1,207 research outputs found
Quantum computation with cold bosonic atoms in an optical lattice
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
tunneling rate between neighbouring sites is unknown, one may perform a
universal set of gates by means of adiabatic passage
The Interspersed Spin Boson Lattice Model
We describe a family of lattice models that support a new class of quantum
magnetism characterized by correlated spin and bosonic ordering [Phys. Rev.
Lett. 112, 180405 (2014)]. We explore the full phase diagram of the model using
Matrix-Product-State methods. Guided by these numerical results, we describe a
modified variational ansatz to improve our analytic description of the
groundstate at low boson frequencies. Additionally, we introduce an
experimental protocol capable of inferring the low-energy excitations of the
system by means of Fano scattering spectroscopy. Finally, we discuss the
implementation and characterization of this model with current circuit-QED
technology.Comment: Submitted to EPJ ST issue on "Novel Quantum Phases and Mesoscopic
Physics in Quantum Gases
Ultrastrong coupling few-photon scattering theory
We study the scattering of photons by a two-level system ultrastrongly
coupled to a one-dimensional waveguide. Using a combination of the polaron
transformation with scattering theory we can compute the one-photon scattering
properties of the qubit for a broad range of coupling strengths, estimating
resonance frequencies, lineshapes and linewidths. We validate numerically and
analytically the accuracy of this technique up to , close to the
Toulouse point , where inelastic scattering becomes relevant. These
methods model recent experiments with superconducting circuits [P.
Forn-D{\'\i}az et al., Nat. Phys. (2016)]
Mapping the spatial distribution of entanglement in optical lattices
We study the entangled states that can be generated using two species of
atoms trapped in independently movable, two-dimensional optical lattices. We
show that using two sets of measurements it is possible to measure a set of
entanglement witness operators distributed over arbitrarily large regions of
the lattice, and use these witnesses to produce two-dimensional plots of the
entanglement content of these states. We also discuss the influence of noise on
the states and on the witnesses, as well as connections to ongoing experiments.Comment: 2 figures, 6 page
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