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Physical Review B

Giant cross-Kerr nonlinearity in carbon nanotube quantum dots with spin-orbit coupling

Hui Sun, Xun‐Li Feng, Shangqing Gong, C. H. Oh

Published May 8, 2009• 36 citations
Publisher

Abstract

We investigate the nonlinear interaction between two weak optical fields in carbon nanotube quantum dots based on electromagnetically induced transparency and spin-orbit coupling. Our results show, owing to the energy differences produced by strong spin-orbit coupling, that a giant cross-Kerr nonlinearity can be achieved with group-velocity matching, while the probe- and signal-fields absorptions are suppressed simultaneously. We demonstrate that such enhanced nonlinear optical effects can be employed to implement controlled-phase gate between pairs of single-photon pulses with high fidelity and to generate entanglement of coherent Schr\"odinger-cat states.

DOI
10.1103/physrevb.79.193404

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We propose an asymmetric quantum well structure to realize strong interaction between two slow optical pulses. The linear optical properties and nonlinear optical responses associated with cross-Kerr nonlinearity are analyzed. Combining the resonant tunneling and the advantages of inverted-Y type scheme, giant cross-Kerr nonlinearity can be achieved with vanishing absorptions. Based on the unique feature, we demonstrate that highly entangled photons can be produced and photonic controlled phase gate can be constructed. In this construction, the scheme is symmetric for the probe and signal pulses. Consequently, the condition of group velocity matching can be fulfilled by adjusting the initial electron distribution.
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