Chinese scientists kept "Schrödinger's cat" alive for more than 20 minutes
Gezixuan reported on November 8 that according to a report by Science and Technology Daily on November 7, Xia Tian, Lu Zhengtian, Zou Changling and others from the University of Science and Technology of China worked together to prepare a spin-based Schrödinger cat state using the laser cold atom method, whose lifetime reached the order of minutes, which helped to improve the measurement sensitivity of the spin precession phase. The results were published in Nature Photonics on November 1.
In the course of the study, the research team successfully achieved a Schrödinger cat state with an ultra-long coherence time. The researchers used the optical lattice to trap ytterbium-173 atoms with 5/2 spin, and prepared a superposition state composed of two states with spin projection of + 5/2 and -5/2 by controlling the laser pulse to induce a nonlinear optical frequency shift for the atom. Since the magnetic quantum numbers of these two states are the farthest apart, their superposition states are called Schrödinger cat states.
This cat state has enhanced magnetic field sensitivity, and at the same time feels exactly the same optical frequency shift in the optical lattice, and is in the "incoherent-free subspace", so it has natural immunity to the intensity noise and spot morphology changes of the optical lattice.
The experimental results showed that the coherence time of the cat state exceeded 20 minutes. With Ramsey interferometry, the researchers confirmed the sensitivity of phase measurements close to the Heisenberg limit.
According to the researchers, the preparation of this long-lived Schrödinger cat state will open up new avenues for atomic magnetometers, quantum information error correction and the exploration of new physics.
Schrödinger's cat is a thought experiment proposed by Austrian physicist Erwin Schrödinger in 1935. Through this thought experiment, Schrödinger pointed out the problems that arise from the application of quantum mechanics to macroscopic objects and the contradictions between them and the common sense of physics. In this thought experiment, due to the random nature of previous events, cats are in a state of superposition of life and death.
The link to the paper attached to IT Home is as follows: