Python orchestration, primitive compilation, deterministic simulation, TTL/photon emulation and traceable outputs.
Quantum Control Systems Engineer
Trapped-ion control software from pulse intent to measurable evidence.
Deterministic timing, hardware adapters, photon acquisition, and evidence-gated calibration.
01 · TIMING
Measurement-aware pulse validation
Specify what real captures must prove across pulse width, alignment, phase window and repeatability.
Width · alignment · phase · repeatability 02 · ARCHITECTURERegistry and adapter-driven control
Keep device I/O, qubit growth and future transport or photonic links outside orchestration branches.
Maintainable · extensible · observable 03 · VERIFICATIONSoftware simulation + electrical emulation
Exercise the same contracts through deterministic simulation and TTL/photon hardware before any ion claim.
No-ion failure-path coverage 04 · FULL STACKOpenQASM → hardware → PMT evidence
Preserve circuit identity through primitive compilation, backend execution, photon acquisition and analysis.
Traceable circuit-to-photon ownershipM4i.66xx AWG/DDS adapter, multi-tone carrier control, SSB upconversion and hardware-specific APIs.
No personal Spectrum operation, eleQtron proprietary topology or physical-ion gate-fidelity claim.
01 · Measurement-aware timing validation
A timing claim is not complete until the scope agrees.
The interactive trace is a literature-informed model of the intended sequence. It defines the signals, timing relationships and acceptance questions that a real capture would need to verify.
Published parameter
MW Qubit 1 · Gate operation
Ref [2] · PRX 15, 021079 (2025)
- A / ΩAmplitude
- Ω1 / 2π = 94.8 kHz
- f / ωFrequency
- fμw ≈ 12.6 GHz
- τDuration
- 313 µs
- φPhase
- φ(t) = 0.749 sin(2π · 94.8 kHz · t)
Notation: A amplitude · Ω/2π Rabi rate · f frequency · ω/2π angular-frequency form · τ duration · φ phase · Δ detuning
Each channel has a fixed color. Pulse height is an ON/OFF envelope unless a paper reports intensity or Rabi frequency; stage widths are visually compressed.Evidence boundary: this is a composite literature model, not one experimental shot and not eleQtron proprietary calibration. Ref [1] reports the cooling sequence at an axial frequency of 117.48(11) kHz; Ref [2] reports the MAGIC gate in a different setup at 98.08 kHz. Unpublished hardware settings are shown as N/R (not reported).
References: [1] Sriarunothai et al., J. Mod. Opt. 65, 560–567 (2018) · [2] Nünnerich et al., Phys. Rev. X 15, 021079 (2025) · [3] eleQtron · MAGIC uses radio-frequency control
Public-evidence system study
The scope is an engineering sidecar—not the shot-loop data plane.
University of Siegen apparatus descriptions place deterministic sequencing, detector acquisition and state discrimination inside the experiment loop. Oscilloscopes observe selected electrical nodes through probes or splitters for commissioning, validation and debugging.
01 · SchedulePython or host software compiles the experiment; a real-time sequencer owns TTL triggers and deterministic I/O.
02 · DriveAOM/EOM channels prepare and detect; AWG/DDS plus microwave conversion deliver coherent control.
03 · Fluoresce369 nm emission passes collection optics, spatial filtering and a narrow-band optical filter.
04 · AcquireEMCCD, PMT or SPAD data enters a frame grabber, counter, TDC, ADC or FPGA for classification and feedback.
- Laser lockPhotodiode, cavity transmission and error signal.
- RF / microwaveIF envelope, trigger, mixer or crystal-detector output.
- Clock / triggerTTL fan-out, camera-ready and AWG trigger alignment, skew and jitter.
- Detector front endPulse amplitude, noise, threshold, saturation and signal integrity.
Software boundary
Python/SCPI can configure the scope, acquire waveforms and emit commissioning, calibration or monitoring artifacts. The real-time controller still owns shot scheduling, while detector interfaces and analysis software own structured photon counts, frames, timestamps and bright/dark decisions.
Not claimed: eleQtron's current oscilloscope vendor, bandwidth, sample rate, channel count or installed topology are not public.System-study references: [4] Piltz, 2016 · EMCCD/PMT triggering and ADwin sequencing · [5] Huber, 2024 · AWG hand-off and image feedback · [6] eleQtron · Python control software and programmatic device control · [7] DLR QSea II · SPAD and control-electronics integration direction
Requested window, sample depth and scope readback must agree. A plausible trace from a shortened pre-trigger record is rejected.
