Quantum Mechanics at 100: A Revolution Still in Progress

In 2025, the world marks a historic milestone: 100 years since the formal birth of quantum mechanics—a field that has fundamentally redefined our understanding of the universe. Recognized by the United Nations as the International Year of Quantum Science and Technology, this centennial celebrates a scientific revolution that is still very much in progress.

Much like evolution transformed biology, quantum theory reshaped physics. What began with early explorations of how energy is absorbed or emitted in quantized packets evolved into a complete framework explaining the behavior of matter and energy at the smallest scales. The word quantum, from the Latin quantus (“how much”), entered scientific language thanks to the groundbreaking work by Max Planck and Albert Einstein in the early 20th century. Their ideas paved the way for the full development of quantum physics in 1925.

That same year, while battling hay fever on the island of Heligoland, Werner Heisenberg penned a revolutionary paper that reframed classical notions of force and motion. His work was soon complemented by Erwin Schrödinger’s wave mechanics, offering an alternative formulation that introduced the now-iconic Schrödinger’s cat paradox, a thought experiment still used to explain the weirdness of quantum physics today.

Beyond Classical Thinking

Rather than discarding classical physics, quantum mechanics revealed that the behavior of subatomic particles defies everyday intuition. Particles no longer follow precise trajectories; instead, they exist in states of probability until measured. This strange behavior lies at the heart of the measurement problem, a puzzle that scientists still grapple with.

Yet quantum theory has become indispensable. It explains how atoms bond, how electromagnetic radiation behaves, and even how stars burn and die. From the structure of matter to the nature of electromagnetism, quantum mechanics is embedded in everything from the design of electromagnets to the function of sensing instruments.

Quantum Technologies in Everyday Life

Far from being abstract, quantum technologies are transforming modern life. The principles of quantum theory power the transistors in every digital device, enable ultra-precise clocks, and drive innovations in quantum computing and secure communication. These technologies are no longer limited to research labs—they’re shaping the future of medicine, defense and data security.

A Global Celebration of Quantum Science

To honor a century of discovery, 2025 will see a host of international events. The celebrations begin at UNESCO headquarters in Paris, followed by special sessions at the American Physical Society’s annual meeting in California. A symbolic return to Heligoland will also take place in June, where physicists will reflect on Heisenberg’s legacy.

In Ghana, whose proposal led to the UN designation, a major conference is scheduled in Kumasi. Meanwhile, Brazil will host a gathering of science historians in Salvador de Bahia to explore the global impact and lesser-known contributors to quantum physics.

Among those voices are overlooked scientists like Lucy Mensing, a collaborator of Heisenberg, who made early contributions to particles and fields but was largely unrecognized. Her story, along with others, will be featured in the new publication Women in the History of Quantum Physics.

The Road Ahead: Quantum’s Unfinished Business

Despite its monumental successes, quantum mechanics remains incomplete. It has helped unify many aspects of physics, leading to the standard model of particles and fields and the landmark discovery of the Higgs boson in 2012. However, the mysteries of dark matter and quantum gravity—the attempt to reconcile gravity with quantum laws, remain unsolved.

As research advances, new questions continue to emerge. What truly happens during measurement? Can we build fault-tolerant quantum computers? How can we harness quantum behavior to develop next-generation sensing instruments?

Looking to the Future

As we celebrate 100 years of quantum science, we are not merely looking back—we’re inviting new minds into the fold. The next breakthroughs in quantum physics may come from unexpected places, and today’s students and innovators will carry the torch forward.
In honoring this centennial, we celebrate not only a theory, but a living, evolving quest to understand the nature of reality itself, one quantized packet at a time.