U Tokyo heat-free device boosts processing 1,000x

The University of Tokyo and NTT said on January 29, 2025 that they had built an optical device that generated and measured quantum entanglement at 60 gigahertz, a rate they described as more than 1,000 times faster than conventional optical entanglement systems. The result was published in *Nature Photonics* the same day, according to the university and NTT. The work was led by PhD student Akito Kawasaki, Assistant Professor Warit Asavanant and Professor Akira Furusawa at the University of Tokyo’s Department of Applied Physics, with NTT as a collaborator. The claim circulating on social media refers to quantum information processing rather than a replacement for ordinary laptop or server chips. NTT said the team used an optical parametric amplifier and phase-control technology to generate entanglement on a picosecond timescale, which it called the first real-time observation of optical quantum entanglement at that speed. The company said conventional generation rates had typically been in the kilohertz-to-megahertz range. (group.ntt) ### What exactly did the researchers build? The January 29, 2025 announcement said the key component was an optical parametric amplifier, or OPA, jointly developed by the University of Tokyo and NTT. That device amplifies quantum states of light and, in this experiment, was paired with phase-control techniques and balanced detectors to produce and observe entanglement at 60 GHz. NTT said that corresponds to picosecond-order operation. (group.ntt) The *Nature Photonics* paper described the result as real-time observation of optical Einstein-Podolsky-Rosen correlation on a picosecond timescale in a continuous-wave system. The paper summary said the setup introduced waveguide optical parametric amplifiers and balanced detectors, allowing broadband operation that reached tens of gigahertz. ### Where does the “1,000 times faster” figure come from? (group.ntt) NTT said earlier optical quantum entanglement generation rates were generally on the order of kilohertz to megahertz, with time scales from microseconds to nanoseconds. Against that baseline, the team’s 60 GHz result is more than three orders of magnitude higher, which is the source of the “more than 1,000 times faster” description used in the company and university materials. (nature.com) The University of Tokyo’s Nano Quantum Information Electronics institute used similar wording, saying the system generated quantum entanglement “more than 1000 times faster than conventional entanglement.” That wording is about the rate of producing entangled optical states, not a benchmark showing every computing task finishes 1,000 times faster. ### Does this mean a one-hour job now takes one second? (group.ntt) No primary source reviewed here states that a task that previously took one hour was completed in one second. The January 29, 2025 NTT release, the University of Tokyo research page and the *Nature Photonics* paper summary all describe bandwidth, clock-speed potential and picosecond-scale observation, but none of them gives a one-hour-to-one-second benchmark for a real computing workload. (nanoquine.iis.u-tokyo.ac.jp) The closest the sources come is a forward-looking claim. NTT said the new technology “makes it possible to achieve a quantum system with a clock speed of several tens of gigahertz,” and the University of Tokyo said that could support optical quantum information processing at speeds beyond conventional systems. Those statements are presented by the researchers and company as future capability, not as a demonstrated end-user benchmark. (group.ntt) ### Why are heat and “heat-free” showing up in posts about this? The available primary materials do not describe the device as “heat-free.” The January 29, 2025 NTT release focuses on ultrafast optical quantum entanglement generation, and the University of Tokyo page uses the same framing. Neither source says the system eliminates heat generation in the way consumer electronics posts sometimes imply. (group.ntt) The likely source of that shorthand is that the work uses light-based quantum states rather than conventional transistor switching, and optical systems are often discussed as a route to lower-power or different thermal constraints. But neither the NTT release nor the university page makes a verified “heat-free” claim for this device. That is an inference from the technology area, not a stated result in the cited materials. (group.ntt) ### What comes next in this research? A March 5, 2025 Science Japan report said another University of Tokyo-led team, working with NTT and NICT, had already used non-classical light pulses in an optical quantum computing platform for the first time. That report linked the January entanglement advance to broader work on scalable continuous-variable optical quantum computing. The January 29, 2025 publication in *Nature Photonics* remains the clearest public record for this specific result, with Akito Kawasaki, Warit Asavanant, Akira Furusawa and NTT named as participants. (group.ntt) NTT and the University of Tokyo said the next step is applying such ultrafast entanglement generation to practical quantum information processing systems operating at several tens of gigahertz. (sj.jst.go.jp)