Tootfinder

Transversal dimension jump for product qLDPC codes
Christine Li, John Preskill, Qian Xu
https://arxiv.org/abs/2510.07269 https://arxiv.org/pdf/2510.07269…

Transversal dimension jump for product qLDPC codes
We introduce transversal dimension jump, a code-switching protocol for lifted product (LP) quantum low-density parity-check (qLDPC) codes across different chain-complex dimensions, enabling universal fault-tolerant quantum computation with low overhead. The construction leverages the product structure of LP codes to implement one-way transversal CNOTs between a 3D code and its 2D component codes, enabling teleportation-based switching. Combined with constant-depth CCZ gates in 3D LP codes and l…

Phase Noise Tolerance for Low-Pilot-Overhead OFDM Terahertz Links Beyond 64-QAM
Bowen Liu, Takasumi Tanabe
https://arxiv.org/abs/2508.05026 https://arxiv.o…

Phase Noise Tolerance for Low-Pilot-Overhead OFDM Terahertz Links Beyond 64-QAM
THz wireless communications have garnered significant attention due to their unprecedented data rates enabled by the abundant untapped spectrum. However, advanced modulation formats beyond 64-QAM remain largely unexplored, as phase errors introduced during up/down-conversion severely limit system performance. Particularly, OFDM transmission is highly susceptible to aggravated ICI induced by phase noise, undermining the orthogonality of subcarriers. While PLLs and pilot-assisted compensation can…

Silicon-Compatible Ionic Control over Multi-State Magnetoelectric Phase Transformations in Correlated Oxide System
Xuanchi Zhou, Jiahui Ji, Wentian Lu, Huihui Ji, Chunwei Yao, Xiaohui Yao, Xiaomei Qiao, Guowei Zhou, Xiaohong Xu
https://arxiv.org/abs/2509.06561

Silicon-Compatible Ionic Control over Multi-State Magnetoelectric Phase Transformations in Correlated Oxide System
Realizing room-temperature ferromagnetic insulators, critical enablers for low-power spintronics, is fundamentally challenged by the long-standing trade-off between ferromagnetic ordering and indirect exchange interactions in insulators. Ionic evolution offers tempting opportunities for accessing exotic magnetoelectric states and physical functionality beyond conventional doping paradigm via tailoring the charge-lattice-orbital-spin interactions. Here, we showcase the precise magneto-ionic cont…

Enhancing Fault-Tolerant Surface Code Decoding with Iterative Lattice Reweighting
Yi Tian, Yi-Cong Zheng, Xiaoting Wang, Ching-Yi Lai
https://arxiv.org/abs/2509.06756 https://…

Enhancing Fault-Tolerant Surface Code Decoding with Iterative Lattice Reweighting
Efficient and realistic error decoding is crucial for fault-tolerant quantum computation (FTQC) on near-term devices. While decoding is a classical post-processing task, its effectiveness depends on accurately modeling quantum noise, which is hardware-dependent. In particular, correlated bit-flip ($X$) and phase-flip ($Z$) errors often arise under circuit-level noise. We introduce the Iterative Reweighting Minimum-Weight Perfect Matching (IRMWPM) decoder, which systematically incorporates such …

Time Resolution Characterization of 4H-SiC LGADs with a ${}^{90}$Sr Source
Tao Yang, Yashas Satapathy, Ben J. Sekely, Abraham Tishelman-Charny, Greg Allion, Gil Atar, Philip Barletta, Carl Haber, Steve Holland, John F. Muth, Spyridon Pavlidis, Stefania Stucci
https://arxiv.org/abs/2509.04638

Time Resolution Characterization of 4H-SiC LGADs with a ${}^{90}$Sr Source
This work presents timing measurements of 4H-SiC Low Gain Avalanche Detectors (4H-SiC LGADs) using beta particles from a ${}^{90}$Sr source. The 4H-SiC LGADs exhibit fast signal responses, and a time resolution of 61~ps was achieved, comparable to that of standard Si LGADs. The present limitation in the time resolution of 4H-SiC LGADs appears to stem from limited charge generation. Nevertheless, their higher voltage tolerance and faster carrier drift suggest that, with increased charge collecti…

