Quantum Computers: The Computers of the Future?

Figure 1: Image of a Quantum Computer (Source)

Ever since its introduction in 1998 by Isaac Chuang and Neil Gershenfeld, quantum computers have been regarded as the computers of the future. Companies such as Google and IBM have been consistently developing quantum computers for practical use, and in 2019, Google claimed to have achieved quantum supremacy. But, what even are quantum computers and what does Google mean by quantum supremacy?

Quantum computers are machines that harness the machinery of quantum mechanics to compute complex problems. Computers today, known as digital, or classical, computers store information in bits. A bit is the most basic unit in computing, which stores values in values in 0 or 1, which you can think of as true and false. However, quantum computers perform calculations in quantum bits or qubits. Qubits can represent 1 and 0 at the same time. This is thanks to a property known as superposition. This added complexity allows quantum computers to perform a calculation that requires a classical computer numerous in a single run.

Quantum supremacy refers to a task performed more quickly on a quantum computer than on a classical computer. In other words, it refers to the moment quantum computers can complete a mathematical calculation far beyond the abilities of the best supercomputers. In 2019, researchers at Google claimed that their quantum computer performed a calculation in 3 minutes 20 seconds that would take about 10,000 years on the best supercomputers. But in 2021, Chinese researchers debunked Google’s claim by performing the same calculation in around five minutes.

On the other hand, researchers at IBM claim to have achieved something more practical. Jay Gambetta, a vice president of IBM Quantum, describes the rise of “the era of utility.” Researchers at IBM used their quantum computers to simulate the behavior of 127 atom-scale bar magnets at a scale where effects predicted by quantum mechanics occur. This setup is also known as the Ising model. While certain simpler configurations can be solved exactly, and both the classical and quantum algorithms yield the same results under simple circumstances, the scale setup by IBM researchers was too complex for an exact solution. Thus, the two computers led to two different results. Surprisingly, they discovered that quantum computers and classical computers produced different results, and it was the quantum computers that were more accurate. This example could be possible evidence that for complex situations, quantum computers are more accurate.

So, what do these results mean?

Although it will take a few more years, even a decade or two, for quantum computers to become applicable to our lives, these results show promising possibilities for quantum computers. Similarly to how quantum computers accurately predicted the Ising model, they will simulate the behavior of matter at the molecular level. This could help in figuring out the properties of exotic materials, accelerating drug discovery, modeling fusion reactions, and many other applications.

Works Cited

Brooks, Michael. “Quantum Computers: What Are They Good For?” Nature News, 24 May 2023, www.nature.com/articles/d41586-023-01692-9.

Chang, Kenneth. “Quantum Computing Advance Begins New Era, IBM Says.” The New York Times, 14 June 2023, www.nytimes.com/2023/06/14/science/ibm-quantum-computing.html.

Giles, Martin. “Explainer: What Is a Quantum Computer?” MIT Technology Review, 20 Oct. 2021, www.technologyreview.com/2019/01/29/66141/what-is-quantum-computing/.

Holton, William Coffeen. "quantum computer". Encyclopedia Britannica, 19 Jun. 2023, https://www.britannica.com/technology/quantum-computer. Accessed 3 July 2023.