Quantifying the resource of sharing a reference frame

We define a new quantity called refbit, which allows one to quantify the resource of sharing a reference frame in quantum communication protocols. By considering both asymptotic and nonasymptotic protocols we find relations between refbits and other communication resources. We also consider the same resources in encoded, reference-frame independent, form. This allows one to rephrase and unify previous work on phase references, reference frames, and superselection rules.Comment: Updated title as PRA did not accept the word "refbit" in the title: PRA accepts neither neologisms (="a meaningless word coined by a psychotic", according to Webster), nor novophasm

Splitting the wavefunctions of two particles in two boxes

I consider two identical quantum particles in two boxes. We can split each box, and thereby the wavefunction of each particle, into two parts. When two half boxes are interchanged and combined with the other halves, where do the two particles end up? I solve this problem for two identical bosons and for two identical fermions. The solution can be used to define a measurement that yields some information about the relative phase between the two parts of a split wavefunction.Comment: The following article has been submitted to the American Journal of Physics. After it is published, it will be found at http://scitation.aip.org/aj

Quantum communication, reference frames and gauge theory

We consider quantum communication in the case that the communicating parties not only do not share a reference frame but use imperfect quantum communication channels, in that each channel applies some fixed but unknown unitary rotation to each qubit. We discuss similarities and differences between reference frames within that quantum communication model and gauge fields in gauge theory. We generalize the concept of refbits and analyze various quantum communication protocols within the communication model.Comment: pretty pointless, published nonetheles