Abstract:

Spontaneous emission is one of the most fundamental phenomena of quantum physics. In contrast to the case of a single atom, spontaneous emission from an atomic ensemble shows significant collective effects if the separations between the atoms is shorter than resonant wavelength. Here we consider a regular atom chain and show that whenever the distance between the neighboring atoms is shorter than half a wavelength, there will be subradiant states of which, under the Markovian approximation, the decay rate scales with the atom number as  N^-(s+1) . We find that this power law scaling is valid independent to the details of the electromagnetic field. Furthermore, we study how such collective behavior is established in the system of waveguide QED. We find that the Zeno time of this system is substantially long so that the field memory effect will impacts the formation of collective emissions.

Profile：

　　Yu-Xiang Zhang obtains his bachelor (2012) and PhD (2016) from the University of Science and Technology of China. During 2017-2022 he works as a postdoc in Aarhus University and Niels Bohr Institute of the University of Copenhagen. Since 2022, he works as an associate professor in Institute of Physics, Chinese Academy of Sciences. His research interests are theories of quantum optics and quantum information.