K. M. Gheri

Publications (4)5.76 Total impact

• Article: Controlled source of entangled photonic qubits

  C Saavedra, K M Gheri, P Torma, J I Cirac, P Zoller
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  ABSTRACT: We consider a general proposal for generating a train of entangled single-photon wavepackets. The photons are created inside a resonator via an interaction with an active medium. In the course of the generation process photons are transferred to the continuum outside the resonator through cavity loss. We show that wave packets generated in this way can be regarded as independent logical qubits. This and the possibility of producing strong entanglement between the qubits suggests many applications in quantum communication. We give a specific example in the context of cavity QED and show that undesired decoherence effects can be efficiently reduced in the considered scheme.
  Physical Review A 05/2000; 61(6):2311. · 2.88 Impact Factor
• Article: Entanglement engineering of one-photon wave packets using a single-atom source

  K.M. Gheri, C. Saavedra, P. Törma, J. I. Cirac, P. Zoller
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  ABSTRACT: We propose a cavity-QED scheme for the controlled generation of sequences of entangled single-photon wave packets. A photon is created inside a cavity via an active medium, such as an atom, and decays into the continuum of radiation modes outside the cavity. Subsequent wave packets generated in this way behave as independent logical quantum bits (qubits). This and the possibility of producing maximally entangled multiqubit states suggest many applications in quantum communication.
  Physical Review A 02/1998; 58(4):2627. · 2.88 Impact Factor
• Source

  Available from: Carlos Saavedra

  Article: Entanglement engineering of one-photon wavepackets using a single-atom source

  K. M. Gheri, C. Saavedra, P. Toermae, J. I. Cirac, P. Zoller
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  ABSTRACT: We propose a cavity-QED scheme for the controlled generation of sequences of entangled single-photon wavepackets. A photon is created inside a cavity via an active medium, such as an atom, and decays into the continuum of radiation modes outside the cavity(coupled, for example to an optical fiber). Subsequent wavepackets generated in this way behave as independent logical qubits. This and the possibility of producing maximally entangled multi-qubit states suggest many applications in quantum communication. Comment: 4 pages, 2 figures
  02/1998;
• Article: INTRACAVITY 2ND-HARMONIC GENERATION USING AN ELECTROMAGNETICALLY INDUCED TRANSPARENCY

  K M Gheri, C Saavedra, D F Walls
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  ABSTRACT: We analyze the quantum-fluctuation properties of second-harmonic radiation generated in the high-efficiency conversion process used in a recent experiment by Hakuta, Marmet, and Stoicheff [Phys. Rev. Lett. 66, 596 (1991)]. We extend their work by studying the second-harmonic generation inside an optical cavity. The active medium inside the cavity is modeled by three-level atoms with degenerate upper levels (1s, 2p, and 2s states of atomic hydrogen) interacting with a strong constant electric field. An enhancement of the conversion efficiency and a reduction of the added noise are found as a result of an electromagnetically induced transparency. We show that the scheme is capable of producing light in a squeezed or coherent state close to a minimum-uncertainty state with a large mean amplitude.
  Physical Review A. 01/1993; 48(4):3344-3361.