We set the first upper limit on the stochastic gravitational wave (GW) background in the frequency range of $1-5\,\mathrm{Hz}$ using a Torsion-bar Antenna (TOBA). A TOBA is a GW detector designed for the detection of low frequency GWs on the ground, with two orthogonal test masses rotated by the incident GWs. We performed a 24-hour observation run using the TOBA and set upper limits, based on frequentist statistics and Bayesian statistics. The most stringent values are $Ω_\mathrm{gw}h_0^2 \leq 6.0 \times10^{18}$ (frequentist) and $Ω_\mathrm{gw}h_0^2 \leq 1.2 \times 10^{20}$ (Bayesian) both at $2.58\,\mathrm{Hz}$, where $h_0$ is the Hubble constant in units of $100\,\mathrm{km/s/Mpc}$ and $Ω_\mathrm{gw}$ is the GW energy density per logarithmic frequency interval in units of the closure density.
Quantum noise and torque correlations in a torsion-bar Sagnac speed meter
National Central University（国立中央大学）；Center for High Energy and High Field (CHiP), National Central University（国立中央大学高能高场中心）；Institute of Physics, Academia Sinica（中央研究院物理学研究所）；Institute of Particle and Nuclear Studies, High Energy Acceleration Research Organization (KEK)（高能加速器研究机构粒子与核研究部）；National Institute of Physics, University of the Philippines - Diliman（菲律宾大学迪利曼分校国立物理研究所）；INFN Sezione di Ferrara（费拉拉意大利国家核物理研究所分部）；National Astronomical Research Institute of Thailand（泰国国家天文研究所）
CHRONOS: Cryogenic sub-Hz cROss torsion bar detector with quantum NOn-demolition Speed meter
National Central University（中央大学）；Center for High Energy and High Field (CHiP), National Central University（中央大学高能高场中心）；Institute of Physics, Academia Sinica（中央研究院物理研究所）；Institute of Particle and Nuclear Studies, High Energy Acceleration Research Organization (KEK)（高能加速器研究机构粒子核研究部）；Department of Physics, Institute of Applied Sciences and Humanities, GLA University（GLA大学应用科学与人文学院物理系）
Instrumental development for Cryogenic sub-Hz cROss torsion bar detector with quantum NOn-demolition Speed meter (CHRONOS)
Institute of Physics, Academia Sinica（中央研究院物理研究所）；Center for High Energy and High Field Physics (CHiP), National Central University（国立中央大学高能高场物理中心）；Department of Physics, National Central University（国立中央大学物理系）；Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK)（高能加速器研究机构粒子与核研究部）；National Institute of Physics, University of the Philippines - Diliman（菲律宾大学迪利曼分校国家物理研究所）
Science of Cryogenic sub-Hz cROss torsion bar detector with quantum NOn-demolition Speed meter (CHRONOS)
National Central University（中央大学）；Center for High Energy and High Field (CHiP), National Central University（国立中央大学高能高场中心）；Institute of Physics, Academia Sinica（中央研究院物理研究所）；Institute of Particle and Nuclear Studies, High Energy Acceleration Research Organization (KEK)（高能加速器研究机构粒子核研究部）；National Institute of Physics, University of the Philippines - Diliman（菲律宾大学迪利曼分校国家物理研究所）
Noise budget of Cryogenic sub-Hz cROss torsion bar detector with quantum NOn-demolition Speed meter (CHRONOS)
National Institute of Physics, University of the Philippines - Diliman（菲律宾大学迪利曼分校国立物理研究所）；Center for High Energy and High Field (CHiP), National Central University（中原大学高能高场中心）；Department of Physics,National Central University（中原大学物理系）；Institute of Physics, Academia Sinica（中央研究院物理研究所）；Institute of Particle and Nuclear Studies, High Energy Acceleration Research Organization (KEK)（高能加速器研究机构粒子与核研究部）
Cryogenic sub-Hz cROss torsion bar detector with quantum NOn-demolition Speed meter (CHRONOS) for gravitational wave detection
National Central University（国立中央大学）；Center for High Energy and High Field (CHiP), National Central University（国立中央大学高能高场中心）；Institute of Physics, Academia Sinica（中央研究院物理研究所）；Institute of Particle and Nuclear Studies, High Energy Acceleration Research Organization (KEK)（高能加速器研究机构粒子核研究部）；National Institute of Physics, University of the Philippines - Diliman（菲律宾大学迪利曼分校国家物理研究所）
