Applied Physicist Quantum RF Sensing (QSS)

Infleqtion is a global quantum technology company solving some of the worlds most challenging problems. We build and integrate quantum computers sensors and networks. From fundamental physics to leading-edge commercial products Infleqtion enables quantum everywhere through an ecosystem of devices and platforms.

Quantum Spectrum also known as QRF develops fieldable radio-frequency sensing systems based on Rydberg atoms. The team combines atomic physics lasers and photonics RF electronics embedded controls software and precision hardware to turn laboratory prototypes into repeatable integrated sensing systems.

Position Summary

Infleqtion is seeking an Applied Physicist to build operate and improve experimental platforms for Rydberg-atom radio-frequency sensing. Reporting to the Director of R&D Quantum RF this physicist will independently own defined experiments and testbeds under senior technical direction translate atomic optical and RF behavior into measurable sensor improvements and carry validated improvements into integrated QRF systems. The role is centered on hands-on laboratory work; modeling supports experiment design and interpretation rather than serving as the principal output.

Job Responsibilities

The duties and responsibilities below describe the essential functions of the role. Depending on business needs the position may perform some or all these duties. Duties responsibilities and activities may change or new ones may be assigned at any time with or without notice.

• Own defined experimental campaigns addressing QRF sensitivity noise stability bandwidth dynamic range and repeatability.

• Build align commission operate maintain and troubleshoot persistent testbeds that integrate lasers and optics atomic-sensing hardware RF and electronic instrumentation controls and data acquisition.

• Design and execute controlled experiments that isolate performance limitations and convert results into specific hardware operating-point calibration or control-system improvements.

• Integrate validated experimental improvements into sensor heads subsystems and complete QRF systems; verify performance against quantitative requirements and documented test methods.

• Characterize vapor cells and RF resonators including thermal optical geometric material field-delivery and repeatability effects that influence sensor performance.

• Establish and maintain laser-frequency locks optical-power stability photodetection and associated noise-characterization methods.

• Calibrate and characterize RF delivery through electrodes resonators antennas TEM or GTEM cells and related test configurations using appropriate RF and microwave instrumentation.

• Develop automated instrument-control parameter-sweep optimization calibration and data-analysis workflows using Python or comparable scientific tools.

• Analyze experimental data with appropriate uncertainty noise and repeatability treatment; use atomic optical or electromagnetic models to guide experiments interpret results and investigate discrepancies among predicted benchtop subsystem and integrated-system performance.

• Translate findings into design recommendations configuration records test procedures technical reports and verification evidence that engineers and technicians can reproduce.

• Work with RF optical-mechanical electrical embedded-software systems and technician personnel to make experimental configurations stable maintainable and transferable.

• Provide occasional support for laboratory or field demonstrations and customer-program testing as assigned following applicable safety export-control configuration-control and documentation requirements.

• Bachelors degree in physics applied physics optical engineering electrical engineering or a closely related field plus at least four years of relevant hands-on experimental experience; a masters degree plus at least two years; or a PhD with directly relevant experimental research. Equivalent combinations of education and experience will be considered.

• Demonstrated hands-on experience personally building aligning operating and troubleshooting complex experimental apparatus that integrates two or more of the following: lasers or optics electronics RF or microwave hardware thermal or mechanical hardware and software or controls.

• Practical experience with laser and optical alignment photodetection electronic instrumentation and diagnosis of noise stability or performance limitations.

• Working knowledge of RF measurements and experience using equipment such as signal generators spectrum analyzers oscilloscopes or vector network analyzers.

• Ability to design controlled experiments analyze noisy data assess measurement uncertainty and repeatability and draw defensible conclusions from incomplete or conflicting results.

• Experience automating experiments and analyzing data using Python or a comparable scientific programming environment.

• Ability to independently plan and execute defined laboratory work document results clearly and collaborate across physics engineering and product disciplines while seeking senior direction for broader architecture and scientific strategy.
• Comfortable working in a fast-moving environment where designs schedules and supplier constraints evolve quickly.

Preferred Qualifications

• Hands-on experience with Rydberg atoms electromagnetically induced transparency AutlerTownes spectroscopy atomic RF electrometry or closely related vapor-cell sensing is strongly preferred.

• Experience with rubidium or cesium vapor cells multi-laser spectroscopy acousto-optic or electro-optic modulators optical-frequency locking optical-power stabilization or low-noise photodetection.

• Experience characterizing RF resonators calibrated RF-field delivery antennas electrodes TEM or GTEM cells or microwave measurement systems.

• Experience integrating precision laboratory instruments into stable repeatable transportable or field-capable systems.

• Familiarity with requirements-based verification configuration-controlled hardware and test evidence for aerospace defense scientific-instrumentation or U.S. government programs; a current or previously held U.S. government security clearance is preferred but not required.

• Experience using Ansys HFSS COMSOL Zemax Rydiqule or related modeling tools to design or interpret experiments.

Working Conditions and Physical Requirements

Work is performed primarily on site in laboratory office and integration/test environments and involves work around laser systems RF and microwave equipment electronic test equipment heated vapor-cell hardware optical tables tools and precision instrumentation. Required personal protective equipment will be provided and must be used in accordance with company requirements. With or without reasonable accommodation the role requires the ability to work at laboratory benches for extended periods perform fine optical and electronic alignment and adjustment tasks and occasionally lift and carry laboratory equipment or components weighing up to forty pounds. Up to 10% of travel may be required.

• Salary Range: per year 00
• 100% company-paid medical dental vision short/long-term disability
• Employer-funded Health Savings Account
• Unlimited PTO
• 401(k) match
• Company-paid Life and AD&D Insurance
• Flexible Savings Account
• Paid FMLA Maternity/Paternity Leave
• Employee Assistance Program
• Student Loan Repayment
• Equity Program

Notice to Recruitment Agencies:

Infleqtion does not accept unsolicited resumes from agencies. Infleqtion is not responsible for any fees related to unsolicited resumes.

Required Experience:

IC