Quantum computing has, for a long time, been a seemingly complex topic only meant for discussion by engineers and physicists. To the average person, the terms ‘superposition,’ ‘qubits,’ and ‘entanglement’ may seem alien and might invoke visions of lengthy, complex equations. However, the essence of quantum computing can be summarized with simple yet powerful information. Computing is nothing more than the utilization of the unique characteristics of small particles to perform advanced information processing tasks.
Why Classical Computers Have Limits
Classical computers show limits in their capabilities when dealing with high-level complexities. Take, for example, the task of searching through every possible configuration of a set of molecules in order to identify a possible candidate for a new therapeutic agent. From a computational standpoint, the levels of arrangements are astronomical, and no supercomputer could computationally assess all of the possibilities in a finite unit of time. Additionally, classical computers struggle with a number of optimization problems, such as the vehicle routing problem, where the goal is to determine the most efficient route for a fleet of delivery vehicles, or the problem of recognizing trends in very large datasets. While these challenges do not fundamentally suggest that classical computers are weak, they do point to the fact that some challenges must be dealt with using a different approach.
The Main Distinction of Qubits and Why It Matters
The single most important distinction concerning classical computers as compared to quantum computers is how each of the two technologies encodes information. The former class of computers stores information using binary bits, whereas quantum computers use qubits as their data units. Each qubit is a very small physical system that can take the form of 0, 1, or some combination of the two. The combination is what is known as superposition. A good analogy to explain this is to think of a spinning coin in which neither heads nor tails is showing. Rather, as the coin spins, it is in a state that is simultaneously heads and tails, and only when the coin is stopped does it land in a definitive showing of one or the other. A qubit has the capacity to hold all of the possibilities for a single question.
Because a qubit can evaluate multiple possibilities at once, quantum computers can avoid the slowdown associated with checking one possibility at a time, unlike classical computers. The computational power of quantum systems increases rapidly as more qubits are added to the system, as the number of combinations increases massively with each added qubit. While exciting with added qubits, it is the unprecedented capacity for parallel exploration of combinations, rather than speed, that sets quantum computers apart.
Understanding Superposition Without Equations
To illustrate the idea of superposition, consider the following example, which doesn’t require a background in physics. Imagine a classical computer trying to guess a three-digit numerical password. It will try one number at a time, and if the password is a number between 000 and 999, it will take a while. Now, suppose a quantum computer is trying to guess the same password. It can superpose all the combinations and can consider 000, 001, 002,… all the way to 999 simultaneously.
The fact that quantum computers take a certain amount of time to solve issues does not imply that they have answers to all questions immediately. They still have to use a carefully chosen algorithm that directs them on how to use superposition. The essential takeaway here is that superposition gives quantum computers the ability to tackle more complex problems more quickly by defining far more possibilities than even classical computers with the use of just a few qubits.
Entanglement and Why It Matters for Quantum Power
Entanglement is the other main pillar of quantum computing. Entanglement occurs when qubits become part of the same quantum state. Altering the state of one qubit will cause the state of the other qubit to change instantaneously, even if they are not situated in the same place. It can truly look like magic, and physicists have repeatedly tested this quantum phenomenon to confirm that it is real.
If you would like to imagine entanglement, think of two dice that, regardless of who is throwing them or where they are being thrown, will always land on the same number. While one die shows a three, the other die will instantly change to three. This synchronized behavior is what allows quantum computers to streamline and unify their calculations, and, unfortunately, this is what classical computers struggle with when they are computationally intensive.
What Can Quantum Computers Do?
Many people think quantum computers will completely replace classical computers, but that is not true. Classical computers are great at doing everyday tasks, like browsing the web or editing a document. That is something quantum computers will never do. They only perform well at a narrow range of very complex tasks that require pattern recognition.
One of these tasks is in the field of chemistry. Because molecules behave according to quantum rules, classical computers are poor at simulating them. Quantum computers, however, can simulate molecules perfectly. This can greatly help in chemistry-related tasks, like drug development, improving materials, or discovering new technologies that are more efficient and cleaner.
Optimization is another such task. Businesses and corporations frequently need to determine the most efficient route, schedule, or arrangement. Classical computers are limited to trial-and-error approximations, but quantum computers will achieve the ability to determine efficient answers and probably do it promptly.
And, of course, there is always cryptography. Most of the systems that are used to encrypt sensitive information are based on complex mathematics that can take classical computers hundreds of years to solve. Quantum computers, however, are likely to break such systems. Luckily, there are new and more sophisticated methods of cryptography being developed that are believed to remain unbreakable even in a quantum world.
All the above things can be done by quantum computers. Combining machine learning and quantum computing is becoming more common. Using quantum processors, detecting more efficient patterns within datasets could enhance forecasting, improve recommendations tailored to the user, and result in more valuable scientific discoveries.
What Makes Quantum Computers So Hard to Build?
Because quantum computers seem advantageous, it could be assumed that they are widely available. They are not, and the reason is that they are highly complex. The technology relies on qubits, which are weak. They are easily influenced and go off balance due to disturbances in the surrounding environment. System breakdown can occur from simple vibrations or minuscule shifts in temperature.
To keep qubits safe, quantum devices are usually kept in extreme conditions near absolute zero. However, even with these severe conditions, mistakes often occur. Scientists are trying to develop methods to control these errors in a way that is more efficient and reduces the number of qubits needing extreme conditions. This is one of the reasons for the large disparity between the number of qubits currently available within a quantum device and the number of functional qubits.
That leads to developing the technology on a larger scale. Currently, only a small number of qubits can perform interesting and useful calculations. However, practical calculations require hundreds and potentially thousands of stable qubits. This is where the most work is needed. Each year, there seem to be more and more advances in stability, structure, and materials for the qubits.
Investments into the research of quantum computers made by various firms, universities, and state institutions continue to be made, even while the technology remains quite underdeveloped. Researchers continue to work consistently, predicting that more functional quantum devices will proliferate within the next ten years.
The Future of Quantum Computing and What It Means for You
Quantum computers are not purely theoretical; they will permeate the everyday lives of people, even those who do not use the devices. New medications can be developed thanks to the advancements in chemistry that will be made. Cheaper, more efficient transport will be possible due to advancements in other optimizations. New models of the climate, for instance, will be able to make more precise predictions, and the improvement of the other sciences will work to improve material sciences to create stronger, lighter things. Finally, machine learning will be able to work more efficiently.
As a long-term tool of technology, quantum computers will not be able to address every concern. It will be integrated with other classical systems developed and designed to perform more mundane and repetitive tasks. In the world of the future, quantum computers will be used alongside hybrid systems of classical computers.