All channels must share one record length, and the expected dark window must prove that the capture contains the intended shot phase.
Repeated captures must agree numerically. A conflicting capture stays a disagreement; it is never averaged into a green result.
TRAPPED-ION CONTROL SYSTEMS
Connect optics, electronics, and control software.
A trapped-ion control architecture assigns a timing owner to each operation, from instrument setup to the detector window, and defines what crosses between software and hardware. Separate measurement points let a team check the plan, electrical timing, optical response, and ion readout.
From experiment intent to the ion and back
Optional qubit drive
Support for ions and laser
Monitoring of I/O and light
GUI / API
- Role
- The experiment interface accepts scan parameters, pulse sequences, or circuits and returns run results.
- How to verify
- Submit a known circuit or small scan and compare the accepted parameters, units, point order, and run ID with the request. This checks intent at the software boundary.
- References
- Example circuit and low-level pulse interfaces · Clark et al. (2021), QSCOUT
Host plan
- Role
- Translate experiment intent into shots using device capabilities, calibration values, and explicit timing constraints.
- How to verify
- Inspect the generated shot plan for operation order, channels, durations, units, and calibration version. Compare a known input with the expected plan before execution.
- References
- Circuit-to-pulse control example · Clark et al. (2021), QSCOUT
Sequencer
- Role
- Place output transitions, waveform triggers, and acquisition gates on a deterministic timeline. ARTIQ kernel and RTIO are one implementation.
- How to verify
- Compare recorded or loopback timestamps with planned events, including relative order and gate boundaries. Scope representative outputs against a shared trigger to verify connector timing.
- References
- Kernel scheduling and RTIO input/output events · ARTIQ RTIO concepts
Timed I/O
- Role
- Logic edges, DDS tones, or AWG waveforms command downstream drivers, switches, and amplifiers.
- How to verify
- Probe the relevant connector with suitable bandwidth and a common timing reference. Check polarity, amplitude, frequency, and pulse widths against the plan. Register readback confirms reported configuration; the trace shows what leaves the connector.
- References
- Example DDS-based pulse hardware · Clark et al. (2021), QSCOUT · Timing of output events · ARTIQ RTIO concepts
Laser & optics
- Role
- Laser sources supply light. Electrically driven AOMs or EOMs modulate selected beams, and delivery optics bring them to the ions for cooling, control, or detection.
- How to verify
- Pick off the beam downstream of the modulator and compare intensity and pulse timing with the electrical trigger. Use a referenced optical frequency or phase measurement for shifts, phase, or sidebands. Check the ion response separately.
- References
- Laser systems and optical delivery in a demonstrator · Pogorelov et al. (2021)
RF / microwave (optional)
- Role
- Where the qubit encoding supports it, a driven antenna or electrode couples an RF or microwave field directly to the ions.
- How to verify
- Check the drive envelope, frequency, and phase at a defined electrical reference. Use an ion resonance or Rabi scan to measure coupling and calibrate pulse area at the ions.
- References
- Demonstration of RF-driven trapped-ion gates · Nünnerich et al. (2025)
Trapped-ion register
- Role
- The confined ions are prepared, evolve under the applied fields, and produce state-dependent fluorescence under the detection beam.
- How to verify
- Measure an ion response such as a resonance or Rabi scan. Interleave known bright and dark preparations to estimate state preparation and readout error before interpreting reduced contrast as a drive error.
- References
- Example optical qubit control and state detection · Pogorelov et al. (2021) · Example ion-response measurements used for gate calibration · Gerster et al. (2022)
PMT / camera
- Role
- Collection optics deliver fluorescence to a photon detector or an imaging sensor. PMTs yield photon pulses; cameras integrate and return image frames.
- How to verify
- Compare bright and dark preparations and background. For a camera, inspect image alignment, saturation, and per-ion regions. For a PMT, compare photon-count distributions under the same detection window.
- References
- Example fluorescence collection and detection · Pogorelov et al. (2021)
Acquisition
- Role
- Acquire PMT counts or event times during the detection gate, or trigger camera exposures and associate the frames with the correct shot.
- How to verify
- Compare the gate or exposure trigger with the detection pulse on a common clock. Check record IDs for drops, duplicates, and shot association. If the result drives a later pulse in the same shot, measure decision and output latency against its deadline.
