Quantum physics one of the most successful theories of modern science describes the way our world works at the most fundamental level. Quantum computing has become one of the leading applications of quantum physics.
Quantum computers have the potential to solve some of the world’s most complex problems that are beyond the reach of even today’s most powerful supercomputers.
Real-world quantum systems cannot be modeled on a classical computer without making poor approximations. Modeling a simple compound i.e. Calcium monofluoride (CaF) makes our best supercomputers completely useless.
Quantum computers are not going to replace classical computers but their radically different way of operating enables them to perform calculations that classical computing cannot. Let’s see how they differ.
Classical computers encode information in bits and each bit can represent a 0 or a 1. These 0s and 1s act as on-off switches that ultimately translate into computing functions.
To perform a simple calculation like solving a maze, a classical computer would test each possible route one at a time to find the correct one. Just as classical computers have bits, quantum computers have qubits. Qubits however make use of two key principles of quantum physics,
- Superposition
- Entanglement
Superposition means that each qubit can represent a 0, a 1, or both at the same time. And entanglement happens when two qubits in a superposition are correlated with one another, meaning the state of 1 whether it’s a 0 or a 1 or both depends on the state of another.
Using these two principles qubits can act as a more sophisticated version of switches helping quantum computers solving difficult problems that are virtually impossible using classical computers.
To illustrate how this makes quantum computers more powerful, let’s look at some numbers. Take a classical 2n bit computer with n representing the number of bits. It can represent and examine only one system state at a time, a 2n qubit computer however would have the power to represent 2 to the power of n system states and perform parallel operations on all those states at once. This means that every time you add just one more qubit to a quantum computer the number of states that can represent and examine doubles.
So, a 50-qubit quantum machine could examine 250 = 1,12,58,99,90,68,42,624 states at once, this exponential increase in power together with the entanglement of qubits is what allows quantum computers to solve certain problems so much more efficiently.
300 qubits could hold more numbers simultaneously that there are atoms in the universe.
While a classical computer solves a problem like a maze by testing each possible route one at a time. A quantum computer uses its entangled quantum states to find the correct route quicker with far fewer calculations.
Think of it this way, technologies that currently run on classical computers can expertly find patterns and insights buried in vast amounts of existing data but quantum computers will deliver solutions where patterns cannot be seen because sufficient data doesn’t exist or the possibilities for discovering an optimal answer are too enormous to ever be processed by a classical computer.
To be in their quantum state qubits must be free from all radiations and kept at a temperature just above that of absolute zero (0 Kelvin or −273.15° Celsius), this voids the entire advantage of the machine. Right now, we can only achieve a quantum superposition for a tiny fraction of a second.
Quantum computers could lead to the discovery of new medicines and materials by helping us untangle the complexities of molecular and chemical interactions. They could help the financial services industry make better investments by finding new ways to model financial data and isolate key global risk factors. They could even transform the supply chain and logistics by finding the optimal routes across global systems like optimizing fleet operations for deliveries during the holiday season.
The manipulation of quantum nature through code is known as a quantum algorithm. Mathematicians and scientists around the world are on a race to build these algorithms for when capable quantum computers arrive.
Quantum computing won’t replace our everyday computers and smartphones but its ability to solve complex problems will open up a new universe of information, transforming our view of the world and the way we navigate it.