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Sample records for 2d circuit qed

  1. Two-qubit parity meters in 3D and 2D circuit QED

    NASA Astrophysics Data System (ADS)

    Dicarlo, Leonardo

    2014-03-01

    Non-demolition measurements of multi-qubit observables and feedback control conditioned on their outcomes are essential for quantum error correction. We present two implementations of two-qubit parity meters in circuit QED. In 3D, we match the dispersive coupling of two qubits to a common cavity to encode parity in the transmission of an applied microwave pulse. In 2D, we first encode the parity of two data qubits in the computational state of an ancillary qubit using resonant interactions, and subsequently project the ancilla using a dedicated, dispersively-coupled resonator. A key advantage of this second scheme is the protection of data qubits from dephasing by measurement photons. First applications of these parity meters include probabilistic entanglement by measurement, and deterministic entanglement using digital feedback control. Current efforts target the implementation of measurement-based bit-flip error correction. Research funded by NWO, FOM, and the European projects SOLID and SCALEQIT.

  2. Engineering stabilizer measurements in circuit QED: I

    NASA Astrophysics Data System (ADS)

    Chou, Kevin; Blumoff, Jacob; Reagor, M.; Axline, C.; Brierley, R.; Nigg, S.; Reinhold, P.; Heeres, R.; Wang, C.; Sliwa, K.; Narla, A.; Hatridge, M.; Jiang, L.; Devoret, M. H.; Girvin, S. M.; Schoekopf, R. J.

    Quantum error correction based on stabilizer codes has emerged as an attractive approach towards building a practical quantum information processor. One requirement for such a device is the ability to perform hardware efficient measurements on registers of qubits. We demonstrate a new protocol to realize such multi-qubit measurements. A key feature of our approach is that it enables arbitrary stabilizer measurements to be selected in software, and requires a relatively small number of buses, ancillae, and control lines. This allows for a minimally complex sample realizing a simple dispersive hamiltonian while maintaining a high degree of decoupling between our fixed-tuned qubits. We experimentally implement these measurements in 3D circuit QED using transmon qubits coupled to a common bus resonator. In this first of two talks, we introduce our 3D cQED system and describe the protocol for measuring n-qubit parities of a three qubit register. We acknowledge funding from ARO.

  3. Perturbative approach to open circuit QED systems

    NASA Astrophysics Data System (ADS)

    Li, Andy C. Y.; Petruccione, Francesco; Koch, Jens

    2014-03-01

    Perturbation theory (PT) is a powerful and commonly used tool in the investigation of closed quantum systems. In the context of open quantum systems, PT based on the Markovian quantum master equation is much less developed. The investigation of open systems mostly relies on exact diagonalization of the Liouville superoperator or quantum trajectories. In this approach, the system size is rather limited by current computational capabilities. Analogous to closed-system PT, we develop a PT suitable for open quantum systems. The proposed method is useful in the analytical understanding of open systems as well as in the numerical calculation of system observables, which would otherwise be impractical. This enables us to investigate a variety of open circuit QED systems, including the open Jaynes-Cummings lattice model.

  4. Engineering stabilizer measurements in circuit QED: II

    NASA Astrophysics Data System (ADS)

    Blumoff, Jacob; Chou, Kevin; Reagor, M.; Axline, C.; Brierly, R.; Nigg, S.; Reinhold, P.; Heeres, R.; Wang, C.; Sliwa, K.; Narla, A.; Hatridge, M.; Jiang, L.; Devoret, M. H.; Girvin, S. M.; Schoelkopf, R. J.

    Quantum error correction based on stabilizer codes has emerged as an attractive approach towards building a practical quantum information processor. One requirement for such a device is the ability to perform hardware efficient measurements on registers of qubits. We demonstrate a new protocol to realize such multi-qubit measurements. A key feature of our approach is that it enables arbitrary stabilizer measurements to be selected in software, and requires a relatively small number of buses, ancillae, and control lines. This allows for a minimally complex sample realizing a simple dispersive hamiltonian while maintaining a high degree of decoupling between our fixed-tuned qubits. We experimentally implement these measurements in 3D circuit QED using transmon qubits coupled to a common bus resonator. In the second of two talks, we present a full characterization of the algorithm describing the outcome dependent projections via quantum process tomography. We acknowledge funding from ARO.

  5. Microwave Photon Detector in Circuit QED

    NASA Astrophysics Data System (ADS)

    Garcia-Ripoll, Juan Jose; Romero, Guillermo; Solano, Enrique

    2009-03-01

    In this work we propose a design for a microwave photodetector based on elements from circuit QED such as the ones used in qubit designs. Our proposal consists on a microwave guide in which we embed circuital elements that can absorb photons and irreversibly change state. These incoherent absorption processes constitute the measurement itself. We first model this design using a general master equation for the propagating photons and the absorbing elements. We find that the detection efficiency for a single absorber is limited to 50%, and that this efficiency can be quickly increased by adding more elements with a moderate separation, obtaining 80% and 90% for two and three absorbers. Our abstract design has at least one possible implementation in which the absorbers are current biased Josephson junction. We demonstrate that the coupling between the guide and the junctions is strong enough, irrespectively of the microwave guide size, and derivate realistic parameters for high fidelity operation with current experiments. Patent pending No. 200802933, Oficina Espanola de Patentes y Marcas, 17/10/2008.

  6. Extensible circuit QED processor architecture with vertical I/O

    NASA Astrophysics Data System (ADS)

    Bruno, Alessandro; Poletto, Stefano; Haider, Nadia; Dicarlo, Leonardo

    Achieving quantum fault tolerance in an extensible architecture is an outstanding challenge across experimental quantum computing platforms today. Traditionally, circuit QED processors have millimeter dimensions and lateral coupling for all input/output (I/O) signals, precluding the increase in qubit numbers beyond ~10. We present a scalable footprint for circuit QED processors with vertically coupled I/O. Our demonstration using centimeter scale chips can accommodate the ~50 qubits needed in next-generation processors targeting the experimental demonstration of quantum fault tolerance. We acknowledge funding from FOM, NWO and the EU FP7 Project SCALEQIT.

  7. Hybrid Circuit QED with Double Quantum Dots

    NASA Astrophysics Data System (ADS)

    Petta, Jason

    2014-03-01

    Cavity quantum electrodynamics explores quantum optics at the most basic level of a single photon interacting with a single atom. We have been able to explore cavity QED in a condensed matter system by placing a double quantum dot (DQD) inside of a high quality factor microwave cavity. Our results show that measurements of the cavity field are sensitive to charge and spin dynamics in the DQD.[2,3] We can explore non-equilibrium physics by applying a finite source-drain bias across the DQD, which results in sequential tunneling. Remarkably, we observe a gain as large as 15 in the cavity transmission when the DQD energy level detuning is matched to the cavity frequency. These results will be discussed in the context of single atom lasing.[4] I will also describe recent progress towards reaching the strong-coupling limit in cavity-coupled Si DQDs. In collaboration with Manas Kulkarni, Yinyu Liu, Karl Petersson, George Stehlik, Jacob Taylor, and Hakan Tureci. We acknowledge support from the Sloan and Packard Foundations, ARO, DARPA, and NSF.

  8. Quantum memory with millisecond coherence in circuit QED

    NASA Astrophysics Data System (ADS)

    Reagor, Matthew; Pfaff, Wolfgang; Axline, Christopher; Heeres, Reinier W.; Ofek, Nissim; Sliwa, Katrina; Holland, Eric; Wang, Chen; Blumoff, Jacob; Chou, Kevin; Hatridge, Michael J.; Frunzio, Luigi; Devoret, Michel H.; Jiang, Liang; Schoelkopf, Robert J.

    2016-07-01

    Significant advances in coherence render superconducting quantum circuits a viable platform for fault-tolerant quantum computing. To further extend capabilities, highly coherent quantum systems could act as quantum memories for these circuits. A useful quantum memory must be rapidly addressable by Josephson-junction-based artificial atoms, while maintaining superior coherence. We demonstrate a superconducting microwave cavity architecture that is highly robust against major sources of loss that are encountered in the engineering of circuit QED systems. The architecture allows for storage of quantum superpositions in a resonator on the millisecond scale, while strong coupling between the resonator and a transmon qubit enables control, encoding, and readout at MHz rates. This extends the maximum available coherence time attainable in superconducting circuits by almost an order of magnitude compared to earlier hardware. Our design is an ideal platform for studying coherent quantum optics and marks an important step towards hardware-efficient quantum computing in Josephson-junction-based quantum circuits.

  9. Engineered circuit QED with dense resonant modes

    NASA Astrophysics Data System (ADS)

    Wilhelm, Frank; Egger, Daniel

    2013-03-01

    In circuit quantum electrodynamics even in the ultrastrong coupling regime, strong quasi-resonant interaction typically involves only one mode of the resonator as the mode spacing is comparable to the frequency of the mode. We are going to present an engineered hybrid transmission line consisting of a left-handed and a right-handed portion that has a low-frequency van-Hove singularity hence showing a dense mode spectrum at an experimentally accessible point. This gives rise to strong multi-mode coupling and can be utilized in multiple ways to create strongly correlated microwave photons. Supported by DARPA through the QuEST program and by NSERC Discovery grants

  10. Approaching perfect microwave photodetection in circuit QED

    SciTech Connect

    Peropadre, B.; Garcia-Ripoll, J. J.; Romero, G.; Johansson, G.; Wilson, C. M.; Solano, E.

    2011-12-15

    In order to apply all ideas from quantum optics to the field of quantum circuits, one of the missing ingredients is a high-efficiency single-photon detector. In this work we propose a design for such a device which successfully reaches 100% efficiency with only one absorber. Our photon detector consists of a three-level system (a phase qubit) coupled to a semi-infinite one-dimensional waveguide (a microwave transmission line) which performs highly efficient photodetection in a simplified manner as compared to previous proposals. Using the tools of quantum optics we extensively study the scattering properties of realistic wave packets against this device, thereby computing the efficiency of the detector. We find that the detector has many operating modes, can detect detuned photons, is robust against design imperfections, and can be made broadband by using more than one absorbing element in the design. Many of these ideas could be translated to other single-mode photonic or plasmonic waveguides interacting with three-level atoms or quantum dots.

  11. Polariton states in circuit QED for electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Gu, Xiu; Huai, Sai-Nan; Nori, Franco; Liu, Yu-xi

    2016-06-01

    Electromagnetically induced transparency (EIT) has been extensively studied in various systems. However, it is not easy to observe in superconducting quantum circuits (SQCs) because the Rabi frequency of the strong-controlling field corresponding to EIT is limited by the decay rates of the SQCs. Here, we show that EIT can be achieved by engineering decay rates in a superconducting circuit QED system through a classical driving field on the qubit. Without such a driving field, the dressed states of the system, describing a superconducting qubit coupled to a cavity field, are approximately product states of the cavity and qubit states in the large-detuning regime. However, the driving field can strongly mix these dressed states. These doubly dressed states, here called polariton states, are formed by the driving field and dressed states, and are a mixture of light and matter. The weights of the qubit and cavity field in the polariton states can now be tuned by the driving field, and thus the decay rates of the polariton states can be changed. We choose the three lowest-energy polariton states with a Λ -type transition in such a driven circuit QED system, and demonstrate how EIT and Autler-Townes splitting can be realized in this compound system. We believe that this study will be helpful for EIT experiments using SQCs.

  12. Exact quantum Bayesian rule for qubit measurements in circuit QED.

    PubMed

    Feng, Wei; Liang, Pengfei; Qin, Lupei; Li, Xin-Qi

    2016-01-01

    Developing efficient framework for quantum measurements is of essential importance to quantum science and technology. In this work, for the important superconducting circuit-QED setup, we present a rigorous and analytic solution for the effective quantum trajectory equation (QTE) after polaron transformation and converted to the form of Stratonovich calculus. We find that the solution is a generalization of the elegant quantum Bayesian approach developed in arXiv:1111.4016 by Korotokov and currently applied to circuit-QED measurements. The new result improves both the diagonal and off-diagonal elements of the qubit density matrix, via amending the distribution probabilities of the output currents and several important phase factors. Compared to numerical integration of the QTE, the resultant quantum Bayesian rule promises higher efficiency to update the measured state, and allows more efficient and analytical studies for some interesting problems such as quantum weak values, past quantum state, and quantum state smoothing. The method of this work opens also a new way to obtain quantum Bayesian formulas for other systems and in more complicated cases. PMID:26841968

  13. Exact quantum Bayesian rule for qubit measurements in circuit QED

    PubMed Central

    Feng, Wei; Liang, Pengfei; Qin, Lupei; Li, Xin-Qi

    2016-01-01

    Developing efficient framework for quantum measurements is of essential importance to quantum science and technology. In this work, for the important superconducting circuit-QED setup, we present a rigorous and analytic solution for the effective quantum trajectory equation (QTE) after polaron transformation and converted to the form of Stratonovich calculus. We find that the solution is a generalization of the elegant quantum Bayesian approach developed in arXiv:1111.4016 by Korotokov and currently applied to circuit-QED measurements. The new result improves both the diagonal and off-diagonal elements of the qubit density matrix, via amending the distribution probabilities of the output currents and several important phase factors. Compared to numerical integration of the QTE, the resultant quantum Bayesian rule promises higher efficiency to update the measured state, and allows more efficient and analytical studies for some interesting problems such as quantum weak values, past quantum state, and quantum state smoothing. The method of this work opens also a new way to obtain quantum Bayesian formulas for other systems and in more complicated cases. PMID:26841968

  14. Exact quantum Bayesian rule for qubit measurements in circuit QED

    NASA Astrophysics Data System (ADS)

    Feng, Wei; Liang, Pengfei; Qin, Lupei; Li, Xin-Qi

    2016-02-01

    Developing efficient framework for quantum measurements is of essential importance to quantum science and technology. In this work, for the important superconducting circuit-QED setup, we present a rigorous and analytic solution for the effective quantum trajectory equation (QTE) after polaron transformation and converted to the form of Stratonovich calculus. We find that the solution is a generalization of the elegant quantum Bayesian approach developed in arXiv:1111.4016 by Korotokov and currently applied to circuit-QED measurements. The new result improves both the diagonal and off-diagonal elements of the qubit density matrix, via amending the distribution probabilities of the output currents and several important phase factors. Compared to numerical integration of the QTE, the resultant quantum Bayesian rule promises higher efficiency to update the measured state, and allows more efficient and analytical studies for some interesting problems such as quantum weak values, past quantum state, and quantum state smoothing. The method of this work opens also a new way to obtain quantum Bayesian formulas for other systems and in more complicated cases.

  15. Extracting Past-Future Vacuum Correlations Using Circuit QED

    NASA Astrophysics Data System (ADS)

    Peropadre, Borja; Sabin, Carlos; Del Rey, Marco; Martin-Martinez, Eduardo

    2013-03-01

    In this work we propose a realistic circuit QED experiment to test the extraction of past-future vacuum entanglement to a pair of superconducting qubits. A qubit P -for past- interacts with a quantum field along an open transmission line for an interval Ton and then, after a time-lapse Toff of no interaction, a second qubit F -for future- starts interacting for a time Ton in a symmetric fashion. After this protocol, past-future quantum correlations will have transferred to the qubits, even if the qubits do not coexist at the same time. We show that this experiment can be realized with current technology and discuss its utility as a possible implementation of a quantum memory. Spanish MICINN Projects No. FIS2011-29287 and No. FIS2009-10061 and CAM research consortium QUITEMAD Grant No. S2009-ESP-1594.

