Walk up music: Both Sides Now, UCLA Medleys A Cappella [opb Joni Mitchell]

“I’ve looked at life from both sides now

from win and lose

and still somehow

it’s life’s illusions I recall…”

Nick enters stage wearing a fictitious backpack, sets it down onstage, and begins to speak.

Some of you probably went on a camping trip this summer. Have you noticed how much has changed in the past 20 years? Your map, camera, and bedtime storyteller now all fit on your wrist, and can sound like Scarlett Johannsen. 

The sheer amount of compute power on your wrist has more serious implications. In war, computational advantage now determines who WINs and who LOSEs. This has driven an exponential growth in global demand for compute power, increasing so quickly that within 15 years we will surpass global energy production. The power will run out.

How can we use our brains to get us out of this crisis? Wait, how does our brain compute? Computers in general perform two basic functions: logic and memory. Logic processes the information in 1s and 0s and sends it a long long way to memory, as UP and DOWN on billions of tiny little switches. Sending this information costs a LOT of energy and time. Our brains actually found a way to drop this energy cost by a factor of 50. How did they do it? In a neuron, logic and memory are in the same place.

I work with a new type of magnet, an ALTERmagnet, which can compute like a neuron. Unlike in conventional magnets, the magnetic clouds around the atoms of an ALTERmagnet ALTERnate as you move from one atom to the next. This splits the spin conduction pathways in the material in real space. So when you attach two wires and apply a voltage this way, the material sends the message “GIVE” and when you switch the wires to this way, the material sends the signal “TAKE”. So it can perform logic. Great! But it can also store the information in the direction of magnetic clouds in the material, whether they are UP or DOWN. Just like that, we’ve mimicked a neuron, putting logic and memory into a cube a few atoms wide. At least in principle. These things were discovered this year.

Thanks to Berkeley Lab, I have all the tools to find the best ALTERmagnet for a sustainable future. Using Berkeley Lab supercomputers I can predict the shapes of magnetic clouds when I arrange the atoms in different patterns, and using an electron microscope I can directly probe the shape of the clouds in real life. By looking at the clouds from both sides now, we can live a little longer to ponder life.

Have you ever been around plants and felt inspired? Well, plants are truly inspiring. They convert carbon dioxide into oxygen using sunlight. Not just that plants also incredibly utilize 100% of the energy they absorb from the sun, while a typical modern-day solar panel utilizes only 20% of the absorbed energy. Wonder why? Actually, the light absorption process in plants involves the creation of a negative charge and a positive charge bound together. This pair of opposite charges is called an exciton. You can think of it as a little energy capturing entity that forms by absorbing energy from the sun and then transport the absorbed energy to the reaction site where carbon dioxide is converted into oxygen. This energy transport is highly efficient with negligible loss. It’s almost like a perfect food delivery service that delivers hot food like it just came out of the kitchen. There’s no heat loss during delivery. Unfortunately, in the materials used currently in our solar panels, this food is way too cold by the time it reaches its destination. In other words, the energy transport is highly inefficient. Imagine having a material that can harness energy from sun with an efficiency comparable to plants. It would cause a huge dent on the impending energy crisis. 

At Berkeley Lab, we have discovered a new material, a carbon-based material, that can allow energy transport using excitons with absolutely zero energy waste. Using computer simulations and supporting experimental evidence we have shown that there’s a unique arrangement of atoms inside this material that allows excitons to not just flow but superflow. When I say superflow I don’t mean speed, I mean the flow of excitons with absolutely zero resistive loss, i.e, energy transport is 100% efficient. And this is guaranteed by the quantum mechanical nature of this material. In fact, materials that can do this are called excitonic superfluids. These were first theorized in 1960s but so far there are only about 10 known candidates in the world, and one of them is this material that we discovered right here at Berkeley Lab. But it comes with a challenge. It’s only at low temperature that excitons superflow in this material. We are working to raise this temperature, possibly reach ambient conditions. Once that happens, this material can have applications going beyond solar power generation, in areas like effective laser design or targeted radiation treatments, possibilities are limitless. So really, next time when you are around plants, I hope you feel truly inspired!