Articles

Tunable coupling of transmission-line microwave resonators mediated by an rf SQUID

We realize tunable coupling between two superconducting transmission line resonators. The coupling is mediated by a non-hysteretic rf SQUID acting as a flux-tunable mutual inductance between the resonators. We...

Authors: Friedrich Wulschner, Jan Goetz, Fabian R Koessel, Elisabeth Hoffmann, Alexander Baust, Peter Eder, Michael Fischer, Max Haeberlein, Manuel J Schwarz, Matthias Pernpeintner, Edwar Xie, Ling Zhong, Christoph W Zollitsch, Borja Peropadre, Juan-Jose Garcia Ripoll, Enrique Solano…

Quantum simulation of the Anderson Hamiltonian with an array of coupled nanoresonators: delocalization and thermalization effects

The possibility of using nanoelectromechanical systems as a simulation tool for quantum many-body effects is explored. It is demonstrated that an array of electrostatically coupled nanoresonators can effective...

Authors: John Lozada-Vera, Alejandro Carrillo, Olimpio P de Sá Neto, Jalil K Moqadam, Matthew D LaHaye and Marcos C de Oliveira

Thermal noise in BEC-phononic gravitational wave detectors

Quasiparticles in a Bose-Einstein condensate are sensitive to space-time distortions. Gravitational waves can induce transformations on the state of phonons that can be observed through quantum state discrimin...

Authors: Carlos Sabín, Jan Kohlrus, David Edward Bruschi and Ivette Fuentes

Quantum interferences reconstruction with low homodyne detection efficiency

Optical homodyne tomography consists in reconstructing the quantum state of an optical field from repeated measurements of its amplitude at different field phases (homodyne data). The experimental noise, which...

Authors: Martina Esposito, Francesco Randi, Kelvin Titimbo, Georgios Kourousias, Alessio Curri, Roberto Floreanini, Fulvio Parmigiani, Daniele Fausti, Klaus Zimmermann and Fabio Benatti

Multi-qubit joint measurements in circuit QED: stochastic master equation analysis

We derive a family of stochastic master equations describing homodyne measurement of multi-qubit diagonal observables in circuit quantum electrodynamics. In the regime where qubit decay can be neglected, our a...

Authors: Ben Criger, Alessandro Ciani and David P DiVincenzo

Macroscopic Quantum Resonators (MAQRO): 2015 update

Do the laws of quantum physics still hold for macroscopic objects - this is at the heart of Schrödinger’s cat paradox - or do gravitation or yet unknown effects set a limit for massive particles? What is the f...

Authors: Rainer Kaltenbaek, Markus Aspelmeyer, Peter F Barker, Angelo Bassi, James Bateman, Kai Bongs, Sougato Bose, Claus Braxmaier, Časlav Brukner, Bruno Christophe, Michael Chwalla, Pierre-François Cohadon, Adrian Michael Cruise, Catalina Curceanu, Kishan Dholakia, Lajos Diósi…

Methodology for bus layout for topological quantum error correcting codes

Most quantum computing architectures can be realized as two-dimensional lattices of qubits that interact with each other. We take transmon qubits and transmission line resonators as promising candidates for qu...

Authors: Martin Wosnitzka, Fabio L Pedrocchi and David P DiVincenzo

Trapped modes in linear quantum stochastic networks with delays

Networks of open quantum systems with feedback have become an active area of research for applications such as quantum control, quantum communication and coherent information processing. A canonical formalism ...

Authors: Gil Tabak and Hideo Mabuchi

Quantum metamaterials in the microwave and optical ranges

Quantum metamaterials generalize the concept of metamaterials (artificial optical media) to the case when their optical properties are determined by the interplay of quantum effects in the constituent ‘artific...

Authors: Alexandre M Zagoskin, Didier Felbacq and Emmanuel Rousseau

Dynamical nuclear polarization using multi-colour control of color centers in diamond

Dynamical nuclear polarization (DNP) transfers the polarization of electron spins at cryogenic temperatures to achieve strong nuclear polarization for applications in nuclear magnetic resonance. Recently intro...

Authors: Pengcheng Yang, Martin B Plenio and Jianming Cai

Quantum teleportation of propagating quantum microwaves

Propagating quantum microwaves have been proposed and successfully implemented to generate entanglement, thereby establishing a promising platform for the realisation of a quantum communication channel. Howeve...

Authors: R Di Candia, KG Fedorov, L Zhong, S Felicetti, EP Menzel, M Sanz, F Deppe, A Marx, R Gross and E Solano

Interpolation approach to Hamiltonian-varying quantum systems and the adiabatic theorem

Quantum control could be implemented by varying the system Hamiltonian. According to adiabatic theorem, a slowly changing Hamiltonian can approximately keep the system at the ground state during the evolution ...

Authors: Yu Pan, Zibo Miao, Nina H Amini, Valery Ugrinovskii and Matthew R James

Neutral impurities in a Bose-Einstein condensate for simulation of the Fröhlich-polaron

We present an experimental system to study the Bose polaron by immersion of single, well-controllable neutral Cs impurities into a Rb Bose-Einstein condensate (BEC). We show that, by proper optical traps, inde...

Authors: Michael Hohmann, Farina Kindermann, Benjamin Gänger, Tobias Lausch, Daniel Mayer, Felix Schmidt and Artur Widera

Longitudinal spin relaxation in nitrogen-vacancy ensembles in diamond

We present an experimental study of the longitudinal electron-spin relaxation of ensembles of negatively charged nitrogen-vacancy (NV⁻) centers in diamond. The measurements were performed with samples having diff...

Authors: Mariusz Mrózek, Daniel Rudnicki, Pauli Kehayias, Andrey Jarmola, Dmitry Budker and Wojciech Gawlik

Hybrid optimization schemes for quantum control

Optimal control theory is a powerful tool for solving control problems in quantum mechanics, ranging from the control of chemical reactions to the implementation of gates in a quantum computer. Gradient-based ...

Authors: Michael H Goerz, K Birgitta Whaley and Christiane P Koch

Single molecule DNA detection with an atomic vapor notch filter

The detection of single molecules has facilitated many advances in life- and material-science. Commonly the fluorescence of dye molecules is detected, which are attached to a non-fluorescent structure under st...

Authors: Denis Uhland, Torsten Rendler, Matthias Widmann, Sang-Yun Lee, Jörg Wrachtrup and Ilja Gerhardt

Gold/diamond nanohybrids for quantum sensing applications

Recent advances in quantum technology have demonstrated the potential use of negatively charged nitrogen-vacancy (NV⁻) centers in diamond for temperature and magnetic sensing at sub-cellular levels. Fluorescent n...

Authors: Pei-Chang Tsai, Oliver Y Chen, Yan-Kai Tzeng, Yuen Yung Hui, Jiun You Guo, Chih-Che Wu, Ming-Shien Chang and Huan-Cheng Chang

Magnetic ordering of nitrogen-vacancy centers in diamond via resonator-mediated coupling

Nitrogen-vacancy centers in diamond, being a promising candidate for quantum information processing, may also be an ideal platform for simulating many-body physics. However, it is difficult to realize interact...

Authors: Bo-Bo Wei, Christian Burk, Jörg Wrachtrup and Ren-Bao Liu

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

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