Positioning and clock synchronization through entanglement

A method is proposed to em- ploy entangled and squeezed light for de- termining the position of a party and for synchronizing distant clocks. An accuracy gain over analogous protocols that employ classical resources is demonstrated and a quantum-cryptographic positioning applica- tion is given, which allows only trusted par- ties to learn the position of whatever must be localized. The presence of a lossy channel and imperfect photodetection is considered. The advantages in using partially entangled states is discussed.