publications

2024

1. 

   Leveraging Hardware Power through Optimal Pulse Profiling for Each Qubit Pair

   Yuchen Zhu, Jinglei Cheng, Boxi Li, and 3 more authors

   2024

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   In the scaling development of quantum computers, the calibration process emerges as a critical challenge. Existing calibration methods, utilizing the same pulse waveform for two-qubit gates across the device, overlook hardware differences among physical qubits and lack efficient parallel calibration. In this paper, we enlarge the pulse candidates for two-qubit gates to three pulse waveforms, and introduce a fine-grained calibration protocol. In the calibration protocol, three policies are proposed to profile each qubit pair with its optimal pulse waveform. Afterwards, calibration subgraphs are introduced to enable parallel calibraton through identifying compatible calibration operations. The protocol is validated on real machine with up to 127 qubits. Real-machine experiments demonstrates a minimum gate error of 0.001 with a median error of 0.006 which is 1.84x reduction compared to default pulse waveform provided by IBM. On device level, a double fold increase in quantum volume as well as 2.3x reduction in error per layered gate are achieved. The proposed protocol leverages the potential current hardware and could server as an important step toward fault-tolerant quantum computing.

   @misc{zhu2024leveraginghardwarepoweroptimal,
     title = {Leveraging Hardware Power through Optimal Pulse Profiling for Each Qubit Pair},
     author = {Zhu, Yuchen and Cheng, Jinglei and Li, Boxi and Zhou, Yidong and Ding, Yufei and Liang, Zhiding},
     journal = {arXiv preprint arXiv:2411.19308},
     year = {2024},
     eprint = {2411.19308},
     archiveprefix = {arXiv},
     primaryclass = {quant-ph},
     url = {https://arxiv.org/abs/2411.19308},
   }

2. 

   CaliScalpel: In-Situ and Fine-Grained Qubit Calibration Integrated with Surface Code Quantum Error Correction

   Xiang Fang, Keyi Yin, Yuchen Zhu, and 8 more authors

   2024

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   Quantum Error Correction (QEC) is a cornerstone of fault-tolerant, large-scale quantum computing. However, qubit error drift significantly degrades QEC performance over time, necessitating periodic calibration. Traditional calibration methods disrupt quantum states, requiring system downtime and making in situ calibration infeasible. We present CaliScalpel, an innovative framework for in situ calibration in surface codes. The core idea behind CaliScalpel is leveraging code deformation to isolate qubits undergoing calibration from logical patches. This allows calibration to proceed concurrently with computation, while code enlargement maintains error correction capabilities with minimal qubit overhead. Additionally, CaliScalpel incorporates optimized calibration schedules derived from detailed device characterization, effectively minimizing physical error rates. Our results show that CaliScalpel achieves concurrent calibration and computation with modest qubit overhead and negligible execution time impact, marking a significant step toward practical in situ calibration in surface-code-based quantum computing systems.

   @misc{fang2024caliscalpelinsitufinegrainedqubit,
     title = {CaliScalpel: In-Situ and Fine-Grained Qubit Calibration Integrated with Surface Code Quantum Error Correction},
     author = {Fang, Xiang and Yin, Keyi and Zhu, Yuchen and Ruan, Jixuan and Tullsen, Dean and Liang, Zhiding and Sornborger, Andrew and Li, Ang and Humble, Travis and Ding, Yufei and Shi, Yunong},
     year = {2024},
     eprint = {2412.02036},
     archiveprefix = {arXiv},
     primaryclass = {quant-ph},
     url = {https://arxiv.org/abs/2412.02036},
   }

3. 

   Towards Fault-tolerant Design of Quaternary Quantum Arithmetic

   Yunchen Zhu, Ruixuan Yang, Yuhang Gu, and 3 more authors

   In 2024 IEEE International Test Conference in Asia (ITC-Asia), 2024

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   Qudit has emerged as a promising system for next-generation quantum computers because of its significant advantages in multi-phase problems and quantum error correction, while multi-qudit operations are yet to be implemented. As one of the basic operations, quantum addition has been widely applied in number factorization and discrete logarithms. Meanwhile, the physical constraints of noisy intermediate-scale quantum (NISQ) devices necessitate the development of fault-tolerant quantum adders and the exploration of quaternary operations on binary devices is still in its infancy. In this work, we propose the first approach for implementing quaternary quantum addition algorithms by employing primitive quantum gates. A library of quaternary quantum gates and quaternary quantum full adders (\(Q^2FA\)) able to produce carry-first results, along with lower depth and fewer T-gates optimizations are proposed and evaluated, where all circuits are implemented on IBM Qiskit SDK. Extensive experiments show that our proposed \(Q^2FA\) design, together with the optimization techniques, reduces T-depth by up to 1.4\(\times\) and T-count by 1.7\(\times\) compared with baseline quantum circuits without depth and T-gate optimizations. Meanwhile, the scalability of the proposed Q^2FA is demonstrated by constructing quantum carry-ripple adders. Under noisy conditions, our proposed design can achieve an overall fidelity increase by 1.4\(\times\).

   @inproceedings{10661353,
     author = {Zhu, Yunchen and Yang, Ruixuan and Gu, Yuhang and Gu, Fangtian and Kong, Lingyi and Li, He},
     booktitle = {2024 IEEE International Test Conference in Asia (ITC-Asia)},
     title = {Towards Fault-tolerant Design of Quaternary Quantum Arithmetic},
     year = {2024},
     volume = {},
     number = {},
     pages = {1-6},
     keywords = {Fault tolerance;Scalability;Qubit;Fault tolerant systems;Logic gates;Noise measurement;Quantum circuit;Quaternary addition;quantum circuits;fault-tolerant design},
     doi = {10.1109/ITC-Asia62534.2024.10661353},
   }

4. 

