The fundamental physics powering every modern processor from Intel, AMD, and Nvidia has just been redefined. For over a century, quantum tunneling—the process that allows electrons to pass through seemingly impassable energy barriers—was treated as a “black box” of quantum mechanics. We knew it happened, and we built our entire digital civilization on it, but we didn’t actually know what the electrons were doing while inside the barrier.
The Mid-Tunnel Collision
New experimental evidence led by Professor Dong Eon Kim of POSTECH’s Department of Physics and the Max Planck Korea-POSTECH Initiative has finally pulled back the curtain. Published in Physical Review Letters, the research reveals that electrons do not simply “slip” through atomic barriers in a straight line.
Instead, the process is far more chaotic. The team discovered that electrons actually loop back and slam into the atomic nucleus in the middle of the tunneling process. This discovery of an internal collision process challenges long-held beliefs about how particles behave when defying classical physics, transforming our understanding of a mechanism that has remained a mystery for 100 years.
This isn’t just a theoretical victory for physics. it is a roadmap for the hardware that defines the modern era.
Defying the Classical Hill
To understand why this matters, one has to look at the gap between classical and quantum mechanics. In a classical world, if you push a ball toward a hill that is too high, the ball simply rolls back down because it lacks the energy to surmount the peak. In the quantum realm, however, particles like electrons behave as both particles and waves.
Because of this wave nature, an electron doesn’t need to “climb” the energy barrier. Instead, it can permeate the wall. While the probability of this happening is small, it is finite, allowing the particle to appear on the other side of a barrier it technically does not have the energy to overcome.
Technical Clarification: The Wave Function
Quantum tunneling is driven by the wave function, which describes the state of a particle. When a particle hits a potential energy barrier, its wave function doesn’t vanish instantly; it decays exponentially inside the barrier. If the barrier is thin enough, the wave function continues on the other side with reduced amplitude, creating the probability that the particle will be found there.
From Microchips to Stellar Fusion
Quantum tunneling is not a niche laboratory curiosity; it is a primary driver of both terrestrial technology and cosmic existence. The implications of the POSTECH and Max Planck findings ripple across several critical fields:
- Semiconductors: This phenomenon is the operating principle for the core components of smartphones and computers. Understanding the precise behavior of electrons during tunneling is key to refining the CPUs and GPUs that power everything from AI workloads to basic mobile apps.
- Data Storage: Engineers harness tunneling in flash memory and tunnel diodes to manage how data is written and stored.
- Precision Imaging: Scanning tunneling microscopes rely on this process to map surfaces at the atomic level.
- Astrophysics: Beyond the lab, tunneling is essential for nuclear fusion—the process that allows the sun to produce light and energy.
By observing the “loop back” collision, researchers may now be able to better predict and control electron behavior, potentially opening doors for more efficient chip architectures or new types of quantum hardware.
Analytical Q&A
Does this change how current chips are manufactured?
Not immediately. Current manufacturing relies on the fact that tunneling occurs. However, this new insight into the internal collision process provides the theoretical foundation needed to optimize future designs and potentially mitigate leakage or inefficiency at smaller nanometer scales.
Why is this only now being solved?
Watching electrons “inside” a tunnel requires unprecedented experimental precision. For a century, we could see the electron before it entered the barrier and after it exited, but the mid-tunnel process remained invisible until this collaboration between POSTECH and Max Planck.
As we push the limits of Moore’s Law and shrink transistors to their absolute physical minimums, will our ability to manipulate these “mid-tunnel collisions” be the key to the next leap in computing power?
