Quantum Computer: The New Era of Simulation
“If you want to make a simulation of nature, you
better make it quantum mechanical.”
Richard Phillips Feynman (1918–1988)
Suppose you’ve designed a coin flip game in your computer. The rules are these: at starting the coin will be showing tail. The computer will choose to flip first that means It can choose to flip or not. Next you can do the same. Next the computer. But either of you won’t reveal your answers to each other. Then at the end if it is tail the computer wins and if it’s a head you win. You can see that there is 50% chance of either of you winning. If you design this with your computer you will find the result around 50% give or take. But what if you could design the same game with a quantum computer? Well then you will find that the computer is winning more than 95% time. To take the joy of yours, winning in 5% of the game you should know that you are winning because of the operational errors.
So what’s the secret here? Why are you losing almost every time? Well that’s because the computer is not letting you win. How so? To dig deeper into that we need to know how quantum computer processes data. Normal computer works with Bits which can be either 0 or 1. But quantum computer works with Qubits or Quantum Bits. Qubits can stay at 0 and 1 state at the same time. This allows quantum computer to process multiple computations simultaneously. This simultaneous state of both 0 and 1 is called superposition. With the help of superposition quantum computer can store vast amount of data. Qubits can be made of electrons, molecules etc. that shows quantum behavior. Another important property of quantum computing is Entanglement. Entanglement is the process by which all Qubits are linked with each other. That means state of one Qubit influences the state of every other Qubits. So entanglement and superposition helps to store all the possible solutions at once.
If we try to model real world quantum systems with our normal computers we will get poor approximations. But with the help of quantum computer we can model those systems. That’s because electrons themselves are in superposition. While orbiting around the atoms electron stays in multiple states at once. Normal super computers can’t work with that much possibilities at a time. Mathematically speaking quantum computer is good at things with a vast amount of possibilities. For example the longest distance between two places. The problem sounds easy. But think about infinite possibilities. How many routes you can take! Doesn’t sound that easy now right?
Quantum computer returns answers as probabilities. With each attempt we will get different but more accurate results. Which is worth it because it is still less time consuming than normal super computers. Quantum codes are designed in that way so that they cancel out wrong answers and amplify correct answers.
Building the environment of a quantum computer is not that easy. That is because to work with the Qubits it has to be kept in a radiation-free state with temperature slightly above absolute zero. Any small disturbance of that environment will pull out the Qubits from its superposition state. This the biggest challenge scientists have to face to build a quantum computer.
Quantum computer can be used to solve modelling complex molecules. The input is number of particles in the input state where output is the state after a certain time period. There is an infinite possibility of things that can happen in between. IBM’s quantum computer successfully calculated the ground state energy of Hydrogen, Lithium Hydride and Beryllium Hydride molecules. Another important use of quantum computing is breaking encryption. Quantum computer with the help of Shore’s algorithm what quantum computer can do within some hours, it will take a billions of years for a normal computer to take a large number and determine what its prime factors are. From AI to weather system quantum computer can be used in so many things.
While this type of quantum computer isn’t built just yet there are some promising researches. IBM and Google like companies are investing on it. Today’s quantum computers looks like those old age big mechanical computers with big helium based cooling systems. But surely it will get smaller in size. Perhaps we will see smaller sized working quantum computers within a decades. IBM announced a brand new quantum computer along with a new quantum computing center in New York. The new quantum computer comes with more than twice as many Qubits (53 total) than its previous quantum computer (20 qubits) and supposedly with exponentially higher performance, since the performance of quantum computers grows exponentially with the number of Qubits. Quantum computing it will change many things around us.
References:
[1] https://www.sciencemag.org/news/2017/09/quantum-computer-simulates-largest-molecule- yet-sparking-hope-future-drug-discoveries
[2] https://www.tomshardware.com/news/ibm-quantum-computer-computing-53qubit,40430.html
[3] “New Thinking: From Einstein to Artificial Intelligence, the Science and Technology that Transformed Our World”, Dagogo Altraide, Chapter 14, First Edition, Mango Publishing Group
