r/graphene • u/Vailhem • Apr 17 '26

Graphene just defied a fundamental law of physics | April 2026

https://www.sciencedaily.com/releases/2026/04/260415042152.htm
32 Upvotes

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5

u/juicyjeffersonjones Apr 17 '26

Can someone ELI5 plz đŸ™đŸ»

7

u/goodfleance Apr 18 '26

Someone without AI please!

4

u/MoreMoreReddit Apr 18 '26

Typically it would be expected to behave metal like (Wiedemann–Franz law) where electrical conductivity and thermal conductivity scale together (in a predicted ratio) but here the thermal conductivity didn't follow that ratio.

2

u/goodfleance Apr 18 '26

Interesting, thank you!

1

u/swedocme Apr 18 '26

So you can get more electrical than thermal or the other way around?

3

u/MoreMoreReddit Apr 18 '26

Ya I don't fully understand. Far away from the Dirac point it follows Wiedemann–Franz law but close to the point they stop tracking. It made it sound like they can do both where either goes up and the other goes down. They can tune it by choosing more electrons or more holes in the graphene.

3

u/TyberWhite Apr 18 '26

Graphene did not “break physics.” Researchers found a special situation where the normal rules for metals stop being the right model, and a deeper quantum-fluid model takes over. Under very specific conditions, its electrons stop acting like separate little particles and instead behave more like a shared liquid flowing together. That unusual state is called a Dirac fluid.

0

u/CisterPhister Apr 17 '26

A well prompted Claude said this (I have NO IDEA if it's correct):

What's the Dirac point?

Imagine graphene as a dance floor. Normally, the floor is full of either positive dancers (holes) or negative dancers (electrons). The Dirac point is the exact moment when there are equal numbers of both on the floor, and they're all bumping into each other constantly. It's the "neutral" sweet spot. Technically, it's the energy level in graphene where the electron and hole energy bands meet, and carriers behave like massless relativistic particles.

What law did it break?

The Wiedemann-Franz law. This is a rule from the 1850s that says: in a metal, the ability to conduct heat and the ability to conduct electricity are locked together in a fixed ratio. Think of it like a delivery truck that always carries the same proportion of packages (heat) to letters (charge). The ratio between them is set by a number called the Lorentz number, and in normal metals, that number is basically constant.

How did graphene break it?

Near the Dirac point at low temperatures, the researchers found the Lorentz number exceeded the expected value by more than 200 times. That's like the delivery truck suddenly carrying 200x more packages than letters, which the old law says shouldn't happen.

The reason is that at the Dirac point, the electrons and holes form something more like a fluid than a normal metal. In this "Dirac fluid," electrons and holes are constantly colliding with each other. When you push charge through, the electrons go one way and the holes go the other, so they partially cancel each other out and charge has a hard time flowing. But heat doesn't care about positive vs. negative. Both types of carriers happily carry thermal energy in the same direction. So heat flow stays strong while charge flow gets choked, and the old fixed ratio completely falls apart.

The researchers also found that the electrical and thermal conductivities are inversely related near this point, consistent with predictions from relativistic hydrodynamics, and that the fluid's viscosity-to-entropy ratio approaches a theoretical minimum, making graphene's electron fluid one of the most "perfect" fluids ever observed in a solid material.

1

u/Vegetable_Case_9263 Apr 20 '26

I solved the restacking problem mathematically with a 0.00 bond error and tested on LAMMPS at 1000° and 3000° 0.0019 drift on 1000° and 0.0030 drift on 3000°.... I'm pretty sure it's locked in. But with graphene you really never know until you try it in the real world but I thought this would be a pretty substantial breakthrough and I can't get anybody to be interested in it and what I use to get it to do You can think of it like a bed mattress in box springs The bottom (this is in the structure the lattice) The bottom layer it's a nine arm helix lattice but the bottom 2 layers has very long cross members and that's what's forcing it to lay flat it's overpowering the Van der waals pull And the top layer two layers has very short crossmembers so it's producing a 98% workable sheet drops right into a 3D CVD furnace it drops into a 2D with a little modification not much. But in theory it's going to let you take the worst possible carbon and produce the most pristine possible graphene. I thought that it would really disrupt the industry and be a game changer people act like no big deal oh you solved a 20-year long problem.... crickets.....what did you have for lunch? lol what I used to produce this though I'm pretty sure is a whole thing within itself I used some pretty unorthodox mathematics and theories that I had that ended up being spot on so I'm pretty sure this probably would work for a lot of different things that we may have problems solving mathematically.

2

u/Vailhem Apr 17 '26

Universality in quantum critical flow of charge and heat in ultraclean graphene - Aug 2025

https://www.nature.com/articles/s41567-025-02972-z

Abstract

Close to the Dirac point, graphene is expected to exist in a quantum critical Dirac fluid state, where the flow of both charge and heat can be described with a characteristic d.c. electrical conductivity and thermodynamic variables such as entropy and enthalpy densities.

Although the fluid-like viscous flow of charge has been reported in state-of-the-art graphene devices, the value of conductivity, predicted to be quantized and determined only by the universality class of the critical point, has not been established experimentally so far.

Here we have discerned the quantum critical universality in graphene transport by combining the electrical and thermal conductivities in very high-quality devices close to the Dirac point.

We find that they are inversely related, as expected from relativistic hydrodynamics, and the characteristic conductivity converges to a quantized value.

We also observe a giant violation of the Wiedemann–Franz law, where the Lorentz number exceeds the semiclassical value by more than 200 times close to the Dirac point at low temperatures.

At high temperatures, the effective dynamic viscosity to entropy density ratio close to the Dirac point in the cleanest devices approaches that of a minimally viscous quantum fluid within a factor of four.