- References
- Timestamped real-time input events · ARTIQ RTIO concepts · Example detector integration · Pogorelov et al. (2021)
Host analysis
- Role
- Classify states, fit scans, and retain shot and calibration context. Host analysis can propose parameters for later shots.
- How to verify
- Replay known records through classification and scan fitting. Compare outputs and uncertainty with a baseline, record the parameter version, and run an independent confirmation scan before applying a calibration candidate.
- References
- Example between-shot calibration from ion measurements · Gerster et al. (2022)
GUI / results interface
- Role
- Return shot outcomes, scan plots, and available calibration candidates to the user or calling program.
- How to verify
- Trace displayed or exported points back to the run ID, raw records, units, and analysis version. Check that a partial run marks missing shots and that the interface labels proposed parameters as candidates.
- References
- Example user-facing experiment workflow · Clark et al. (2021), QSCOUT
Trap RF / DC
- Role
- Trap RF and DC electrode potentials confine the ions and set their equilibrium positions. Some platforms also time DC transport waveforms.
- How to verify
- Check available RF monitor readings and DC readbacks at defined points. Confirm trapping conditions with ion observables such as secular frequencies or a micromotion diagnostic.
- References
- Example trap and electrical subsystems · Pogorelov et al. (2021)
Laser lock
- Role
- A local servo stabilizes a laser using an optical error signal. The host can inspect lock status alongside other readiness signals.
- How to verify
- Record lock status and error signal over the shot series. Use a suitable independent frequency reference if the experiment requires a bound on absolute drift or detuning.
- References
- Example laser frequency stabilization architecture · Pogorelov et al. (2021)
Device readbacks
- Role
- A host monitor records reported setpoints, device state, and health diagnostics with their sources and time bases.
- How to verify
- Compare requested settings with timestamped device responses and check for stale or missing values. Measure the physical output independently when the claim concerns pulse timing, RF amplitude, or phase.
- References
- Distinction between host activity and timed I/O events · ARTIQ RTIO concepts · Example timed control electronics · Clark et al. (2021), QSCOUT
Optical pickoff
- Role
- A pickoff sends sampled light to a photodetector and scope for an intensity-versus-time measurement.
- How to verify
- Check detector bandwidth and saturation, then compare light level, pulse edges, and extinction against a trigger. Use a suitable interferometric, heterodyne, or spectral measurement to resolve phase or sideband content.
- References
- Context for optical modulation and delivery subsystems · Pogorelov et al. (2021)
Who owns each part of the experiment?
Non-real-time
The host configures the trap RF drive and DC electrode biases, including compensation electrodes where present. It also manages auxiliary power supplies and reads back their output and status.
Before arming, check RF and DC readbacks, power-supply status, and laser-lock status. Wavemeter readings can be collected between shots.
Real-time
A real-time sequencer schedules output events and acquisition windows. In ARTIQ, a core device and RTIO implement this timing model. For an AOM-driven beam, timed RF drive controls the optical pulse, subject to actuator and propagation delays.
At the measurement point, check alignment of pulse edges, widths, and detector windows.
Feedback control
A feedback controller compares a measured signal with its setpoint and drives an actuator to reduce the error. For optical-power stabilization, a photodetector measures the beam and the controller adjusts the AOM RF amplitude.
For each loop, define the sensor, error signal, controller, actuator, control bandwidth, latency, and response to loss of signal.
Software layer
Software translates circuit and scan intent into an executable plan, maps operations to device capabilities, and associates acquisition and analysis with the run. The host and real-time sequencer execute the parts they own.
For every run, record parameters, calibration provenance, configuration, and run identity so the result can be traced back to its inputs.
From trap setup to a timed shot
The host checks hardware readiness before handing the shot to the sequencer.
Non-real-time hardware
- Trap RF drive setpoint and monitor
- DC and compensation electrodes voltage setpoints and readbacks
- Auxiliary power supplies output enable and status
Host sends setpoints
Devices return readbacks
Devices return readbacks
Host software
Apply settings, check readbacks, and confirm readiness.
Arm the shot
after checks pass
after checks pass
Real-time sequencer
Run the planned output and acquisition events on a deterministic timeline (for example, RTIO).
Monitor AOM and EOM optical signals and electrical control state
Observe the control electronics through controller telemetry and device readbacks, alongside sampled-light waveforms from a photodetector. Keep the source, units, and timestamp basis with each observation.
Control electronics
Expose supported digital levels, switch states, frequency settings, and health diagnostics.
Monitoring interface
Read available status through a controller telemetry stream or device-query interface.
Host collector
Normalize units, retain the source and timestamp basis, and track connection and data freshness.
Electronic monitor
Display settings, readbacks, diagnostic flags, and stale or unknown fields with their source labels.
Each value identifies its source as a requested setting, device readback, or instrument measurement. Controller snapshots may miss short pulses. Verifying RF output amplitude, phase, and pulse timing requires an instrument with suitable bandwidth and a defined measurement reference.
AOM / EOM branch
Sample the modulated beam at a defined optical pickoff.
Photodetector
Convert sampled optical intensity into an electrical waveform within the detector bandwidth.
Scope record
Acquire the detector trace with the relevant timing reference.
Optical monitor
Show light presence, relative level, pulse timing, and capture freshness.
A direct photodetector trace measures intensity and timing. Resolving optical phase, frequency, or EOM sidebands requires a suitable interferometric, heterodyne, or spectral measurement and a defined reference.
Ion fluorescence
The collection optics deliver light during the detection stage.
PMT pulses
Photon detections produce electrical pulses for the counting input.
Gated counts
The real-time counter accumulates pulses within the shot's detection window.
Readout result
Store the counts and classify them using the selected readout calibration.
Readout monitor
Display count rate, count distributions, classification, and data freshness.
A monitoring rate retains its integration window so counts per shot and counts per second remain traceable. An unexpected drop can prompt checks of the beam, collection path, detector, or acquisition timing.
The host reads acquired records for these views. A feedback action adds a separately defined decision rule, actuator, and timing deadline.
Individual addressing · optics + electrical control
An RF frequency chooses the ion; the optics turn it into a position.
A global Raman beam covers the whole chain. A second, tightly focused beam selects one ion: the acousto-optic deflector (AOD) frequency sets where it lands, while the global-beam DDS phase sets the rotation axis and amplitude × duration sets the angle. Ref U1 does not draw this Raman path; the panel describes the addressing design without lab-specific wiring.
01 · Individual AOMShifts the addressing beam's frequency; the zero order is blocked. Its phase is not controlled and drops into a per-ion constant.
02 · Expand along the chainAnamorphic expansion only along the ion axis: a larger input gives a tighter focus and more resolvable AOD spots.
03 · AOD pair · +1 / −1Two relay-imaged deflectors at the same frequency: angles add, frequency shifts cancel (+f − f = 0), so the Raman beat note stays fixed when the target ion changes. This design, not [9], which compensates a single AOD upstream.
04 · Fourier lens + objectiveAngle becomes a parallel offset imaged onto the chain: each RF frequency maps to one ion position.
- AOD frequency → which ionOne tone per addressed ion; two tones address an MS pair.
- Global DDS phase → rotation axisRx / Ry and virtual Z; the AOD phase stays fixed. Phase tracking gives every ion its own reference, so switching away and back keeps it coherent.
- Amplitude × duration → rotation angleThe angle is Ωτ and the pulse length is scaled from the π-time. AOD diffraction efficiency changes with frequency, so each ion needs its own π-time, valid only at the amplitude it was measured at.
- TTL gate → pulse windowThe acoustic wave must fill the beam before the light is fully on; that fill time must be measured, not assumed (≈240 ns in [9]).
Design consequence
Both deflectors share one drive, so their frequencies are equal by construction, and the common programmable RF phase cancels up to a fixed delay constant. The AOD therefore cannot set a per-ion MS phase; that needs another mechanism, such as addressed π pulses that apply a real Z before the gate. With two tones, cross terms land at the pair's midpoint, shifted by ±(fA − fB), so pairs use an odd ion spacing; third-order intermodulation (2fA − fB) can still hit outer neighbours and has to be measured as crosstalk.
Not claimed: ion-measured beam waists, neighbour crosstalk, per-ion π-times, the AOD frequency-to-ion map and the acoustic fill time; figures in the cited work are literature values.Addressing references: [8] Debnath et al., Nature 536, 63 (2016) · individually addressed Raman beams · [9] Yu et al., arXiv:2601.01647 (2026) · AOD addressing, anamorphic expansion and Fourier imaging
03 · Timing verification system
Test the same contract through two independent realities.
A fast deterministic simulator checks logic and data contracts. An electrically live lane runs the production hardware-timed control core with real TTL/DDS envelopes and a controlled photon source—still without ions.
