Physics Shaken: IISc Discovery Reveals Graphene Defies 200-Year-Old Fundamental Law
For nearly two centuries, a fundamental rule has governed our understanding of metals, a principle taught in every introductory physics textbook: the Wiedemann-Franz Law. In simple terms, this law states that electrical conductivity and thermal (heat) conductivity are partners. If a material is a good conductor of electricity, it must also be a good conductor of heat. When one rises, the other rises. When one falls, the other falls.
This rule, first noted in 1853, has been a reliable cornerstone of physics. It's based on the idea that the same free-moving electrons that carry an electrical charge also carry thermal energy.
Until now.
In a groundbreaking 2025 study published in the prestigious journal
The Discovery: When Heat and Electricity Part Ways
The
In their ultra-clean samples, as the electrical conductivity increased, the thermal conductivity dramatically dropped.
This is the exact opposite of what the 200-year-old law predicts. It's like finding a material that lets electricity flow perfectly while simultaneously acting as a heat insulator. This phenomenon isn't just a minor anomaly; it's a fundamental break from established condensed-matter physics.
So, what causes this bizarre, rule-breaking behavior?
Welcome to the Dirac Point: Where Electrons Flow Like Water
The key to this mystery lies at a unique electronic tipping point in graphene known as the “Dirac point.”
At this specific point, graphene exists in a strange quantum state where it is neither a traditional metal nor an insulator. The researchers found that at this critical juncture, the electrons stop behaving like individual particles bouncing around (as they do in normal metals) and begin to flow collectively.
They form what physicists call a “Dirac fluid”—a nearly perfect, collective "electron soup."
In this exotic fluid state, the standard rules of physics no longer apply. The collective flow of the electron sea allows for high electrical conductivity. However, the very nature of this fluid state suppresses the mechanisms that typically transfer heat. The particles are so strongly correlated in their movement that they can't effectively carry thermal energy, leading to the observed drop in thermal conductivity.
Why This Graphene Discovery Matters: From Your Desk to a Black Hole
This discovery does far more than just force a rewrite of physics textbooks. It has profound implications that stretch from material science to the deepest mysteries of the cosmos.
This "Dirac fluid" in graphene is one of the first successful examples of creating a quantum critical flow in a lab. Why is that exciting? Because this same kind of "perfect fluid" physics is believed to exist in some of the most extreme environments in the universe:
Black Holes: The study of
and the behavior of matter near an event horizon are thought to be governed by similar "perfect fluid" principles.black hole thermodynamics The Early Universe: The quark-gluon plasma that existed fractions of a second after the Big Bang is another example of this extreme state of matter.
High-Energy Colliders: The "goo" created in particle colliders like the
shows similar properties.LHC at CERN
Before now, studying these phenomena required building multi-billion-dollar colliders or pointing telescopes at distant, unseeable objects. Now, thanks to the IISc team's work with graphene, we have a "tabletop window" into the same extreme physics.
This breakthrough not only shatters an old law but also provides a brand-new tool to probe the mysteries of quantum entanglement and the very fabric of matter itself.
(Source: "Universality in quantum critical flow of charge and heat in ultraclean graphene." Nature Physics, 2025).
Here are some YouTube videos that cover this breakthrough discovery:
Graphene Breakthrough: Electrons Behave Like Frictionless Fluid, Defying Textbook Laws
Channel: Spotlight & Sports
URL: http://www.youtube.com/watch?v=2gTqh8e2CO4
This video specifically mentions the groundbreaking research by scientists at the Indian Institute of Science (IISc).
Graphene Breaks a 170-Year-Old Law of Physics
Channel: HD Physics
URL: http://www.youtube.com/watch?v=W3pbCWWZEWY
This directly addresses how graphene shattered a long-standing law of physics.


Comments
Post a Comment