Quantum mechanics was once one of the strangest and most debated ideas in science. A century ago, even some of the greatest physicists struggled with its meaning. Today, the same theory has become the foundation for many of the technologies shaping modern life.
From lasers and microchips to secure communication systems, advanced imaging, gravitational wave detection, and quantum computers, quantum mechanics has moved from abstract theory to practical innovation.
In a new perspective article published in Science, Dr. Marlan Scully of Texas A&M University and William G. Unruh reflect on 100 years of quantum mechanics and how the field continues to open new paths in physics, engineering, medicine, and technology. The article describes how quantum mechanics has evolved from a theory used to explain particles and fields into a foundation for modern and emerging technologies.
From Strange Theory to Modern Technology
Quantum mechanics began as a way to explain the behaviour of matter and energy at very small scales. It challenged older ideas about how the universe works, especially because particles could appear to behave like both waves and objects, exist in multiple possible states, and become connected in ways that defied everyday experience.
One of the most famous examples of quantum strangeness is Schrรถdingerโs cat, a thought experiment introduced in 1935 to show how unusual quantum theory appeared. The idea suggested that, under certain quantum rules, a cat could be considered both alive and dead until observed.
What once seemed like a philosophical puzzle has now become a practical scientific tool. Concepts such as quantum superposition, coherence, and entanglement are now central to technologies such as quantum computing, quantum cryptography, and extremely sensitive measurement systems.
How Quantum Ideas Power Everyday Life
Quantum mechanics is behind many technologies people use or benefit from daily. Lasers, which depend on quantum principles, are used in barcode scanners, eye surgery, fibre-optic communication, manufacturing, and scientific instruments.
Modern electronics also rely on quantum physics. Microchips, semiconductors, and many digital devices are possible because scientists understand how electrons behave in materials at the quantum level.
Quantum principles are also improving secure communication. Quantum cryptography uses the behaviour of particles to help create highly secure methods of transmitting information.
In astronomy, quantum techniques support instruments such as gravitational wave detectors. These detectors use advanced light-based methods to observe tiny ripples in spacetime caused by massive cosmic events.
Quantum Mechanics in Medicine and Energy
Quantum-based tools are also becoming important in medicine and biology. Imaging and spectroscopy techniques allow researchers to study molecules, viruses, and biological structures at very small scales.
Scullyโs work in coherent nanoscale laser spectroscopy has helped advance methods for examining molecules with high precision. Such tools can improve understanding of biological processes and support future medical breakthroughs.
Quantum mechanics is also inspiring new ideas in energy. One example is the study of quantum heat engines, which use quantum effects to challenge traditional limits in thermodynamics. These systems could eventually influence the development of new energy technologies.
Big Questions Still Remain
Despite its success, quantum mechanics still raises major questions. Scientists are still trying to understand how quantum theory connects with gravity, how quantum computers may transform medicine and materials science, and what future quantum technologies may reveal about the universe.
The field also continues to influence research into turbulence, superfluid helium, quantum gravity, and the deep structure of reality.
A century after it first unsettled physicists, quantum mechanics remains one of the most powerful and surprising theories in science. What began as a strange explanation of tiny particles has become a driver of modern technologyโand its greatest breakthroughs may still be ahead.
Journal Reference:
Scully, M. O., & Unruh, W. G. (2025). One hundred years of quantum mechanics. Science, 390(6777), 998โ1000. https://doi.org/10.1126/science.ady6092