I

Infleqtion

Full-stack quantum hardware and software

Quantum Software Engineer - Nuclear

Full-Time
$110k - $182k/yr+ 401(k) match + Equity Program
Mid
Bachelor's, Master's, PhD
Chicago, IL, USA
HybridThree days on-site per week required.
Software Engineering
No H1B Sponsorship

About the job

Requirements
  • A Bachelor of Science or Master of Science degree in Computer Science, Physics, Applied Mathematics, Electrical Engineering, or a closely related field.
  • High proficiency in programming, with fluency in Python preferred; proficiency in C, C++, or Julia is also accepted with the ability to rapidly upskill in Python.
  • General familiarity with nuclear physics, including nuclear structure, Goldstone diagrams, fermionic algebra, and Folk Space.
  • Specific experience in at least one nuclear physics subfield, such as quantum chromodynamics, effective field theory, or many-body physics.
  • Experience with quantum algorithms for physical science applications, such as quantum phase estimation, the variational quantum eigensolver, and Hamiltonian simulation.
  • Experience applying quantum algorithms to nuclear physics.
  • Familiarity with artificial intelligence, including machine learning, large language models, and agentic artificial intelligence.
  • Experience with open-source quantum software frameworks such as Cirq or Qiskit, including modifying the libraries.
  • Professional-level verbal, written, and presentation communication skills.
  • Ability to work in a collaborative, cross-functional, team-oriented, and matrixed environment.
  • Ability to learn new and complex topics quickly and execute productization efforts.
  • Ability to work in the office any three days per week.
  • Ability to travel domestically and potentially internationally up to 10%.
Responsibilities
  • Conduct research and development toward advances in quantum technology, focusing on nuclear physics applications.
  • Write and test code applying quantum algorithms to nuclear physics problems.
  • Interface and collaborate with external groups interested in using quantum computing to solve nuclear physics problems.
  • Contribute to government and commercial nuclear proposals.
  • Collaborate with experimental physicists and software engineers to connect theoretical concepts with practical implementation.
  • Publish research findings in scientific journals and present them at conferences.
  • Stay current with developments in quantum algorithms and nuclear physics.
  • Provide guidance and support to other team members in a collaborative research environment.
Desired Qualifications
  • A PhD in quantum computation, Physics, Computer Science, or a directly related field.
  • Familiarity with quantum computing concepts including error correction, fault tolerance, native gate decomposition, qubit mapping and routing, and variational quantum algorithms.
  • Experience with the advanced open-source quantum software framework Stim.
  • Familiarity with professional software engineering practices including coverage, integration testing, type checking, unit testing, and version control.
  • Experience with backend development using FastAPI, PostgreSQL, and SQLAlchemy.
  • Experience with cloud development, especially on Google Cloud Platform and Amazon Web Services.
  • Familiarity with continuous integration and continuous delivery, automated actions, issue tracking, version control, and other GitHub features.
  • Familiarity with security best practices including access control, encryption at rest, key rotation, and logging.
  • Exposure to or interest in front-end and graphical user interface development using React, JavaScript, HTML, CSS, or PyQt.

About the company

Infleqtion builds neutral-atom quantum hardware and complementary software for computing, sensing, and security. Its hardware uses lasers to cool and trap neutral atoms and perform quantum operations, with products like Sqale for computation, Tiqker clocks for precise timing, RF receivers for spectrum sensing, and inertial sensors for GPS-denied navigation; its Superstaq software optimizes algorithms across different quantum machines. The company differentiates itself by vertically integrating hardware and software and leveraging neutral-atom technology to scale, along with a history of strategic acquisitions and a NYSE listing. Its goal is to accelerate practical quantum adoption by expanding its roadmap and serving government and commercial customers across computation, sensing, navigation, and secure communications.

Company Size

201-500

Company Stage

Growth Equity (Non-Venture Capital)

Total Funding

$936.6M

Headquarters

Louisville, Colorado

Founded

2007

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Simplify's Take

What believers are saying

  • NASA's August 27, 2026 award doubled QGGPf funding to $40 million.
  • September 10, 2026 Cisco collaboration opens distributed-quantum networking and telecom integration opportunities.
  • Shunkai became Japan's first operational neutral-atom quantum computer on September 7, 2026.

