--- title: 'Computational Physicist - Fluid Dynamics at Xcimer Energy' canonical: 'https://feeny.ai/job/computational-physicist-fluid-dynamics-xcimer-energy-denver-20az9ksd47d3' type: 'job' last_seen: '2026-09-13' --- # Computational Physicist - Fluid Dynamics at Xcimer Energy - **Company:** Xcimer Energy - **Location:** Denver, CO - **Compensation:** $160k–$200k - **Employment:** full-time - **Work type:** onsite - **Posted:** 2026-08-31 - **Last confirmed live:** 2026-09-13 - **Apply:** https://jobs.lever.co/xcimer/a77fe287-1b08-4905-a12a-da36bc4c02ed ## Job description Xcimer Energy leverages decades of research on Inertial Fusion Energy (IFE) combined with groundbreaking new laser architecture. Our mission is to deploy fusion power plants to meet global decarbonization goals as fast as possible. Xcimer has assembled a team of leaders in tough tech, fusion science, and manufacturing with a track record of rapid execution. Supported by leading investors, Xcimer is uniquely positioned to deliver limitless, clean, fusion power to combat climate change. Join us in powering a better world with inertial fusion! This is a full-time, onsite role based at our headquarters in Denver, CO. As a Computational Physicist (Fluid Dynamics) at Xcimer, you will contribute to the theoretical and computational development of multi-material radiation hydrodynamics models that support inertial confinement fusion (ICF). This role focuses on numerical methods for computational fluid dynamics (CFD), with emphasis on high-fidelity modeling of complex multi-physics systems relevant to fusion energy. You will work closely with senior scientists and software engineers to develop, analyze, verify, and validate numerical methods and simulation capabilities within Xcimer's radiation hydrodynamics codebase. This is a hands-on technical role that blends mathematical modeling, numerical analysis, and high-performance scientific computing. The ideal candidate brings deep expertise in numerical methods for fluid dynamics, hands-on experience with invariant-domain preserving (IDP) methods, strong experience with finite element frameworks (particularly deal.II), and the ability to contribute meaningfully to code development, scientific publications, and collaborative research efforts. ## Responsibilities Multi-Material & Radiation Hydrodynamics Modeling - Implement and improve multi-material modeling approaches (e.g., interface tracking/capturing, mixture models, or related techniques). - Support coupling of hydrodynamics with radiation transport and other relevant physics modules for various equation of state and opacity models. - Assist in developing robust algorithms for extreme thermodynamic and flow regimes relevant to ICF. Numerical Methods & Theoretical Development - Develop and analyze certifiably robust, invariant-domain preserving (IDP) numerical methods for computational fluid dynamics with emphasis on multi-material flows. - Contribute to mathematical modeling for multi-material systems relevant to inertial confinement fusion. - Support development of radiation hydrodynamics formulations, discretizations, and stabilization strategies. - Investigate accuracy, stability, and convergence properties of numerical schemes. - Contribute to solving complex inverse and forward problems in high-energy-density physics. Verification, Validation & Scientific Rigor - Collaborate with Xcimer's verification and validation function to validate multi-material numerics, contributing domain expertise on expected physical behavior. - Contribute multi-material test problems and physical judgment to the shared benchmark suite. - Help ensure multi-material results are reproducible and scientifically credible, in partnership with the team that owns V&V methodology. Communication & Collaboration - Collaborate closely with physicists, applied mathematicians, and software engineers. - Contribute to internal technical documentation and external scientific publications. - Present findings in technical meetings and contribute to peer-reviewed journal articles and conference papers. ## Qualifications - Education: Ph.D. in Mathematics (preferred), Applied Mathematics, Computational Physics, or a closely related field, with a focus on numerical methods for fluid dynamics. - Strong background in numerical analysis for PDEs, particularly for fluid dynamics. - Hands-on experience with invariant-domain preserving (IDP) methods or comparable certifiably robust discretization frameworks for hyperbolic/compressible flow. - Experience with finite element methods and hands-on development using deal.II (strongly preferred) or similar frameworks. - Experience developing scientific software in C++. - Experience working in high-performance computing