New Faculty: Trithep Devakul & Jon Simon

NEW FACULTY: TRITHEP DEVAKUL

Hello Stanford! I am delighted to be introducing myself as the newest faculty member in the condensed matter theory group here at Stanford. I am so excited to become a part of the vibrant physics community here.

I spent my childhood in Thailand before crossing the globe to do my bachelor’s degree at Northeastern University. I knew from early on that I wanted to do physics, and specifically condensed matter physics: I was just fascinated by how so much of the world around us, like a simple bar magnet, arises from the collective behavior of quantum particles acting in harmony.

I spent a couple years working in an experimental lab, before taking the leap and doing a summer project in theory. The rest is history. I fell in love with the field: it was the perfect mix of fundamental and applied physics. Plus, the field is so incredibly broad and diverse that I could never get bored of it. I went on to do my PhD at Princeton, a postdoc at MIT, and now Stanford. My general research interests lie in exploring all the exotic states of matter that can arise in quantum systems.

Of all the things I’ve worked on, what I am the most excited about in the coming years is the field of moiré materials. These are a relatively new class of 2D systems formed by taking two or more atomically thin materials, like graphene, and stacking them on top of each other with a small twist. The mismatch between the atomic lattices of the two layers generates a long-period interference pattern known as a moiré pattern (see figure). Electrons moving in the material see the moiré pattern, and the result is that they effectively behave as if they are in a magnified “artificial crystal” (typical moiré periods are =5-10 nm, much larger than inter-atomic distances of 0.1 nm).

I find these systems so interesting because they force us to reconsider the way we think about electrons in materials. In most materials, the kinetic energy of the electron is dominant, and other aspects can often be treated as small corrections. This is inverted here: the moiré lattice works to suppress the kinetic energy, thus enabling other aspects, in particular electron-electron interactions, to take center stage. Studying the physics of such strongly interacting systems is a hard problem at the cutting edge of condensed matter physics.

The physics here mirrors that of the “quantum Hall” regime, where kinetic energy is suppressed by the application of a strong magnetic field. This setting has historically been a stage for breakthrough discoveries, such as the fractional quantum Hall effect famously solved by Laughlin’s wavefunction. What makes moiré materials so compelling is their ability to reproduce many aspects of this setting without any external magnetic field. Furthermore, they are an entirely unique material platform with their own set of tuning knobs. I believe we have only begun to explore the potential of these systems and am eagerly looking forward to seeing where the field will go in the next few years.

I feel truly fortunate to be coming to Stanford at this exciting time. I can’t wait to begin building my own research group and interacting with the Stanford physics community. I am equally excited to begin my teaching journey here – I will be teaching Physics 111 this fall and look forward to engaging with the next generation of physicists!

NEW FACULTY: JON SIMON

I joined the physics faculty at Stanford after a decade at the University of Chicago. My group specializes in quantum control of light, focusing in particular on developing tools to (1) collect, trap & manipulate photons, and (2) entangle the photons by coordinating their absorption by - - and re-emission from -- atoms. I collaborate closely with David Schuster, both in electric- skateboarding & drone piloting, and through our groups, in exploration of quantum science.

Among the various directions that this exploration of light has taken me, I have focused on making matter from light and using it as a platform to study how quantum mechanics impacts the properties of materials. Photons are a rather strange thing to make matter out of, as they do not interact with one another as electrons do, nor do they respond to forces by changing their speed (that is, they have no mass). My group has developed tools to make photon traps (resonators) that imbue the photons with properties that behave like mass, charge & coupling to magnetic fields, and with the ability to collide with one another through coupling to highly excited “Rydberg” atoms and superconducting circuits. This journey has led to the first crystals made of light, the first topological molecule made of light, and the first strongly correlated fluids of light. My team is now exploring ways to leverage entanglement to directly extract properties of these exotic quantum states through manybody interference effects (what they call “Manybody Ramsey Interferometry”).

Beyond making quantum matter out of light, I’m fascinated by the challenges associated with development of next-generation quantum hardware: there are a variety of advanced quantum computing platforms coming online today, from arrays of atoms individually trapped in laser beams to ions, to superconducting circuits. These platforms share substantial quantum coherence (the ability to preserve entanglement for long periods of time without being “observed” by the outside world) and strong interactions (the ability to generate entanglement). The analogy to the development of the transistor would suggest that industrial partners should take it from here, “scaling up” these proof-of-concept demonstrations. The reality is that entanglement and the objects that preserve it are so delicate that “scaling” is actually a fundamental-science- rather than systems-engineering- challenge. My group is developing tools to more efficiently measure large quantum systems using arrays of optical cavities and even new approaches to interconvert quantum information between platforms where it is easy to manipulate and platforms where it is easy to transmit over long distances. The variety of technical challenges intrinsic to these problems now transcend the technical capabilities of the Simon & Schuster collaboration, resulting in three-way-efforts with the Safavi-Naeini lab who specialize in nanophotonics and quantum sensing.

I’m also the director of Q-FARM, a cat enthusiast, and a mediocre chess player. I’ve been working with research groups around physics & applied physics to develop laser-cut lab logos to put on lab doors (what I call “art”); if you have ideas for your lab door definitely reach out to me.