  16. Quantum speed limit for a circuit-QED computer

    NASA Astrophysics Data System (ADS)

    Motzoi, Felix; Goerz, Michael; Theis, Lukas; Kessler, Torsten; Whaley, Birgitta; Wilhelm, Frank

    We examine the controlability and design landscape for circuit QED. We show that the speed limit for universal gates is on the order of 10ns for typical experimental parameters, with one cavity and two transmons. The results include simultaneous gates on different qubits (where the speed limit is given by the energy separation) as well as two-qubit gates, and neither requires qubit-frequency tuning, which can degrade coherence and increase overhead. This result shows that the coupling strength does not impose a fundamental limitation on the speed, and significantly outperforms current experimental implementations. Moreover we obtain fast speeds both in the near-resonant and dispersive cavity regime, and for both direct qubit control and control through the cavity.

  17. Quantum gates by qubit frequency modulation in circuit QED

    NASA Astrophysics Data System (ADS)

    Beaudoin, Felix; da Silva, Marcus P.; Johnson, Blake R.; Ohki, Thomas A.; Dutton, Zachary; Blais, Alexandre

    2012-02-01

    Several types of two-qubit gates have been realized experimentally in circuit QED. These are based, for example, on tuning the pair of qubits in resonance with each other [Majer, Nature 449, 443-447 (2007)] or on a microwave pulse on one qubit at the transition frequency of a second qubit [Chow, Phys. Rev. Lett. 107, 080502 (2011)]. Another realization is based on a sequence of blue-sideband transitions generated by microwave pulses [Leek, Phys. Rev. B 79, 180511(R) (2009)]. Here, we propose a different approach relying on oscillations of the qubit frequency using a flux-bias line. We explain how frequency modulation leads to tunable qubit-resonator and qubit-qubit interactions. We also show how this form of quantum control leads to faster (first-order) sideband transitions and consider applications to two-qubit gates.

  18. Deep strong coupling in a circuit QED system (1) - Introduction

    NASA Astrophysics Data System (ADS)

    Semba, Kouichi; Fuse, Tomoko; Yoshihara, Fumiki; Ashhab, Sahel

    Recently, light-matter interaction at the single-photon level has been demonstrated in superconducting circuits (circuit-QED). The interaction energy between a superconducting artificial atom and an excitation quantum of a harmonic oscillator in the microwave region has been shown to be very large, at least a few thousand times that of the atom-photon interaction obtained using Rydberg atoms. It is also intriguing that, depending on the circuit design, the relevant physical parameters of this system can be controlled at will. In particular, an interaction energy as large as the transition energy of a superconducting artificial atom or a harmonic oscillator is possible, where totally new states, such as a spontaneously generated Schrödinger-cat-like correlated ground state of light and matter, have been predicted. In this talk, I will introduce the motivation and the significance of the research, methods to achieve such a strong interaction, and a brief overview of the obtained results. This work was supported by JSPS KAKENHI Grant Number 25220601.

  19. Decoherence and Relaxation in Driven Circuit QED Systems

    SciTech Connect

    Andre, Stephan; Brosco, Valentina; Schoen, Gerd; Fedorov, Arkady; Shnirman, Alexander

    2008-11-07

    Recent experiments on quantum state engineering with superconducting circuits realized concepts originally introduced in the field of quantum optics. Motivated by one such experiment we investigate a Josephson qubit coupled to a slow LC oscillator with frequency much lower than the qubit's energy splitting. The qubit is ac-driven to perform Rabi oscillations, and the Rabi frequency is tuned to resonance with the oscillator. The properties of this driven circuit QED system depend strongly on relaxation and decoherence effects in the qubit. We investigate both one-photon and two-photon qubit-oscillator coupling, the latter being dominant at the symmetry point of the qubit. When the qubit driving frequency is blue detuned, we find that the system exhibits lasing behavior; for red detuning the qubit cools the oscillator. Similar behavior is expected in an accessible range of parameters for a Josephson qubit coupled to a nano-mechanical oscillator. In a different parameter regime, furthering the analogies between superconducting and quantum optical systems, we investigate Sisyphus damping, which is the key element of the Sisyphus cooling protocol, as well as its exact opposite, Sisyphus amplification.

  20. 2D bifurcations and Newtonian properties of memristive Chua's circuits

    NASA Astrophysics Data System (ADS)

    Marszalek, W.; Podhaisky, H.

    2016-01-01

    Two interesting properties of Chua's circuits are presented. First, two-parameter bifurcation diagrams of Chua's oscillatory circuits with memristors are presented. To obtain various 2D bifurcation images a substantial numerical effort, possibly with parallel computations, is needed. The numerical algorithm is described first and its numerical code for 2D bifurcation image creation is available for free downloading. Several color 2D images and the corresponding 1D greyscale bifurcation diagrams are included. Secondly, Chua's circuits are linked to Newton's law φ ''= F(t,φ,φ')/m with φ=\\text{flux} , constant m > 0, and the force term F(t,φ,φ') containing memory terms. Finally, the jounce scalar equations for Chua's circuits are also discussed.

  1. Observing the nonequilibrium dynamics of the quantum transverse-field Ising chain in circuit QED.

    PubMed

    Viehmann, Oliver; von Delft, Jan; Marquardt, Florian

    2013-01-18

    We show how a quantum Ising spin chain in a time-dependent transverse magnetic field can be simulated and experimentally probed in the framework of circuit QED with current technology. The proposed setup provides a new platform for observing the nonequilibrium dynamics of interacting many-body systems. We calculate its spectrum to offer a guideline for its initial experimental characterization. We demonstrate that quench dynamics and the propagation of localized excitations can be observed with the proposed setup and discuss further possible applications and modifications of this circuit QED quantum simulator. PMID:23373908

  2. Circuit-QED-based scalable architectures for quantum information processing with superconducting qubits

    NASA Astrophysics Data System (ADS)

    Billangeon, P.-M.; Tsai, J. S.; Nakamura, Y.

    2015-03-01

    We discuss different ways of generating entanglement in the original picture of circuit QED (XcQED) and several restrictions that arise in the context of a large-scale quantum architecture. To alleviate some of the issues posed by the presence of the nonlinearities inherent to these systems, we introduce a layout for circuit QED, wherein an artificial atom is coupled to a quantized radiation field via its longitudinal degree of freedom (ZcQED). This system is akin to ion traps used in atomic physics, but it relies on fixed coupling between the atom and the resonator. We describe a scalable architecture for processing quantum information with superconducting qubits, which is free from any type of residual interaction between the atomic and photonic degrees of freedom. Tunable interactions can be realized based on sideband transitions, and the system can be operated out of the Lamb-Dicke regime, allowing it to benefit from the possibility of achieving large coupling strengths between atoms and resonators. We also discuss a readout scheme that does not require any extra circuits and allows a qubit-specific measurement of the state of the quantum register inspired by the electron shelving technique. This scheme is quantum nondemolition (QND)-like, and allows for single-shot determination of the qubit states.

  3. Transparency and amplification in a hybrid system of the mechanical resonator and circuit QED

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Sun, HuiChen; Zhang, Jing; Liu, YuXi

    2012-12-01

    We theoretically study the transparency and amplification of a weak probe field applied to the cavity in hybrid systems formed by a driven superconducting circuit QED system and a mechanical resonator, or a driven optomechanical system and a superconducting qubit. We find that both the mechanical resonator and the superconducting qubit can result in the transparency to a weak probe field in such hybrid systems when a strong driving field is applied to the cavity. We also find that the weak probe field can be amplified in some parameter regimes. We further study the statistical properties of the output field via the degrees of second-order coherence. We find that the nonclassicality of the output field strongly depends on the system parameters. Our studies show that one can control single-photon transmission in the optomechanical system via a tunable artificial atom or in the circuit QED system via a mechanical resonator.

  4. Realizing a topological transition in a non-Hermitian quantum walk with circuit QED

    NASA Astrophysics Data System (ADS)

    Huang, Yizhou; Yin, Zhang-qi; Yang, W. L.

    2016-08-01

    We extend the non-Hermitian one-dimensional quantum walk model [Phys. Rev. Lett. 102, 065703 (2009), 10.1103/PhysRevLett.102.065703] by taking the dephasing effect into account. We prove that the feature of topological transition does not change even when dephasing between the sites within units is present. The potential experimental observation of our theoretical results in the circuit QED system consisting of superconducting qubit coupled to a superconducting resonator mode is discussed and numerically simulated. The results clearly show a topological transition in quantum walk and display the robustness of such a system to the decay and dephasing of qubits. We also discuss how to extend this model to higher dimension in the circuit QED system.

  5. Deterministic creation and stabilization of entanglement in circuit QED by homodyne-mediated feedback control

    SciTech Connect

    Liu Zhuo; Kuang Luelin; Hu Kai; Xu Luting; Wei Suhua; Guo Lingzhen; Li Xinqi

    2010-09-15

    In a solid-state circuit QED system, we demonstrate that a homodyne-current-based feedback can create and stabilize highly entangled two-qubit states in the presence of a moderate noisy environment. Particularly, we present an extended analysis for the current-based Markovian feedback, which leads to an improved feedback scheme. We show that this is essential to achieve a desirable control effect by the use of dispersive measurement.

  6. Entangled Schrodinger cats in circuit QED: Experimental Architecture

    NASA Astrophysics Data System (ADS)

    Wang, Chen; Gao, Yvonne Y.; Reinhold, Philip; Heeres, Reinier W.; Ofek, Nissim; Chou, Kevin; Axline, Christopher; Frunzio, Luigi; Devoret, Michel H.; Schoelkopf, Robert J.

    The development of quantum information technology relies on creating and controling entanglement over an increasingly large Hilbert space. Superconducting cavities offer high-dimensional spaces for quantum states in a low-loss and hardware-efficient fashion, making it an ideal memory of quantum information and an important element towards fault-tolerant quantum computation. In this talk we present a cQED architecture that allows quantum control over the coherent state basis of two superconducting cavities with millisecond coherence. In particular, we show deterministic entanglement of coherent-state microwave fields in two superconducting cavities of the form: 1/√{ 2}βaβa +/- -βa -βa . We engineer the capability to measure the joint photon number parity to achieve complete state tomography of the two-cavity state. Following widespread efforts of realizing ``Schrodinger's cat''-like mesoscopic superposition in various physical systems, this experiment demonstrates mesoscopic entanglement between two ``Schrodinger's cats''.

  7. Quantum simulations of relativistic quantum physics in circuit QED

    NASA Astrophysics Data System (ADS)

    Pedernales, J. S.; Di Candia, R.; Ballester, D.; Solano, E.

    2013-05-01

    We present a scheme for simulating relativistic quantum physics in circuit quantum electrodynamics. By using three classical microwave drives, we show that a superconducting qubit strongly coupled to a resonator field mode can be used to simulate the dynamics of the Dirac equation and Klein paradox in all regimes. Using the same setup we also propose the implementation of the Foldy-Wouthuysen canonical transformation, after which the time derivative of the position operator becomes a constant of the motion.

  8. Demonstrating Multi-Qubit Operations in a Superconducting 3D circuit QED Architecture

    NASA Astrophysics Data System (ADS)

    Paik, Hanhee; Sandberg, M. O.; Mezzacapo, A.; McClure, D. T.; Abdo, B.; Dial, O. E.; Cross, A. W.; Corcoles, A. D.; Sheldon, S.; Magesan, E.; Srinivasan, S. J.; Gambetta, J. M.; Chow, J. M.; Bogorin, D.; Plourde, B. L. T.

    We present our recent results on multi-qubit operations in a superconducting 3D circuit QED (cQED) system using a resonator-induced phase (RIP) gate. In our system, four qubits are coupled by a single bus resonator. The RIP gate is implemented by applying a microwave pulse to the bus that performs entangling operations. We demonstrate controlled-phase gates using RIP on 2-qubit subsystems with gate fidelities between 95%-97% evaluated by randomized benchmarking. Via a multi-qubit echo scheme, we perform isolated two-qubit interactions in the full 4-qubit system to generate a GHZ state. We acknowledge support from IARPA under Contract W911NF-10-1-0324.

  9. Ultrastrong coupling in two-resonator circuit QED

    NASA Astrophysics Data System (ADS)

    Baust, A.; Hoffmann, E.; Haeberlein, M.; Schwarz, M. J.; Eder, P.; Goetz, J.; Wulschner, F.; Xie, E.; Zhong, L.; Quijandría, F.; Zueco, D.; Ripoll, J.-J. García; García-Álvarez, L.; Romero, G.; Solano, E.; Fedorov, K. G.; Menzel, E. P.; Deppe, F.; Marx, A.; Gross, R.

    2016-06-01

    We report on ultrastrong coupling between a superconducting flux qubit and a resonant mode of a system comprised of two superconducting coplanar stripline resonators coupled galvanically to the qubit. With a coupling strength as high as 17.5 % of the mode frequency, exceeding that of previous circuit quantum electrodynamics experiments, we observe a pronounced Bloch-Siegert shift. The spectroscopic response of our multimode system reveals a clear breakdown of the Jaynes-Cummings approximation. In contrast to earlier experiments, the high coupling strength is achieved without making use of an additional inductance provided by a Josephson junction.

  10. Deterministic implementations of quantum gates with circuit QEDs via Stark-chirped rapid adiabatic passages

    NASA Astrophysics Data System (ADS)

    Chen, Jingwei; Wei, L. F.

    2015-10-01

    We show that a set of universal quantum gates could be implemented robustly in a circuit QED system by using Stark-chirped rapid adiabatic passage (SCRAP) technique. Under the adiabatic limit we find that the population transfers could be deterministically passaged from one selected quantum states to the others, and thus the desired quantum gates can be implemented. The proposed SCRAP-based gates are insensitive to the details of the operations and thus relax the designs of the applied pulses, operational imperfections, and the decoherence of the system.

  11. Generation of a macroscopic entangled coherent state using quantum memories in circuit QED

    PubMed Central

    Liu, Tong; Su, Qi-Ping; Xiong, Shao-Jie; Liu, Jin-Ming; Yang, Chui-Ping; Nori, Franco

    2016-01-01

    W-type entangled states can be used as quantum channels for, e.g., quantum teleportation, quantum dense coding, and quantum key distribution. In this work, we propose a way to generate a macroscopic W-type entangled coherent state using quantum memories in circuit QED. The memories considered here are nitrogen-vacancy center ensembles (NVEs), each located in a different cavity. This proposal does not require initially preparing each NVE in a coherent state instead of a ground state, which should significantly reduce its experimental difficulty. For most of the operation time, each cavity remains in a vacuum state, thus decoherence caused by the cavity decay and the unwanted inter-cavity crosstalk are greatly suppressed. Moreover, only one external-cavity coupler qubit is needed, which simplifies the circuit. PMID:27562055

  12. Coupling qubits in circuit-QED cavities connected by a bridge qubit

    NASA Astrophysics Data System (ADS)

    Kim, Mun Dae; Kim, Jaewan

    2016-01-01

    We analyze a coupling scheme for qubits in different cavities of circuit-QED architecture. In contrast to the usual scheme where the cavities are coupled by an interface capacitance we employ a bridge qubit connecting cavities to mediate two-qubit coupling. This active-coupling scheme makes it possible to switch on or off and adjust the strength of qubit-qubit coupling, which is essential for scalability of quantum circuits. By transforming the Hamiltonian we obtain an exact expression of two-qubit coupling in the rotating-wave approximation. For the general case of n qubits the Hamiltonian can produce the W state as an eigenstate of the system. We calculate the decay rate of the coupled qubit-resonator system to find that it is viable in real experiments.

