(1) A photon has zero rest mass, but it carries energy and momentum.

(2) The world of the realist is populated by electrons and photons , quarks and gluons.

(3) Until now, physicists have only been able to entangle photons , electrons and atoms, using different methods in each case.

(4) The team has also made progress in using photons to carry quantum information between calcium qubits.

(5) Tiny particles such as photons or atoms can readily be put into a quantum superposition existing in two different states or places at once.