Particle-free quantum communication is achieved in the lab

Four years ago, theoretical physicists proposed a new quantum-communication scheme with a striking feature: it did not require the transmission of any physical particles. The research raised eyebrows, but now a team of physicists in China claims it has demonstrated that the "counterfactual" scheme works. The group built an optical apparatus that it says can transfer a simple image while sending (almost) no photons in the process.