Quantum Computers

Aug 5

Written By Sidhya Peddinti- CuriouSTEM Staff

Classical Computers

We all use computers in our daily lives. These computers are called classical computers. They use memory chips to store data in binary states - 0s and 1s called bits. Everything you see and use on your computer from emails, Tweets, songs, and Youtube videos are long strings of these binary bits. This means that the classical computers we use today assume that the state of any particle is only binary (Either on/off).

Quantum Physics

Quantum computers are made on the basis of quantum physics, which allows for particles to be in two different states at the same time! The famous Schrodinger’s cat theory explains quantum physics in a simple way- If you place a cat in a box with radioactive material that could potentially harm the cat, you wouldn’t know if the cat is alive or dead until you open the box. This means that the cat is both alive and dead until the box is opened and its state is observed. Similarly, particles can exist in the superposition of states and collapse down to a single state (binary) when they interact with other particles. Based on the theory of quantum physics, quantum computers are built.

Structure of Quantum Computers

Unlike classical computers, the memory of quantum computers is made up of qubits. These computers can be made from any particle that can hold two states at the same time. Built with thousands of such qubits, in theory, quantum computers can deliver huge leaps of processing power that can easily exceed today’s classical computers and even supercomputers. All of this is possible because of the quantum features of qubits. These features are Superposition and Entanglement. A superposition state is when a qubit can hold either 1 or 0, or a superposition of both 1 and 0 (Meaning that it is 1 and 0 at the same time). An entanglement state is when two qubits can coexist in pairs in an entanglement in such a way that changing one pair would automatically change the other, even if they are separated by very long distance. This phenomenon was referred to as “Spooky action at a distance” by famous scientist Albert Einstein. Because of these two properties, qubits add up to provide exponential power for number crunching and processing powers in quantum computers. Unfortunately, with great power comes great error rates. The quantum state of qubits are extremely fragile. They can easily get disrupted from their entangled or superposition states with minute changes in temperature or vibrations in its environment. This will cause the qubits to lose their quantum state and become decoherent. Decoherence ultimately results in a loss of qubits before completing the job at hand. Researchers try to avoid this decoherence by protecting qubits from contact with the outside world by using super cooled fridges and vacuum chambers.

Quantum Supremacy

The concept of quantum computers exceeding the compute capacity of classical or supercomputers is called quantum supremacy. Scientists have been researching the power of supercomputers for 30 years. But, can this power be used for something that is useful and worthy? Google led an experiment called “Quantum Supremacy” with a quantum computer called “Sycamore” that had 54 qubits. In this experiment, they proved that Sycamore performed target calculations in 200 milliseconds. Google predicted that the world’s fastest supercomputer would take 10,000 years to complete the same computation!

Quantum Computer Applications

One of the most promising applications of quantum computers is understanding the atom at a molecular level. Auto manufacturers are working with quantum computers to understand the chemical composition of electrical vehicle batteries so they can exponentially improve performance. Pharmaceutical companies are using quantum computers to compare chemical compounds in order to create new drugs. Quantum computers are also being researched in machines to work on optimization problems, for their ability to crunch numbers extremely fast. For example, Airbus, the world’s largest airline manufacturer, is using quantum computers to find out the most fuel efficient ascent and descent paths for aircrafts. Volkswagen released a service for buses and taxis to find the best route in cities to minimize traffic congestion. Researchers are also using these computers to improve artificial intelligence capabilities. A world where quantum computers are used in full capacity across many industries may be many years in the future, but when it happens, it will transform the whole world around us and turbocharge global innovation to a newer level!