is unnerving to know them. We can predict accurately what happens in the real world with force, mass and acceleration. But the sub-atomic world is completely different. It is strange to think that the atoms that form our universe and us are made of particles that behave so bizarrely inside.
Anyway, researches made a discovery that particles at sub-atomic level or in a state of ‘superposition’ – means the particles are in different states at the same time. Out of this discovery, the quantum computing was born.
Traditional computers work on bits – which are always in the state of 0 or 1. This means they are always approaching a problem ‘logically’ and hence not fit to take on problems of ‘uncertainty’.
Quantum computers work on what they call as qubits – which are in the state of 0 and 1 at the same time or somewhere on a spectrum between the two. It is like spinning a coin – until you measure it, the coin can land on heads or tails. A qubit allows for uncertainty and hence so much more powerful.
Qubits have another interesting property called ‘entanglement’ – which means magically, one particle determines the outcome of another particle, without even being physically close to it.
Quantum computers are still not ready for prime time and most likely will never be in our laptops or smartphones. But when they are ready, quantum computers will solve problems that traditional computers can only dream of in the fields ranging from artificial intelligence, cryptography, molecular biology to name a few.
You can play with quantum computers here on IBM website.