The New Era of Computing: From Transistors to Qubits
Day 9 — Quantum30 challenge
For the past few days, we discussed topics like superposition, entanglement, etc. Now it is time to apply these and enter a new sub-branch of quantum physics.
The journey of computing has been nothing short of remarkable. From room-sized machines to handheld devices, the transformation in size and capability has been awe-inspiring. While classical computers powered by transistors have propelled us thus far, the march toward miniaturization is inevitably facing quantum limits. This article explores the basics of classical computers, their limitations, and the emergence of quantum computing as a potential solution.
Classical Computers: A Foundation Built on Transistors
Classical computers are the backbone of modern technology, constructed from transistors, the elemental building blocks. These transistors act as binary switches, enabling the representation of information in the form of 0s and 1s. These switches are organized into logic gates, which in turn are combined into modules, eventually forming integrated chips (ICs) that power our devices.
Currently, the size of the transistors is in the order of nanometers, and according to a law called ‘Moore’s law’ — the number of transistors in an IC doubles every two years — the size of transistors is also getting smaller. But how far will this continue? Can we make the transistor size equal or closer to the size of the electrons?
The answer is NO. Because so far in our series, we know that when you go down to that size, weird phenomena are inevitably going to occur. And that’s exactly what happens. That weird phenomenon is called ‘Quantum Tunneling’ and just to keep things short, it means that electrons can cross through the energy barriers (transistors in this case) that should originally be confining them. This can lead to information loss. rendering ultra-small transistors unreliable. The idea of making transistors as small as electrons is alluring, but the fundamental limits imposed by quantum physics necessitate a different path.
So as we are already thinking of the quantum scale, why not think of using the quantum properties to our advantage? Here is where Quantum Computing enters.
Quantum Computing: Leverage of Quantum Properties
In classical computers, we use bits for communication which can have only two values 0 or 1. Quantum computers, on the other hand, use quantum bit—qubit for short, which is the superposition of 0 and 1. This superposition enables parallel computation, enhancing computational capabilities. A key feature of quantum operations is their non-destructive nature — measuring qubits during computation would collapse their superposition, rendering the computation meaningless.
Quantum Parallelism
Imagine the power of simultaneously exploring multiple paths in a computation. Quantum computing’s quantum parallelism achieves precisely that.
If a computer has 3 bits, the 8 possible combinations of 0s and 1s are possible (000,001,010,….111), and out of these, it can only use one combination for the computation of a specific task. But if it has 3 qubits, it can use all 8 combinations simultaneously. This potential for exponential speedup becomes a game-changer for certain complex problems, where classical computers struggle. Also, remember, the input and output for quantum computers before measuring is in superposition states. It collapses when we measure the output.
Quantum Algorithms
Now we are done with the computation, and have also measured the result, how do we know whether it is right or not? For that, we use quantum algorithms. We would be discussing these more in the near future, but for now, Quantum algorithms are a set of procedures that are used to solve certain problems in quantum computers. While simple arithmetic tasks like addition and multiplication remain the stronghold of classical computers and not their quantum counterpart (quanterpart..lol!), quantum algorithms shine in intricate problems.
Challenges in Quantum Computing Adoption
One of the main hurdles in quantum computing is the maintenance of the quantum states. In order to avoid disruptions in qubits, caused due to the environment and temperature fluctuations, quantum computers need to be kept isolated and maintained at extremely low temperatures of almost absolute zero temperatures or even lower, making their practical implementation complex and expensive.
Conclusion
Quantum computing emerges as a beacon of hope for tackling complex problems that classical computers struggle with. Despite being in a developmental state, they have found their utility in various fields like cryptography, security, quantum simulations, etc.