Aguilar-Saavedra J A, Casas J A
Instituto de Física Teórica, <a href="https://ror.org/022r8mj40">IFT-UAM/CSIC</a>, c/ Nicolás Cabrera 13-15, 28049 Madrid, Spain.
Phys Rev Lett. 2024 Sep 13;133(11):111801. doi: 10.1103/PhysRevLett.133.111801.
Particle decays do not constitute a spin "measurement" in the quantum-mechanical sense but still modify the spin state, in particular, for an entangled system. We show that for a spin-entangled pair of particles the entanglement of the system can increase after the decay of one particle. This unique phenomenon has no equivalent for stable particles and could be observable in top pair production at a high-energy polarized e^{+}e^{-} collider.
粒子衰变在量子力学意义上并不构成自旋“测量”，但仍会改变自旋状态，特别是对于一个纠缠系统。我们表明，对于一对自旋纠缠的粒子，在其中一个粒子衰变后，系统的纠缠度会增加。这种独特现象对于稳定粒子而言并不存在，并且在高能极化e⁺e⁻对撞机上的顶夸克对产生过程中可能是可观测的。
