In one of our previous articles, we introduced the topic of ‘Quantum Computing in the Landscape of Software Development.’ In response, some readers expressed interest in learning more, particularly about the concept of quantum supremacy. Therefore, this article will explore in detail what quantum supremacy is, why it matters, and how it could potentially reshape the future of computing and industries around the world.

What is Quantum Supremacy?

To understand quantum supremacy, we first need to explore how quantum computers work.

Traditional computers process data in bits, which are binary and can either be a 0 or a 1. These bits form the building blocks for performing calculations and running algorithms.

Quantum computers, however, operate using qubits (quantum bits). Unlike bits, qubits can exist in multiple states at once, thanks to superposition. This means a qubit can be 0, 1, or both simultaneously, exponentially increasing the computational power of quantum machines (see Figure 1).

Furthermore, qubits leverage entanglement, a quantum property that allows qubits to be interdependent regardless of distance. Entanglement enables quantum computers to process information in parallel, solving complex problems much faster than classical computers (see Figure 2).

Quantum supremacy refers to the moment when a quantum computer outperforms the most powerful classical supercomputers in solving a specific problem. It doesn’t mean that quantum computers can solve every problem better than classical computers, but they excel in tasks that involve massive datasets or extremely complex calculations.

In 2019, Google’s quantum computer, Sycamore (see Figure 3), achieved quantum supremacy by solving a mathematical problem in 200 seconds that would have taken the world’s fastest supercomputer approximately 10,000 years. This landmark event confirmed that quantum machines could surpass classical systems in specific scenarios, though the task itself didn’t have immediate practical applications.

Global Efforts in Quantum Computing

While Google’s achievement was a milestone, many other institutions across the world are making significant strides in quantum computing. Countries like India and China are heavily investing in quantum research, recognizing its potential to impact technology and security.

• India launched the National Quantum Mission (NQM) in 2023, with the goal of building quantum computers and fostering quantum research by 2030. Indian institutions like the Indian Institutes of Technology (IITs) and the Tata Institute of Fundamental Research are at the forefront of this initiative, working on quantum communication and cryptography.
• China has made quantum computing a national priority, investing billions in quantum research. Companies like Alibaba and Baidu have developed quantum computing platforms, while Chinese researchers have already made breakthroughs in quantum communication and cryptography. In 2020, a Chinese team led by Jiuzhang claimed to achieve quantum supremacy by solving a problem that classical computers couldn’t handle.
• IBM, Microsoft, and other global tech giants are also actively working to bring quantum computing to mainstream use. IBM’s Qiskit platform offers tools for developers to experiment with quantum algorithms, and they have been steadily advancing the scalability of quantum processors.

Why Quantum Supremacy Matters

Quantum supremacy marks the beginning of a new era in computing. While classical computers excel at many tasks, they struggle with highly complex problems, such as those in drug discovery or climate modelling. Quantum computers could address these challenges, potentially unlocking breakthroughs in medicine, cryptography, and beyond. Google’s demonstration was just the start.

As countries like China and India ramp up efforts and tech giants drive innovation, the race to realize quantum supremacy is accelerating. Though quantum computers are not yet suited for everyday tasks, they promise to revolutionize industries and reshape how we tackle the world’s most complex problems. As governments, corporations, and researchers continue to push the limits, quantum computing stands out as one of the most exciting technological advancements, offering solutions to previously unsolvable challenges.

Challenges Ahead

Despite the progress, several significant challenges remain before quantum computers can be used in practical, everyday applications:

• Error Rates: Quantum computers are highly sensitive to external disturbances, leading to high error rates in calculations. Improving quantum error correction is a major focus for researchers.
• Scalability: Current quantum computers are small, handling only a few qubits at a time. Building large-scale quantum machines is difficult, as managing many qubits simultaneously introduces new challenges in stability and coherence.
• Real-World Use Cases: While we have demonstrated quantum supremacy in controlled scenarios, finding practical problems that quantum computers can solve better than classical ones are still an ongoing challenge.

By Dr. Nandana Kumara – Hamilton