Quantum Process Tomography of an Optically-Controlled Kerr Non-linearity

Abstract

Any optical quantum information processing machine would be comprised of fully-characterized constituent devices for both single state manipulations and tasks involving the interaction between multiple quantum optical states. Ideally for the latter, would be an apparatus capable of deterministic optical phase shifts that operate on input quantum states with the action mediated solely by auxiliary signal fields. Here we present the complete experimental characterization of a system designed for optically controlled phase shifts acting on single-photon level probe coherent states. Our setup is based on a warm vapor of rubidium atoms under the conditions of electromagnetically induced transparency with its dispersion properties modified through the use of an optically triggered N-type Kerr non-linearity. We fully characterize the performance of our device by sending in a set of input probe states and measuring the corresponding output via balanced homodyne tomography and subsequently performing the technique of coherent state quantum process tomography. This method provides us with the precise knowledge of how our optical phase shift will modify any arbitrary input quantum state engineered in the mode of the reconstruction.

arXiv comment6 pages, 5 figures

References in corpus (15)

• Quantum information with continuous variables
• Continuous-variable optical quantum state tomography
• Cavity-based quantum networks with single atoms and optical photons
• Nanophotonic quantum phase switch with a single atom
• Efficient all-optical switching using slow light within a hollow fiber
• Quantum information transfer using photons
• A Quantum Gate between a Flying Optical Photon and a Single Trapped Atom
• All-Optical Switch and Transistor Gated by One Stored Photon
• Iterative maximum-likelihood reconstruction in quantum homodyne tomography
• Prospective applications of optical quantum memories
• Impossibility of large phase shifts via the "giant Kerr effect" with single-photon wavepackets
• Complete Characterization of Quantum-Optical Processes
• Nonlinear pi phase shift for single fiber-guided photons interacting with a single atom
• Memory for Light as a Quantum Process
• Experimental characterization of bosonic photon creation and annihilation operators