On the 7th, it was learned from the University of Science and Technology of China that the research team used laser cold atom method to prepare spin based Schr ö dinger cat states with a lifetime of minutes. The relevant results were recently published in Nature Photonics. In quantum precision measurement, spin precession is not only an effective probe for measuring many physical phenomena such as magnetic fields and inertia, but also can be used to explore new physics beyond the standard model. When measuring spin precession, the high spin Schr ö dinger cat state has significant advantages. On the one hand, the high spin quantum number amplifies the precession frequency signal, and on the other hand, the cat state is insensitive to some environmental interference factors, thereby suppressing measurement noise. However, the application of cat states in experiments faces two major technical challenges: one is how to achieve efficient manipulation of unitary transformations in high-dimensional quantum space, and the other is the need to maintain sufficient quantum coherence time. During the research process, the research team successfully achieved a Schr ö dinger cat state with ultra long coherence time. Researchers used a photonic lattice to trap ytterbium-173 atoms with spin of 5/2. By controlling the laser pulse to induce nonlinear optical frequency shift on the atoms, they prepared a superposition state consisting of spin projected states of+5/2 and -5/2. Due to the farthest distance between the magnetic quantum numbers of these two states, their superposition state is called the Schr ö dinger cat state. This cat state has enhanced magnetic field sensitivity and feels the exact same optical frequency shift in the optical lattice, located in the "incoherent subspace", thus having a natural immunity to the intensity noise and spot morphology changes in the optical lattice. The experimental results indicate that the coherence time of the cat state has exceeded 20 minutes. Through Ramsey interferometry, researchers have confirmed phase measurement sensitivity close to the Heisenberg limit. Researchers say that the preparation of this long-lived Schr ö dinger cat state will open up new avenues for atomic magnetometers, quantum information correction, and exploration of new physics. (New Society)