Ultrafast all-optical quantum teleportation
Takumi Suzuki, Takaya Hoshi, Akito Kawasaki, Shotaro Oki, Konhi Ichii, Hironari Nagayoshi, Kazuma Takahashi, Takahiro Kashiwazaki
Abstract
Light's intrinsic carrier frequency of hundreds of terahertz theoretically enables information processing at terahertz clock rates. In optical quantum computing, continuous-variable quantum teleportation is the fundamental building block for deterministic logic operations. This protocol transfers unknown quantum states between nodes using quantum entanglement and real-time feedforward of measurement outcomes. However, electrical feedforward bottlenecks currently restrict operational bandwidths to approximately 100 megahertz, preventing the exploitation of light's ultimate speed. Here we show 1-terahertz-bandwidth all-optical quantum teleportation, completely bypassing this electronic limitation. By transferring Bell measurement outcomes optically, we successfully teleported vacuum states across the terahertz band and real-time random coherent wavepackets with a 42-picosecond temporal width. Evaluating the intrinsic state transfer quality, we achieved teleportation fidelities of for the broadband vacuum states and for the dynamic coherent wavepackets. Both results strictly surpass the classical limit of , demonstrating genuine quantum teleportation at ultrafast speeds. Our results establish that optical quantum processing speeds are constrained solely by the nonlinear medium's 1-picosecond-scale response, rather than classical electrical interfaces. This methodology provides a cornerstone for terahertz-clock quantum computers capable of overcoming Moore's law, and paves the way for a high-capacity, telecom-compatible quantum internet.
AI Impact Assessments
(3 models)Scientific Impact Assessment: Ultrafast All-Optical Quantum Teleportation
1. Core Contribution
This paper demonstrates continuous-variable (CV) quantum teleportation with a 1 THz operational bandwidth by replacing the conventional optical-electrical-optical (O-E-O) feedforward pathway with an all-optical feedforward scheme based on phase-sensitive amplification (PSA) in PPLN waveguide optical parametric amplifiers (OPAs). The key innovation is the complete elimination of opto-electronic conversion in the feedforward loop, which has been the primary bandwidth bottleneck since the first demonstration of deterministic CV quantum teleportation in 1998. The concept itself was proposed by Ralph in 1999, making this a quarter-century-delayed experimental realization.
The demonstration includes two complementary measurements: (1) frequency-domain characterization showing 1 THz bandwidth teleportation of vacuum states, and (2) time-domain real-time measurement of teleported random coherent wavepackets with 42 ps temporal modes. Both achieve fidelities (F=0.784 and F=0.770 respectively) exceeding the classical limit of 0.5 and the no-cloning threshold of 2/3.
2. Methodological Rigor
Strengths in experimental design:
Concerns and limitations:
3. Potential Impact
Quantum computing: If CV measurement-based quantum computing matures, this result is foundational. The 10,000× bandwidth improvement over O-E-O methods is transformative for time-domain multiplexed architectures, where clock rate directly determines the number of temporal modes in a fixed-length delay line. The claim of million-mode scalability, while aspirational, becomes geometrically plausible at picosecond wavepacket durations.
Quantum communications: THz-bandwidth teleportation is directly compatible with telecom fiber infrastructure and could enable high-capacity quantum repeaters. The telecom wavelength (1545 nm) operation enhances practical relevance.
Broader impact: The all-optical PSA approach for circumventing electronic bottlenecks has implications beyond quantum teleportation—any CV quantum protocol requiring feedforward (gate teleportation, error correction) benefits from this methodology.
However, several caveats temper the impact:
4. Timeliness & Relevance
This work is highly timely. The Furusawa group has been systematically building toward this demonstration, with recent papers on broadband squeezing generation, picosecond entanglement observation, and all-optical feedforward methodology (refs [23-25]). The convergence of high-quality PPLN waveguide technology with the all-optical processing concept makes this a natural culmination. The work directly addresses the most critical engineering bottleneck in CV optical quantum computing.
5. Strengths & Limitations
Key strengths:
Notable weaknesses:
Overall Assessment
This is a significant experimental achievement that resolves a long-standing bandwidth bottleneck in CV quantum teleportation. The 10,000× bandwidth improvement is genuine and important. However, the paper's claims substantially overreach the demonstrated capabilities, and the path from this proof-of-principle to practical quantum computing remains extremely long. The work is best understood as an important enabling technology demonstration rather than a direct step toward quantum computational advantage.
Generated Apr 17, 2026
Comparison History (228)
Paper 1 demonstrates a fundamental physical breakthrough, overcoming a major electronic bottleneck to achieve a 10,000-fold increase in operational bandwidth (100 MHz to 1 THz) for quantum teleportation. This experimental achievement paves the way for scalable, THz-clock optical quantum computers and high-capacity quantum internets, offering broad and long-lasting real-world impact. While Paper 2 presents an elegant theoretical solution to the barren plateau problem in variational quantum circuits, its impact is largely constrained to near-term (NISQ) algorithms. Paper 1's hardware realization of ultrafast all-optical teleportation promises a more foundational, long-term scientific and technological transformation.
