The paper by Julsgaard, Kozhekin, and Polzik reports an experimental demonstration of entanglement between two macroscopic objects, each consisting of about \(10^{12}\) atoms. The entanglement is generated through the interaction of cesium gas samples with a pulse of light, which performs a non-local Bell measurement on the collective spins of the samples. The entangled spin state can be maintained for 0.5 milliseconds. This experiment not only demonstrates the feasibility of generating entanglement at the macroscopic level but also paves the way for quantum information processing, including quantum teleportation and quantum memory. The entanglement is achieved by measuring the sum of the \(z\) and \(y\) components of the spins of the two samples, which are conserved during the measurement process. The degree of entanglement calculated from the experimental data is \(\xi = (35 \pm 7)\%\), and the expected fidelity of teleportation is \(F = 55\%\), exceeding the classical limit of 50%. The long-lived entanglement is attributed to the high symmetry of the generated state, which minimizes the impact of decoherence and loss of coherence for individual atoms.The paper by Julsgaard, Kozhekin, and Polzik reports an experimental demonstration of entanglement between two macroscopic objects, each consisting of about \(10^{12}\) atoms. The entanglement is generated through the interaction of cesium gas samples with a pulse of light, which performs a non-local Bell measurement on the collective spins of the samples. The entangled spin state can be maintained for 0.5 milliseconds. This experiment not only demonstrates the feasibility of generating entanglement at the macroscopic level but also paves the way for quantum information processing, including quantum teleportation and quantum memory. The entanglement is achieved by measuring the sum of the \(z\) and \(y\) components of the spins of the two samples, which are conserved during the measurement process. The degree of entanglement calculated from the experimental data is \(\xi = (35 \pm 7)\%\), and the expected fidelity of teleportation is \(F = 55\%\), exceeding the classical limit of 50%. The long-lived entanglement is attributed to the high symmetry of the generated state, which minimizes the impact of decoherence and loss of coherence for individual atoms.