EleQtron, a spin-off from the University of Siegen, recently delivered a quantum computer implementing its patented MAGIC (MAgnetic Gradient Induced Coupling) quantum processors. Unlike other designs, MAGIC uses microwave radiation rather than lasers to control and manipulate qubits.
The process begins with laser ablation in a high vacuum to create a string of Ytterbium (¹7¹Yb+) ions. This method can form a register of up to 30 ions, each functioning as a qubit. Key to implementing quantum algorithms is the use of a magnetic field and an oscillating electric field to generate a Paul trap (quadrupole ion trap). Many systems use lasers at this stage to manipulate qubits and execute quantum gates, but these require exceptional accuracy, high stability, and significant power.
By comparison, microwaves are technically simpler and use only about one-fifth of the power. A high-frequency oscillator source combined with Spectrum’s DDS output through a single sideband (SSB) mixer generates a signal around 12.64 GHz. Thanks to the Zeeman effect from the magnetic field, each ion can be individually “addressed” by modulating the signal in 3–5 MHz increments. This method offers low crosstalk and integrates seamlessly with chip-based ion traps. The DDS card generates the multi-tone signals needed for precise control and manipulation of the qubits.
When eleQtron reached the limits of its existing AWG hardware, the team turned to Spectrum Instrumentation. Qubit control requires signals to be modified in amplitude, phase offset, pulse length, and frequency, enabling the desired Rabi frequency that governs quantum operation speed. Such demands push the capabilities of traditional AWGs.
The team was recommended Spectrum’s M4i.66xx-series of 16-bit AWGs, a widely respected instrument line among quantum researchers. These PCIe cards provide one, two, or four synchronous channels with up to 1.25 GS/s output rate and feature a large onboard memory that can be segmented to replay multiple waveforms. With optimized drivers, data transfer rates of 2.8 GB/s are achievable, and up to eight cards can be synchronized if required. With additional DDS firmware, the outputs support up to 20 sine wave cores on a single channel. Each DDS core can be programmed for frequency, amplitude, phase, and slopes, allowing ultrafast changes with a resolution of 6.4 ns.
This flexibility enables control of more qubits and supports increasingly complex quantum circuits. For eleQtron, the DDS solution was a key enabler of their concept.
