2009/06/01 by Home, Dipankar, Pan, A. K., Adhikari, S. +2
#FOS: Physical sciences #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.0906.0270
By sending a classical two-level system, one can transfer information about only two distinguishable outcomes. Here we show that in quantum mechanics, using both the spin and path degrees of freedom of a spin-1/2 particle, and a Mach-Zehnder type interferometric arrangement with two suitable Stern-Gerlach detectors, it is possible to transfer information about four distinguishable outcomes. This procedure does not require using quantum entanglement as a resource as in the well-known protocol of dense coding, but instead hinges entirely on the quantum superposition principle. We also study probabilistic dense coding using our set-up and show that the dense coding scheme using quantum superposition cannot be optimized any further by extending the interferometric arrangement with more beam splitters.