The doe had taken to standing outside my window at warm dusk, quietly looking in with what I can only describe as cautious curiosity and slight bewilderment. On my fourth reading of the same paper on quantum state tomography, I understood it just as well as she did.
I got into physics when I was seven years old, by reading a children's book. George's Secret Key to the Universe by Lucy and Stephen Hawking follows George, a boy whose parents distrust technology. His neighbors, Annie and her dad, have a supercomputer named Cosmos that can open a portal to anywhere in the universe. The book is full of bumpy comet rides, tender emotional beats, and a stressful trip to the edge of a black hole. What made this book special was that they wove real essays, graphs, and images from Hawking’s published work into the fabric of the story. Reading this was an earnest invitation to further explore the questions I always wondered about and was the first time that asking “how does that work?” felt more important than before.
My first major academic research project started this past summer. If you look at my research profile up until then, you would find that it was rather scattered, previously having done three mostly unrelated projects—from classical optics to computational astrophysics to analog circuits. Coming sort of full circle, I wanted to tackle quantum optics next, knowing next to nothing about it. After spending the first three weeks in rigorous optical hardware training whilst concurrently teaching myself quantum optics, something clicked after going down a deep literature review rabbit hole. I found a group that was working on a similar setup to ours and read their paper on it. Over the next week digging deeper, I came to the conclusion that very few people had applied the setup I was working on to specific biological samples.
No one tells you that asking a good question first requires being confused for a very long time. The problem at hand started taking a semi-solid form in my head before I knew the math to help define and describe it, which is a generally haphazard way of doing things. Curating a robust reading list was hard; I pulled from Google Scholar, seminal textbooks, course materials from MIT, UMichigan, and URochester, and leaned on what I learned in conversations with my professor and post-doc. I read the papers they recommended, the papers they cited, then the papers that those papers cited, rooting everything back to the core of my project on spontaneous parametric down conversion, and loved every second of connecting the dots as they started to make sense. Conducting your own research, on any topic, requires two things: curiosity and discipline. The deeper I went, the more my hunch about medical applications worked, which only made me burrow deeper in order to structure a proper proposal.
Richard Feynman said that the first principle of science is to not fool yourself, and that you are the easiest person to fool. Believing you have a working understanding of optics from theory alone is a foolish mistake. You can only develop a feel for what a method can tell you and what its limitations are when you actually work with the instrumentation, adjusting the lenses and mirrors and encountering systematic error due to hysteresis in the spring mechanisms of their holders. Most modern physics research is mostly that, where you have to find the limits of the problem and are curious enough to push it a little further.
My job this summer was supposed to be aligning the setup, checking it, and getting good images and data from it using increasingly complex detectors, which is a good way to learn because systematic limitations invite invention. What inspired me to go even beyond that was stepping back and talking to people: professors, post-docs, lab managers, research scientists, graduate students, and so many more pillars of academia. Science is collaborative, and having a shared curiosity inspires some beautifully fruitful conversations, which is the best learning resource I've found.
Quantum state tomography recovers a state you can never observe directly, by measuring it again and again from different angles. Learning something new works the same way. It takes curiosity, hard work, and most of all, discipline. Although the seasons change and I don’t live in the same place anymore, I know the doe still stops by to peer into that window at dusk, searching for a new perspective to her worldview.