  13. Generation of a macroscopic entangled coherent state using quantum memories in circuit QED.

    PubMed

    Liu, Tong; Su, Qi-Ping; Xiong, Shao-Jie; Liu, Jin-Ming; Yang, Chui-Ping; Nori, Franco

    2016-01-01

    W-type entangled states can be used as quantum channels for, e.g., quantum teleportation, quantum dense coding, and quantum key distribution. In this work, we propose a way to generate a macroscopic W-type entangled coherent state using quantum memories in circuit QED. The memories considered here are nitrogen-vacancy center ensembles (NVEs), each located in a different cavity. This proposal does not require initially preparing each NVE in a coherent state instead of a ground state, which should significantly reduce its experimental difficulty. For most of the operation time, each cavity remains in a vacuum state, thus decoherence caused by the cavity decay and the unwanted inter-cavity crosstalk are greatly suppressed. Moreover, only one external-cavity coupler qubit is needed, which simplifies the circuit. PMID:27562055

  14. Controllable preparation of two-mode entangled coherent states in circuit QED

    NASA Astrophysics Data System (ADS)

    Ji, Ying-Hua; Liu, Yong-Mei

    2014-11-01

    Although the multi-level structure of superconducting qubits may result in calculation errors, it can be rationally used to effectively improve the speed of gate operations. Utilizing a current-biased Josephson junction (λ-type rf-SQUID) as a tunable coupler for superconducting transmission line resonators (TLRs), under the large detuning condition, we demonstrate the controllable generation of entangled coherent states in circuit quantum electrodynamics (circuit QED). The coupling between the TLRs and the qubit can be effectively regulated by an external bias current or coupling capacitor. Further investigations indicate that the maximum entangled state can be obtained through measuring the excited state of the superconducting qubits. Then, the influence of the TLR decay on the prepared entangled states is analyzed.

  15. Photon-number splitting of squeezed light by a single qubit in circuit QED

    NASA Astrophysics Data System (ADS)

    Moon, Kyungsun

    2013-10-01

    We theoretically propose an efficient way to generate and detect squeezed light by a single qubit in circuit QED. By tuning the qubit energy splitting close to the fundamental frequency of the first harmonic mode (FHM) in a transmission line resonator and placing the qubit at the nodal point of the third harmonic mode, one can generate the resonantly enhanced squeezing of the FHM upon pumping with the second harmonic mode. In order to investigate the photon number splitting for the squeezed FHM, we have numerically calculated the qubit absorption spectrum, which exhibits regularly spaced peaks at frequencies separated by twice the effective dispersive shift. It is also shown that adding a small pump field for the FHM makes additional peaks develop in between the dominant ones as well.

  16. Fast resonator reset in circuit QED using open quantum system optimal control

    NASA Astrophysics Data System (ADS)

    Boutin, Samuel; Andersen, Christian Kraglund; Venkatraman, Jayameenakshi; Blais, Alexandre

    Practical implementations of quantum information processing requires repetitive qubit readout. In circuit QED, where readout is performed using a resonator dispersively coupled to the qubits, the measurement repetition rate is limited by the resonator reset time. This reset is usually performed passively by waiting several resonator decay times. Alternatively, it was recently shown that a simple pulse sequence allows to decrease the reset time to twice the resonator decay time. In this work, we show how to further optimize the ring-down pulse sequence by using optimal control theory for open quantum systems. Using a new implementation of the open GRAPE algorithm that is well suited to large Hilbert spaces, we find active resonator reset procedures that are faster than a single resonator decay time. Simple quantum speed limits for this kind of active reset processes will be discussed

  17. Implementing N-quantum phase gate via circuit QED with qubit-qubit interaction

    NASA Astrophysics Data System (ADS)

    Said, T.; Chouikh, A.; Essammouni, K.; Bennai, M.

    2016-02-01

    We propose a method for realizing a quantum phase gate of one qubit simultaneously controlling N target qubits based on the qubit-qubit interaction. We show how to implement the proposed gate with one transmon qubit simultaneously controlling N transmon qubits in a circuit QED driven by a strong microwave field. In our scheme, the operation time of this phase gate is independent of the number N of qubits. On the other hand, this gate can be realized in a time of nanosecond-scale much smaller than the decoherence time and dephasing time both being the time of microsecond-scale. Numerical simulation of the occupation probabilities of the second excited lever shows that the scheme could be achieved efficiently within current technology.

  18. Circuit-QED-based superconducting quantum simulator for the Holstein-polaron model

    NASA Astrophysics Data System (ADS)

    Mei, Feng; Stojanović, Vladimir; Siddiqi, Irfan; Tian, Lin

    2014-03-01

    We propose an analog quantum simulator for the Holstein molecular-crystal model based on a superconducting circuit-QED system in the dispersive regime. The many-body Hamiltonian of this model includes both bosonic and fermionic degrees of freedom. By varying the driving field on the superconducting resonators, one can readily access both the adiabatic and anti-adiabatic regimes of this model, and reach the strong e-ph coupling limit required for small-polaron formation. We show that small-polaron state of arbitrary quasimomentum can be generated by applying a microwave pulse to the resonators. We also show that significant squeezing in the resonator modes can be achieved in the polaron-crossover regime through a measurement-based scheme. The project was supported by NSF-0956064, NSF-0916303, SNSF, NCCR QSIT, and NSF-0939514.

  19. Flexible, low-latency architecture for qubit control and measurement in circuit QED

    NASA Astrophysics Data System (ADS)

    Vlothuizen, Wouter; Deurloo, D.; Sterke, J. De; Vermeulen, R.; Schouten, R. N.; Dicarlo, Leo

    Increasing qubit numbers in circuit QED requires an extensible architecture for digital waveform generation of qubit control and measurement signals. For quantum error correction, the ability to select from a number of predetermined waveforms based on measurement results will become paramount. We present a room-temperature architecture with very low latency from measurement to waveform output. This modular FPGA-based system can generate both baseband and RF modulated signals using DACs clocked at 1 GHz. A backplane that interconnects several modules allows exchange of (measurement) information between modules and maintains deterministic timing across those modules. We replace the typical line based sequencer used in arbitrary waveform generators by a user programmable processor that treats waveforms and measurements as instructions added to a conventional CPU architecture. This allows for flexible coding of triggering, repetitions, delays and interactions between measurement and signal generation. We acknowledge funding from the Dutch Research Organization (NWO), an ERC Synergy Grant, and European project SCALEQIT.

  20. Controllable high-fidelity quantum state transfer and entanglement generation in circuit QED

    PubMed Central

    Xu, Peng; Yang, Xu-Chen; Mei, Feng; Xue, Zheng-Yuan

    2016-01-01

    We propose a scheme to realize controllable quantum state transfer and entanglement generation among transmon qubits in the typical circuit QED setup based on adiabatic passage. Through designing the time-dependent driven pulses applied on the transmon qubits, we find that fast quantum sate transfer can be achieved between arbitrary two qubits and quantum entanglement among the qubits also can also be engineered. Furthermore, we numerically analyzed the influence of the decoherence on our scheme with the current experimental accessible systematical parameters. The result shows that our scheme is very robust against both the cavity decay and qubit relaxation, the fidelities of the state transfer and entanglement preparation process could be very high. In addition, our scheme is also shown to be insensitive to the inhomogeneous of qubit-resonator coupling strengths. PMID:26804326

  1. High-Kinetic-Inductance Superconducting Nanowire Resonators for Circuit QED in a Magnetic Field

    NASA Astrophysics Data System (ADS)

    Samkharadze, N.; Bruno, A.; Scarlino, P.; Zheng, G.; DiVincenzo, D. P.; DiCarlo, L.; Vandersypen, L. M. K.

    2016-04-01

    We present superconducting microwave-frequency resonators based on NbTiN nanowires. The small cross section of the nanowires minimizes vortex generation, making the resonators resilient to magnetic fields. Measured intrinsic quality factors exceed 2 ×105 in a 6-T in-plane magnetic field and 3 ×104 in a 350-mT perpendicular magnetic field. Because of their high characteristic impedance, these resonators are expected to develop zero-point voltage fluctuations one order of magnitude larger than in standard coplanar waveguide resonators. These properties make the nanowire resonators well suited for circuit QED experiments needing strong coupling to quantum systems with small electric dipole moments and requiring a magnetic field, such as electrons in single and double quantum dots.

  2. Theory of degenerate three-wave mixing using circuit QED in solid-state circuits

    SciTech Connect

    Cao, Ye; Huo, Wen Yi; Ai, Qing; Long, Gui Lu

    2011-11-15

    We study the theory of degenerate three-wave mixing and the generation of squeezed microwaves using circuit quantum electrodynamics in solid state circuits. The Hamiltonian for degenerate three-wave mixing, which seemed to be given phenomenologically in quantum optics, is derived by quantum mechanical calculations. The nonlinear medium needed in three-wave mixing is composed of a series of superconducting charge qubits which are located inside two superconducting transmission-line resonators. Here, the multiqubit ensemble is present to enhance the effective coupling constant between the two modes in the transmission-line resonators. In the squeezing process, the qubits are kept in their ground states so that their decoherence does not corrupt the squeezing. The main obstacle preventing a large squeezing efficiency is the decay rate of the transmission-line resonator.

  3. 2D and 3D heterogeneous photonic integrated circuits

    NASA Astrophysics Data System (ADS)

    Yoo, S. J. Ben

    2014-03-01

    Exponential increases in the amount of data that need to be sensed, communicated, and processed are continuing to drive the complexity of our computing, networking, and sensing systems. High degrees of integration is essential in scalable, practical, and cost-effective microsystems. In electronics, high-density 2D integration has naturally evolved towards 3D integration by stacking of memory and processor chips with through-silicon-vias. In photonics, too, we anticipate highdegrees of 3D integration of photonic components to become a prevailing method in realizing future microsystems for information and communication technologies. However, compared to electronics, photonic 3D integration face a number of challenges. This paper will review two methods of 3D photonic integration --- fs laser inscription and layer stacking, and discuss applications and future prospects.

  4. Theory of implementation of an impedance-matched Λ system in circuit QED

    NASA Astrophysics Data System (ADS)

    Koshino, Kazuki; Inomata, Kunihiro; Yamamoto, Tsuyoshi; Nakamura, Yasunobu

    2014-03-01

    In one-dimensional optical setups, light-matter interaction is drastically enhanced by the interference between the incident and scattered fields. Particularly, in an impedance-matched Λ-type three-level system, which has two identical radiative decay rates from the top level and interacts with a semi-infinite one-dimensional field in reflection geometry, a single photon deterministically induces the Raman transition and switches the electronic state of the system. Here we theoretically investigate a circuit QED system composed of a driven superconducting qubit and a resonator in the dispersive regime. We show that the dressed states of this system constitute an impedance-matched Λ system under a proper choice of the frequency and power of the qubit drive. When we apply a resonant probe field to this system, it is down-converted nearly perfectly after a single reflection as long as the probe power is sufficiently weak. This indicates a deterministic quantum dynamics induced by single photons, which is applicable, for example, to the detection of single microwave photons and the bidirectional quantum memory (swapping) between a microwave photon and a superconducting qubit. This work was partly supported by FIRST, MEXT KAKENHI (21102002 and 25400417), SCOPE (111507004) and NICT.

  5. Encoding a Qubit into a Cavity Mode in Circuit-QED using Phase Estimation

    NASA Astrophysics Data System (ADS)

    Terhal, Barbara; Weigand, Daniel

    Gottesman, Kitaev and Preskill have formulated a way of encoding a qubit into an oscillator such that the qubit is protected against small shifts (translations) in phase space. The idea underlying this encoding is that error processes of low rate can be expanded into small shift errors. The qubit space is defined as an eigenspace of two mutually commuting displacement operators which act as large shifts/translations in phase space. We propose and analyze the approximate creation of these qubit states by coupling the oscillator to a sequence of ancilla qubits realizing the protocol of approximate phase estimation for a displacement operator. We analyze the performance of repeated and adaptive phase estimation as the experimentally most viable schemes given a realistic upper limit on the number of photons in the oscillator. We propose a physical implementation of the protocol using the dispersive coupling between an ancilla transmon qubit and a cavity mode in circuit-QED. We estimate that in a current experimental set-up one can prepare a good code state from a squeezed vacuum state using 8 rounds of adaptive phase estimation lasting in total about 4 microsec., with at least 80

  6. Encoding a qubit into a cavity mode in circuit QED using phase estimation

    NASA Astrophysics Data System (ADS)

    Terhal, B. M.; Weigand, D.

    2016-01-01

    Gottesman, Kitaev, and Preskill have formulated a way of encoding a qubit into an oscillator such that the qubit is protected against small shifts (translations) in phase space. The idea underlying this encoding is that error processes of low rate can be expanded into small shift errors. The qubit space is defined as an eigenspace of two mutually commuting displacement operators Sp and Sq which act as large shifts or translations in phase space. We propose and analyze the approximate creation of these qubit states by coupling the oscillator to a sequence of ancilla qubits. This preparation of the states uses the idea of phase estimation where the phase of the displacement operator, say Sp, is approximately determined. We consider several possible forms of phase estimation. We analyze the performance of repeated and adaptive phase estimation as the simplest and experimentally most viable schemes given a realistic upper limit on the number of photons in the oscillator. We propose a detailed physical implementation of this protocol using the dispersive coupling between a transmon ancilla qubit and a cavity mode in circuit QED. We provide an estimate that in a current experimental setup one can prepare a good code state from a squeezed vacuum state using eight rounds of adaptive phase estimation, lasting in total about 4 μ s , with 94 % (heralded) chance of success.

  7. Simultaneous measurement of non-commuting observables in circuit QED: Experiment

    NASA Astrophysics Data System (ADS)

    Hacohen-Gourgy, Shay; Martin, Leigh; Flurin, Emmanuel; Whaley, Brigitta; Siddiqi, Irfan

    The existence of incompatible measurements lies at the heart of numerous fundamental concepts in quantum mechanics, such as entanglement, contextuality and measurement-disturbance tradeoffs. We implement a novel technique for simultaneously and continuously measuring a pair of non-commuting observables in a circuit-QED architecture, which features a transmon qubit coupled to two modes of an electromagnetic cavity. By driving the transmon on resonance, we form an effective, low-frequency two-level system on which we perform the non-commuting measurements. To this end, we use microwave tones near the cavity's resonances to implement cooling and backaction-evading measurements familiar from optomechanics. Control of the relative amplitude and phase of these sideband tones enables qubit state measurement along an arbitrary axis of the Bloch sphere. We apply this technique to both modes of the cavity simultaneously, with distinct axes chosen for each mode. This realizes a continuous and simultaneous measurement of two non-commuting observables. We use high quantum-efficiency parametric amplifiers to track the resulting quantum trajectories of the qubit, enabling a measurement of the mutual disturbance of the two observables. This research is supported by the ARO.

