Quantum gambling using two nonorthogonal states - art. no. 064302

We give a (remote) quantum-gambling scheme that makes use of the fact that quantum nonorthogonal states cannot be distinguished with certainty. In the proposed scheme, two participants Alice and Bob can be regarded as playing a game of making guesses on identities of quantum states that are in one o f two given nonorthogonal states: if Bob makes a correct (an incorrect) gue ss on the identity of a quantum state that Alice has sent, he wins (loses). It is shown that the proposed scheme is secure against the nonentanglement attack. It can also be shown heuristically that the scheme is secure in th e case of the entanglement attack.