RF/Superconducting Device Physicist

Snowcap Compute Inc.; San Francisco (CA); On-site; USD 150,000 - 260,000; Full time

Benefits offered by this job

Relocation help

Medical/Dental/Vision

401(k)

Job summary

Snowcap Compute Inc. seeks a physicist to own end-to-end characterization of Josephson junction devices and PCL logic cells at low temperatures. You will design measurement protocols, extract parameters, and write methodologies that guide future campaigns.

You will collaborate with fab, design, and test engineers, driving feedback loops and ensuring reproducibility. This is a standing, on-site role in a cutting-edge, small-team environment.

Qualifications

• A PhD in physics, applied physics, or EE with superconducting focus.
• Hands-on characterization of superconducting devices at cryogenic temps.
• Experience with measurement reproducibility and uncertainty.

Responsibilities

• Characterize Josephson devices and PCL logic end-to-end.
• Design/custom protocols to extract device parameters.
• Translate device data into actionable process feedback.
• Document methodologies for replication by peers.

Skills

Josephson junctions

Cryogenic measurement

Data analysis

Python

Publication experience

Education

PhD in physics or electrical engineering

Tools

Microwave simulation

Job description

About the Role

Every new process variant and every new design generation Snowcap runs requires deep, rigorous characterization of the underlying Josephson junctions and the PCL logic cells built on them. The interpretation of that data — not just its capture — is what tells the fab whether the process moved and tells the design team whether the cells will behave. This is the role that owns that work.

You will own characterization methodology end to end. That means designing custom measurement protocols, extracting device parameters at low temperature, interpreting the physics behind anomalies, and writing the methodology docs that the rest of the company reasons from. You will work directly with fab process engineers, design leads, and test engineers in a flat, matrixed organization. There are no layers between you and the problem.

This is a standing role at Snowcap. We will always be hiring physicists at this caliber. The methodologies you establish become the basis on which every subsequent measurement campaign — and every subsequent process and design decision that flows from it — is built.

What You'll Own

• Own end-to-end characterization of Josephson junction devices and PCL logic cells at low temperature, from measurement design through interpretation.
• Design and execute custom measurement protocols to extract device parameters — including the ones that no standard procedure exists for yet.
• Drive process-measurement feedback loops with the fab team: translate what we see at the device level into actionable signal about process drift, integration issues, and yield levers.
• Interpret characterization data to inform circuit and process design decisions — and push back when the data does not support a proposed change.
• Establish publication-quality documentation of measurement methodologies that other physicists, engineers, and external collaborators can replicate.
• Push the noise floor and calibration practices of our cryogenic measurement environments to keep pace with the precision the chip program demands.
• Partner with physics and engineering peers — translate fluently between the two languages so that device physics conclusions land cleanly with circuit, layout, and process teams.
• Mentor junior researchers and lab staff on superconducting measurement technique, calibration discipline, and experimental rigor.

What We Need to See

• PhD in physics, applied physics, or electrical engineering with a focus on superconducting devices — or equivalent research depth demonstrated through industry work that closed the loop on real device measurement campaigns.
• Direct, hands‑on characterization experience with Josephson junctions, SQUIDs, or related superconducting circuits at low temperature — not just adjacent simulation or theory.
• Deep, practical understanding of cryogenic measurement environments: noise floors, thermal anchoring, RF/microwave signal integrity through the cold chain, and where calibration assumptions break.
• Track record of experimental rigor: reproducibility, uncertainty quantification, and methodology documentation that others have actually used.
• Fluency across physics and engineering audiences — you can hand a measurement report to a device designer and the same conclusions to a process engineer, and both leave with what they needed.
• Published methodology or measurement work that reflects ownership of an experimental program, not just contribution to one.

Ways to Stand Out

• Postdoctoral or staff scientist experience at a leading superconducting electronics, qubit hardware, or cryogenic detector research group.
• Hands‑on familiarity with NbTiN, NbN, or similar superconducting thin‑film process platforms — and the device‑level signatures their process variations leave behind.
• Strong Python or scientific computing skills for measurement automation, data analysis, and the tooling that turns one‑off scripts into a methodology pipeline others can run.
• EM and microwave simulation experience for cryogenic component, interconnect, or detector design — especially where simulation had to predict and match real measurement outcomes.
• Experience bridging research‑scale measurement with production‑grade characterization workflows, where reproducibility and throughput matter as much as precision.
• Publications, shipped instruments, open methodology codebases, or patents that reflect ownership beyond the scope of a job description.

The Environment

Snowcap is a small, technically elite team doing work that has never been done at commercial scale. The characterization methodologies you build here will not be inherited from a prior program — there is no prior program. You will write them, defend them, and revise them as we learn what these devices actually do.

We are a flat, matrixed organization. You will work daily with fab process engineers, device designers, cryogenic test engineers, and physics peers — not through layers of management. Decisions move fast. When a measurement contradicts a planned process change, the conversation happens that afternoon, not next quarter.

This role is on‑site. The lab is real, the dilution refrigerators are loaded, and the devices coming off the line do not always do what theory predicted. If you need a mature characterization program with a settled methodology to operate from, this is not the right fit. If you want to write that methodology yourself, you are in the right place.

Why Snowcap

Snowcap Compute is building the world's first commercial superconducting digital computer. Our chips operate at 4.5 Kelvin on Josephson junction‑based PCL logic, consuming a fraction of the power of any CMOS system. We are not improving the existing paradigm — we are replacing it.

We are a technically elite, small team at the intersection of quantum physics, cryogenic engineering, and advanced semiconductor manufacturing. Every person on this team has a direct line of sight to the product. The work you do here will be visible, consequential, and unprecedented.

This is a standing physics role. We will always be hiring at this caliber, and every physicist we add changes what the company can measure, understand, and ship. The methodology you set becomes the foundation that the next physicist builds on.

Compensation

• Full medical, dental, and vision
• 401(k)
• Relocation assistance available for candidates outside the area

Base salary range is shown in USD, posted in good faith and in compliance with California pay transparency law (SB 1162). The range spans the early‑career PhD entry floor through the senior individual‑contributor band — the offer Snowcap reasonably expects to make depends on the level of the seat being filled, plus experience, publications, and location. Range is exclusive of equity, bonus, and benefits. Range reflects the San Francisco Bay Area market; offers for the same role based in Jacksonville Metro, FL are typically 15–25% lower in line with local market norms.

• Based in the San Francisco Bay Area or Jacksonville Metro, FL
• On‑Site