Juan José García-Ripoll

Publications (10)24.88 Total impact

• Article: Phase stabilization of a frequency comb using multi-pulse quantum interferometry

  Andrea Cadarso, Jordi Mur-Petit, Juan José García-Ripoll
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  ABSTRACT: From the interaction between a frequency comb and an atomic qubit, we derive quantum protocols for the determination of the carrier-envelope offset phase, using the qubit coherence as a reference, and without the need of frequency doubling or an octave spanning comb. Compared with a trivial interference protocol, the multi-pulse protocol results in a polynomial enhancement of the sensitivity O(N^{-2}) with the number N of laser pulses involved. We present specializations of the protocols using optical or hyperfine qubits, Lambda-schemes and Raman transitions, and introduce methods where the reference is another phase-stable cw-laser or frequency comb.
  02/2013;
• Article: Circuit QED bright source for chiral entangled light based on dissipation

  Fernando Quijandría, Diego Porras, Juan José García-Ripoll, David Zueco
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  ABSTRACT: Based on a circuit QED qubit-cavity array a source of two-mode entangled microwave radiation is designed. Our scheme is rooted in the combination of external driving, collective phenomena and dissipation. On top of that the reflexion symmetry is broken via external driving permitting the appearance of chiral emission. Our findings go beyond the applications and are relevant for fundamental physics, since we show how to implement quantum lattice models exhibiting criticality driven by dissipation.
  12/2012;
• Article: Generating and verifying graph states for fault-tolerant measurement-based quantum computing in 2D optical lattices

  Jaewoo Joo, Emilio Alba, Juan José García-Ripoll, Timothy P. Spiller
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  ABSTRACT: We propose two schemes for implementing graph states useful for faulttolerant measurement-based quantum computation in 2D optical lattices. We show that bilayer cluster and surface code states can be created by just global single-row and controlled-Z operations. The schemes benefit from the accessibility of atom addressing on 2D optical lattices and the existence of a verification protocol which allows us to ensure the experimental feasibility of measuring the fidelity of the system against the ideal graph state. The simulation results show potential for a physical realisation toward fault-tolerant measurement-based quantum computation in the presence of defects in optical lattices.
  07/2012;
• Article: Shaping an itinerant quantum field into a multimode squeezed vacuum by dissipation.

  Diego Porras, Juan José García-Ripoll
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  ABSTRACT: We show that inducing sidebands in the emission of a single emitter into a one-dimensional waveguide, together with a dissipative repumping process, a photon field is cooled down to a multimode squeezed vacuum. Our method does not require being in the strong coupling regime, works with a continuum of propagating field modes, and leads to sources of tunable multimode squeezed light in circuit-QED systems.
  Physical Review Letters 01/2012; 108(4):043602. · 7.37 Impact Factor
• Source

  Available from: Juan León

  Article: Fermi problem with artificial atoms in circuit QED.

  Carlos Sabín, Marco del Rey, Juan José García-Ripoll, Juan León
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  ABSTRACT: We propose a feasible experimental test of a 1D version of the Fermi problem using superconducting qubits. We give an explicit nonperturbative proof of strict causality in this model, showing that the probability of excitation of a two-level artificial atom with a dipolar coupling to a quantum field is completely independent of the other qubit until signals from it may arrive. We explain why this is in perfect agreement with the existence of nonlocal correlations and previous results which were used to claim apparent causality problems for Fermi's two-atom system.
  Physical Review Letters 10/2011; 107(15):150402. · 7.37 Impact Factor
• Source

  Available from: ArXiv

  Article: Microwave photonics with Josephson junction arrays: negative refraction index and entanglement through disorder

  David Zueco, Juan José Mazo, Enrique Solano, Juan José García-Ripoll
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  ABSTRACT: We study different architectures for a photonic crystal in the microwave regime based on superconducting transmission lines interrupted by Josephson junctions, both in one and two dimensions. A study of the scattering properties of a single junction in the line shows that the junction behaves as a perfect mirror when the photon frequency matches the Josephson plasma frequency. We generalize our calculations to periodic arrangements of junctions, demonstrating that they can be used for tunable band engineering, forming what we call a quantum circuit crystal. Two applications are discussed in detail. In a two-dimensional structure we demonstrate the phenomenon of negative refraction. We finish by studying the creation of stationary entanglement between two superconducting qubits interacting through a disordered media.
  10/2011;
• Source

  Available from: ArXiv

  Article: Shaping an Itinerant Quantum Field by Dissipation

  Diego Porras, Juan José García-Ripoll
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  ABSTRACT: We show that inducing sidebands in the emission of a single emitter into a one dimensional waveguide, together with a dissipative re-pumping process, a photon field is cooled down to a squeezed vacuum. Our method does not require to be in the strong coupling regime, works with a continuum of propagating field modes and it may lead to sources of tunable multimode squeezed light in circuit QED systems.
  07/2011;
• Source

  Available from: ArXiv

  Article: Dynamical creation of bosonic cooper-like pairs.

  Tassilo Keilmann, Juan José García-Ripoll
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  ABSTRACT: We propose a scheme to create a metastable state of paired bosonic atoms in an optical lattice. The most salient features of this state are that the wave function of each pair is a Bell state and that the pair size spans half the lattice, similar to fermionic Cooper pairs. This mesoscopic state can be created with a dynamical process that involves crossing a quantum phase transition and which is supported by the symmetries of the physical system. We characterize the final state by means of a measurable two-particle correlator that detects both the presence of the pairs and their size.
  Physical Review Letters 03/2008; 100(11):110406. · 7.37 Impact Factor
• Source

  Available from: ArXiv

  Article: Quantum computation with cold bosonic atoms in an optical lattice.

  Juan José García-Ripoll, Juan Ignacio Cirac
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  ABSTRACT: We analyse an implementation of a quantum computer using bosonic atoms in an optical lattice. We show that, even though the number of atoms per site and the tunnelling rate between neighbouring sites is unknown, one may operate a universal set of gates by means of adiabatic passage.
  Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 08/2003; 361(1808):1537-48. · 2.77 Impact Factor
• Source

  Available from: Geza Toth

  Article: Efficient algorithm for multiqudit twirling for ensemble quantum computation

  Géza Tóth, Juan José García-Ripoll
  Physical Review A, v.75 (2007).