Browsing by Author "Baranger, HU"
Now showing items 1-20 of 26
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Bound on quantum computation time: Quantum error correction in a critical environment
(Physical Review A - Atomic, Molecular, and Optical Physics, 2010-08-31)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
(Physical Review B - Condensed Matter and Materials Physics, 2010-10-28)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 world-line quantum Monte Carlo (QMC) method. Extrapolation ... -
Detecting a Majorana-fermion zero mode using a quantum dot
(Physical Review B - Condensed Matter and Materials Physics, 2011-11-16)We propose an experimental setup for detecting a Majorana zero mode consisting of a spinless quantum dot coupled to the end of a p-wave superconducting nanowire. The Majorana bound state at the end of the wire strongly influences ... -
Detecting photon-photon interactions in a superconducting circuit
(Physical Review B - Condensed Matter and Materials Physics, 2015-10-06)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 high-impedance transmission line from a bath perspective
(Physical Review A, 2016-03-28)We investigate the quantum dynamics of a generic model of light-matter interaction in the context of high-impedance waveguides, focusing on the behavior of the photonic states generated in the waveguide. The model treated ... -
From weak- to strong-coupling mesoscopic Fermi liquids
(EPL, 2012-01-01)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 spin-boson model: Environmental entanglement and the biased two-state system
(Physical Review B - Condensed Matter and Materials Physics, 2014-08-07)We develop a systematic variational coherent-state expansion for the many-body ground state of the spin-boson model, in which a quantum two-level system is coupled to a continuum of harmonic oscillators. Energetic constraints ... -
Kondo effect and mesoscopic fluctuations
(Pramana - Journal of Physics, 2011-11-01)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
(Physical Review B - Condensed Matter and Materials Physics, 2012-04-27)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 sample-to-sample mesoscopic fluctuations. ... -
Mesoscopic fluctuations in the Fermi-liquid regime of the Kondo problem
(European Physical Journal B, 2013-08-01)We consider the low temperature regime of the mesoscopic Kondo problem, and in particular the relevance of a Fermi-liquid 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
(Physical Review A, 2017-07-21)We investigate interference and correlation effects when several detuned emitters are placed along a one-dimensional photonic waveguide. Such a setup allows multiple interactions between the photons and the strongly coupled ... -
Non-Markovian Dynamics of a Qubit Due to Single-Photon Scattering in a Waveguide
(New Journal of Physics, 2018-04-16)We investigate the open dynamics of a qubit due to scattering of a single photon in an infinite or semi-infinite waveguide. Through an exact solution of the time-dependent multi-photon scattering problem, we find the qubitʼs ... -
Observation of majorana quantum critical behaviour in a resonant level coupled to a dissipative environment
(Nature Physics, 2013-01-01)A quantum phase transition is an abrupt change between two distinct ground states of a many-body 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
(Nature Physics, 2013)A quantum phase transition is an abrupt change between two distinct ground states of a many-body system, driven by an external parameter. In the vicinity of the quantum critical point (QCP) where the transition occurs, a ... -
One-dimensional waveguide coupled to multiple qubits: Photon-photon correlations
(EPJ Quantum Technology, 2014-12-01)For a one-dimensional (1D) waveguide coupled to two or three qubits, we show that the photon-photon correlations have a wide variety of behavior, with structure that depends sensitively on the frequency and on the qubit-qubit ... -
Photon correlations generated by inelastic scattering in a one-dimensional waveguide coupled to three-level systems
(Physica E: Low-Dimensional Systems and Nanostructures, 2016-04-01)© 2015 Elsevier B.V. All rights reserved.We study photon correlations generated by scattering from three-level systems (3LS) in one dimension. The two systems studied are a 3LS in a semi-infinite waveguide (3LS plus a mirror) ... -
Quantum interference and complex photon statistics in waveguide QED
(Physical Review A, 2018-02-07)We obtain photon statistics by using a quantum jump approach tailored to a system in which one or two qubits are coupled to a one-dimensional waveguide. Photons confined in the waveguide have strong interference effects, ... -
Stabilizing spin coherence through environmental entanglement in strongly dissipative quantum systems
(Physical Review B - Condensed Matter and Materials Physics, 2014-03-18)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 four-level system to a waveguide
(Physical Review A - Atomic, Molecular, and Optical Physics, 2012-04-19)We study the generation of strongly correlated photons by coupling an atom to photonic quantum fields in a one-dimensional waveguide. Specifically, we consider a three-level or four-level system for the atom. Photon-photon ... -
Time-dependent transport through molecular junctions.
(J Chem Phys, 2010-06-21)We investigate transport properties of molecular junctions under two types of bias--a short time pulse or an ac bias--by combining a solution for Green's functions in the time domain with electronic structure information ...