  8. Fast universal quantum gates on microwave photons with all-resonance operations in circuit QED.

    PubMed

    Hua, Ming; Tao, Ming-Jie; Deng, Fu-Guo

    2015-01-01

    Stark shift on a superconducting qubit in circuit quantum electrodynamics (QED) has been used to construct universal quantum entangling gates on superconducting resonators in previous works. It is a second-order coupling effect between the resonator and the qubit in the dispersive regime, which leads to a slow state-selective rotation on the qubit. Here, we present two proposals to construct the fast universal quantum gates on superconducting resonators in a microwave-photon quantum processor composed of multiple superconducting resonators coupled to a superconducting transmon qutrit, that is, the controlled-phase (c-phase) gate on two microwave-photon resonators and the controlled-controlled phase (cc-phase) gates on three resonators, resorting to quantum resonance operations, without any drive field. Compared with previous works, our universal quantum gates have the higher fidelities and shorter operation times in theory. The numerical simulation shows that the fidelity of our c-phase gate is 99.57% within about 38.1 ns and that of our cc-phase gate is 99.25% within about 73.3 ns. PMID:25787147

  9. Preparation of Entangled Coherent States and Correspondence Between Entanglement and Non-Classical Properties in Circuit QED

    NASA Astrophysics Data System (ADS)

    Hu, Juju; Xu, Lin

    2015-07-01

    We demonstrate the controllable generation of entangled coherent states in circuit quantum electrodynamics (circuit QED). In our scheme, the easy integration of solid-state quantum circuit is exploited. In particular, through manipulating the external capacitor or external classical microwave impulse, the coupling between superconducting qubits and cavity can be manipulated, the entanglement effect between qubit and field modes can be enhanced and the decoherence effect can be effectively suppressed. We further discuss the correspondence between quantum entanglement and some non-classical effects such as the squeezing of entangled coherent state field, the anti-buching effect. The results show that the time evolution of the quantum entanglement between field modes is always accompanied by the synchronous changes of certain non-classical effect. When the quantum entanglement reaches maximum, the anti-bunching (or compression effect) almost reaches maximum synchronously. Once entanglement sudden death occurs, the non-classical effects disappear.

  10. Fabrication and characterization of highly disordered TiN thin films by reactive evaporation for circuit-QED

    NASA Astrophysics Data System (ADS)

    Lin, Yen-Hsiang; Mencia, Raymond; Nguyen, Baolong; Manucharyan, Vladimir

    Titanium nitride (TiN) has been identified as one of the potentially new materials for circuit-QED. In particular, disordered TiN films close to superconductor-insulator transition can be beneficial to greatly enhance kinetic inductance due to low superfluid density. Here we report TiN thin films prepared by e-beam evaporation within a nitrogen rich environment. By controlling nitrogen gas flow rate, the normal sheet resistance of TiN film can be tuned higher than 1kOhms while superconductivity still remains above 2K. Here, we present our characterization results and microwave measurement of quality factor Q and kinetic inductance L.

  11. Engineering non-linear resonator mode interactions in circuit QED by continuous driving: Manipulation of a photonic quantum memory

    NASA Astrophysics Data System (ADS)

    Reagor, Matthew; Pfaff, Wolfgang; Heeres, Reinier; Ofek, Nissim; Chou, Kevin; Blumoff, Jacob; Leghtas, Zaki; Touzard, Steven; Sliwa, Katrina; Holland, Eric; Albert, Victor V.; Frunzio, Luigi; Devoret, Michel H.; Jiang, Liang; Schoelkopf, Robert J.

    2015-03-01

    Recent advances in circuit QED have shown great potential for using microwave resonators as quantum memories. In particular, it is possible to encode the state of a quantum bit in non-classical photonic states inside a high-Q linear resonator. An outstanding challenge is to perform controlled operations on such a photonic state. We demonstrate experimentally how a continuous drive on a transmon qubit coupled to a high-Q storage resonator can be used to induce non-linear dynamics of the resonator. Tailoring the drive properties allows us to cancel or enhance non-linearities in the system such that we can manipulate the state stored in the cavity. This approach can be used to either counteract undesirable evolution due to the bare Hamiltonian of the system or, ultimately, to perform logical operations on the state encoded in the cavity field. Our method provides a promising pathway towards performing universal control for quantum states stored in high-coherence resonators in the circuit QED platform.

  12. Active resonator reset in the non-linear regime of circuit QED to improve multi-round quantum parity checks

    NASA Astrophysics Data System (ADS)

    Bultink, Cornelis Christiaan; Rol, M. A.; Fu, X.; Dikken, B. C. S.; de Sterke, J. C.; Vermeulen, R. F. L.; Schouten, R. N.; Bruno, A.; Bertels, K. L. M.; Dicarlo, L.

    Reliable quantum parity measurements are essential for fault-tolerant quantum computing. In quantum processors based on circuit QED, the fidelity and speed of multi-round quantum parity checks using an ancillary qubit can be compromised by photons remaining in the readout resonator post measurement, leading to ancilla dephasing and gate errors. The challenge of quickly depleting photons is biggest when maximizing the single-shot readout fidelity involves strong pulses turning the resonators non-linear. We experimentally demonstrate the numerical optimization of counter pulses for fast photon depletion in this non-analytic regime. We compare two methods, one using digital feedback and another running open loop. We assess both methods by minimizing the average number of rounds to ancilla measurement error. We acknowledge funding from the EU FP7 project SCALEQIT, FOM, and an ERC Synergy Grant.

  13. Spin Circuit Model for Spin Orbit Torques in 2D Channels

    NASA Astrophysics Data System (ADS)

    Hong, Seokmin

    2015-03-01

    Recently, the unique coupling between charge and spin in topological insulators has been explored through various types of electrical measurements, which could have interesting applications. In this talk, we present a spin circuit model for spin orbit torques in topological insulator surface states and other 2D channels. We show with a simple example that results from the circuit model agree well with those obtained from nonequilibrium Green's function (NEGF) based quantum transport simulation. Some predictions of our model have already received experimental support and we hope this model can provide a unifying framework that can be used to critically evaluate experimental results, to explore new types of devices as well as to answer fundamental questions regarding these materials. The model for spin-orbit torques described here can be incorporated into a broader spin-circuit approach which, we believe, provides a natural platform for multi-physics, multi-component spintronic devices. This work was supported by FAME, a Semiconductor Research Corporation program sponsored by MARCO and DARPA.

  14. Engagement of neural circuits underlying 2D spatial navigation in a rodent virtual reality system

    PubMed Central

    Aronov, Dmitriy; Tank, David W.

    2015-01-01

    SUMMARY Virtual reality (VR) enables precise control of an animal’s environment and otherwise impossible experimental manipulations. Neural activity in navigating rodents has been studied on virtual linear tracks. However, the spatial navigation system’s engagement in complete two-dimensional environments has not been shown. We describe a VR setup for rats, including control software and a large-scale electrophysiology system, which supports 2D navigation by allowing animals to rotate and walk in any direction. The entorhinal-hippocampal circuit, including place cells, grid cells, head direction cells and border cells, showed 2D activity patterns in VR similar to those in the real world. Hippocampal neurons exhibited various remapping responses to changes in the appearance or the shape of the virtual environment, including a novel form in which a VR-induced cue conflict caused remapping to lock to geometry rather than salient cues. These results suggest a general-purpose tool for novel types of experimental manipulations in navigating rats. PMID:25374363

  15. Spin Circuit Model for 2D Channels with Spin-Orbit Coupling

    PubMed Central

    Hong, Seokmin; Sayed, Shehrin; Datta, Supriyo

    2016-01-01

    In this paper we present a general theory for an arbitrary 2D channel with “spin momentum locking” due to spin-orbit coupling. It is based on a semiclassical model that classifies all the channel electronic states into four groups based on the sign of the z-component of the spin (up (U), down (D)) and the sign of the x-component of the velocity (+, −). This could be viewed as an extension of the standard spin diffusion model which uses two separate electrochemical potentials for U and D states. Our model uses four: U+, D+, U−, and D−. We use this formulation to develop an equivalent spin circuit that is also benchmarked against a full non-equilibrium Green’s function (NEGF) model. The circuit representation can be used to interpret experiments and estimate important quantities of interest like the charge to spin conversion ratio or the maximum spin current that can be extracted. The model should be applicable to topological insulator surface states with parallel channels as well as to other layered structures with interfacial spin-orbit coupling. PMID:26932563

  16. Spin Circuit Model for 2D Channels with Spin-Orbit Coupling.

    PubMed

    Hong, Seokmin; Sayed, Shehrin; Datta, Supriyo

    2016-01-01

    In this paper we present a general theory for an arbitrary 2D channel with "spin momentum locking" due to spin-orbit coupling. It is based on a semiclassical model that classifies all the channel electronic states into four groups based on the sign of the z-component of the spin (up (U), down (D)) and the sign of the x-component of the velocity (+, -). This could be viewed as an extension of the standard spin diffusion model which uses two separate electrochemical potentials for U and D states. Our model uses four: U+, D+, U-, and D-. We use this formulation to develop an equivalent spin circuit that is also benchmarked against a full non-equilibrium Green's function (NEGF) model. The circuit representation can be used to interpret experiments and estimate important quantities of interest like the charge to spin conversion ratio or the maximum spin current that can be extracted. The model should be applicable to topological insulator surface states with parallel channels as well as to other layered structures with interfacial spin-orbit coupling. PMID:26932563

  17. Spin Circuit Model for 2D Channels with Spin-Orbit Coupling

    NASA Astrophysics Data System (ADS)

    Hong, Seokmin; Sayed, Shehrin; Datta, Supriyo

    2016-03-01

    In this paper we present a general theory for an arbitrary 2D channel with “spin momentum locking” due to spin-orbit coupling. It is based on a semiclassical model that classifies all the channel electronic states into four groups based on the sign of the z-component of the spin (up (U), down (D)) and the sign of the x-component of the velocity (+, -). This could be viewed as an extension of the standard spin diffusion model which uses two separate electrochemical potentials for U and D states. Our model uses four: U+, D+, U-, and D-. We use this formulation to develop an equivalent spin circuit that is also benchmarked against a full non-equilibrium Green’s function (NEGF) model. The circuit representation can be used to interpret experiments and estimate important quantities of interest like the charge to spin conversion ratio or the maximum spin current that can be extracted. The model should be applicable to topological insulator surface states with parallel channels as well as to other layered structures with interfacial spin-orbit coupling.

  18. Circuit QED Flip-Flop Memory with All-Microwave Switching

    NASA Astrophysics Data System (ADS)

    Andersen, Christian Kraglund; Mølmer, Klaus

    2015-02-01

    We present a theoretical proposal for a microwave-driven circuit composed of superconducting resonators and qubits, which shows a bistable behavior, and we present a simple mechanism that allows single- or few-photon microwave pulses to work as set and reset signals that switch the circuit between its stable modes. The resulting system constitutes an ultralow-energy set-reset flip-flop device, and we show that its memory lifetime far exceeds the lifetime of states stored in any of its separate components.

  19. Effect of Multiphoton Processes on Geometric Quantum Computation in Superconducting Circuit QED

    NASA Astrophysics Data System (ADS)

    Chen, Chang-Yong

    2012-11-01

    We study the influence of multi-photon processes on the geometric quantum computation in the systems of superconducting qubits based on the displacement-like and the general squeezed operator methods. As an example, we focus on the question about how to implement a two-qubit geometric phase gate using superconducting circuit quantum electrodynamics with both single- and two-photon interaction between the qubits and the cavity modes. We find that the multiphoton processes are not only controllable but also improve the gating speed. The comparison with other physical systems and experimental feasibility are discussed in detail.

  20. Spin-boson model with an engineered reservoir in circuit QED

    NASA Astrophysics Data System (ADS)

    Deppe, Frank; Haeberlein, M.; Eder, P.; Goetz, J.; Fischer, M.; Wulschner, F.; Xie, E.; Fedorov, K. G.; Marx, A.; Gross, R.

    A superconducting qubit coupled to an open transmission line represents an implementation of the spin-boson model with an engineered environment. Using a flux qubit with a large mutual inductance to the transmission line, we confirm in a resonance fluorescence experiment that the spectral function J (ω) of this environment is Ohmic over a frequency range of several gigahertz. Furthermore, partial reflectors implemented into the transmission line modify the spectral function of the transmission line. For weak enough reflectors, we find that the resulting broad peak can be interpreted in terms of an enhanced spontaneous emission rate. Our work [M. Haeberlein et al., arXiv:1506.09114 (2015)] lays the ground for future quantum simulations of other, more involved, impurity models with superconducting circuits. We acknowledge support by the German Research Foundation through SFB 631 and FE 1564/1-1, the EU project PROMISCE, and Elite Network of Bavaria through the program ExQM.

  1. Photon-assisted tunnelling with nonclassical microwaves in hybrid circuit QED systems

    NASA Astrophysics Data System (ADS)

    Souquet, Jean-René; Woolley, Matthew; Gabelli, Julien; Simon, Pascal; Clerk, Aashish

    2015-03-01

    Motivated by recent experiments where superconducting microwave circuits have been coupled to electrons in semiconductor nanostructures, we study theoretically the interplay of non-classical light produced in a cavity with electron transport through a tunnel junction. We demonstrate that this basic light-matter interaction is naturally characterized by non-positive definite quasi-probability distributions which are intimately connected to the Glauber-Sudarshan P-function. We further demonstrate that this negative quasiprobability has unequivocal signatures on the differential conductance that should be easily detectable in state of art experiments. This thus turns the tunnel junction into a non-trivial probe of the microwave state. We also discuss the non-trivial backaction of the junction current on the cavity.

  2. Preparation of subradiant states using local qubit control in circuit QED

    SciTech Connect

    Filipp, S.; Loo, A. F. van; Baur, M.; Steffen, L.; Wallraff, A.

    2011-12-15

    Transitions between quantum states by photon absorption or emission are intimately related to the symmetries of the system which lead to selection rules and the formation of dark states. In a circuit quantum electrodynamics setup, in which two resonant superconducting qubits are coupled through an on-chip cavity and driven via the common cavity field, one single-excitation state remains dark. Here, we demonstrate that this dark state can be excited using local phase control of individual qubit drives to change the symmetry of the excitation field. We observe that the dark state decay via spontaneous emission into the cavity is suppressed, a characteristic signature of subradiance. This local control technique could be used to prepare and study highly correlated quantum states of cavity-coupled qubits.

  3. Quantum nondemolition photon detection in circuit QED and the quantum Zeno effect

    SciTech Connect

    Helmer, Ferdinand; Marquardt, Florian; Mariantoni, Matteo; Solano, Enrique

    2009-05-15

    We analyze the detection of itinerant photons using a quantum nondemolition measurement. An important example is the dispersive detection of microwave photons in circuit quantum electrodynamics, which can be realized via the nonlinear interaction between photons inside a superconducting transmission line resonator. We show that the back action due to the continuous measurement imposes a limit on the detector efficiency in such a scheme. We illustrate this using a setup where signal photons have to enter a cavity in order to be detected dispersively. In this approach, the measurement signal is the phase shift imparted to an intense beam passing through a second cavity mode. The restrictions on the fidelity are a consequence of the quantum Zeno effect, and we discuss both analytical results and quantum trajectory simulations of the measurement process.

  4. Design and characterization of low-loss 2D grating couplers for silicon photonics integrated circuits

    NASA Astrophysics Data System (ADS)

    Lacava, C.; Carrol, L.; Bozzola, A.; Marchetti, R.; Minzioni, P.; Cristiani, I.; Fournier, M.; Bernabe, S.; Gerace, D.; Andreani, L. C.

