Articles

Quantum learning of coherent states

We develop a quantum learning scheme for binary discrimination of coherent states of light. This is a problem of technological relevance for the reading of information stored in a digital memory. In our settin...

Authors: Gael Sentís, Mădălin Guţă and Gerardo Adesso

Nonlinearity and nonclassicality in a nanomechanical resonator

We address quantitatively the relationship between the nonlinearity of a mechanical resonator and the nonclassicality of its ground state. In particular, we analyze the nonclassical properties of the nonlinear...

Authors: Berihu Teklu, Alessandro Ferraro, Mauro Paternostro and Matteo G A Paris

Generating nonclassical quantum input field states with modulating filters

We give explicit constructions of quantum dynamical filters which generate nonclassical states (coherent states, cat states, shaped single and multi-photon states) of quantum optical fields as inputs to genera...

Authors: John E Gough and Guofeng Zhang

On the generalization of linear least mean squares estimation to quantum systems with non-commutative outputs

The purpose of this paper is to study the problem of generalizing the Belavkin-Kalman filter to the case where the classical measurement signal is replaced by a fully quantum non-commutative output signal. We ...

Authors: Nina H Amini, Zibo Miao, Yu Pan, Matthew R James and Hideo Mabuchi

Improved mirror position estimation using resonant quantum smoothing

Quantum parameter estimation, the ability to precisely obtain a classical value in a quantum system, is very important to many key quantum technologies. Many of these technologies rely on an optical probe, eit...

Authors: Trevor A Wheatley, Mankei Tsang, Ian R Petersen and Elanor H Huntington

Quantum lattice Boltzmann is a quantum walk

Numerical methods for the 1-D Dirac equation based on operator splitting and on the quantum lattice Boltzmann (QLB) schemes are reviewed. It is shown that these discretizations fall within the class of quantum...

Authors: Sauro Succi, François Fillion-Gourdeau and Silvia Palpacelli

Walsh-synthesized noise filters for quantum logic

We study a novel class of open-loop control protocols constructed to perform arbitrary nontrivial single-qubit logic operations robust against time-dependent non-Markovian noise. Amplitude and phase modulation...

Authors: Harrison Ball and Michael J Biercuk

A coherent perceptron for all-optical learning

We present nonlinear photonic circuit models for constructing programmable linear transformations and use these to realize a coherent perceptron, i.e., an all-optical linear classifier capable of learning the ...

Authors: Nikolas Tezak and Hideo Mabuchi

A Trotter-Kato theorem for quantum Markov limits

Using the Trotter-Kato theorem we prove the convergence of the unitary dynamics generated by an increasingly singular Hamiltonian in the case of a single field coupling. The limit dynamics is a quantum stochas...

Authors: Luc Bouten, Rolf Gohm, John Gough and Hendra Nurdin

Fermionic models with superconducting circuits

We propose a method for the efficient quantum simulation of fermionic systems with superconducting circuits. It consists in the suitable use of Jordan-Wigner mapping, Trotter decomposition, and multiqubit gate...

Authors: Urtzi Las Heras, Laura García-Álvarez, Antonio Mezzacapo, Enrique Solano and Lucas Lamata

Qubit decoherence due to detector switching

We discuss the noise occurring during a classical dissipative switching process as it would be detected by a quantum bit used as a detector for noise. In particular we study the switching-induced decoherence duri...

Authors: Ioana Serban and Frank K Wilhelm

Topological zero-dimensional photonic modes in chiral coupled-cavity arrays

We show theoretically that a properly chosen one-dimensional array of coupled photonic resonators (cavities) may possess localized zero-dimensional topological modes bearing resemblance with the corresponding ...

Authors: Vassilios Yannopapas

Phase diagram of a QED-cavity array coupled via a N-type level scheme

We study the zero-temperature phase diagram of a one-dimensional array of QED cavities where, besides the single-photon hopping, an additional coupling between neighboring cavities is mediated by an N-type four-l...

Authors: Jiasen Jin, Rosario Fazio and Davide Rossini

Characterization of how dissipation and dephasing errors accumulate in quantum computers

We study the achievements of quantum circuits comprised of several one- and two-qubit gates subject to dissipation and dephasing. Quantum process matrices are determined for the basic one- and two-qubit gate o...

Authors: Jake Gulliksen, Durga Bhaktavatsala Rao Dasari and Klaus Mølmer

Analog quantum simulation of gravitational waves in a Bose-Einstein condensate

We show how to vary the physical properties of a Bose-Einstein condensate (BEC) in order to mimic an effective gravitational-wave spacetime. In particular, we focus in the simulation of the recently discovered...

