What makes a quantum computer so unique?

 Google released it's first quantum computer in 2018 and opened new dimensions in the field of computing. This computer is much faster than the best supercomputers available to date. This quantum computer was named Bristlecone. It could perform calculations and simulations that could take our supercomputers years in just a few hours. So, what gives this supercomputer such incredible computing strength? What makes it different from classical computers? Let's dig into it!

Here are some advantages that a quantum computer has over a classical computer:

• Very high processing speed.
• Efficient parallel processing capabilities.
• Can process a large amount of data.
• They can perform intensive simulations more quickly.
• Less power consumption due to the use of quantum tunneling.
• Accelerated machine learning.

Now, the name, Quantum Computer itself implies that the computer might be working on some principles of quantum mechanics. And it sure is. But, to understand this clearly, we first need to understand how a classical computer works. You must have heard that your PC works on ones and zeroes. These are called bits. A bit is basically the presence of electric current. If there is an electric current flowing in the device, it is represented as 1 and no current is represented as 0. Classical computers work by manipulating these ones and zeroes. Each part of information is divided into bits. These bits are then processed and decoded whenever you need them. A typical computer processor has millions of tiny nanoscale transistors on it to process all the information. So, when you ask your computer to open an image, the information about the image that is stored in the form of bits is decoded by the processor, and then it is displayed to you. 

Now back to the quantum computer. This computer has quantum bits, called 'qubits'. These qubits are basically electrons. Now, you might be knowing that electrons have spins, positive and negative. So here, the positive spin is the 1 in a classic computer and the negative spin is the 0. Now, this is where things act differently. Electrons are sub-atomic particles and they obey the laws of quantum mechanics. So, they can exist in more than multiple states of spin at the same time by the law of superposition. So, the qubits can have values 1 and 0 but along with that, they can assume any value between 1 and 0. This is what allows the quantum computer such high processing power. The number of qubits on such a processor is less than 100, compared to the millions of transistors on the classical computer, but they are not restricted to just two values. So, at a given time, a qubit can be in any state of superposition between 1 and 0. 

But to preserve this state of electrons, they should be cooled down to very low temperatures, as low as 4 Kelvin. So, liquid helium is used to cool them. Clearly, these computers can only be used for research work since we cannot use them for daily operations due to their requirements. Let's hope that sometime in the future, these problems would be solved!!

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