skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Generating entangled states of two ququarts using linear optical elements

Abstract

We propose linear optical schemes for generating entangled states of two ququarts (four-dimensional quantum systems) in which the single-ququart state is constructed with frequency-nondegenerate biphoton polarization states of spontaneous parametric down-conversion. We show explicitly that it is possible to generate various two-ququart entangled states by interfering two ququarts at a linear optical beam splitter (an ordinary 50-50 beam splitter, a polarizing beam splitter, or a dichroic beam splitter)

Authors:
;  [1]
+ Show Author Affiliations
  1. Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 790-784 (Korea, Republic of)
Publication Date:
OSTI Identifier:
20982420
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.75.034309; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BEAM SPLITTING; FOUR-DIMENSIONAL CALCULATIONS; POLARIZED BEAMS; QUANTUM ENTANGLEMENT; QUANTUM MECHANICS

Citation Formats

Baek, So-Young, and Kim, Yoon-Ho. Generating entangled states of two ququarts using linear optical elements. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.034309.
Copy to clipboard
Baek, So-Young, & Kim, Yoon-Ho. Generating entangled states of two ququarts using linear optical elements. United States. doi:10.1103/PHYSREVA.75.034309.
Copy to clipboard
Baek, So-Young, and Kim, Yoon-Ho. Thu . "Generating entangled states of two ququarts using linear optical elements". United States. doi:10.1103/PHYSREVA.75.034309.
Copy to clipboard
@article{osti_20982420,
title = {Generating entangled states of two ququarts using linear optical elements},
author = {Baek, So-Young and Kim, Yoon-Ho},
abstractNote = {We propose linear optical schemes for generating entangled states of two ququarts (four-dimensional quantum systems) in which the single-ququart state is constructed with frequency-nondegenerate biphoton polarization states of spontaneous parametric down-conversion. We show explicitly that it is possible to generate various two-ququart entangled states by interfering two ququarts at a linear optical beam splitter (an ordinary 50-50 beam splitter, a polarizing beam splitter, or a dichroic beam splitter)},
doi = {10.1103/PHYSREVA.75.034309},
journal = {Physical Review. A},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
Copy to clipboard
Journal Article:
DOI:  10.1103/PHYSREVA.75.034309
Other availability
Find in Google Scholar Find in Google Scholar
Search WorldCat Search WorldCat to find libraries that may hold this journal
Save / Share:
Export Metadata
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.

  • ; ; - Physical Review. A
    We have studied the system of hard-core bosons on a two-dimensional optical lattice using a variational algorithm based on projected entangled-pair states. We have investigated the ground-state properties of the system as well as the responses of the system to sudden changes in the parameters. We have compared our results to mean-field results based on a Gutzwiller ansatz.

  • ; ; ; ... - Physical Review. A
    We describe a mechanism for a controlled generation of a pure Bell state with correlated atoms that involve two or zero excitations. The mechanism inhibits transitions into singly excited collective states of a two-atom system by shifting them from their unperturbed energies. The shift is accomplished by the dipole-dipole interaction between the atoms. The creation of the Bell state is found to be dependent on the relaxation of the atomic excitation. When the relaxation is not present or can be ignored, the state of the system evolves harmonically between a separable to the maximally entangled state. We follow the temporalmore » evolution of the state and find that the concurrence can be different from zero only in the presence of the dipole-dipole interaction. Furthermore, in the limit of a large dipole-dipole interaction, the concurrence reduces to that predicted for an X state of the system. A general inequality is found which shows that the concurrence of an X-state system is a lower bound for the concurrence of the two-atom system. With the relaxation present, the general state of the system is a mixed state that under a strong dipole-dipole interaction reduces the system to an X-state form. We find that mixed states admit of lower level of entanglement, and the entanglement may occur over a finite range of time. A simple analytical expression is obtained for the steady-state concurrence which shows that there is a threshold value for the dipole-dipole interaction relative to the Rabi frequency of the driving field above which the atoms can be entangled over the entire time of the evolution.« less

  • ; ; - Physical Review. A
    We propose a simple scheme for the generation of four-photon polarization-entangled decoherence-free states by using a pair of spontaneous parametric down-conversions and one tunable beam splitter. The scheme is based on post-selection strategy and feasible by current experimental technology.

  • ; ; - Physical Review. A
    We propose a scheme to implement a single-mode quantum filter, which selectively eliminates the one-photon state in a quantum state {alpha} vertical bar 0>+{beta} vertical bar 1>+{gamma} vertical bar 2>. The vacuum state and the two-photon state are transmitted without any change. This scheme requires single-photon sources, linear optical elements, and photon detectors. Furthermore, we demonstrate how this filter can be used to realize a two-qubit projective measurement and to generate multiphoton polarization entangled states.

  • ; ; ; ... - Physical Review. A
    We introduce schemes for linear-optical quantum state generation. A quantum state generator is a device that prepares a desired quantum state using product inputs from photon sources, linear-optical networks, and postselection using photon counters. We show that this device can be concisely described in terms of polynomial equations and unitary constraints. We illustrate the power of this language by applying the Groebner-basis technique along with the notion of vacuum extensions to solve the problem of how to construct a quantum state generator analytically for any desired state, and use methods of convex optimization to identify bounds to success probabilities. Inmore » particular, we disprove a conjecture concerning the preparation of the maximally path-entangled |n,0>+|0,n> (NOON) state by providing a counterexample using these methods, and we derive a new upper bound on the resources required for NOON-state generation.« less