Authors: Tupac Bravo, Carlos Sabín and Ivette Fuentes

Creation of two-dimensional Coulomb crystals of ions in oblate Paul traps for quantum simulations

We develop the theory to describe the equilibrium ion positions and phonon modes for a trapped ion quantum simulator in an oblate Paul trap that creates two-dimensional Coulomb crystals in a triangular lattice...

Authors: Bryce Yoshimura, Marybeth Stork, Danilo Dadic, Wesley C Campbell and James K Freericks

Thermalization of strongly interacting bosons after spontaneous emissions in optical lattices

We study the out-of-equilibrium dynamics of bosonic atoms in a 1D optical lattice, after the ground-state is excited by a single spontaneous emission event, i.e. after an absorption and re-emission of a lattic...

Authors: Johannes Schachenmayer, Lode Pollet, Matthias Troyer and Andrew J Daley

A dynamic systems approach to fermions and their relation to spins

The key dynamic properties of fermionic systems, like controllability, reachability, and simulability, are investigated in a general Lie-theoretical frame for quantum systems theory. It just requires knowing d...

Authors: Zoltán Zimborás, Robert Zeier, Michael Keyl and Thomas Schulte-Herbrüggen

Minimal ancilla mediated quantum computation

Schemes of universal quantum computation in which the interactions between the computational elements, in a computational register, are mediated by some ancillary system are of interest due to their relevance ...

Authors: Timothy J Proctor and Viv Kendon

Propagation of quantum correlations after a quench in the Mott-insulator regime of the Bose-Hubbard model

We study a quantum quench in the Bose-Hubbard model where the tunneling rate J is suddenly switched from zero to a finite value in the Mott regime. In order to solve the many-body quantum dynamics far from equili...

Authors: Konstantin V Krutitsky, Patrick Navez, Friedemann Queisser and Ralf Schützhold

What is a quantum simulator?

Quantum simulators are devices that actively use quantum effects to answer questions about model systems and, through them, real systems. In this review we expand on this definition by answering several fundam...

Authors: Tomi H Johnson, Stephen R Clark and Dieter Jaksch

Efficient quantum simulation of fermionic and bosonic models in trapped ions

We analyze the efficiency of quantum simulations of fermionic and bosonic models in trapped ions. In particular, we study the optimal time of entangling gates and the required number of total elementary gates....

Authors: Lucas Lamata, Antonio Mezzacapo, Jorge Casanova and Enrique Solano

Efficient quantum simulation of fermionic and bosonic models in trapped ions

We analyze the efficiency of quantum simulations of fermionic and bosonic models in trapped ions. In particular, we study the optimal time of entangling gates and the required number of total elementary gates....

Authors: Lucas Lamata, Antonio Mezzacapo, Jorge Casanova and Enrique Solano

Quantum and classical nonlinear dynamics in a microwave cavity

We consider a quarter wave coplanar microwave cavity terminated to ground via asuperconducting quantum interference device. By modulating the flux through the loop,the cavity frequency is modulated. The flux i...

Authors: Charles H Meaney, Hyunchul Nha, Timothy Duty and Gerard J Milburn

Trapped-ion quantum simulation of tunable-range Heisenberg chains

Quantum-optical techniques allow for generating controllable spin-spin interactions between ions, making trapped ions an ideal quantum simulator of Heisenberg chains. A single parameter, the detuning of the Ra...

Authors: Tobias Graß and Maciej Lewenstein

Negative-resistance models for parametrically flux-pumped superconducting quantum interference devices

A Superconducting QUantum Interference Device (SQUID) modulated by a fast oscillating magnetic flux can be used as a parametric amplifier, providing gain with very little added noise. Here, we develop lineariz...

Authors: Kyle M Sundqvist and Per Delsing

Gain, noise and intermodulation in a nonlinear superconducting resonator

A superconducting microwave resonator is modified with several weak links to make it nonlinear and operated as a phase-insensitive microwave amplifier. Signal gain is demonstrated by intermodulation with a str...

Authors: Erik A Tholén, Adem Ergül, David Schaeffer and David B Haviland

The circuit quantum electrodynamical Josephson interferometer

Arrays of circuit cavities offer fascinating perspectives for exploring quantum many-body systems in a driven dissipative regime where excitation losses are continuously compensated by coherent input drives. H...

Authors: Robert Jirschik and Michael J Hartmann

One-dimensional waveguide coupled to multiple qubits: photon-photon correlations

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...

Authors: Yao-Lung L Fang, Huaixiu Zheng and Harold U Baranger

Controlling the dynamic range of a Josephson parametric amplifier

One of the central challenges in the development of parametric amplifiers is the control of the dynamic range relative to its gain and bandwidth, which typically limits quantum limited amplification to signals...

Authors: Christopher Eichler and Andreas Wallraff

Editorial

Authors: Gerard Milburn