University of Tokyo Lifts Cat-State Amplitude to 1.69 at 5MHz for Quantum Computing
Updated
Updated · Quantum Zeitgeist · Jul 15
University of Tokyo Lifts Cat-State Amplitude to 1.69 at 5MHz for Quantum Computing
1 articles · Updated · Quantum Zeitgeist · Jul 15
Summary
A University of Tokyo-led team generated optical Schrödinger cat states with an effective amplitude of 1.69 using picosecond pulses, pushing past the long-standing sub-1 limit that constrained scalable photonic quantum computing.
Picosecond multi-photon subtraction removed the nanosecond temporal bottleneck, letting the researchers produce non-Gaussian states at a 5MHz pump repetition rate compatible with time-multiplexed architectures.
The experiment also produced states with up to four negative regions in their Wigner functions, a signature of strong non-classical behavior needed for universal quantum computation and cat-code error correction.
The result still falls short of a fully scalable processor because coherence times remain limited and error correction has not yet been implemented, though the amplitude is nearing levels considered useful for fault-tolerant designs.
The advance gives researchers a platform to test adaptive breeding and logical-qubit schemes, marking a practical step toward faster photonic quantum computers.
As researchers achieve higher cat state amplitudes, are Oxford’s new 'squeezed-cat states' already a more promising path for error correction?
This new method creates powerful quantum states faster than ever, but what major hurdle still separates this from building a useful quantum computer?
With breakthroughs in both photonic and superconducting qubits, which technology is now leading the race to a commercially viable quantum computer?
High-Amplitude Cat States (1.69) Generated at University of Tokyo: A Leap Toward Practical Fault-Tolerant Quantum Computers
Overview
On July 22, 2026, a team at the University of Tokyo led by Professor Akira Furusawa made a major leap in optical quantum computing by generating high-amplitude Schrödinger cat states, reaching a world-record amplitude of 1.69. This was achieved using picosecond light pulses at a rapid 5 MHz repetition rate. Schrödinger cat states are essential for robust quantum computation because they help encode quantum information and support error correction, making quantum computers more stable and practical. This breakthrough brings the field closer to building fault-tolerant quantum computers capable of solving complex problems.