Stochastic Biophysics PhD - Expert

Obsidian; San Francisco (CA); Remote; USD 110,000 - 152,000; Part time

Job summary

Obsidian is seeking researchers to work on research-level physics problems in their own subfield. This is a remote, part-time engagement with written reasoning required for every assignment.

You will align with your publication record to select areas, and start immediately for an 8–10 week window at about 10 hours per week, with compensation at $80–$110 per hour based on depth of subdomain match.

Qualifications

• PhD in biophysics, statistical physics, applied mathematics or closely related field.
• Three to five representative papers with arXiv IDs or DOIs, ideally from the last five years.
• Proficiency with LaTeX, Python, SymPy and Jupyter.

Responsibilities

• Create, solve, review, or audit research problems in your subfield.
• Match researchers to appropriate subareas based on publications.
• Provide complete written reasoning for each assignment.

Skills

LaTeX

Python

SymPy

Jupyter

Education

PhD in biophysics

PhD in statistical physics

PhD in applied mathematics

Tools

VS Code

Job description

About the work

CritPt is a public benchmark of research-level physics challenges, built to test whether frontier AI models can carry out genuine physics research reasoning rather than textbook problem solving. The benchmark paper is arXiv:2509.26574 and we recommend reading it before applying. It will tell you quickly whether this work interests you.

We are engaging physicists to work on research-level physics problems in their own subfield. Depending on where your publication record fits, that can mean creating problems, solving them, reviewing completed work, or auditing it. We agree the specific assignment with you once you are matched to an area.

This is research-grade work rather than volume work. Whatever you produce has to be complete enough for another specialist in your subfield to follow and verify independently, so written reasoning is part of every assignment.

Research areas in this panel

One area. We match narrowly: you need to have published on this specific phenomenon, not in biophysics broadly.

1. Stochastic autocatalytic growth: chemical master equation, branching processes: Autocatalytic reaction cycles, stochastic Hinshelwood cycle, chemical master equation processes, circulant matrix spectra, transient oscillations toward balanced exponential growth, moment hierarchies for reaction networks, generating-function methods.

If you also work on long-range dispersal, heavy‑tailed jump processes or front propagation in range expansions, say so on the form. A closely related area sits in our statistical physics panel and draws on the same methods.

Methods we expect to find in your own publications

You should be able to point to your own papers demonstrating at least one of the following families:

• Chemical master equation and the stochastic Hinshelwood cycle
• Multi‑type branching processes and circulant matrix spectra
• Moment hierarchies for reaction networks
• Generating‑function methods

Who we are looking for

A PhD in biophysics, statistical physics, applied mathematics or a closely related field. This is a hard requirement. Postdoctoral researchers, research scientists and junior faculty are the strongest fit. Senior PhD students with a strong first‑author record are welcome to apply.

Published work on stochastic growth or reaction‑network dynamics specifically. This is the single most common reason we decline otherwise excellent researchers. Command of the methods is not enough if you have not published on the phenomenon itself.

A verifiable publication record. Three to five representative papers with arXiv IDs or DOIs, ideally from the last five years. First author strongly preferred. Every paper you list will be checked against the public record.

Working proficiency with LaTeX, Python, SymPy and Jupyter. Some familiarity with an agentic coding extension in VS Code is useful. Gaps there are acceptable if you declare them honestly.

English at B2 or above, including written reasoning. A large part of the value you add is how clearly you set out your argument.

Application steps

1. We verify your papers and authorship against the public record.
2. Then one of two things happens. Either we onboard you directly, or we invite you to a short live alignment call to agree the area and the assignment with you.
3. A brief 30 to 45 minute assessment may be added, but only where we need it. Most applicants will not see one.

Commitment and rate

10 hours per week, sustained across an 8 to 10 week window, starting immediately. Remote and asynchronous with no fixed hours.

$80 to $110 per hour, set by depth of subdomain match.