My Research Interests and Projects

I have done research in many subfields of physics. The unifying thread running through all of my projects has been a focus on the foundations of theoretical physics, from dark matter to nonequilibrium statistical mechanics, and the application of these fundamental theories to hard problems like quantum computing and the origin of life. Below is a description of some of my interests and works. For a more complete list, please see my CV.

Nonequilibrium Statistical Physics of Evolution and Adaptation

Living things are nonequilibrium systems. That is, they are sustained by flows of energy, eating food and expelling waste, only returning to thermodynamic equilibrium when they die. These nonequilibrium flows facilitate biology's unique driving force, Darwinian evolution [1]. It is through evolutionary selection and adaptation to environments that today's vast diversity of organisms was able to emerge. But, unlike equilibrium statistical mechanics, which has a unifying theory taught as part of the standard physics curriculum, the nonequilibrium physics of flows, adaptation, and evolution is more piecemeal. I am interested in connecting microscopic nonequilibrium statistical mechanics models to the macroscopic adaptive behaviors they cause, ultimately formulating a "statistical mechanical theory of evolution."

Select Publications:
[1] C.D. Kocher and K.A. Dill. "Darwinian evolution as a dynamical principle." Proceedings of the National Academy of Sciences 120.11 (2023): e2218390120. Link

Origin of Life Biophysics

Uncovering the origin of life on earth remains a grand challenge problem for the natural sciences. Some headway has been made by reasoning about which biological macromolecules were the first to appear, as in the well-known "RNA world" hypothesis. However, new approaches are needed for further advances. My research focuses instead on the physical driving forces, powered by nonequilibrium supplies of energy and other flows, that could have compelled the emergence of life from simple chemistry. I am trying to find the prebiotic origins and characteristics not of molecule types, but of the dynamical principles of self-organization [1], adaptation, and persistence. As an example of this type of reasoning, my collaborators and I have argued that evolutionary dynamics, biology's essential driving force, has a definitive, universal beginning [2], and that Darwinian evolution arises naturally in the protein folding process [3, 4]. We are actively working on creating a full origins of life narrative using our "driving forces" perspective [5].

Select Publications:
[1] C.D. Kocher, L. Agozzino, and K.A. Dill. "Nanoscale catalyst chemotaxis can drive the assembly of functional pathways." The Journal of Physical Chemistry B 125.31 (2021): 8781-8786. Link
[2] C.D. Kocher and K.A. Dill. "The prebiotic emergence of biological evolution." R. Soc. Open Sci. 11:240431. (2024). Link
[3] C.D. Kocher and K.A. Dill. "Origins of life: first came evolutionary dynamics." QRB discovery 4 (2023): e4. Link
[4] C.D. Kocher and K.A. Dill, "Origins of Life: The Protein Folding Problem all over again?" PNAS 121, 34, e2315000121, (2024). Link
[5] C.D. Kocher, "Characterizing the Nonequilibrium Driving Forces Responsible for the Emergence of Life" (2024). Electronic Dissertations and Theses. 71. Link

Dark Matter Detection (Past)

Dark matter makes up most of the universe's matter. We know of its existence due to its gravitational interaction with the normal atoms and particles that we can see, but we do not have an experimentally observed candidate particle for it. Many experiments are looking for signatures of particle dark matter that additionally interacts via the weak force. The LUX-ZEPLIN (LZ) experiment is one of those efforts [1]. In brief, the LZ experiment wants to observe the light created from hypothetical dark matter interactions with xenon nuclei; in the event that no interaction event is observed, LZ wants to put more stringent constraints on the properties of putative dark matter candidate particles [2]. To do so, LZ needs light detectors, photomultiplier tubes (PMTs), that meet strict requirements. At Brown, my role was to help design and implement the test program for the LZ PMTs in order to ensure that the experiment could offer world-leading sensitivity results for dark matter detection, as it recently reported for its first run [3]. I was also part of the machine learning working group looking for ways to add neural networks to the data analysis pipeline.

Select Publications and Resources:
[1] The LZ Experiment's Website
[2] D.S. Akerib, et al. "The LUX-ZEPLIN (LZ) Experiment." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 953 (2020). Link
[3] J. Aalbers, et al. "First dark matter search results from the LUX-ZEPLIN (LZ) experiment." Phys. Rev. Lett. 131.4 (2023): 041002. Link

Quantum Computing (Past)

Quantum computing uses the property of superposition of states to make new, better computer algorithms; bits are no longer just 0 or 1, but any combination of the two states, leading to incredible computational power. When large, error-correcting quantum computers are built, they will radically alter the world. For now, we only have some small, noisy quantum computers. For my SULI project, I explored the ability of these near-term quantum computers to solve problems in quantum mechanics and other disciplines [1].

Select Publications:
[1] C.D. Kocher and M. McGuigan, “Simulating 0+1 Dimensional Quantum Gravity on Quantum Computers: Mini-Superspace Quantum Cosmology and the World Line Approach in Quantum Field Theory,” 2018 New York Scientific Data Summit (NYSDS), Upton, NY, 2018. Link

Quantum Chaos (Past)

Chaotic systems, ones that are very sensitive to small changes in initial conditions, have been thoroughly studied as phenomena of classical physics. In recent years, quantum mechanical versions of chaotic systems have become topics of intense focus. I reviewed some of this literature for my senior thesis project at Brown, focusing on applications of the theory to simple quantum systems [1].

Select Publications:
[1] My Bachelor's Thesis.