NONCLASSICAL PROPERTIES AND QUANTUM RESOURCES OF HIERARCHICAL PHOTONIC SUPERPOSITION STATES
Volkoff T.J.

Received: April 24, 2015

DOI: 10.7868/S004445101511005X

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We motivate and introduce a class of ``hierarchical'' quantum superposition states of N coupled quantum oscillators. Unlike other well-known multimode photonic Schrödinger-cat states such as entangled coherent states, the hierarchical superposition states are characterized as two-branch superpositions of tensor products of single-mode Schrödinger-cat states. In addition to analyzing the photon statistics and quasiprobability distributions of prominent examples of these nonclassical states, we consider their usefulness for high-precision quantum metrology of nonlinear optical Hamiltonians and quantify their mode entanglement. We propose two methods for generating hierarchical superpositions in N=2 coupled microwave cavities, exploiting currently existing quantum optical technology for generating entanglement between spatially separated electromagnetic field modes.