I can guarantee this is fewer than 10 years out of date.
The majority of the universe is made of dark matter, a substance with such impact that we see traces of it across the cosmos: from the oldest, most distant light it's possible to observe (the cosmic microwave background) to the speeds of stars in our own galaxy. Its properties match none of the known fundamental particles, but they could match those of the axion, which was originally theorized in 1978 for a totally unrelated reason. To test whether they're a component of dark matter, the axion dark matter experiment (ADMX) uses a powerful superconducting magnet to convert the axions passing through it into photons (light). From there, the light signal must be made as strong as possible (using resonating cavities and amplifiers) and the background noise must be suppressed (by cooling to below 1 Kelvin, using superconducting cabling, and ultra low-noise amplification). ADMX's tunable resonator currently enhances signals around 1 GHz (corresponding to axions of mass 30 μeV), and has excluded the possibility that the axion has that mass. The search, then, continues upwards in frequency (and downwards, but that is the domain of Dark Matter Radio).
My work at Stanford is prototyping for the next phase of ADMX with Professor Chao-Lin Kuo. We design and build high-volume (around 10 L) microwave resonators at high frequency (above 5 GHz). Achieving a properly identified resonance requires careful metrology, precise alignment using a hexapod positioner, and realistic electromagnetic simulations for comparison. I developed an automated alignment algorithm for these resonators, enabling remote operation and reducing workload. I conducted a search for dark photons using one of our resonators. I helped design a cryogenic test setup for a larger resonator to demonstrate high quality factor and cryogenic alignment capability, and am currently commissioning it.
The superconducting quasiparticle-amplifying transmon (SQUAT, pictured) is a detector for rare, low-energy events such as collisions with dark matter or incident THz-range photons. They have potenitally extremely low energy threshold and background rates, and are readily multiplexed (allowing for large arrays of many pixels), though they have yet to be fully demonstrated. The device consists of two capacitor fins (blue and purple, also act as a THz antenna) linked by a Josephson junction (inset), forming a qubit that's directly coupled to the radio frequency (rf) feedline (yellow). The qubit is weakly charge-sensitive, meaning a differential charge on the capacitor creates a splitting in the energy of the ground state of the qubit into two states: the even and odd parity states. The parity state of the qubit is continuously monitored by reading the phase of an rf signal passed through the feedline. When a particle hits the detector, it breaks Cooper pairs in the superconducting fins, generating quasiparticles there. The quasiparticles diffuse to the junction, and some tunnel across (potentially many dozens of times -- amplifying its impact). Each tunneling event causes a flip in the parity state of the qubit, which we can detect. Rare events are thus seen as a spike in the parity switching rate.
Much like LIGO uses the interference between photons to detect gravitational waves, the MAGIS experiment aims to use atomic states of strontium to the same end. Lasers are used extensively to cool, excite, and even move these atoms by tens of meters. During my rotation with Professor Jason Hogan, I worked on the design and testing of part of the optical system for the delivery of these lasers. I also assembled and aligned a 922 nm (infrared) laser.
During my entire undergrad, I worked with Professors Cynthia Chiang and Jonathan Sievers at McGill University. The group's goal is to take measurements of the faint glow of neutral hydrogen, prevalent in the cosmic dark ages before the first stars formed, using radio interferometry. Since those signals happen to have roughly the same frequency as FM radio, these antennas must be very far from population centers, where power is not easily accessible. So, I was tasked with designing, building, and testing solar and wind power systems for an antenna on Marion Island. I was credited for that in a paper, and even got the MagPi magazine to interview me about the project.
I also deployed a prototype antenna system (pictured) at the McGill Arctic Research Station (MARS), with Professor Chiang and Dr. Raul Monsalve of EDGES. I used the data I collected there to show that MARS is indeed an excellent site for our observations. I wrote a paper about that, and our work was featured in the PCSP Science Report.
I can't shake a strange interest in the idea that 'complexity' (or 'computational irreducibility') must arise at some sort of 'phase transition' between 'ordered' and 'chaotic' phases. That there is some deep connection between the behaviour of dynamical systems (water, birds, etc.) and universal computers at that transition. That the system 'self-organizes' and new 'emergent' behaviours appear, possibly touching on the origin of life. Frustratingly, the words in scare quotes above don't have precise definitions. This makes doing general analysis of this problem very hard. So, a lot of people have turned to cellular automata (CA) as their system to investigate. CA are dynamical systems, and have been studied in that context. They are also capable of universal computation, and have been studied as computational systems. This duality makes them prime playgrounds for this kind of pontificating.
CA and their λ parameter are explained well here, where there is also an interactive demo which is quite entrancing. Christopher Langton in his thesis conjectured that CA undergo a phase transition as you change the rules governing them from low-λ to high-λ. Indeed, in the figure, there is a vague jump from low-entropy 'ordered' states to high-entropy 'chaotic' ones as λ increases. Unfortunately, there is no single value for λ at which the jump occurs, meaning that no precise comparison can be drawn between this 'transition' and physcial phase transitions, which always occur at a sharp value of some parameter. It's clear that λ is not the right parameter to scan across to look for this transition. It isn't clear, however, what to replace it with, or even that changing the rules underlying the CA is the right way to perturb them. In the Ising model, for example, the phase transition is along temperature, a parameter in the model, not along changing interaction rules. Perhaps CA are just too simple to have a real transition, even if some can exhibit ordered, chaotic, and even computationally universal behaviour.