Verification lanes implementedDeterministic software simulation
Compile the exact primitive OpenQASM, execute synthetic counts and verify repeatable evidence without lab network access.
- Same primitive circuit and execution contract
- Deterministic replay and evidence hash
- Freshness, all-dark and capability failures are injectable
- Proves software behavior—not RTIO or wiring
Electrically live control path
The production control core runs on the test master; a scope observes physical 369/935 envelopes while controlled TTL photon pulses exercise the counter/readout chain.
- Real FPGA-backed scheduling and deterministic timeline
- Scope-visible DDS/TTL timing envelopes
- Controlled photon counts through the acquisition boundary
- Proves electrical/dataflow integration—not ion physics
Fail-closed evidence ladder: software-sim results cannot enter calibration; electrically live results cannot claim state preparation or gate fidelity; physical-ion verified capability remains explicitly separate.
04 · Circuit-to-photon full stack
Own every boundary from algorithm to evidence.
The system does not stop at compilation or pulse generation. It carries circuit identity through execution, photon acquisition, analysis and a claim that includes its own limitation.
OpenQASM → control contract → counts implemented Spectrum M4i.66xx AWG/DDS: integration targetThe diagram distinguishes implemented software contracts from the publicly documented eleQtron microwave backend, which is presented as an integration target rather than personal hands-on evidence. Horizontal scrolling is available on narrow screens.
PUBLIC ELEQTRON QUBIT-CONTROL PATH · REF [4]
Python contract to microwave carrier.
Python / control services
↓
Spectrum M4i.66xx AWG + M4i.66xx-DDS
↓
SSB mixer + microwave LO
↓
fμw ≈ 12.64 GHz → 171Yb+ MAGIC processor
Spectrum’s official eleQtron case study identifies the M4i.66xx series as the microwave qubit-control AWG family. The control-software and FPGA boundaries are consistent with eleQtron’s public engineering roles: Python APIs/data interfaces above hardware-specific I/O, and FPGA signal generation plus real-time feedback below.
fkcarrier frequency
φkcarrier phase
Akcarrier amplitude
dfk/dtfrequency slope
dAk/dtamplitude slope
16 bit · up to 1.25 GS/sPCIe AWG family; one, two or four synchronous channels.
k = 1…20 carriers/outputEach carrier exposes fk, φk, Ak, dfk/dt and dAk/dt.
Δtcmd ≈ 6.4 nsfμw ≈ 12.64 GHz after SSB mixing; Δfion ≈ 3–5 MHz.
References: [4] Spectrum Instrumentation · DDS technology enables microwave ion control for quantum computing · [5] eleQtron · Senior Software Engineer—Python control software · [6] eleQtron · FPGA Engineer—Quantum Computing
Claim boundary: the public source confirms the M4i.66xx series, not an exact installed submodel. M4i.6631 appears in the article image caption only. No claim is made about eleQtron’s laser, camera, trap-DAC or laboratory-wide sequencer stack.
Selected research · application bridge
Translate application questions into executable quantum workflows.
Collaborations across quantum machine learning, generative chemistry and quantum chemistry gave me a working vocabulary on both sides of the interface: domain objectives and benchmarks on one side; circuits, simulators, hardware constraints and defensible evidence on the other. Google Scholar profile ↗
01 · ASKApplication objective & success metric
02 · MODELPhysics assumptions & algorithm choice
03 · EXECUTECircuit, backend & resource constraints
04 · EXPLAINEvidence, benchmark & limitations
Unentangled quantum reinforcement learning agents in the OpenAI Gym
Application → experimentTurned standard reinforcement-learning tasks and metrics into a single-qubit variational workflow, classical post-processing and execution on real IBM quantum machines.
Read the arXiv preprintExploring the Advantages of Quantum Generative Adversarial Networks in Generative Chemistry
Domain objective → hybrid modelConnected small-molecule generation goals to hybrid quantum-classical GAN components, then compared physicochemical, goal-directed and validity trade-offs.
Read the ACS paperQuantum simulation of preferred tautomeric state prediction
Scientific workflow → resource constraintsMapped a drug-discovery question through active-space selection, qubit-efficient encoding and VQE while retaining benchmark and hardware-resource limits.
Publisher-stated contribution: performed noiseless and noisy quantum simulations with Yu Shee.
Read the npj paperThese publications evidence cross-domain collaboration in quantum applications. They complement—but do not replace—the separately labelled software and electrical evidence for the trapped-ion control system above.