Paper 2 demonstrates a breakthrough experimental achievement by bypassing the electrical feedforward bottleneck in quantum teleportation, enabling a 10,000-fold increase in operational bandwidth (from 100 MHz to 1 THz). While Paper 1 offers a highly valuable theoretical advance in quantum error correction for atom arrays, Paper 2's realization of ultrafast all-optical teleportation provides a fundamental paradigm shift. Its methodology directly paves the way for terahertz-clock optical quantum computers and high-capacity quantum internet, offering broader cross-disciplinary applications and more immediate transformative potential in quantum communication and computing.
Paper 1 demonstrates a major enabling advance: terahertz-bandwidth, all-optical feedforward for continuous-variable teleportation, removing a fundamental electronic bottleneck and directly impacting scalability and clock speed of optical quantum processing and networking. The result is timely, technologically relevant (telecom-compatible), and broadly enabling across photonic QC, quantum communications, and ultrafast measurement/control. Paper 2 is highly novel for many-body chiral cascaded physics and valuable for quantum simulation, but is currently smaller-scale (four qubits) and more specialized to superconducting-waveguide platforms, with narrower immediate application breadth.
Paper 2 likely has higher impact because it addresses a dominant near-term bottleneck for the leading quantum-computing platform: scalable, low-power cryogenic control with >99.9% gate fidelity and very low leakage. The plug-and-play, chip-to-chip, millikelvin controller is immediately relevant to building larger superconducting systems and could be adopted broadly across academia and industry. Paper 1 is highly novel (THz all-optical teleportation) but is earlier-stage, narrower in applicability, and farther from integration into mainstream quantum processors, reducing near-term cross-field and real-world impact.
Paper 1 demonstrates a groundbreaking experimental achievement—all-optical quantum teleportation at 1-THz bandwidth, overcoming a fundamental electronic bottleneck by four orders of magnitude. This is a rare, hardware-level breakthrough with transformative implications for terahertz quantum computing and a high-speed quantum internet, offering broad, timely, real-world impact. Paper 2 is a rigorous, valuable theoretical contribution to QEC with novel insights (codespace-dependent channels, correlations as resource), but its impact is more incremental and confined to the error-correction subfield. Paper 1's experimental novelty and breadth give it higher potential impact.
Paper 2 likely has higher impact due to a major bottleneck breakthrough: replacing electronic feedforward with all-optical feedforward to achieve 1‑THz-bandwidth continuous-variable quantum teleportation, a core primitive for deterministic optical quantum computing. The result is timely and broadly relevant across quantum information, photonics, and communications, with clear pathways to terahertz-clock quantum processors and telecom-compatible quantum networks. Paper 1 is novel and valuable for sensing/integration, but its impact is more specialized (masers/RF magnetometry) and may face narrower adoption than an ultrafast teleportation platform primitive.
Paper 2 addresses the central bottleneck in quantum computing scalability—qubit count—achieving 11,000 atoms, an order-of-magnitude leap toward fault-tolerant systems. Its metasurface approach offers a practical, generalizable engineering solution with clear near-term impact. While Paper 1 demonstrates impressive ultrafast teleportation with genuine novelty, its fidelities are modest and applications remain more specialized. Scaling qubits is currently the most critical, timely obstacle across the entire field, giving Paper 2 broader and more immediate significance for realizing practical quantum computers.
Paper 2 likely has higher impact: it removes a major bottleneck (electronic feedforward) in continuous-variable optical teleportation by demonstrating 1‑THz all-optical operation with fidelities well above the classical limit, enabling fundamentally faster photonic quantum processing and high-rate quantum networking. The result is timely and broadly relevant across quantum communication, photonic computing, ultrafast optics, and integrated nonlinear platforms. Paper 1 is novel and important for neutral-atom motional bosonic encodings, but its applications are more platform-specific and may scale more slowly than a bandwidth-unlocking teleportation primitive.
Paper 1 likely has higher impact: it demonstrates a concrete, high-bandwidth (1 THz) all-optical quantum teleportation that removes a known electronics bottleneck, with clear metrics (fidelities above the classical limit) and immediate relevance to scalable photonic quantum computing and quantum networking. The advance is both timely and broadly enabling across quantum information, ultrafast optics, and telecom engineering. Paper 2 is novel and potentially far-reaching for polariton chemistry and room-temperature quantum phenomena, but its claims (O(1) scaling, “macroscopically entangled” electronic states) may face higher validation and adoption barriers, making near-term impact less certain.
Paper 1 likely has higher scientific impact due to a major enabling advance—terahertz-bandwidth, all-optical feedforward continuous-variable teleportation—removing a well-known electronics bottleneck and directly affecting scalable, deterministic photonic quantum computing and quantum networking. It is highly timely, broad in implications (ultrafast quantum processors, telecom-compatible quantum internet), and represents a platform-level capability shift. Paper 2 is methodologically rigorous and impactful for quantum metrology, extending HOM sensing dynamic range and robustness, but its applications are comparatively narrower and less transformative across quantum information processing.