TY - JOUR T1 - Photon-Photon Interactions via Rydberg Blockade JF - Physical Review Letters Y1 - 2011 A1 - Alexey V. Gorshkov A1 - Johannes Otterbach A1 - Michael Fleischhauer A1 - Thomas Pohl A1 - Mikhail D. Lukin AB - We develop the theory of light propagation under the conditions of electromagnetically induced transparency (EIT) in systems involving strongly interacting Rydberg states. Taking into account the quantum nature and the spatial propagation of light, we analyze interactions involving few-photon pulses. We demonstrate that this system can be used for the generation of nonclassical states of light including trains of single photons with an avoided volume between them, for implementing photon-photon quantum gates, as well as for studying many-body phenomena with strongly correlated photons. VL - 107 UR - http://arxiv.org/abs/1103.3700v1 CP - 13 J1 - Phys. Rev. Lett. U5 - 10.1103/PhysRevLett.107.133602 ER - TY - JOUR T1 - Photonic Phase Gate via an Exchange of Fermionic Spin Waves in a Spin Chain JF - Physical Review Letters Y1 - 2010 A1 - Alexey V. Gorshkov A1 - Johannes Otterbach A1 - Eugene Demler A1 - Michael Fleischhauer A1 - Mikhail D. Lukin AB - We propose a new protocol for implementing the two-qubit photonic phase gate. In our approach, the pi phase is acquired by mapping two single photons into atomic excitations with fermionic character and exchanging their positions. The fermionic excitations are realized as spin waves in a spin chain, while photon storage techniques provide the interface between the photons and the spin waves. Possible imperfections and experimental systems suitable for implementing the gate are discussed. VL - 105 UR - http://arxiv.org/abs/1001.0968v3 CP - 6 J1 - Phys. Rev. Lett. U5 - 10.1103/PhysRevLett.105.060502 ER -