Chapter 1: The Quest for Quantum Supremacy

The journey toward realizing quantum computing has long been filled with skepticism. This technology involves intricate manipulation of ions and photons and often requires extreme cooling near absolute zero. However, just three days ago, a machine located in a provincial area of an ambitious and newly empowered China demonstrated quantum supremacy for the second time in human history.

Quantum supremacy signifies the ability of a quantum computer to perform tasks that are infeasible for classical computers. The first demonstration occurred in 2019 when Google's Sycamore processor accomplished a calculation in just over three minutes, a task that would have taken a classical computer approximately 10,000 years to complete. Following this, IBM contested Google's claim, arguing that their supercomputers could have achieved the same result in just three days. Yet, as of now, no one has challenged China's latest assertion of quantum supremacy, which boasts even more impressive results.

The Chinese quantum computing system, known as Jiuzhang, completed a computation in 200 seconds that would supposedly take one of the world's most powerful supercomputers—China's Sunway TaihuLight—an astounding 2 billion years to solve. This gives Jiuzhang a quantum advantage of 10¹?. The findings were made public on December 3rd.

Given this estimation, it is reasonable to conclude that no classical computer could replicate Jiuzhang's performance on that remarkable autumn day. While Google's quantum circuits utilized extremely cold superconducting loops, the Chinese team's system operated with photons—light packets that transmitted quantum data through optical circuits, with their paths manipulated by mirrors. Ultimately, the photon was detected, and this data played a role in the final computation. This process is akin to reading one of Google's 53 qubits (quantum bits), where the qubits in this scenario were photons. A significant advantage of using photons is that they can operate at room temperature, as opposed to the near absolute zero required by superconducting circuits.

Jiuzhang addressed the boson-sampling problem—a task that, while serving as a tool for achieving quantum advantage, may eventually find practical applications in machine learning and quantum chemistry. However, unlike Google's Sycamore, Jiuzhang was specifically designed for this calculation and is currently non-programmable, limiting its immediate practical uses. If programmability is achieved in the future, Jiuzhang could simulate molecular structures and potentially revolutionize various major industries, which is the overarching ambition of quantum computing.

Despite these advancements, it may take time before Jiuzhang, or any quantum computer, demonstrates practical or commercial applications. To realize their full potential, quantum machines must surpass the current limitations of qubit numbers, which are typically in the double digits. Hundreds, if not millions, of qubits will be necessary for these systems to become truly transformative.

As I elaborated in a recent article, there exists a competitive race between China and the US to lead in the advancement of this groundbreaking technology. Both nations harbor security concerns, as the immense processing power of quantum computers poses a risk to current internet encryption, making crucial financial and governmental communications vulnerable to cyber threats. While the US has historically led in quantum computing innovations, China has allocated $10 billion to position itself as the global hub for quantum research. With its goal of achieving supremacy by 2020, China is actively making strides to compete against the EU and the US.

Regardless of which nation achieves advanced quantum computing first, experts agree that the advancements will be beneficial for humanity as a whole. Those who have been skeptical of this new wave of computing technology are now faced with the remarkable achievements of two quantum processors—each located in vastly different parts of the world—both striving to revolutionize the field.

Chapter 2: The Implications of Quantum Supremacy

To gain a deeper understanding of the implications of this groundbreaking achievement, let's explore the following video: