Entanglement-assisted communication in the absence of shared reference frame

Abstract

Alice wants to convey the value of a parameter to Bob with whom she does not share a reference frame. What physical object can she use for this task? Shall she encode this value into the angle between two physical vectors such as the angle between two spins? Can she benefit from using entanglement? We approach these questions here and show that an entangled state of two qubits has three parameters that are invariant under changes of the reference frame. We also calculate the average information gain, when each one of these parameters is used for communication. We compare our result with the special case of separable states and find that entanglement enhances the information gain.

11 pages, 7 figures

References in corpus (7)

• Reference frames, superselection rules, and quantum information
• The resource theory of quantum reference frames: manipulations and monotones
• Extending Noether's theorem by quantifying the asymmetry of quantum states
• Classical and quantum communication without a shared reference frame
• The WAY theorem and the quantum resource theory of asymmetry
• Decoherence-full subsystems and the cryptographic power of a private shared reference frame
• Optimal measurements for relative quantum information