论文标题
COMPAQT：可扩展量子置量控制的压缩波形内存体系结构
COMPAQT: Compressed Waveform Memory Architecture for Scalable Qubit Control
论文作者
论文摘要
在超导体系结构上，使用微波脉冲来操纵量子的状态。通常，脉冲存储在波形内存中，然后流到数字到Analog转换器（DAC）中以合成门操作。波形内存需要每秒几十千兆字节才能操纵量子。不幸的是，所需的内存带宽随量子数的数量线性增长。结果，带宽需求限制了我们可以同时控制的量子数量。例如，在当前基于RFSOCS的Qubit Control平台上，我们可以控制少于40个Quinbits。此外，旨在在紧张的功率预算内运行的低温ASIC控制器的高内存带宽转化为巨大的功率耗散，从而限制了可扩展性。在本文中，我们表明波形是高度可压缩的，并且我们利用该属性启用可扩展，高效的微体系结构compaqt-压缩波形内存体系结构进行量子控制。波形内存仅读取，并且CompaQt利用它在编译时压缩波形并将压缩波形存储在片上存储器中。要生成脉冲，CompaQT在运行时将波形解压缩，然后将解压缩波形流到DACS。使用硬件有效的离散余弦变换，CompaQt平均可以实现波形内存带宽5倍，这可以使RFSOC设置中控制的量子数总数增加5倍。此外，低温CMOS ASIC控制器的Compaqt微体系结构可能会导致未压缩基线的2.5倍功率降低。我们还提出了一种自适应压缩方案，以进一步降低减压发动机消耗的功率，最大减少功率。尽管使用有损耗的压缩方案，但使用CompaQT时，我们的保真度降解率少于0.1％。
On superconducting architectures, the state of a qubit is manipulated by using microwave pulses. Typically, the pulses are stored in the waveform memory and then streamed to the Digital-to-Analog Converter (DAC) to synthesize the gate operations. The waveform memory requires tens of gigabytes per second of bandwidth to manipulate the qubit. Unfortunately, the required memory bandwidth grows linearly with the number of qubits. As a result, the bandwidth demand limits the number of qubits we can control concurrently. For example, on current RFSoCs-based qubit control platforms, we can control less than 40 qubits. In addition, the high memory bandwidth for cryogenic ASIC controllers designed to operate within a tight power budget translates to significant power dissipation, thus limiting scalability. In this paper, we show that waveforms are highly compressible, and we leverage this property to enable a scalable and efficient microarchitecture COMPAQT - Compressed Waveform Memory Architecture for Qubit Control. Waveform memory is read-only and COMPAQT leverages this to compress waveforms at compile time and store the compressed waveform in the on-chip memory. To generate the pulse, COMPAQT decompresses the waveform at runtime and then streams the decompressed waveform to the DACs. Using the hardware-efficient discrete cosine transform, COMPAQT can achieve, on average, 5x increase in the waveform memory bandwidth, which can enable 5x increase in the total number of qubits controlled in an RFSoC setup. Moreover, COMPAQT microarchitecture for cryogenic CMOS ASIC controllers can result in a 2.5x power reduction over uncompressed baseline. We also propose an adaptive compression scheme to further reduce the power consumed by the decompression engine, enabling up to 4x power reduction. We see less than 0.1% degradation in fidelity when using COMPAQT despite using a lossy compression scheme.