    2016-03-01

    We present the characterization of Silicon-on-insulator (SOI) photonic-crystal based 2D grating-couplers (2D-GCs) fabricated by CEA-Leti in the frame of the FP7 Fabulous project, which is dedicated to the realization of devices and systems for low-cost and high-performance passives-optical-networks. On the analyzed samples different test structures are present, including 2D-GC connected to another 2D-GC by different waveguides (in a Mach-Zehnder like configuration), and 2D-GC connected to two separate 2D-GCs, so as to allow a complete assessment of different parameters. Measurements were carried out using a tunable laser source operating in the extended telecom bandwidth and a fiber-based polarization controlling system at the input of device-under-test. The measured data yielded an overall fiber-to-fiber loss of 7.5 dB for the structure composed by an input 2D-GC connected to two identical 2D-GCs. This value was obtained at the peak wavelength of the grating, and the 3-dB bandwidth of the 2D-GC was assessed to be 43 nm. Assuming that the waveguide losses are negligible, so as to make a worst-case analysis, the coupling efficiency of the single 2D-GC results to be equal to -3.75 dB, constituting, to the best of our knowledge, the lowest value ever reported for a fully CMOS compatible 2D-GC. It is worth noting that both the obtained values are in good agreement with those expected by the numerical simulations performed using full 3D analysis by Lumerical FDTD-solutions.

  5. Lab on a Biomembrane: Rapid prototyping and manipulation of 2D fluidic lipid bilayers circuits

    PubMed Central

    Ainla, Alar; Gözen, Irep; Hakonen, Bodil; Jesorka, Aldo

    2013-01-01

    Lipid bilayer membranes are among the most ubiquitous structures in the living world, with intricate structural features and a multitude of biological functions. It is attractive to recreate these structures in the laboratory, as this allows mimicking and studying the properties of biomembranes and their constituents, and to specifically exploit the intrinsic two-dimensional fluidity. Even though diverse strategies for membrane fabrication have been reported, the development of related applications and technologies has been hindered by the unavailability of both versatile and simple methods. Here we report a rapid prototyping technology for two-dimensional fluidic devices, based on in-situ generated circuits of phospholipid films. In this “lab on a molecularly thin membrane”, various chemical and physical operations, such as writing, erasing, functionalization, and molecular transport, can be applied to user-defined regions of a membrane circuit. This concept is an enabling technology for research on molecular membranes and their technological use. PMID:24067786

  6. AC Loss Calculation of REBCO Cables by the Combination of Electric Circuit Model and 2D Finite Element Method

    NASA Astrophysics Data System (ADS)

    Noji, H.

    This study investigates the losses in a two conducting-layer REBCO cable fabricated by researchers at Furukawa Electric Co. Ltd. The losses were calculated using a combination of my electric circuit (EC) model with a two-dimensional finite element method (2D FEM). The helical pitches of the tapes in each layer, P1 and P2, were adjusted to equalize the current in both cable layers, although the loss calculation assumed infinite helical pitches and the same current in each layer at first. The results showed that the losses depended on the relative tape-position angle between the layers (θ/θ'), because the vertical field between adjacent tapes in the same layer varied with θ/θ'. When simulating the real cable, the helical pitches were adjusted and the layer currents were calculated by the EC model. These currents were input to the 2D FEM to compute the losses. The losses changed along the cable length because the difference between P1 and P2 altered the θ/θ' along this direction. The average angle-dependent and position-dependent losses were equal and closely approximated the measured losses. As an example to reduce the loss in this cable, the angle and the helical pitches were fixed at θ/θ' = 0.5 and P1 = P2 = 100 mm (S-direction). The calculation with these conditions indicated that the loss is about one order of magnitude lower than the measurement.

  7. Charge Number Dependence of the Dephasing Rates of a Graphene Double Quantum Dot in a Circuit QED Architecture.

    PubMed

    Deng, Guang-Wei; Wei, Da; Johansson, J R; Zhang, Miao-Lei; Li, Shu-Xiao; Li, Hai-Ou; Cao, Gang; Xiao, Ming; Tu, Tao; Guo, Guang-Can; Jiang, Hong-Wen; Nori, Franco; Guo, Guo-Ping

    2015-09-18

    We use an on-chip superconducting resonator as a sensitive meter to probe the properties of graphene double quantum dots at microwave frequencies. Specifically, we investigate the charge dephasing rates in a circuit quantum electrodynamics architecture. The dephasing rates strongly depend on the number of charges in the dots, and the variation has a period of four charges, over an extended range of charge numbers. Although the exact mechanism of this fourfold periodicity in dephasing rates is an open problem, our observations hint at the fourfold degeneracy expected in graphene from its spin and valley degrees of freedom. PMID:26431005

  8. Quantum entanglement in circuit QED

    SciTech Connect

    Milburn, G. J.; Meaney, Charles

    2008-11-07

    We show that the ground state of a very strongly coupled two level system based on a superconducting island and a microwave cavity field can undergo a morphological change as the coupling strength is increased. This looks like a quantum phase transition and is characterized by the appearance of entanglement between the cavity field and the two level system.

  9. 1-D, 2-D and 3-D Negative-Refraction Metamaterials at Optical Frequencies: Optical Nano-Transmission-Line and Circuit Theory

    NASA Astrophysics Data System (ADS)

    Engheta, Nader; Alu, Andrea

    2006-03-01

    In recent years metamaterials have offered new possibilities for overcoming some of the intrinsic limitations in wave propagation. Their realization at microwave frequencies has followed two different paths; one consisting of embedding resonant inclusions in a host dielectric, and the other following a transmission-line approach, i.e., building 1-D, 2-D, or 3-D cascades of circuit elements, respectively, as linear, planar or bulk right- or left-handed metamaterials. The latter is known to provide larger bandwidth and better robustness to ohmic losses. Extending these concepts to optical frequencies is a challenging task, due to changes in material response to electromagnetic waves at these frequencies. However, recently we have studied theoretically how it may be possible to have circuit nano-elements at these frequencies by properly exploiting plasmonic resonances. Here we present our theoretical work on translating the circuit concepts of right- and left-handed metamaterials into optical frequencies by applying the analogy between nanoparticles and nanocircuit elements in transmission lines. We discuss how it is possible to synthesize optical negative-refraction metamaterials by properly cascading plasmonic and non-plasmonic elements in 1-D, 2-D and 3-D geometries.

  10. The Tenth Circuit View of Title VII Discovery--EEOC v. University of New Mexico, 504 F. 2d 1296 (10th Cir. 1974); Rich v. Martin Marietta Corp., 522 F. 2d 353 (10th Cir. 1975)

    ERIC Educational Resources Information Center

    Hoeltgen, Kristine A.

    1976-01-01

    In both these cases the Tenth Circuit continued the trend begun in earlier Title VII cases of giving a liberal interpretation to the scope of discovery. In these decisions the court began to speak more particularly of the factors to be considered in acting on motions to compel discovery. (Author/LBH)

  11. The QED Workshop

    SciTech Connect

    Pieper, G.W.

    1994-07-01

    On May 18--20, 1994, Argonne National Laboratory hosted the QED Workshop. The workshop was supported by special funding from the Office of Naval Research. The purpose of the workshop was to assemble of a group of researchers to consider whether it is desirable and feasible to build a proof-checked encyclopedia of mathematics, with an associated facility for theorem proving and proof checking. Among the projects represented were Coq, Eves, HOL, ILF, Imps, MathPert, Mizar, NQTHM, NuPrl, OTTER, Proof Pad, Qu-Prolog, and RRL. Although the content of the QED project is highly technical rigorously proof-checked mathematics of all sorts the discussions at the workshop were rarely technical. No prepared talks or papers were given. Instead, the discussions focused primarily on such political, sociological, practical, and aesthetic questions, such as Why do it? Who are the customers? How can one get mathematicians interested? What sort of interfaces are desirable? The most important conclusion of the workshop was that QED is an idea worthy pursuing, a statement with which virtually all the participants agreed. In this document, the authors capture some of the discussions and outline suggestions for the start of a QED scientific community.

  12. Krein regularization of QED

    NASA Astrophysics Data System (ADS)

    Forghan, B.; Takook, M. V.; Zarei, A.

    2012-09-01

    In this paper, the electron self-energy, photon self-energy and vertex functions are explicitly calculated in Krein space quantization including quantum metric fluctuation. The results are automatically regularized or finite. The magnetic anomaly and Lamb shift are also calculated in the one loop approximation in this method. Finally, the obtained results are compared to conventional QED results.

  13. QED in Krein Space Quantization

    NASA Astrophysics Data System (ADS)

    Zarei, A.; Forghan, B.; Takook, M. V.

    2011-08-01

    In this paper we consider the QED in Krein space quantization. We show that the theory is automatically regularized. The three primitive divergences integrals in usual QED are considered in Krein QED. The photon self energy, electron self energy and vertex function are calculated in this formalism. We show that these quantities are finite. The infrared and ultraviolet divergencies do not appear. We discuss that Krein space quantization is similar to Pauli-Villars regularization, so we have called it the "Krein regularization".

  14. Towards bootstrapping QED3

    NASA Astrophysics Data System (ADS)

    Chester, Shai M.; Pufu, Silviu S.

    2016-08-01

    We initiate the conformal bootstrap study of Quantum Electrodynamics in 2+1 space-time dimensions (QED3) with N flavors of charged fermions by focusing on the 4-point function of four monopole operators with the lowest unit of topological charge. We obtain upper bounds on the scaling dimension of the doubly-charged monopole operator, with and without assuming other gaps in the operator spectrum. Intriguingly, we find a (gap-dependent) kink in these bounds that comes reasonably close to the large N extrapolation of the scaling dimensions of the singly-charged and doubly-charged monopole operators down to N = 4 and N = 6.

  15. Quenched QED in the chiral limit. [QED (quantum electrodynamics)

    SciTech Connect

    Vandermark, S.W.

    1993-01-01

    The main goal in this project has been to understand, through analytical methods, whether there could be a continuum limit for QED. This possibility is motivated by recent lattice simulations on quenched QED which apparently exhibit a chiral phase transition at strong coupling in the chiral limit. Another goal is to develop a novel perturbation expansion which may also be usefully applied to other theories. The author begins with the general expression for the chiral order parameter, ([bar [psi

  16. Call for Papers: Cavity QED

    NASA Astrophysics Data System (ADS)

    Lange, W.; Gerard, J.-M.

    2003-06-01

    Cavity QED interactions of light and matter have been investigated in a wide range of systems covering the spectrum from microwaves to optical frequencies, using media as diverse as single atoms and semiconductors. Impressive progress has been achieved technologically as well as conceptually. This topical issue of Journal of Optics B: Quantum and Semiclassical Optics is intended to provide a comprehensive account of the current state of the art of cavity QED by uniting contributions from researchers active across this field. As Guest Editors of this topical issue, we invite manuscripts on current theoretical and experimental work on any aspects of cavity QED. The topics to be covered will include, but are not limited to: bulletCavity QED in optical microcavities bulletSemiconductor cavity QED bulletQuantum dot cavity QED bulletRydberg atoms in microwave cavities bulletPhotonic crystal cavity QED bulletMicrosphere resonators bulletMicrolasers and micromasers bulletMicrodroplets bulletDielectric cavity QED bulletCavity QED-based quantum information processing bulletQuantum state engineering in cavities The DEADLINE for submission of contributions is 31 July 2003 to allow the topical issue to appear in about February 2004. All papers will be peer-reviewed in accordance with the normal refereeing procedures and standards of Journal of Optics B: Quantum and Semiclassical Optics. Advice on publishing your work in the journal may be found at www.iop.org/journals/authors/jopb. Submissions should ideally be in either standard LaTeX form or Microsoft Word. There are no page charges for publication. In addition to the usual 50 free reprints, the corresponding author of each paper published will receive a complimentary copy of the topical issue. Contributions to the topical issue should if possible be submitted electronically at www.iop.org/journals/jopb. or by e-mail to jopb@iop.org. Authors unable to submit online or by e-mail may send hard copy contributions (enclosing the

  17. Multiphoton quantum Rabi oscillations in ultrastrong cavity QED

    NASA Astrophysics Data System (ADS)

    Garziano, Luigi; Stassi, Roberto; Macrı, Vincenzo; Kockum, Anton Frisk; Savasta, Salvatore; Nori, Franco

    2015-12-01

    When an atom is strongly coupled to a cavity, the two systems can exchange a single photon through a coherent Rabi oscillation. This process enables precise quantum-state engineering and manipulation of atoms and photons in a cavity, which play a central role in quantum information and measurement. Recently, a new regime of cavity QED was reached experimentally where the strength of the interaction between light and artificial atoms (qubits) becomes comparable to the atomic transition frequency or the resonance frequency of the cavity mode. Here we show that this regime can strongly modify the concept of vacuum Rabi oscillations, enabling multiphoton exchanges between the qubit and the resonator. We find that experimental state-of-the-art circuit-QED systems can undergo two- and three-photon vacuum Rabi oscillations. These anomalous Rabi oscillations can be exploited for the realization of efficient Fock-state sources of light and complex entangled states of qubits.

  18. Digital Quantum Rabi and Dicke Models in Superconducting Circuits

    NASA Astrophysics Data System (ADS)

    Mezzacapo, A.; Las Heras, U.; Pedernales, J. S.; Dicarlo, L.; Solano, E.; Lamata, L.

    2014-12-01

    We propose the analog-digital quantum simulation of the quantum Rabi and Dicke models using circuit quantum electrodynamics (QED). We find that all physical regimes, in particular those which are impossible to realize in typical cavity QED setups, can be simulated via unitary decomposition into digital steps. Furthermore, we show the emergence of the Dirac equation dynamics from the quantum Rabi model when the mode frequency vanishes. Finally, we analyze the feasibility of this proposal under realistic superconducting circuit scenarios.

  19. High-Q 3D coaxial resonators for cavity QED

    NASA Astrophysics Data System (ADS)

    Yoon, Taekwan; Owens, John C.; Naik, Ravi; Lachapelle, Aman; Ma, Ruichao; Simon, Jonathan; Schuster, David I.

    Three-dimensional microwave resonators provide an alternative approach to transmission-line resonators used in most current circuit QED experiments. Their large mode volume greatly reduces the surface dielectric losses that limits the coherence of superconducting circuits, and the well-isolated and controlled cavity modes further suppress coupling to the environment. In this work, we focus on unibody 3D coaxial cavities which are only evanescently coupled and free from losses due to metal-metal interfaces, allowing us to reach extremely high quality-factors. We achieve quality-factor of up to 170 million using 4N6 Aluminum at superconducting temperatures, corresponding to an energy ringdown time of ~4ms. We extend our methods to other materials including Niobium, NbTi, and copper coated with Tin-Lead solder. These cavities can be further explored to study their properties under magnetic field or upon coupling to superconducting Josephson junction qubits, e.g. 3D transmon qubits. Such 3D cavity QED system can be used for quantum information applications, or quantum simulation in coupled cavity arrays.

  20. Mass renormalization in cavity QED

    SciTech Connect

    Matloob, Reza

    2011-01-15

    We show that the presence of a background medium and a boundary surface or surfaces in cavity QED produces no change in the energy shift of a free charged particle due to its coupling to the fluctuating electromagnetic field of the vacuum. This clarifies that the electromagnetic and the observed mass of the charged particle are not affected by the modification of the field of the vacuum. The calculations are nonrelativistic and restricted to the dipole approximation but are otherwise based on the general requirements of causality.

  1. Paraelectricity in magnetized massless QED.

    PubMed

    Ferrer, Efrain J; de la Incera, Vivian; Sanchez, Angel

    2011-07-22

    We show that the chiral-symmetry-broken phase of massless QED in the presence of a magnetic field exhibits strong paraelectricity. A large anisotropic electric susceptibility develops in the infrared region, where most of the fermions are confined to their lowest Landau level, and dynamical mass and anomalous magnetic moment are generated via the magnetic catalysis mechanism. The nonperturbative nature of this effect is reflected in the dependence of the electric susceptibility on the fine-structure constant. The strong paraelectricity is linked to the electric dipole moments of the particle-antiparticle pairs that form the chiral condensate. The significant electric susceptibility can be used as a probe to detect the realization of the magnetic catalysis of chiral symmetry breaking in physical systems. PMID:21866991

  2. Parallel stitching of 2D materials

    DOE PAGESBeta

    Ling, Xi; Wu, Lijun; Lin, Yuxuan; Ma, Qiong; Wang, Ziqiang; Song, Yi; Yu, Lili; Huang, Shengxi; Fang, Wenjing; Zhang, Xu; et al

    2016-01-27

    Diverse parallel stitched 2D heterostructures, including metal–semiconductor, semiconductor–semiconductor, and insulator–semiconductor, are synthesized directly through selective “sowing” of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. Lastly, the methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.

