Quantum Optics Seminar by Nishino Yohei

Quantum teleportation for gravitational-wave detectors

We present a set of quantum-noise–reduction strategies for gravitational-wave detectors that exploit quantum teleportation. Although these detectors measure displacements with high precision, their sensitivity is fundamentally limited by the interplay of quantum shot noise and radiation-pressure noise. The tradeoff between these two noise sources establishes the standard quantum limit (SQL), a direct manifestation of Heisenberg’s uncertainty principle. Many proposals have aimed to surpass the SQL, yet several entail substantial alterations to the detectors’ basic Michelson configuration. Recent insights show that quantum-teleportation techniques can overcome this limitation: by leveraging parallel processing—a hallmark of quantum information processing—one can boost sensitivity beyond the SQL at minimal additional cost. We provide a theoretical demonstration for integrating quantum teleportation into (1) frequency-dependent squeezing/readout and (2) quantum speed measurement, all without extra infrastructure or optics. These approaches therefore emerge as promising options for next-generation gravitational-wave detectors.