environments (MPI-based parallelism and large-scale simulations). - Familiarity with multi-material modeling techniques in CFD. - Experience with verification and validation of numerical methods. - Strong written and verbal communication skills, with demonstrated ability to contribute to scientific publications. - Must be a U.S. citizen or national, U.S. permanent resident (current Green Card holder), or lawfully admitted into the U.S. as a refugee or granted asylum. Desired - Background in radiation hydrodynamics, high-energy-density physics, or related multi-physics domains. - Experience with mathematical modeling for multi-material compressible flows. - Experience coupling hydrodynamics with radiation transport. - Experience contributing to large, research-grade scientific codebases. - Demonstrated ability to balance theoretical rigor with practical computational implementation. ## Equal Employment Opportunity Xcimer Energy is proud to be an Equal Opportunity/Affirmative Action Employer and is committed to attracting, retaining, and developing a highly qualified, diverse, and dedicated work force. Xcimer Energy hires and promotes people on the basis of their qualifications, performance, and abilities. We support the establishment and maintenance of a workplace that fosters trust, equality, and teamwork, in which all employees recognize and appreciate the diversity of individual team members. We provide all qualified applicants for employment and employees with equal opportunities for hire, promotion, and other terms and conditions of employment, regardless of their race, color, religion, gender, sexual orientation, gender identity, national origin/ethnicity, age, physical or mental disability, genetic factors, military/veteran status, or any other status or characteristic protected by federal, state, and/or local law. Xcimer Energy will consider for employment qualified applicants with criminal histories in a manner consistent with applicable federal, state, and local laws. For more information on “EEO Is the Law,” please see [here](https://www.dol.gov/sites/dolgov/files/ofccp/regs/compliance/posters/pdf/eeopost.pdf) and [here](https://www.dol.gov/sites/dolgov/files/ofccp/regs/compliance/posters/pdf/OFCCP_EEO_Supplement_Final_JRF_QA_508c.pdf). ## Benefits Xcimer offers a comprehensive benefits package designed to support employee health, well-being, and long-term success. Benefits include medical, dental, and vision coverage; basic and supplemental life insurance; short- and long-term disability; paid parental leave for employees at the time of birth or adoption; and a 401(k) with a company match of up to 6%. Eligible employees also receive equity, allowing them to share in the company’s long-term success. Xcimer operates under a flexible Paid Time Off (ATO) approach. Rather than a fixed number of vacation days, employees are trusted to take the time they need to rest and recharge while meeting the expectations of their role and team. In addition, employees receive paid sick time, 13 company-paid holidays, and an annual paid company shutdown. Benefits are available to regular employees, including part-time and fixed-term roles, as well as interns, with eligibility varying by benefit. ## About Xcimer Energy ## Company Overview - **One-liner**: Xcimer Energy is building the world’s most powerful excimer lasers to commercialize inertial fusion energy, delivering safe, affordable, and effectively limitless power while also strengthening national security. - **Entity Type**: Private (Series A; total funding ~$200M) - **Headquarters**: Denver, Colorado, United States (with manufacturing operations in Tucson, Arizona) - **Founded**: 2022 - **Founders**: Conner Galloway (CEO, CSO) and Alexander Valys (President, CTO) ## Core Business - **Primary industry/industries**: Fusion energy (inertial confinement fusion), laser systems, national security/defense - **Target customers**: B2B / B2G (utilities, government, defense contractors, national laboratories) - **Mission or purpose statement**: “Transform decades of scientific progress into commercial fusion plants to deliver safe, affordable, and effectively limitless energy—while improving air defense and national security.” ## Products & Services - **Phoenix (2026)**: Prototype system demonstrating core laser technology and laser architecture in Denver. - **Anvil (2028)**: 200 kJ, two-sided inertial fusion energy (IFE) excimer beamline demonstrator using Argos laser modules – the largest laser amplifiers in the world. - **Vulcan (2031)**: Engineering (wall-plug) breakeven demonstration – world’s largest laser, combining many Argos modules to achieve 4 MJ of laser energy on target, upgradeable to 12 MJ. - **Athena (2035)**: First