  3. Parallel Stitching of 2D Materials.

    PubMed

    Ling, Xi; Lin, Yuxuan; Ma, Qiong; Wang, Ziqiang; Song, Yi; Yu, Lili; Huang, Shengxi; Fang, Wenjing; Zhang, Xu; Hsu, Allen L; Bie, Yaqing; Lee, Yi-Hsien; Zhu, Yimei; Wu, Lijun; Li, Ju; Jarillo-Herrero, Pablo; Dresselhaus, Mildred; Palacios, Tomás; Kong, Jing

    2016-03-01

    Diverse parallel stitched 2D heterostructures, including metal-semiconductor, semiconductor-semiconductor, and insulator-semiconductor, are synthesized directly through selective "sowing" of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. The methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits. PMID:26813882

  4. Effect of Cavity QED on Entanglement

    NASA Astrophysics Data System (ADS)

    Rfifi, Saad; Siyouri, Fatimazahra

    2016-06-01

    We use a quantum electrodynamics model, to study the evolution of maximally entangled bipartite states (Bell states), as well as a maximally entangled tripartite states as a multipartite system. Furthermore, we study the entanglement behaviour of these output states in cavity QED as function of interaction time and the coupling strength. The present study discusses the separability and the entanglement limit of such states after interaction with a cavity QED.

  5. Hamiltonian anomalies of bound states in QED

    SciTech Connect

    Shilin, V. I.; Pervushin, V. N.

    2013-10-15

    The Bound State in QED is described in systematic way by means of nonlocal irreducible representations of the nonhomogeneous Poincare group and Dirac's method of quantization. As an example of application of this method we calculate triangle diagram Para-Positronium {yields} {gamma}{gamma}. We show that the Hamiltonian approach to Bound State in QED leads to anomaly-type contribution to creation of pair of parapositronium by two photon.

  6. Cavity State Reservoir Engineering in Circuit Quantum Electrodynamics

    NASA Astrophysics Data System (ADS)

    Holland, Eric T.

    Engineered quantum systems are poised to revolutionize information science in the near future. A persistent challenge in applied quantum technology is creating controllable, quantum interactions while preventing information loss to the environment, decoherence. In this thesis, we realize mesoscopic superconducting circuits whose macroscopic collective degrees of freedom, such as voltages and currents, behave quantum mechanically. We couple these mesoscopic devices to microwave cavities forming a cavity quantum electrodynamics (QED) architecture comprised entirely of circuit elements. This application of cavity QED is dubbed Circuit QED and is an interdisciplinary field seated at the intersection of electrical engineering, superconductivity, quantum optics, and quantum information science. Two popular methods for taming active quantum systems in the presence of decoherence are discrete feedback conditioned on an ancillary system or quantum reservoir engineering. Quantum reservoir engineering maintains a desired subset of a Hilbert space through a combination of drives and designed entropy evacuation. Circuit QED provides a favorable platform for investigating quantum reservoir engineering proposals. A major advancement of this thesis is the development of a quantum reservoir engineering protocol which maintains the quantum state of a microwave cavity in the presence of decoherence. This thesis synthesizes strongly coupled, coherent devices whose solutions to its driven, dissipative Hamiltonian are predicted a priori. This work lays the foundation for future advancements in cavity centered quantum reservoir engineering protocols realizing hardware efficient circuit QED designs.

  7. Amplitude Bistability in the Multimode Regime of Circuit-QED

    NASA Astrophysics Data System (ADS)

    Malekakhlagh, Moein; Sundaresan, Neereja; Liu, Yanbing; Sadri, Darius; Houck, Andrew; Tureci, Hakan; Mesoscopic Quantum Optics Group Team; Quantum computing; condensed matter physics with microwave photons Team

    2015-03-01

    In theory of dynamical systems, bistability refers to a situation where the system has two possible stable equilibrium states. For certain optical devices, it is possible to have two resonant transmission states that only differ in amplitude and is referred as ``optical amplitude bistability.'' This phenomenon occurs due to nonlinear nature of light-matter interaction where the light absorption or blockade by the absorber strongly depends on the drive strength. The transition between these two bistable solutions happens when the absorber is saturated and no longer capable of blocking light. In this talk, we study the dynamics of a transmon qubit coupled to a large number of modes of a long superconducting resonator and driven by an external microwave drive. We introduce a generalized theory of multimode amplitude bistability first discussed by C.M. Savage and H.J. Carmichael for a resonant single mode cavity. We will demonstrate that bistability is a characteristic of the entire system including the qubit and all modes of the resonator and can be characterized analytically by the knowledge of two collective cooperativity parameters.

  8. Theory and practice of dressed coherent states in circuit QED

    NASA Astrophysics Data System (ADS)

    Wilhelm, Frank; Govia, Luke C. G.

    In the dispersive regime of qubit-cavity coupling, classical cavity drive populates the cavity, but leaves the qubit state unaffected. However, the dispersive Hamiltonian is derived after both a frame transformation and an approximation. Therefore, to connect to external experimental devices, the inverse frame transformation from the dispersive frame back to the lab frame is necessary. We show that in the lab frame the system is best described by an entangled state known as the dressed coherent state, and thus even in the dispersive regime, entanglement is generated between the qubit and the cavity. Also, we show that further qubit evolution depends on both the amplitude and phase of the dressed coherent state. This provides a limitation to readout in the dispersive regime. We show that only in the limit of infinite measurement time is this protocol QND, as the formation of a dressed coherent state in the qubit-cavity system applies an effective rotation to the qubit state. We show how this rotation can be corrected by a unitary operation, leading to improved qubit initialization by measurement and unitary feedback.] L.C.G. Govia and F.K. Wllhelm Phys. Rev. Applied 4, 054001 (2015) LC.G. Govia and F.K. Wilhelm, arXiv:1506.04997 Supported by the ARO under contract W911NF-14-1-0080 and the European Union through ScaleQIT. LCGG acknowledges support from NSERC through an NSERC PGS-D.

  9. Zeno physics in ultrastrong-coupling circuit QED

    SciTech Connect

    Lizuain, I.; Casanova, J.; Muga, J. G.; Garcia-Ripoll, J. J.; Solano, E.

    2010-06-15

    We study the Zeno and anti-Zeno effects in a superconducting qubit interacting strongly and ultrastrongly with a microwave resonator. Using a model of a frequently measured two-level system interacting with a quantized mode, we predict different behaviors and total control of the Zeno times depending on whether the rotating-wave approximation can be applied in the Jaynes-Cummings model. As an example, we show the dependence of our results with the properties of the initial field states.

  10. Aniso2D

    Energy Science and Technology Software Center (ESTSC)

    2005-07-01

    Aniso2d is a two-dimensional seismic forward modeling code. The earth is parameterized by an X-Z plane in which the seismic properties Can have monoclinic with x-z plane symmetry. The program uses a user define time-domain wavelet to produce synthetic seismograms anrwhere within the two-dimensional media.

  11. QED spectra in the path integral formalism

    NASA Astrophysics Data System (ADS)

    Simonov, Yu. A.

    2014-07-01

    Relativistic Hamiltonians, derived from the path integrals, are known to provide a simple and useful formalism for hadron spectroscopy in QCD. The accuracy of this approach is tested using the QED systems, and the calculated spectrum is shown to reproduce exactly that of the Dirac hydrogen atom, while the Breit-Fermi nonrelativistic expansion is obtained using Foldy-Wouthuizen transformation. The calculated positronium spectrum, including spin-dependent terms, coincides with the standard QED perturbation theory to the considered order O(α4).

  12. Mesh2d

    SciTech Connect

    Greg Flach, Frank Smith

    2011-12-31

    Mesh2d is a Fortran90 program designed to generate two-dimensional structured grids of the form [x(i),y(i,j)] where [x,y] are grid coordinates identified by indices (i,j). The x(i) coordinates alone can be used to specify a one-dimensional grid. Because the x-coordinates vary only with the i index, a two-dimensional grid is composed in part of straight vertical lines. However, the nominally horizontal y(i,j0) coordinates along index i are permitted to undulate or otherwise vary. Mesh2d also assigns an integer material type to each grid cell, mtyp(i,j), in a user-specified manner. The complete grid is specified through three separate input files defining the x(i), y(i,j), and mtyp(i,j) variations.

  13. Mesh2d

    Energy Science and Technology Software Center (ESTSC)

    2011-12-31

    Mesh2d is a Fortran90 program designed to generate two-dimensional structured grids of the form [x(i),y(i,j)] where [x,y] are grid coordinates identified by indices (i,j). The x(i) coordinates alone can be used to specify a one-dimensional grid. Because the x-coordinates vary only with the i index, a two-dimensional grid is composed in part of straight vertical lines. However, the nominally horizontal y(i,j0) coordinates along index i are permitted to undulate or otherwise vary. Mesh2d also assignsmore » an integer material type to each grid cell, mtyp(i,j), in a user-specified manner. The complete grid is specified through three separate input files defining the x(i), y(i,j), and mtyp(i,j) variations.« less

  14. Vertical 2D Heterostructures

    NASA Astrophysics Data System (ADS)

    Lotsch, Bettina V.

    2015-07-01

    Graphene's legacy has become an integral part of today's condensed matter science and has equipped a whole generation of scientists with an armory of concepts and techniques that open up new perspectives for the postgraphene area. In particular, the judicious combination of 2D building blocks into vertical heterostructures has recently been identified as a promising route to rationally engineer complex multilayer systems and artificial solids with intriguing properties. The present review highlights recent developments in the rapidly emerging field of 2D nanoarchitectonics from a materials chemistry perspective, with a focus on the types of heterostructures available, their assembly strategies, and their emerging properties. This overview is intended to bridge the gap between two major—yet largely disjunct—developments in 2D heterostructures, which are firmly rooted in solid-state chemistry or physics. Although the underlying types of heterostructures differ with respect to their dimensions, layer alignment, and interfacial quality, there is common ground, and future synergies between the various assembly strategies are to be expected.

  15. An architecture for integrating planar and 3D cQED devices

    NASA Astrophysics Data System (ADS)

    Axline, C.; Reagor, M.; Heeres, R.; Reinhold, P.; Wang, C.; Shain, K.; Pfaff, W.; Chu, Y.; Frunzio, L.; Schoelkopf, R. J.

    2016-07-01

    Numerous loss mechanisms can limit coherence and scalability of planar and 3D-based circuit quantum electrodynamics (cQED) devices, particularly due to their packaging. The low loss and natural isolation of 3D enclosures make them good candidates for coherent scaling. We introduce a coaxial transmission line device architecture with coherence similar to traditional 3D cQED systems. Measurements demonstrate well-controlled external and on-chip couplings, a spectrum absent of cross-talk or spurious modes, and excellent resonator and qubit lifetimes. We integrate a resonator-qubit system in this architecture with a seamless 3D cavity, and separately pattern a qubit, readout resonator, Purcell filter, and high-Q stripline resonator on a single chip. Device coherence and its ease of integration make this a promising tool for complex experiments.

  16. Dynamically Induced Zeeman Effect in Massless QED

    SciTech Connect

    Ferrer, Efrain J.; Incera, Vivian de la

    2009-02-06

    It is shown that in nonperturbative massless QED an anomalous magnetic moment is dynamically induced by an applied magnetic field. The induced magnetic moment produces a Zeeman splitting for electrons in Landau levels higher than l=0. The expressions for the nonperturbative Lande g factor and Bohr magneton are obtained. Possible applications of this effect are outlined.

  17. One-way quantum computation with circuit quantum electrodynamics

    SciTech Connect

    Wu Chunwang; Han Yang; Chen Pingxing; Li Chengzu; Zhong Xiaojun

    2010-03-15

    In this Brief Report, we propose a potential scheme to implement one-way quantum computation with circuit quantum electrodynamics (QED). Large cluster states of charge qubits can be generated in just one step with a superconducting transmission line resonator (TLR) playing the role of a dispersive coupler. A single-qubit measurement in the arbitrary basis can be implemented using a single electron transistor with the help of one-qubit gates. By examining the main decoherence sources, we show that circuit QED is a promising architecture for one-way quantum computation.

  18. Non-Equilibrium Dynamics of C-QED Arrays in Strong Correlation Regime

    NASA Astrophysics Data System (ADS)

    Zhang, Xin-Ding; Li, Zhi-Hang; Zhang, Xiao-Ming

    2016-07-01

    Recently increasing interests are attracted in the physics of controlled arrays of nonlinear cavity resonators because of the rapid experimental progress achieved in cavity and circuit quantum electrodynamics (QED). For a driven-dissipative two-dimentional planar C-QED array, standard Markov master equation is generally used to study the dynamics of this system. However, when in the case that the on-site photon-photon interaction enters strong correlation regime, standard Markov master equation may lead to incorrect results. In this paper we study the non-equilibrium dynamics of a two-dimentional C-QED array, which is homogeneously pumped by an external pulse, at the same time dissipation exits. We study the evolution of the average photon number of a single cavity by deriving a modified master equation to. In comparison with the standard master equation, the numerical result obtained by our newly derived master equation shows significant difference for the non-equilibrium dynamics of the system.

  19. Interacting Photons in Waveguide-QED and Applications in Quantum Information Processing

    NASA Astrophysics Data System (ADS)

    Zheng, Huaixiu

    Strong coupling between light and matter has been demonstrated both in classical cavity quantum electrodynamics (QED) systems and in more recent circuit-QED experiments. This enables the generation of strong nonlinear photon-photon interactions at the single-photon level, which is of great interest for the observation of quantum nonlinear optical phenomena, the control of light quanta in quantum information protocols such as quantum networking, as well as the study of strongly correlated quantum many-body systems using light. Recently, strong coupling has also been realized in a variety of one-dimensional (1D) waveguide- QED experimental systems, which in turn makes them promising candidates for quantum information processing. Compared to cavity-QED systems, there are two new features in waveguide-QED: the existence of a continuum of states and the restricted 1D phase space, which together bring in new physical effects, such as the bound-state effects. This thesis consists of two parts: 1) understanding the fundamental interaction between local quantum objects, such as two-level systems and four-level systems, and photons confined in the waveguide; 2) exploring its implications in quantum information processing, in particular photonic quantum computation and quantum key distribution. First, we demonstrate that by coupling a two-level system (TLS) or three/four-level system to a 1D continuum, strongly-correlated photons can be generated inside the waveguide. Photon-photon bound states, which decay exponentially as a function of the relative coordinates of photons, appear in multiphoton scattering processes. As a result, photon bunching and antibunching can be observed in the photon-photon correlation function, and nonclassical light source can be generated on demand. In the case of an N-type four-level system, we show that the effective photon-photon interaction mediated by the four-level system, gives rise to a variety of nonlinear optical phenomena, including

  20. Strong coupling QED with two fermionic flavors

    SciTech Connect

    Wang, K.C.