What critics are saying

  • Quantum hardware revenues remain contract-driven; NASA's $20 million extension ends after 2027.
  • Cisco and Riverlane can commoditize networking and error-correction layers, squeezing Infleqtion's software moat.
  • If 2030 fault-tolerant milestones slip, investors reprice INFQ as a science project, not a platform.

What makes Infleqtion unique

  • Infleqtion pairs neutral-atom hardware with Superstaq software, plus full-stack sensing and networking, since 2007.
  • On September 24, 2026, Sqale reached 30 entangled logical qubits using 80 physical qubits.
  • The February 2026 NYSE listing raised over $550 million, funding commercialization and deployment.

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Benefits

Health Insurance

Dental Insurance

Vision Insurance

Life Insurance

Disability Insurance

Unlimited Paid Time Off

401(k) Company Match

Paid Maternity/Paternity Leave

Student Loan Repayment

Family Leave

Short Term & Long Term Disability

Stock Options

Company Equity

Growth & Insights and Company News

Headcount

6 month growth

-2%

1 year growth

0%

2 year growth

-9%
Quantum Zeitgeist
Oct 13th, 2026
Infleqtion UK wins Innovate UK funding to build deployable Rydberg atom direction finder

Infleqtion UK is developing a quantum radio frequency direction finding system with funding from Innovate UK. The amount was not disclosed. The product, called Quantum Spectrum-DF, uses Rydberg atoms to detect and locate high-frequency signals with optical techniques instead of conventional antennas. Infleqtion says this allows a compact system for platforms that cannot carry traditional equipment because of weight or space limits. Leonardo is working with Infleqtion on the project. "For defence platforms, reducing size, weight and power consumption while preserving operational effectiveness is a significant advantage," said Oliver Sims, electronic warfare chief technologist at Leonardo. The system builds on an earlier tested prototype and targets defence and civilian uses, including spectrum surveillance, passive radar, and resilient navigation.

Seeking Alpha
Oct 8th, 2026
Infleqtion: quantum revenue before quantum computing.

Infleqtion: quantum revenue before quantum computing. 18.28K Followers Summary. * Infleqtion generated $23.4 million of H1 revenue, but one customer still represented 82% of second-quarter sales. * Quantum computing is beginning to monetize, with finance, energy, and precision-medicine customer engagements already generating revenue for Infleqtion. * Infleqtion demonstrated 30 logical qubits using 80 physical qubits, advancing from just two logical qubits in 2024. * Infleqtion holds approximately $582 million of liquidity without debt, providing substantial runway despite continued operating losses and cash burn. * At nearly 50x FY2026 revenue, INFQ's valuation already requires commercialization to catch up rapidly with its technological progress. Investment thesis. The debate surrounding Infleqtion, Inc. (INFQ) appears to me as a debate about the timing of fault-tolerant quantum computing. I do not want to get into the technicality of when that will

Asia Pacific Defence Reporter
Oct 8th, 2026
Nova Systems and Infleqtion partner to accelerate AUKUS quantum capability.

