Quantum Computing: Breaking the Limits of Human Technology

Written By: Kesavan Rangarajan

The device you are using right now, whether it is a phone or computer, has thousands of tiny components, which make up everything you see. Arguably the most important part of your device is the CPU. A CPU (Central Processing Unit) is the brain of a device. It contains many smaller and simpler components, the base being a transistor. A transistor is a lever, which allows electrons to flow through them, creating an on-or-off signal. On-or-off signals are the basis of the binary system, a number system where each digit is either 1 or 0, on or off. Over time, transistors have shrunken to be extremely small. Most transistors are around 14 nanometers long. This is 500 times smaller than a red blood cell! However, as transistors shrink to the size of just a few atoms, the electrons transport themselves to the other side of the gate in a process called quantum tunneling. This is where quantum physics comes into play.

Animation of a transistor (Quantum Computers Explained – Limits of Human Technology)

For regular computers, the most simple aspect is a bit, which can be either 0 or 1. However, quantum computers use qubits, which are in any portion of both 0 and 1 at the same time. This is called a superposition and opens many opportunities in computing. However, as soon as this qubit is measured, it has to decide to be either 0 or 1. For example, a group of four regular bits (called a byte) can have 16 possible combinations, but can only be one of them at a time. However, four qubits can be all 16 of those combinations at the same time. This property makes quantum computers far faster and more efficient than regular computers. This processing power increases exponentially as the number of qubits increases.

Animation of a qubit in superposition (Quantum Computers Explained - Limits of Human Technology)

Another interesting thing that qubits do involves entanglement. Quantum entanglement is a process where some quantum particles (qubits in our case) get entangled and become connected with others. When one qubit changes, the other qubits entangled with it react to that change instantaneously, no matter how far apart they are. This property allows scientists to infer properties about other qubits just by measuring their entangled partner.

Not only are quantum computers faster than regular computers, but they also create new algorithms that can solve problems that were previously thought to be impossible. One of the most famous quantum algorithms is Shor’s algorithm, which breaks our current methods of encryption. All data you send online uses public key encryption, which comprises sending others a message encrypted using your public key that they can decode using their own private key. Determining your own public key on a regular computer can take tears, however, future quantum computers can determine your private key in just a few minutes.

This poses a serious threat to cyber security, so in 2016, NIST, the National Institute of Standards and Technology, launched a competition to find quantum-safe encryption methods. 3 of the 4 passing algorithms used lattices, a method where your private key vectors create a certain lattice structure, made by a combination of these vectors. These vectors are used to determine an encryption algorithm based on a point in the lattice. However, your public key vectors, which create the same lattice structure, are more complicated vectors. This makes it exponentially more difficult to decrypt the message, as it takes many more combinations to get to that same point in the lattice. This encryption algorithm becomes more secure when more dimensions are added to the lattice. Quantum computers bring many possibilities to computer science as a whole. However, these possibilities create numerous problems, including cybersecurity concerns. In the next few decades, it is certain there will be several important advancements in computer science, with one of the main contributors being quantum computing; it is a remarkable time to be ambitious and curious towards what these powerful computers can do.

Works Cited

How Quantum Computers Break The Internet... Starting Now, Veritasium, 20 Mar. 2023, https://www.youtube.com/watch?v=-UrdExQW0cs. Accessed 22 Sept. 2023.

“Post-Quantum Cryptography: CSRC.” CSRC, csrc.nist.gov/projects/post-quantum-cryptography. Accessed 22 Sept. 2023.

Quantum Computers Explained – Limits of Human Technology, Kurzgesagt - In a Nutshell, 8 Dec. 2015, https://www.youtube.com/watch?v=JhHMJCUmq28.