    1990-11-01

    We report the recent results of our simulation of strong coupling QED, with non-compact action, on lattices 10{sup 4} and 16{sup 4}. Since we are dealing with two staggered fermionic flavors, we use hybrid algorithm to do the simulation. In addition to the measurement of the chiral order parameter {l angle}{bar {psi}}{psi}{r angle}, we also measure magnetic monopole susceptibility, {chi}, throughout the region of chiral transition. 6 refs., 6 figs.

  1. High-contrast qubit interactions using multimode cavity QED.

    PubMed

    McKay, David C; Naik, Ravi; Reinhold, Philip; Bishop, Lev S; Schuster, David I

    2015-02-27

    We introduce a new multimode cavity QED architecture for superconducting circuits that can be used to implement photonic memories, more efficient Purcell filters, and quantum simulations of photonic materials. We show that qubit interactions mediated by multimode cavities can have exponentially improved contrast for two qubit gates without sacrificing gate speed. Using two qubits coupled via a three-mode cavity system we spectroscopically observe multimode strong couplings up to 102 MHz and demonstrate suppressed interactions off resonance of 10 kHz when the qubits are ≈600  MHz detuned from the cavity resonance. We study Landau-Zener transitions in our multimode systems and demonstrate quasiadiabatic loading of single photons into the multimode cavity in 25 ns. We introduce an adiabatic gate protocol to realize a controlled-Z gate between the qubits in 95 ns and create a Bell state with 94.7% fidelity. This corresponds to an on/off ratio (gate contrast) of 1000. PMID:25768741

  2. Euler-Heisenberg-Weiss action for QCD +QED

    NASA Astrophysics Data System (ADS)

    Ozaki, Sho; Arai, Takashi; Hattori, Koichi; Itakura, Kazunori

    2015-07-01

    We derive an analytic expression for one-loop effective action of QCD +QED at zero and finite temperatures by using the Schwinger proper time method. The result is a nonlinear effective action not only for electromagnetic and chromo-electromagnetic fields but also for the Polyakov loop, and thus reproduces the Euler-Heisenberg action in QED, QCD, and QED +QCD , and also the Weiss potential for the Polyakov loop at finite temperature. As applications of this "Euler-Heisenberg-Weiss" action in QCD +QED , we investigate quark pair productions induced by QCD +QED fields at zero temperature and the Polyakov loop in the presence of strong electromagnetic fields. Quark one-loop contribution to the effective potential of the Polyakov loop explicitly breaks the center symmetry, and is found to be enhanced by the magnetic field, which is consistent with the inverse magnetic catalysis observed in lattice QCD simulation.

  3. High divergent 2D grating

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Ma, Jianyong; Zhou, Changhe

    2014-11-01

    A 3×3 high divergent 2D-grating with period of 3.842μm at wavelength of 850nm under normal incidence is designed and fabricated in this paper. This high divergent 2D-grating is designed by the vector theory. The Rigorous Coupled Wave Analysis (RCWA) in association with the simulated annealing (SA) is adopted to calculate and optimize this 2D-grating.The properties of this grating are also investigated by the RCWA. The diffraction angles are more than 10 degrees in the whole wavelength band, which are bigger than the traditional 2D-grating. In addition, the small period of grating increases the difficulties of fabrication. So we fabricate the 2D-gratings by direct laser writing (DLW) instead of traditional manufacturing method. Then the method of ICP etching is used to obtain the high divergent 2D-grating.

  4. Cavity QED detection of interfering matter waves

    SciTech Connect

    Bourdel, T.; Donner, T.; Ritter, S.; Oettl, A.; Koehl, M.; Esslinger, T.

    2006-04-15

    We observe the build-up of a matter wave interference pattern from single atom detection events in a double-slit experiment. The interference arises from two overlapping atom laser beams extracted from a rubidium Bose-Einstein condensate. Our detector is a high-finesse optical cavity which realizes a quantum measurement of the presence of an atom and thereby projects delocalized atoms into a state with zero or one atom in the resonator. The experiment reveals simultaneously the granular and the wave nature of matter. We present a setup which is suited for applications in atom interferometry and cavity QED.

  5. Numerical simulations of two-dimensional QED

    SciTech Connect

    Carson, S.R.; Kenway, R.D.

    1986-02-01

    We describe the computer simulation of two-dimensional QED on a 64 x 64 Euclidean space-time lattice using the Susskind lattice fermion action. Theorder parameter for chiral symmetry breaking and the low-lying meson masses are calculated for both the model with two continuum flavours, which arises naturally in this formulation, and the model with one continuum falvour obtained by including a nonsymmetric mass term and setting one fermion mass equal to the cut-off. Results are compared with those obtined using the quenched approximation, and with analytic predictions.

  6. QED effects in the pseudoscalar meson sector

    NASA Astrophysics Data System (ADS)

    Horsley, R.; Nakamura, Y.; Perlt, H.; Pleiter, D.; Rakow, P. E. L.; Schierholz, G.; Schiller, A.; Stokes, R.; Stüben, H.; Young, R. D.; Zanotti, J. M.

    2016-04-01

    In this paper we present results on the pseudoscalar meson masses from a fully dynamical simulation of QCD+QED, concentrating particularly on violations of isospin symmetry. We calculate the π +- π 0 splitting and also look at other isospin violating mass differences. We have presented results for these isospin splittings in [1]. In this paper we give more details of the techniques employed, discussing in particular the question of how much of the symmetry violation is due to QCD, arising from the different masses of the u and d quarks, and how much is due to QED, arising from the different charges of the quarks. This decomposition is not unique, it depends on the renormalisation scheme and scale. We suggest a renormalisation scheme in which Dashen's theorem for neutral mesons holds, so that the electromagnetic self-energies of the neutral mesons are zero, and discuss how the self-energies change when we transform to a scheme such as overline{M S} , in which Dashen's theorem for neutral mesons is violated.

  7. AnisWave 2D

    Energy Science and Technology Software Center (ESTSC)

    2004-08-01

    AnisWave2D is a 2D finite-difference code for a simulating seismic wave propagation in fully anisotropic materials. The code is implemented to run in parallel over multiple processors and is fully portable. A mesh refinement algorithm has been utilized to allow the grid-spacing to be tailored to the velocity model, avoiding the over-sampling of high-velocity materials that usually occurs in fixed-grid schemes.

  8. Recurrent Delocalization and Quasiequilibration of Photons in Coupled Systems in Circuit Quantum Electrodynamics

    NASA Astrophysics Data System (ADS)

    Hwang, Myung-Joong; Kim, M. S.; Choi, Mahn-Soo

    2016-04-01

    We explore the photon population dynamics in two coupled circuit QED systems. For a sufficiently weak intercavity photon hopping, as the photon-cavity coupling increases, the dynamics undergoes double transitions first from a delocalized to a localized phase and then from the localized to another delocalized phase. The latter delocalized phase is distinguished from the former one; instead of oscillating between the two cavities, the photons rapidly quasiequilibrate over the two cavities. These intriguing features are attributed to an interplay between two qualitatively distinctive nonlinear behaviors of the circuit QED systems in the utrastrong coupling regime, whose distinction has been widely overlooked.

  9. Recurrent Delocalization and Quasiequilibration of Photons in Coupled Systems in Circuit Quantum Electrodynamics.

    PubMed

    Hwang, Myung-Joong; Kim, M S; Choi, Mahn-Soo

    2016-04-15

    We explore the photon population dynamics in two coupled circuit QED systems. For a sufficiently weak intercavity photon hopping, as the photon-cavity coupling increases, the dynamics undergoes double transitions first from a delocalized to a localized phase and then from the localized to another delocalized phase. The latter delocalized phase is distinguished from the former one; instead of oscillating between the two cavities, the photons rapidly quasiequilibrate over the two cavities. These intriguing features are attributed to an interplay between two qualitatively distinctive nonlinear behaviors of the circuit QED systems in the utrastrong coupling regime, whose distinction has been widely overlooked. PMID:27127967

  10. Tunable-cavity QED with phase qubits

    NASA Astrophysics Data System (ADS)

    Whittaker, Jed D.; da Silva, Fabio; Allman, Michael Shane; Lecocq, Florent; Cicak, Katarina; Sirois, Adam; Teufel, John; Aumentado, Jose; Simmonds, Raymond W.

    2014-03-01

    We describe a tunable-cavity QED architecture with an rf SQUID phase qubit inductively coupled to a single-mode, resonant cavity with a tunable frequency that allows for both tunneling and dispersive measurements. Dispersive measurement is well characterized by a three-level model, strongly dependent on qubit anharmonicity, qubit-cavity coupling and detuning. The tunable cavity frequency provides dynamic control over the coupling strength and qubit-cavity detuning helping to minimize Purcell losses and cavity-induced dephasing during qubit operation. The maximum decay time T1 = 1 . 5 μs is limited by dielectric losses from a design geometry similar to planar transmon qubits. This work supported by NIST and NSA grant EAO140639.

  11. QED vacuum polarization on a momentum lattice

    SciTech Connect

    Kroeger, H.; Lafrance, R.; Marleau, L. )

    1992-12-15

    We study the effect of a momentum ([ital k]) lattice as a regulator of quantum field theory. An an example, we compute the vacuum polarization in noncompact (linearized) QED from [ital k]-lattice perturbation theory to one-loop order and study the continuum limit. The amplitude has a finite part plus logarithmically, linearly, and quadratically divergent terms. The amplitude violates gauge invariance (Ward identity) and Lorentz (Euclidean) invariance and is nonlocal. For example, the linear term [similar to][Lambda][vert bar][ital k][vert bar] is nonlocal. Renormalization requires nonlocal counterterms, which is not inconsistent because the original action on the [ital k] lattice already has a nonlocality. We explicitly give the counterterms, which render the amplitude Lorentz and gauge invariant to recover the standard result.

  12. N = 2 SUSY QED and nonlinear/linear SUSY relation

    SciTech Connect

    Shima, Kazunari; Tsuda, Motomu

    2008-11-23

    Nonlinear supersymmetric general relativity (NLSUSY GR) elucidates the observed mysterious relations between the cosmology and the (low energy) particle physics and gives new insights into the origin of mass through the (N = 2) SUSY (QED) theory in NL/linear(L) SUSY relation. For the minimal and realistic N = 2 SUSY in the SGM scenario we extract the SUSY QED theory systematically from a NLSUSY model by means of the linearization of NLSUSY in two-dimensional spacetime.

  13. Measuring circuit

    DOEpatents

    Sun, Shan C.; Chaprnka, Anthony G.

    1977-01-11

    An automatic gain control circuit functions to adjust the magnitude of an input signal supplied to a measuring circuit to a level within the dynamic range of the measuring circuit while a log-ratio circuit adjusts the magnitude of the output signal from the measuring circuit to the level of the input signal and optimizes the signal-to-noise ratio performance of the measuring circuit.

  14. Stacking up 2D materials

    NASA Astrophysics Data System (ADS)

    Mayor, Louise

    2016-05-01

    Graphene might be the most famous example, but there are other 2D materials and compounds too. Louise Mayor explains how these atomically thin sheets can be layered together to create flexible “van der Waals heterostructures”, which could lead to a range of novel applications.

  15. Quantum measurements of atoms using cavity QED

    SciTech Connect

    Dada, Adetunmise C.; Andersson, Erika; Jones, Martin L.; Kendon, Vivien M.; Everitt, Mark S.

    2011-04-15

    Generalized quantum measurements are an important extension of projective or von Neumann measurements in that they can be used to describe any measurement that can be implemented on a quantum system. We describe how to realize two nonstandard quantum measurements using cavity QED. The first measurement optimally and unambiguously distinguishes between two nonorthogonal quantum states. The second example is a measurement that demonstrates superadditive quantum coding gain. The experimental tools used are single-atom unitary operations effected by Ramsey pulses and two-atom Tavis-Cummings interactions. We show how the superadditive quantum coding gain is affected by errors in the field-ionization detection of atoms and that even with rather high levels of experimental imperfections, a reasonable amount of superadditivity can still be seen. To date, these types of measurements have been realized only on photons. It would be of great interest to have realizations using other physical systems. This is for fundamental reasons but also since quantum coding gain in general increases with code word length, and a realization using atoms could be more easily scaled than existing realizations using photons.

  16. Critical number of flavors in QED

    SciTech Connect

    Bashir, A.; Gutierrez-Guerrero, L. X.; Calcaneo-Roldan, C.; Tejeda-Yeomans, M. E.

    2011-02-01

    We demonstrate that in unquenched quantum electrodynamics (QED), chiral symmetry breaking ceases to exist above a critical number of fermion flavors N{sub f}. This is a necessary and sufficient consequence of the fact that there exists a critical value of electromagnetic coupling {alpha} beyond which dynamical mass generation gets triggered. We employ a multiplicatively renormalizable photon propagator involving leading logarithms to all orders in {alpha} to illustrate this. We study the flavor and coupling dependence of the dynamically generated mass analytically as well as numerically. We also derive the scaling laws for the dynamical mass as a function of {alpha} and N{sub f}. Up to a multiplicative constant, these scaling laws are related through ({alpha},{alpha}{sub c}){r_reversible}(1/N{sub f},1/N{sub f}{sup c}). Calculation of the mass anomalous dimension {gamma}{sub m} shows that it is always greater than its value in the quenched case. We also evaluate the {beta} function. The criticality plane is drawn in the ({alpha},N{sub f}) phase space which clearly depicts how larger N{sub f} is required to restore chiral symmetry for an increasing interaction strength.

  17. Quantum optics, cavity QED, and quantum optomechanics

    NASA Astrophysics Data System (ADS)

    Meystre, Pierre

    2013-05-01

    Quantum optomechanics provides a universal tool to achieve the quantum control of mechanical motion. It does that in devices spanning a vast range of parameters, with mechanical frequencies from a few Hertz to GHz, and with masses from 10-20 g to several kilos. Its underlying ideas can be traced back to the study of gravitational wave antennas, quantum optics, cavity QED and laser cooling which, when combined with the recent availability of advanced micromechanical and nanomechanical devices, opens a path to the realization of macroscopic mechanical systems that operate deep in the quantum regime. At the fundamental level this development paves the way to experiments that will lead to a more profound understanding of quantum mechanics; and from the point of view of applications, quantum optomechanical techniques will provide motion and force sensing near the fundamental limit imposed by quantum mechanics (quantum metrology) and significantly expand the toolbox of quantum information science. After a brief summary of key historical developments, the talk will give a broad overview of the current state of the art of quantum optomechanics, and comment on future prospects both in applied and in fundamental science. Work supported by NSF, ARO and the DARPA QuASAR and ORCHID programs.

  18. MOSS2D V1

    Energy Science and Technology Software Center (ESTSC)

    2001-01-31

    This software reduces the data from two-dimensional kSA MOS program, k-Space Associates, Ann Arbor, MI. Initial MOS data is recorded without headers in 38 columns, with one row of data per acquisition per lase beam tracked. The final MOSS 2d data file is reduced, graphed, and saved in a tab-delimited column format with headers that can be plotted in any graphing software.

  19. Simulating MEMS Chevron Actuator for Strain Engineering 2D Materials

    NASA Astrophysics Data System (ADS)

    Vutukuru, Mounika; Christopher, Jason; Bishop, David; Swan, Anna

    2D materials pose an exciting paradigm shift in the world of electronics. These crystalline materials have demonstrated high electric and thermal conductivities and tensile strength, showing great potential as the new building blocks of basic electronic circuits. However, strain engineering 2D materials for novel devices remains a difficult experimental feat. We propose the integration of 2D materials with MEMS devices to investigate the strain dependence on material properties such as electrical and thermal conductivity, refractive index, mechanical elasticity, and band gap. MEMS Chevron actuators, provides the most accessible framework to study strain in 2D materials due to their high output force displacements for low input power. Here, we simulate Chevron actuators on COMSOL to optimize actuator design parameters and accurately capture the behavior of the devices while under the external force of a 2D material. Through stationary state analysis, we analyze the response of the device through IV characteristics, displacement and temperature curves. We conclude that the simulation precisely models the real-world device through experimental confirmation, proving that the integration of 2D materials with MEMS is a viable option for constructing novel strain engineered devices. The authors acknowledge support from NSF DMR1411008.