Nova Systems and Infleqtion partner to accelerate AUKUS quantum capability. - Oct 8, 2026 Nova Systems and U.S. headquartered quantum technology leader Infleqtion have formed a strategic partnership to fast-track the adoption of quantum technologies across Australia's Defence sector, supporting AUKUS capability priorities and strengthening the nation's advanced defence capabilities. Australia leads the world in quantum research, yet the path from innovation to Defence capability remains challenging. This partnership will bridge that divide, enabling Nova Systems to integrate and assure advanced quantum technologies for real-world Defence and national security applications. As a trusted Australian partner to Defence for more than 25 years, Nova brings the capability assurance and systems integration expertise needed to turn quantum innovation into sovereign capability at scale. "This partnership brings together Australian, UK and US expertise with a shared vision to move quantum technology into real-world operational applications," said Nova Systems CEO Dean Rosenfield. "Our role is not simply to introduce new technology, but to integrate, test and assure advanced solutions that meet the demanding requirements of Defence and national security customers. By partnering with Infleqtion, we're combining leading quantum technology with proven systems integration and Test & Evaluation, Certification & Systems Assurance expertise to deliver capability outcomes faster." "As part of this agreement, Infleqtion brings our experience developing quantum sensing and computing technology for defence and commercial applications," said Matthew Kinsella, CEO of Infleqtion. "This allows us to combine Infleqtion's capabilities with Nova Systems' strengths in systems integration, test and evaluation, and capability assurance to assess performance and suitability for operational use, enabling the development of trusted quantum-based defence solutions in Australia." The agreement positions both organisations as leaders in the delivery of integrated quantum-enabled solutions, supporting Australia's sovereign capability objectives while strengthening collaboration opportunities across AUKUS partners in Defence, critical infrastructure and national security sectors. "Australia has an opportunity to turn its quantum expertise into a lasting advantage for defence," said Chris O'Brien, managing director of Infleqtion Australia. "By combining Infleqtion's quantum expertise with Nova Systems' understanding of Australian defence requirements, we aim to accelerate the path from promising technology to trusted capability. Together, we can help Australian personnel operate more effectively in contested environments while strengthening collaboration across AUKUS partners." The partnership reinforces Nova Systems' commitment to delivering advanced technology solutions for Defence and demonstrates the value of combining sovereign Australian leadership with trusted U.S. technology partners and Nova's established presence across Australia and the United Kingdom.

Yahoo Finance
Oct 7th, 2026
Infleqtion unveils chip-scale quantum sensor with Honeywell, shares down 32% YTD despite analyst targets

Infleqtion has announced a chip-scale optical cavity developed with Honeywell Aerospace and UC Santa Barbara, aiming to shrink quantum sensors into handheld devices using semiconductor-style manufacturing. Despite this technical milestone, the company's share price has fallen 13.6% over the past week and 32.1% year-to-date. The stock now trades at $11.64, well below the analyst fair value estimate of $21.83. However, Infleqtion's price-to-book ratio of 4.6x exceeds both the US tech sector average of 2.8x and peer average of 1.7x. The company's neutral atom systems operate at room temperature using a common hardware and software stack across computing and sensing applications. Nonetheless, reliance on government contracts, ongoing losses, and cash burn pose risks to the undervaluation thesis.

Brenna Hassett
Oct 6th, 2026
Silicon nitride cavity shrinks critical optics for quantum hardware.

