The vast majority of physical objects we deal with are almost exclusively made of atoms. Due to their discrete level structure, single atoms have proved to be excellent emitters of nonclassical light, i.e. single photons. We demonstrate experimentally that this nonclassical behaviour is preserved when scaling up the number of atoms in the source ensemble by several orders of magnitude., Lukáš Slodička, Ondřej Číp a Radim Filip., and Obsahuje bibliografické odkazy
We have proposed a probabilistic quantum amplifier, which is capable of amplifyzing weak light signals in such a way that phase of the light is not only preserved, but its resolution is improved as well! Surprisingly, this "noise-free" amplification is achieved by addition of incoherent thermal noise followed by a photon subtraction scheme. The amplifier, which has been already experimentally implemented, might in the future become a valuable tool for quantum metrology of quantum communication., Petr Marek, Radim Filip., and Obsahuje bibliografii