# Quantum leap in computer science

Quantum computers work differently from the classical computers we work on today. Exploiting the principles of quantum mechanics, they can easily tackle computational problems that may be tough for the classical computer as the size of the numbers and number of inputs involved grows bigger.

**Classical computers** contain computer chips which contain transistors. A transistor is the simplest form of a data processor that can open or close the way for information bits, which can be set to a series of 0s or 1s in a specific sequence that is used to represent data.

**Quantum computers** differ from classical computers in that improvement for the latter mainly relies on advancement in the materials that make up transistors and microchips; Quantum computers do not use transistors (or classical bits). Instead, they use qubits. Qubits are the basic units for processing information in a quantum computer, they can be any value from 0 to 1, or have properties of both of these values simultaneously; this representation is called “**superpositioning**”.

Any interference from its environment will immediately force it to collapse out of its superposition, this phenomenon is called **decoherence**. e*xample: In the coin analogy, the decoherence would be a hand smacking the coin down to read either heads or tails.*

Superpositioning is what gives quantum computers speed and parallelism, as each qubit can represent a quantitative solution to a problem. Further, qubits can be connected with other qubits in a process called **entanglement**; each entangled qubit adds two more dimensions to the system.

When qubits are entangled, makes a quantum computer more powerful than a classical computer. With the information stored in superposition, the problems can be solved exponentially faster. i.e. a machine with less than a 100 qubits can solve problems with a lot of data that are even theoretically beyond the capabilities of the today’s most powerful supercomputers.

Now we are talking about **Quantum supremacy,** which refers to quantum computers being able to solve a problem that a classical computer cannot. Very recently, Google used a 53-qubit processor to generate a sequence of millions of numbers. Though these numbers appeared randomly generated, they conform to an algorithm generated by Google. A classical supercomputer checked some of these values and they were correct. Google’s quantum computer, named Sycamore, claimed ‘supremacy’ because it reportedly did the task in 200 seconds that would have apparently taken a supercomputer 10,000 years to complete.

From now on, Quantum computing will be in news from different strong players who are going to challenge the current day computing, we may still be years away from having quantum computers that are useful for practical tasks, but Google’s findings could finally have provided proof that such a future is possible in the first place.