commercial laser fusion power plant, delivering 400 MW of electricity to the grid. - **National Security Applications**: Nuclear Weapons Effects Testing (NWET), stockpile stewardship, and directed energy systems. ## Market Standing - **Valuation/Market Cap**: Not publicly available - **Key Metric**: Total funding – “nearly $200 million” per FAQ page; “more than $150M raised” per media page (conflicting reports, both cited) - **Notable Investors/Partners**: Hedosophia, Breakthrough Energy Ventures, Lowercarbon Capital, Prelude Ventures, Emerson Collective, Starlight Ventures, Wireframe Ventures, Leitmotif Ventures, Gigascale Capital. Also partners with Los Alamos National Laboratory, Lawrence Livermore National Laboratory, Oak Ridge National Laboratory, Naval Research Laboratory, MIT, University of Rochester, General Atomics, Westinghouse. - **Growth Signals**: Headcount of 109 employees (+45.6% YoY), plans to double the team over the next year, 32 open positions across 5 departments, largest laser fusion award from U.S. Department of Energy’s Milestone-Based Fusion Development Program. ## Competitive Advantages - **Excimer laser architecture (KrF)**: 30x lower cost per joule than the solid-state lasers used at NIF; technology is commercially proven in semiconductor lithography. - **Scientifically validated approach**: Only fusion method that has achieved scientific breakeven in the laboratory (NIF ignition). - **Aggressive but grounded roadmap**: Wall-plug breakeven by 2031, grid power by 2035 – one of the fastest timelines in the industry. - **Dual-use technology**: Fusion energy platform also serves critical national security applications, opening additional funding and partnership avenues. ## Strategic Focus - Complete Phoenix and Anvil milestones to de-risk laser architecture. - Hire and scale the team (targeting double the current headcount). - Secure site for Vulcan and prepare for engineering breakeven demonstration. - Advance commercial fusion power plant (Athena) design and regulatory pathways. - Expand defense and government partnerships. ## Why Work Here - **Culture highlights**: Values precision, creativity, collaboration, and questioning assumptions. Team includes top talent from fusion, energy, defense, aerospace, semiconductor lithography, and academia. - **Work environment**: Primarily onsite in Denver, CO (engineering roles); flexible work environment, dog-friendly office, free lunch Tuesdays and Thursdays. - **Notable perks**: Competitive wages, equity compensation plan, comprehensive health/dental/vision insurance, 401k with employer match, up to 12 weeks paid parental leave, 13 paid holidays, generous sick leave and vacation, relocation package, professional growth opportunities. - **Internship program**: Highly competitive, hands-on experience in fusion science and engineering; strong track record of converting interns to full-time hires. ## Sources 1. [xcimer.energy/company](https://xcimer.energy/company/) 2. [xcimer.energy/careers](https://xcimer.energy/careers/) 3. [xcimer.energy/faq](https://xcimer.energy/faq/) 4. [xcimer.energy/media](https://xcimer.energy/media/) 5. [linkedin.com/company/xcimer-energy-corporation](https://linkedin.com/company/xcimer-energy-corporation) ## Other roles at Xcimer Energy - [Summer 2027 Internship - Physics](https://feeny.ai/job/summer-2027-internship-physics-xcimer-energy-denver-rxez3syb9xhx) — Denver, CO - [Summer 2027 Internship - Optical Engineering](https://feeny.ai/job/summer-2027-internship-optical-engineering-xcimer-energy-denver-bpxgc6w56qn9) — Denver, CO - [Summer 2027 Internship - Mechanical Engineering](https://feeny.ai/job/summer-2027-internship-mechanical-engineering-xcimer-energy-denver-kdgkh864pf88) — Denver, CO - [Summer 2027 Internship - Electrical and Pulsed Power Engineering](https://feeny.ai/job/summer-2027-internship-electrical-and-pulsed-power-engineering-xcimer-energy-vqhsgjrzb8qb) — Denver, CO - [Summer 2027 Internship - Computational and Software Engineering](https://feeny.ai/job/summer-2027-internship-computational-and-software-engineering-xcimer-energy-t32p0nv8kyvy) — Denver, CO - [Data Engineer](https://feeny.ai/job/data-engineer-xcimer-energy-denver-nf6k4sr1dzcn) — Denver, CO - [Laser/Optical Simulation Engineer](https://feeny.ai/job/laser-optical-simulation-engineer-xcimer-energy-denver-5xmhb2cckepp) — Denver, CO - [Senior Thermal Analyst](https://feeny.ai/job/senior-thermal-analyst-xcimer-energy-denver-y978v74dnnj9) — Denver, CO - [Senior Scientific Software Engineer](https://feeny.ai/job/senior-scientific-software-engineer-xcimer-energy-denver-89we5hqhpzsb) — Denver, CO - [Senior Platform Engineer](https://feeny.ai/job/senior-platform-engineer-xcimer-energy-denver-4j9nqnw3z7hg) — Denver, CO