Browsing by Author "Baranger, HU"
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Bound on quantum computation time: Quantum error correction in a critical environment
Novais, E; Mucciolo, ER; Baranger, HU (Physical Review A  Atomic, Molecular, and Optical Physics, 20100831)We obtain an upper bound on the time available for quantum computation for a given quantum computer and decohering environment with quantum error correction implemented. First, we derive an explicit quantum evolution operator ... 
Conductance of quantum impurity models from quantum monte carlo
Liu, D; Chandrasekharan, S; Baranger, HU (Physical Review B  Condensed Matter and Materials Physics, 20101028)The conductance of two Anderson impurity models, one with twofold and another with fourfold degeneracy, representing two types of quantum dots, is calculated using a worldline quantum Monte Carlo (QMC) method. Extrapolation ... 
Detecting a Majoranafermion zero mode using a quantum dot
Liu, DE; Baranger, HU (Physical Review B  Condensed Matter and Materials Physics, 20111116)We propose an experimental setup for detecting a Majorana zero mode consisting of a spinless quantum dot coupled to the end of a pwave superconducting nanowire. The Majorana bound state at the end of the wire strongly influences ... 
Detecting photonphoton interactions in a superconducting circuit
Jin, LJ; Houzet, M; Meyer, JS; Baranger, HU; Hekking, FWJ (Physical Review B  Condensed Matter and Materials Physics, 20151006)A local interaction between photons can be engineered by coupling a nonlinear system to a transmission line. The required transmission line can be conveniently formed from a chain of Josephson junctions. The nonlinearity ... 
Dynamics of a qubit in a highimpedance transmission line from a bath perspective
Bera, S; Baranger, HU; Florens, S (Physical Review A, 20160328)We investigate the quantum dynamics of a generic model of lightmatter interaction in the context of highimpedance waveguides, focusing on the behavior of the photonic states generated in the waveguide. The model treated ... 
From weak to strongcoupling mesoscopic Fermi liquids
Liu, DE; Burdin, S; Baranger, HU; Ullmo, D (EPL, 20120101)We study mesoscopic fluctuations in a system in which there is a continuous connection between two distinct Fermi liquids, asking whether the mesoscopic variation in the two limits is correlated. The particular system studied ... 
Generalized multipolaron expansion for the spinboson model: Environmental entanglement and the biased twostate system
Bera, S; Nazir, A; Chin, AW; Baranger, HU; Florens, S (Physical Review B  Condensed Matter and Materials Physics, 20140807)We develop a systematic variational coherentstate expansion for the manybody ground state of the spinboson model, in which a quantum twolevel system is coupled to a continuum of harmonic oscillators. Energetic constraints ... 
Kondo effect and mesoscopic fluctuations
Ullmo, D; Burdin, S; Liu, DE; Baranger, HU (Pramana  Journal of Physics, 20111101)Two important themes in nanoscale physics in the last two decades are correlations between electrons and mesoscopic fluctuations. Here we review our recent work on the intersection of these two themes. The setting is the ... 
Mesoscopic Anderson box: Connecting weak to strong coupling
Liu, DE; Burdin, S; Baranger, HU; Ullmo, D (Physical Review B  Condensed Matter and Materials Physics, 20120427)We study the Anderson impurity problem in a mesoscopic setting, namely the "Anderson box," in which the impurity is coupled to finite reservoir having a discrete spectrum and large sampletosample mesoscopic fluctuations. ... 
Mesoscopic fluctuations in the Fermiliquid regime of the Kondo problem
Ullmo, D; Liu, DE; Burdin, S; Baranger, HU (European Physical Journal B, 20130801)We consider the low temperature regime of the mesoscopic Kondo problem, and in particular the relevance of a Fermiliquid description of this regime. Mesoscopic fluctuations of both the quasiparticle energy levels and the ... 
Multiple emitters in a waveguide: Nonreciprocity and correlated photons at perfect elastic transmission
Fang, YLL; Baranger, HU (Physical Review A, 20170721)We investigate interference and correlation effects when several detuned emitters are placed along a onedimensional photonic waveguide. Such a setup allows multiple interactions between the photons and the strongly coupled ... 
NonMarkovian Dynamics of a Qubit Due to SinglePhoton Scattering in a Waveguide
Fang, YLL; Ciccarello, F; Baranger, HU (New Journal of Physics, 20180416)We investigate the open dynamics of a qubit due to scattering of a single photon in an infinite or semiinfinite waveguide. Through an exact solution of the timedependent multiphoton scattering problem, we find the qubitʼs ... 
Observation of majorana quantum critical behaviour in a resonant level coupled to a dissipative environment
Mebrahtu, HT; Borzenets, IV; Zheng, H; Bomze, YV; Smirnov, AI; Florens, S; Baranger, HU; ... (8 authors) (Nature Physics, 20130101)A quantum phase transition is an abrupt change between two distinct ground states of a manybody system, driven by an external parameter. In the vicinity of the quantum critical point (QCP) where the transition occurs, a ... 
Observation of Majorana quantum critical behaviour in a resonant level coupled to a dissipative environment
Mebrahtu, HT; Borzenets, IV; Zheng, H; Bomze, YV; Smirnov, AI; Florens, S; Baranger, HU; ... (8 authors) (Nature Physics, 2013)A quantum phase transition is an abrupt change between two distinct ground states of a manybody system, driven by an external parameter. In the vicinity of the quantum critical point (QCP) where the transition occurs, a ... 
Onedimensional waveguide coupled to multiple qubits: Photonphoton correlations
Fang, YLL; Zheng, H; Baranger, HU (EPJ Quantum Technology, 20141201)For a onedimensional (1D) waveguide coupled to two or three qubits, we show that the photonphoton correlations have a wide variety of behavior, with structure that depends sensitively on the frequency and on the qubitqubit ... 
Photon correlations generated by inelastic scattering in a onedimensional waveguide coupled to threelevel systems
Fang, YLL; Baranger, HU (Physica E: LowDimensional Systems and Nanostructures, 20160401)© 2015 Elsevier B.V. All rights reserved.We study photon correlations generated by scattering from threelevel systems (3LS) in one dimension. The two systems studied are a 3LS in a semiinfinite waveguide (3LS plus a mirror) ... 
Quantum interference and complex photon statistics in waveguide QED
Zhang, XHH; Baranger, HU (Physical Review A, 20180207)We obtain photon statistics by using a quantum jump approach tailored to a system in which one or two qubits are coupled to a onedimensional waveguide. Photons confined in the waveguide have strong interference effects, ... 
Stabilizing spin coherence through environmental entanglement in strongly dissipative quantum systems
Bera, S; Florens, S; Baranger, HU; Roch, N; Nazir, A; Chin, AW (Physical Review B  Condensed Matter and Materials Physics, 20140318)The key feature of a quantum spin coupled to a harmonic bath  a model dissipative quantum system  is competition between oscillator potential energy and spin tunneling rate. We show that these opposing tendencies cause ... 
Strongly correlated photons generated by coupling a three or fourlevel system to a waveguide
Zheng, H; Gauthier, DJ; Baranger, HU (Physical Review A  Atomic, Molecular, and Optical Physics, 20120419)We study the generation of strongly correlated photons by coupling an atom to photonic quantum fields in a onedimensional waveguide. Specifically, we consider a threelevel or fourlevel system for the atom. Photonphoton ... 
Timedependent transport through molecular junctions.
Ke, SH; Liu, R; Yang, W; Baranger, HU (J Chem Phys, 20100621)We investigate transport properties of molecular junctions under two types of biasa short time pulse or an ac biasby combining a solution for Green's functions in the time domain with electronic structure information ...