An Efficient, Reliable and Observable Collective Communication Library in Large-scale GPU Training Clusters
Ziteng Chen (Infrawaves), Xiaohe Hu (Infrawaves), Menghao Zhang (Beihang University), Yanmin Jia (Infrawaves), Yan Zhang (Infrawaves), Mingjun Zhang (Infrawaves), Da Liu (Infrawaves), Fangzheng Jiao (Beihang University), Jun Chen (Infrawaves), He Liu (Infrawaves), Aohan Zeng (Tsinghua University), Shuaixing Duan (Zhipu AI), Ruya Gu (Infrawaves), Yang Jing (Infrawaves), Bowen Han …

An Efficient, Reliable and Observable Collective Communication Library in Large-scale GPU Training Clusters
Large-scale LLM training requires collective communication libraries to exchange data among distributed GPUs. As a company dedicated to building and operating large-scale GPU training clusters, we encounter several challenges when using NCCL in production, including 1) limited efficiency with costly and cumbersome P2P communication, 2) poor tolerance to frequent RNIC port failures, and 3) insufficient observability of transient collective communication anomalies. To address these issues, we pro…

Impacts of Phase Noise on M-ary QAM THz Wireless Communications
Bowen Liu, Takasumi Tanabe
https://arxiv.org/abs/2508.01291 https://arxiv.org/pdf/2508.0129…

Impacts of Phase Noise on M-ary QAM THz Wireless Communications
THz technology is positioned as a key enabler for next-generation wireless links due to the extensive untapped bandwidth and inherent compatibility with silicon photonics. Here, the phase noise of THz sources is modeled to characterized its impacts on a QAM-based wireless communication system. Particularly, common and instantaneous phase errors are unveiled and presented via constellation diagrams. In addition, tolerance of phase noise under different M-ary modulation formats is explored. Meanw…

Odontoceti: Ultra-Fast DAG Consensus with Two Round Commitment
Preston Vander Vos
https://arxiv.org/abs/2510.01216 https://arxiv.org/pdf/2510.01216

Odontoceti: Ultra-Fast DAG Consensus with Two Round Commitment
Users of blockchains value scalability, expecting fast confirmations and immediate transaction processing. Odontoceti, the latest in DAG-based consensus, addresses these concerns by prioritizing low latency and high throughput, making a strategic trade-off in security by operating with a 20% fault tolerance instead of the established 33% level. It is the first DAG-based protocol to achieve commitment in just two communication rounds, delivering median latency of 300 milliseconds while processin…

A Quantum Computer Based on Donor-Cluster Arrays in Silicon
Shihang Zhang, Chunhui Zhang, Guanyong Wang, Tao Xin, Guangchong Hu, Yu He, Peihao Huang
https://arxiv.org/abs/2509.24749

A Quantum Computer Based on Donor-Cluster Arrays in Silicon
Significant advances in silicon spin qubits highlight the potential of silicon quantum dots for scalable quantum computing, given their compatibility with industrial fabrication and long coherence times. In particular, phosphorus (P)-doped spin qubits possess excellent coherence and have demonstrated high-fidelity two-qubit gates exceeding 99.9%. However, scaling P-donor systems is challenging due to crosstalk caused by the uniformity of individual P donors and the low tolerance for imprecise a…

Fermion-to-Fermion Low-Density Parity-Check Codes
Chong-Yuan Xu, Ze-Chuan Liu, Yong Xu
https://arxiv.org/abs/2508.15323 https://arxiv.org/pdf/2508.15323

Fermion-to-Fermion Low-Density Parity-Check Codes
Simulating fermionic systems on qubit-based quantum computers often demands significant computational resources due to the requirement to map fermions to qubits. Thus, designing a fault-tolerant quantum computer that operates directly with fermions offers an effective solution to this challenge. Here, we introduce a protocol for fault-tolerant fermionic quantum computation utilizing fermion-to-fermion low-density parity-check codes. Our method employs a fermionic low-density parity-check code m…