   Coqa: Blazing Fast Compiler Optimizations for QAOA

   Yuchen Zhu, Yidong Zhou, Jinglei Cheng, and 4 more authors

   In 2024 IEEE/ACM International Conference on Computer Aided Design (ICCAD), 2024

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   The Quantum Approximate Optimization Algorithm (QAOA) is one of the most promising candidates for achieving quantum advantage over classical computers. However, existing compilers lack specialized methods for optimizing QAOA circuits. There are circuit patterns inside the QAOA circuits, and current quantum hardware has specific qubit connectivity topologies. Therefore, we propose Coqa to optimize QAOA circuit compilation tailored to different types of quantum hardware. Our method integrates a linear nearest-neighbor (LNN) topology and efficiently map the patterns of QAOA circuits to the LNN topology by heuristically checking the interaction based on the weight of problem Hamiltonian. This approach allows us to reduce the number of SWAP gates during compilation, which directly impacts the circuit depth and overall fidelity of the quantum computation. By leveraging the inherent patterns in QAOA circuits, our approach achieves more efficient compilation compared to general-purpose compilers. With our proposed method, we are able to achieve an average of 30% reduction in gate count and a 39x acceleration in compilation time across our benchmarks.

   @inproceedings{zhu2024coqa,
     title = {Coqa: Blazing Fast Compiler Optimizations for QAOA},
     author = {Zhu, Yuchen and Zhou, Yidong and Cheng, Jinglei and Jin, Yuwei and Li, Boxi and Niu, Siyuan and Liang, Zhiding},
     booktitle = {2024 IEEE/ACM International Conference on Computer Aided Design (ICCAD)},
     journal = {arXiv preprint arXiv:2408.08365},
     year = {2024},
     volume = {},
     number = {},
   }

5. 

   EPOC: A Novel Pulse Generation Framework Incorporating Advanced Synthesis Techniques for Quantum Circuits

   Jinglei Cheng, Yuchen Zhu, Yidong Zhou, and 3 more authors

   arXiv preprint arXiv:2405.03804, 2024

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   In this paper we propose EPOC, an efficient pulse generation framework for quantum circuits that combines ZX-Calculus, circuit partitioning, and circuit synthesis to accelerate pulse generation. Unlike previous works that focus on generating pulses from unitary matrices without exploring equivalent representations, EPOC employs a finer granularity approach by grouping quantum gates and decomposing the resulting unitary matrices into smaller ones using synthesis techniques. This enables increased parallelism and decreased latency in quantum pulses. EPOC also continuously optimizes the circuit by identifying equivalent representations, leading to further reductions in circuit latency while minimizing the computational overhead associated with quantum optimal control. We introduce circuit synthesis into the workflow of quantum optimal control for the first time and achieve a 31.74% reduction in latency compared to previous work and a 76.80% reduction compared to the gate-based method for creating pulses. The approach demonstrates the potential for significant performance improvements in quantum circuits while minimizing computational overhead.

   @article{cheng2024epoc,
     title = {EPOC: A Novel Pulse Generation Framework Incorporating Advanced Synthesis Techniques for Quantum Circuits},
     author = {Cheng, Jinglei and Zhu, Yuchen and Zhou, Yidong and Ren, Hang and Song, Zhixin and Liang, Zhiding},
     journal = {arXiv preprint arXiv:2405.03804},
     year = {2024},
   }

6. 

   In Situ Polymer-Solution-Processed Graphene–PDMS Nanocomposites for Application in Intracranial Pressure Sensors

   Hua Hong, Junjie Zhang, Yuchen Zhu, and 8 more authors

   Nanomaterials, 2024

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   Polydimethylsiloxane (PDMS) has emerged as a promising candidate for the dielectric layer in implantable sensors due to its exceptional biocompatibility, stability, and flexibility. This study introduces an innovative approach to produce graphene-reinforced PDMS (Gr-PDMS), where graphite powders are exfoliated into mono- and few-layer graphene sheets within the polymer solution, concurrently forming cross-linkages with PDMS. This method yields a uniformly distributed graphene within the polymer matrix with improved interfaces between graphene and PDMS, significantly reducing the percolation threshold of graphene dispersed in PDMS from 10% to 5%. As-synthesized Gr-PDMS exhibits improved mechanical and electrical properties, tested for potential use in capacitive pressure sensors. The results demonstrate an impressive pressure sensitivity up to 0.0273 kpa−1, 45 times higher than that of pristine PDMS and 2.5 times higher than the reported literature value. The Gr-PDMS showcases excellent pressure sensing ability and stability, fulfilling the requirements for implantable intracranial pressure (ICP) sensors.

   @article{nano14050399,
     author = {Hong, Hua and Zhang, Junjie and Zhu, Yuchen and Tse, Stephen D. and Guo, Hongxuan and Lai, Yilin and Xi, Yubo and He, Longbing and Zhu, Zhen and Yin, Kuibo and Sun, Litao},
     title = {In Situ Polymer-Solution-Processed Graphene–PDMS Nanocomposites for Application in Intracranial Pressure Sensors},
     journal = {Nanomaterials},
     volume = {14},
     year = {2024},
     number = {5},
     article-number = {399},
     url = {https://www.mdpi.com/2079-4991/14/5/399},
     pubmedid = {38470730},
     issn = {2079-4991},
     doi = {10.3390/nano14050399},
   }