Silicon nitride cavity shrinks critical optics for quantum hardware. Infleqtion, Honeywell Aerospace and UC Santa Barbara have built a silicon-nitride optical-cavity prototype intended to reduce the size of laser-stabilization hardware, although its field performance and quantitative advantage over bulk optics have not yet been reported. A piece of optics that can occupy a substantial laboratory assembly has been integrated onto a silicon-nitride chip. On October 6, 2026, Infleqtion announced that its collaboration with Honeywell Aerospace and the University of California, Santa Barbara (UCSB) had produced an integrated optical-cavity prototype for neutral-atom quantum processors, quantum sensors and optical atomic clocks. The company presents the work as a route toward more compact, potentially handheld quantum instruments. The announcement is documented in an Infleqtion technical release, but it does not constitute a peer-reviewed performance study. No sample count, statistical analysis, confidence interval or independent replication is reported, so the result should be read as a fabrication and integration milestone rather than a validated system benchmark. The cavity problem Neutral-atom systems depend on spectrally precise lasers to cool and trap atoms, manipulate internal states and perform quantum gates. The required optical frequencies can drift because of temperature changes, mechanical disturbance, electronics and intrinsic laser noise. An optical cavity provides a frequency reference: light circulates in a resonant structure, and feedback electronics use the resonance to correct laser fluctuations. In many laboratory systems, that reference is assembled from bulk optical components, including mirrors, mounts, spacers, isolators, lenses and vibration-control hardware. Such arrangements can deliver excellent performance, but they occupy space and require careful alignment. The new device changes the physical packaging of the reference rather than introducing a new quantum algorithm or demonstrating a new qubit architecture. What was fabricated Infleqtion engineers and Professor Daniel J. Blumenthal's Optical Communications and Photonic Integration, or OCAQπ, Group at UCSB jointly designed the prototype. Honeywell Aerospace fabricated it on its own photonic manufacturing line using silicon-nitride, or Si[3]N[4], integration processes. Honeywell says it has developed the relevant silicon-nitride photonic-integration processes for approximately a decade, linking the demonstration to an existing foundry capability rather than to laboratory-only fabrication. Silicon nitride is used here as an integrated photonic material, not as a qubit medium. Its role is to guide and confine light in a resonant structure that can act as a stable reference for laser-frequency control. A wafer-compatible process may eventually allow repeated fabrication and tighter integration with waveguides, couplers and control electronics, although fabrication compatibility alone does not establish high yield or uniform performance. Blumenthal's research profile at UCSB covers integrated lasers and photonic components for optical atomic clocks, atom interferometers, and experiments involving neutral atoms and trapped ions. That background is relevant because the same frequency-control problem appears across several precision-quantum platforms. Similar photonic-integration questions also feature in research communities associated with MIT and in peer-reviewed literature published by Nature, where miniaturization must be evaluated together with noise, thermal stability and packaging. The work also builds on photonic intellectual property developed by SiNoptiq, a UCSB spin-off founded by Blumenthal and acquired by Infleqtion in 2024. The acquisition connects university-developed technology with Infleqtion's neutral-atom hardware program, but it does not by itself establish production yield, long-term operating stability or commercial readiness. What the announcement does not establish The available official materials do not disclose the chip or cavity dimensions, optical quality factor, resonance linewidth, propagation loss, thermal coefficient, achieved frequency stability, packaging results or field-test data. They also provide no clock-accuracy measurement, sensor-sensitivity result, atom number, gate fidelity or processor benchmark. Consequently, a quantitative advantage over conventional bulk-glass cavities cannot yet be confirmed. This limitation is important in precision photonics. A smaller resonator is useful only if it preserves the frequency reference quality needed by the surrounding instrument. Relevant tests would normally include environmental sensitivity, vibration response, temperature cycling, coupling efficiency, long-term drift and performance after packaging. The announcement does not report those measurements, nor does it provide p-values, confidence intervals or a comparison group. From laboratory optics to hardware The practical attraction is straightforward: every external optical component adds alignment, packaging and environmental-control demands. A cavity integrated with photonic circuitry could reduce the volume of the optical subsystem and simplify assembly in equipment intended for deployment outside a laboratory. The proposed application set includes atomic timing devices, quantum-enhanced inertial navigation, compact sensors and neutral-atom quantum computers. Miniaturization, however, does not remove the underlying engineering requirements. A useful instrument would still need a narrow-linewidth laser, efficient coupling into the chip, stable mechanical and thermal packaging, control electronics and calibration that survives temperature changes and vibration. The cavity would also have to maintain the required reference quality when connected to the rest of the instrument rather than operated as an isolated prototype. These constraints resemble those faced by other precision technologies, from navigation instruments to space-qualified timing systems. NASA and CERN, for example, routinely treat packaging, environmental qualification and system-level calibration as separate engineering questions from the performance of an individual optical component. The same distinction applies here: integration is a prerequisite for a compact system, not proof that the final system has been achieved. Integration is not deployment The broader quantum industry is moving on several fronts at once. Some groups are expanding research networks and processor scale, while others are compressing the optical and electronic subsystems that make quantum control possible. The Infleqtion-Honeywell-UCSB prototype belongs to the second effort: it addresses the physical footprint and manufacturability of laser stabilization. The announcement gives no evidence that complete system-level tests have been completed. It does not report independent replication or a controlled comparison with the bulk-glass cavities used in relevant laboratory systems. A foundry process can make repeated fabrication possible in principle, but wafer processing alone does not guarantee cavity uniformity, usable yield, economical packaging or stable operation under field conditions. The most defensible conclusion is therefore narrow but significant. Infleqtion, Honeywell Aerospace and UCSB have demonstrated a silicon-nitride integrated-cavity prototype and connected it to a manufacturing pathway that Honeywell says has been developed over roughly ten years. The result supports continued engineering toward smaller quantum hardware, while the central performance questions-dimensions, losses, linewidth, stability, environmental robustness and deployment-remain open for future measurements.