In the world of cutting-edge science, quantum mechanics continues to push the boundaries of what we know and understand. As we stand on the brink of a new era in quantum research, **Hannes Pichler**, a key researcher and board member at quantA and professor at the University of Innsbruck, sheds light on how the field of quantum mechanics, particularly through research on neutral atoms, is opening the door to the next revolution: the creation of **fault-tolerant quantum computers**.

Quantum mechanics, a theory that defies everyday intuition, emerged almost 100 years ago with Erwin Schrödinger’s famous equation. His work on atoms, particularly hydrogen, laid the foundation for understanding the very building blocks of matter. Fast forward to today, and researchers like Pichler are exploring new questions—questions that delve deep into the properties of complex materials and systems that involve quantum phenomena. These questions range from “How can we make materials conduct electricity without energy loss?” to “How can we synthesize complex chemical compounds?”

While individual atoms can now be described with remarkable precision thanks to quantum mechanics, systems that involve many particles present an exponentially greater challenge. To describe a system of just 300 particles, you would need more numbers than there are atoms in the visible universe—a task that no classical computer can handle.

This is where the concept of **quantum computers** enters the stage. First envisioned by Richard Feynman in 1981, quantum computers use the principles of quantum mechanics to process information in ways that classical computers cannot. Instead of bits that represent 0s and 1s, **quantum computers** rely on **qubits**, which can exist in a superposition of both states simultaneously. A quantum computer with 300 qubits could simulate a quantum system of 300 particles, unlocking new realms of understanding.

One of the most promising approaches to building quantum computers involves **neutral atoms**. Pichler explains that by using laser light, scientists can trap individual atoms in highly focused beams known as **optical tweezers**. These atoms can then be arranged and manipulated, literally building a quantum computer **atom by atom**. Researchers are now able to create systems with hundreds, even thousands of atoms, each acting as a qubit.

But controlling the position of qubits is just one piece of the puzzle. The real breakthrough lies in the interactions between qubits, which are crucial for performing the complex operations that quantum computers need. Atoms, being neutral, don't naturally interact with each other, but by exciting atoms into a highly energetic state known as the **Rydberg state**, they become thousands of times larger and act like tiny antennas, allowing them to communicate and perform quantum operations.

The real challenge for quantum computers is ensuring the reliability of these quantum operations. Even the smallest disturbances can cause quantum states to collapse, leading to errors. However, as Pichler notes, the field has made enormous progress. Just five years ago, one in five quantum operations would result in an error. Today, researchers can perform hundreds of error-free operations in a row, bringing us closer to the realization of **fault-tolerant quantum algorithms**.

This breakthrough heralds a new era where quantum computers could one day serve as powerful tools for discovering new physics, solving complex problems, and even simulating systems that are beyond the capabilities of classical computers.

To borrow from Schrödinger himself, while he once remarked that experimenting with individual particles was as unlikely as breeding ichthyosaurs in a zoo, today's advances show just how far we've come. Quantum science is poised to revolutionize our understanding of the universe, and the journey is only beginning.

As we celebrate **100 years of quantum science** in 2025, these developments are paving the way for the future — one atom at a time.

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