Quantum error rejection code with spontaneous parametric down conversion

Constructing Four-Photon States for Quantum Communication and Information Processing

We provide a method for constructing a set of four-photon states suitable for quantum communication applications. Among these states is a set of concatenated quantum code states that span a decoherence-free subspace that is robust under collective-local as well as global dephasing noise. This method requires only the use of spontaneous parametric down-conversion, quantum state post-selection, a...

ENTANGLED STATE PREPARATION FOR OPTICAL QUANTUM COMMUNICATION: Creating and characterizing photon pairs from Spontaneous Parametric Down Conversion inside bulk uniaxial crystals

Quantum entanglement swapping with spontaneous parametric down conversion

Two remote parties that have never interacted each other can be entangled through entanglement swapping operation done by a third party. Currently existing entanglement swapping experiments are done probabilistically by post-selection, i.e., once a successful swapping is verified, the resultant entanglement is destructed. We propose a simple non-post-selection scheme to demonstrate the high qua...

Lab1: Entanglement and Bell’s Inequalities

In this laboratory, entanglement as one of the key concepts in quantum mechanics was introduced, and we concentrated on the polarized entangled photons. Bell’s inequality was used as a criterion of quantum and classic. The polarized entangled photons were created by Spontaneous Parametric Down-Conversion in Beta Barium Borate crystals. The coincidence counts were measured as the number of entan...

Theory of spontaneous parametric down-conversion from photonic crystals

An effective-medium approach is used to derive a set of coupled-mode equations describing quadratic parametric interactions in a one-dimensional inhomogeneous medium of finite length. The solutions for both copropagating and counterpropagating interactions are used to study the quantum-mechanical process of spontaneous parametric down-conversion (SPDC). An example is studied in which the inhomo...