  20. Nanoimprint lithography: 2D or not 2D? A review

    NASA Astrophysics Data System (ADS)

    Schift, Helmut

    2015-11-01

    Nanoimprint lithography (NIL) is more than a planar high-end technology for the patterning of wafer-like substrates. It is essentially a 3D process, because it replicates various stamp topographies by 3D displacement of material and takes advantage of the bending of stamps while the mold cavities are filled. But at the same time, it keeps all assets of a 2D technique being able to pattern thin masking layers like in photon- and electron-based traditional lithography. This review reports about 20 years of development of replication techniques at Paul Scherrer Institut, with a focus on 3D aspects of molding, which enable NIL to stay 2D, but at the same time enable 3D applications which are "more than Moore." As an example, the manufacturing of a demonstrator for backlighting applications based on thermally activated selective topography equilibration will be presented. This technique allows generating almost arbitrary sloped, convex and concave profiles in the same polymer film with dimensions in micro- and nanometer scale.

  1. Two-resonator circuit quantum electrodynamics: A superconducting quantum switch

    NASA Astrophysics Data System (ADS)

    Mariantoni, Matteo; Deppe, Frank; Marx, A.; Gross, R.; Wilhelm, F. K.; Solano, E.

    2008-09-01

    We introduce a systematic formalism for two-resonator circuit QED, where two on-chip microwave resonators are simultaneously coupled to one superconducting qubit. Within this framework, we demonstrate that the qubit can function as a quantum switch between the two resonators, which are assumed to be originally independent. In this three-circuit network, the qubit mediates a geometric second-order circuit interaction between the otherwise decoupled resonators. In the dispersive regime, it also gives rise to a dynamic second-order perturbative interaction. The geometric and dynamic coupling strengths can be tuned to be equal, thus permitting to switch on and off the interaction between the two resonators via a qubit population inversion or a shifting of the qubit operation point. We also show that our quantum switch represents a flexible architecture for the manipulation and generation of nonclassical microwave field states as well as the creation of controlled multipartite entanglement in circuit QED. In addition, we clarify the role played by the geometric interaction, which constitutes a fundamental property characteristic of superconducting quantum circuits without a counterpart in quantum-optical systems. We develop a detailed theory of the geometric second-order coupling by means of circuit transformations for superconducting charge and flux qubits. Furthermore, we show the robustness of the quantum switch operation with respect to decoherence mechanisms. Finally, we propose a realistic design for a two-resonator circuit QED setup based on a flux qubit and estimate all the related parameters. In this manner, we show that this setup can be used to implement a superconducting quantum switch with available technology.

  2. Simplicity in the structure of QED and gravity amplitudes

    NASA Astrophysics Data System (ADS)

    Badger, Simon; Bjerrum-Bohr, N. E. J.; Vanhove, Pierre

    2009-02-01

    We investigate generic properties of one-loop amplitudes in unordered gauge theories in four dimensions. For such theories the organisation of amplitudes in manifestly crossing symmetric expressions poses restrictions on their structure and results in remarkable cancellations. We show that one-loop multi-photon amplitudes in QED with at least eight external photons are given only by scalar box integral functions. This QED `no-triangle' property is true for all helicity configurations and has similarities to the `no-triangle' property found in the case of maximal Script N = 8 supergravity. Results are derived both via a world-line formalism as well as using on-shell unitarity methods. We show that the simple structure of the loop amplitude originates from the extremely good BCFW scaling behaviour of the QED tree-amplitude.

  3. Simulating Topological Effects with Photons in Coupled QED Cavity Arrays

    NASA Astrophysics Data System (ADS)

    Noh, Changsuk; Angelakis, Dimitris G.

    2014-01-01

    We provide a pedagogical account of an early proposal realizing fractional quantum Hall effect (FQHE) using coupled quantum electrodynamics (QED) cavity arrays (CQCAs). We start with a brief introduction on the basics of quantum Hall effects and then review the early proposals in the simulation of spin-models and fractional quantum Hall (FQH) physics with photons in coupled atom-cavity arrays. We calculate the energy gap and the overlap between the ground state of the system and the corresponding Laughlin wavefunction to analyze the FQH physics arising in the system and discuss possibilities to reach the ground state using adiabatic methods used in Cavity QED.

  4. Cavity QED based tuneable, delayed-choice quantum eraser

    NASA Astrophysics Data System (ADS)

    Imran, Muhammad; Abbas, Tasawar; -ul-Islam, Rameez; Ikram, Manzoor

    2016-01-01

    We propose an experimentally feasible idea for the delayed-choice quantum eraser, having adjustable path distinguishability/fringe visibility. The schematics are based on resonant, dispersive and Ramsey interactions of atoms under cavity QED scenario. The option for tuneability of the fringes in a delayed-choice setup stringently marks the conception of the time in the quantum theory, operational meanings of the state vector reduction and raises questions about Ψ-ontic models while helping to shed out the controversies surrounding the quantum eraser theme. The proposal can be efficiently executed experimentally within the prevailing cavity QED experimental research scenario with good overall success probability and fidelity.

  5. ADDER CIRCUIT

    DOEpatents

    Jacobsohn, D.H.; Merrill, L.C.

    1959-01-20

    An improved parallel addition unit is described which is especially adapted for use in electronic digital computers and characterized by propagation of the carry signal through each of a plurality of denominationally ordered stages within a minimum time interval. In its broadest aspects, the invention incorporates a fast multistage parallel digital adder including a plurality of adder circuits, carry-propagation circuit means in all but the most significant digit stage, means for conditioning each carry-propagation circuit during the time period in which information is placed into the adder circuits, and means coupling carry-generation portions of thc adder circuit to the carry propagating means.

  6. APFEL: A PDF evolution library with QED corrections

    NASA Astrophysics Data System (ADS)

    Bertone, Valerio; Carrazza, Stefano; Rojo, Juan

    2014-06-01

    Quantum electrodynamics and electroweak corrections are important ingredients for many theoretical predictions at the LHC. This paper documents APFEL, a new PDF evolution package that allows for the first time to perform DGLAP evolution up to NNLO in QCD and to LO in QED, in the variable-flavor-number scheme and with either pole or MS bar heavy quark masses. APFEL consistently accounts for the QED corrections to the evolution of quark and gluon PDFs and for the contribution from the photon PDF in the proton. The coupled QCD ⊗ QED equations are solved in x-space by means of higher order interpolation, followed by Runge-Kutta solution of the resulting discretized evolution equations. APFEL is based on an innovative and flexible methodology for the sequential solution of the QCD and QED evolution equations and their combination. In addition to PDF evolution, APFEL provides a module that computes Deep-Inelastic Scattering structure functions in the FONLL general-mass variable-flavor-number scheme up to O(αs2) . All the functionalities of APFEL can be accessed via a Graphical User Interface, supplemented with a variety of plotting tools for PDFs, parton luminosities and structure functions. Written in FORTRAN 77, APFEL can also be used via the C/C++ and Python interfaces, and is publicly available from the HepForge repository.

  7. Cavity QED with atom chips and micro-resonators

    NASA Astrophysics Data System (ADS)

    Lev, Benjamin; Barclay, Paul; Kerckhoff, Joseph; Painter, Oskar; Mabuchi, Hideo

    2006-05-01

    Cavity QED provides a rich experimental setting for quantum information processing, both in the implementation of quantum logic gates and in the development of quantum networks. Moreover, studies of cavity QED will help elucidate the dynamics of continuously observed open quantum systems with quantum- limited feedback. To achieve these goals in cavity QED, a neutral atom must be tightly confined inside a high-finesse cavity with small mode volume for long periods of time. Microfabricated wires on a substrate---known as an atom chip---can create sufficiently high-curvature magnetic potentials to trap atoms in the Lamb- Dicke regime. The integration of micro-resonators, such as microdisks and photonic bandgap cavities, with atom chips forms a robust and scalable system capable of probing the strong- coupling regime of cavity QED with magnetically trapped atoms. We have recently built an atom-cavity chip utilizing a fiber taper coupled microdisk resonator. This device combines laser cooling and trapping of neutral atoms with magnetic microtraps and waveguides to deliver cold atoms to the small mode volume of the high-Q cavity. We will relate our progress toward detecting single atoms with this device.

  8. Non-perturbative QED Analysis with Schwinger-Dyson Equations

    SciTech Connect

    Kizilersue, Ayse; Sizer, Tom; Williams, Anthony G.

    2011-05-24

    We give a brief account of unquenched QED studies in four dimensions using Schwinger-Dyson Equations. In these numerical studies of fermion and boson propagators, we employ a recent realistic unquenched fermion-boson vertex, comparing it against commonly used vertices in previous quenched studies.

  9. Slavnov-Taylor identities for noncommutative QED{sub 4}

    SciTech Connect

    Charneski, B.; Gomes, M.; Silva, A. J. da; Mariz, T.; Nascimento, J. R.

    2010-05-15

    In this work we present an analysis of the one-loop Slavnov-Taylor identities in noncommutative QED{sub 4}. The vectorial fermion-photon and the triple photon vertex functions were studied, with the conclusion that no anomalies arise.

  10. Atomic teleportation via cavity QED and position measurements: Efficiency analysis

    NASA Astrophysics Data System (ADS)

    Tumminello, M.; Ciccarello, F.

    2008-07-01

    We have recently presented a novel protocol to teleport an unknown atomic state via cavity QED and position measurements. Here, after a brief review of our scheme, we provide a quantitative study of its efficiency. This is accomplished by an explicit description of the measurement process that allows us to derive the fidelity with respect to the atomic internal state to be teleported.

  11. Dynamics of symmetry breaking in strongly coupled QED

    SciTech Connect

    Bardeen, W.A.

    1988-10-01

    I review the dynamical structure of strong coupled QED in the quenched planar limit. The symmetry structure of this theory is examined with reference to the nature of both chiral and scale symmetry breaking. The renormalization structure of the strong coupled phase is analysed. The compatibility of spontaneous scale and chiral symmetry breaking is studied using effective lagrangian methods. 14 refs., 3 figs.

  12. Structure and decay in the QED vacuum

    NASA Astrophysics Data System (ADS)

    Labun, Lance Andrew

    This thesis is a guide to a selection of the author's published work that connect and contribute to understanding the vacuum of quantum electrodynamics in strong, prescribed electromagnetic fields. This theme is elaborated over the course of two chapters: The first chapter sets the context, defining the relevant objects and conditions of the study and reviewing established knowledge upon which this study builds. The second chapter organizes and explains important results appearing in the published work. The papers 1. (Labun and Rafelski, 2009) "Vacuum Decay Time in Strong External Fields" 2. (Labun and Rafelski, 2010a) "Dark Energy Simulacrum in Nonlinear Electrodynamics" 3. (Labun and Rafelski, 2010b) "QED Energy-Momentum Trace as a Force in Astrophysics" 4. (Labun and Rafelski, 2010c) "Strong Field Physics: Probing Critical Acceleration and Inertia with Laser Pulses and Quark-Gluon Plasma" 5. (Labun and Rafelski, 2010d) "Vacuum Structure and Dark Energy" 6. (Labun and Rafelski, 2011) "Spectra of Particles from Laser-Induced Vacuum Decay" are presented in their published format as appendices. Related literature is cited throughout the body where it directly supports the content of this overview; more extensive references are found within the attached papers. This study begins with the first non-perturbative result in quantum electrodynamics, a result obtained by Heisenberg and Euler (1936) for the energy of a zero-particle state in a prescribed, long-wavelength electromagnetic field. The resulting Euler-Heisenberg effective potential generates a nonlinear theory of electromagnetism and exhibits the ability of the electrical fields to decay into electron-positron pairs. Context for phenomena arising from the Euler-Heisenberg effective potential is established by considering the energy-momentum tensor of a general nonlinear electromagnetic theory. The mass of a field configuration is defined, and I discuss two of its consequences pertinent to efforts to observe

  13. Universal Quantum Cloning Machine in Circuit Quantum Electrodynamics

    NASA Astrophysics Data System (ADS)

    Lv, Dan-Dan; Lu, Hong; Yu, Ya-Fei; Feng, Xun-Li; Zhang, Zhi-Ming

    2010-02-01

    We propose a scheme for realizing the 1 → 2 universal quantum cloning machine (UQCM) with superconducting quantum interference device (SQUID) qubits in circuit quantum electrodynamics (circuit QED). In this scheme, in order to implement UQCM, we only need phase shift gate operation on SQUID qubits and the Raman transitions. The cavity number we need is only one. Thus our scheme is simple and has advantages in the experimental realization. Furthermore, both the cavity and the SQUID qubits are virtually excited, so the decoherence can be neglected.

  14. Modelling RF sources using 2-D PIC codes

    SciTech Connect

    Eppley, K.R.

    1993-03-01

    In recent years, many types of RF sources have been successfully modelled using 2-D PIC codes. Both cross field devices (magnetrons, cross field amplifiers, etc.) and pencil beam devices (klystrons, gyrotrons, TWT`S, lasertrons, etc.) have been simulated. All these devices involve the interaction of an electron beam with an RF circuit. For many applications, the RF structure may be approximated by an equivalent circuit, which appears in the simulation as a boundary condition on the electric field (``port approximation``). The drive term for the circuit is calculated from the energy transfer between beam and field in the drift space. For some applications it may be necessary to model the actual geometry of the structure, although this is more expensive. One problem not entirely solved is how to accurately model in 2-D the coupling to an external waveguide. Frequently this is approximated by a radial transmission line, but this sometimes yields incorrect results. We also discuss issues in modelling the cathode and injecting the beam into the PIC simulation.

  15. Modelling RF sources using 2-D PIC codes

    SciTech Connect

    Eppley, K.R.

    1993-03-01

    In recent years, many types of RF sources have been successfully modelled using 2-D PIC codes. Both cross field devices (magnetrons, cross field amplifiers, etc.) and pencil beam devices (klystrons, gyrotrons, TWT'S, lasertrons, etc.) have been simulated. All these devices involve the interaction of an electron beam with an RF circuit. For many applications, the RF structure may be approximated by an equivalent circuit, which appears in the simulation as a boundary condition on the electric field ( port approximation''). The drive term for the circuit is calculated from the energy transfer between beam and field in the drift space. For some applications it may be necessary to model the actual geometry of the structure, although this is more expensive. One problem not entirely solved is how to accurately model in 2-D the coupling to an external waveguide. Frequently this is approximated by a radial transmission line, but this sometimes yields incorrect results. We also discuss issues in modelling the cathode and injecting the beam into the PIC simulation.

  16. Waveguide-QED-Based Photonic Quantum Computation

    NASA Astrophysics Data System (ADS)

    Zheng, Huaixiu; Gauthier, Daniel J.; Baranger, Harold U.

    2013-08-01

    We propose a new scheme for quantum computation using flying qubits—propagating photons in a one-dimensional waveguide interacting with matter qubits. Photon-photon interactions are mediated by the coupling to a four-level system, based on which photon-photon π-phase gates (controlled-not) can be implemented for universal quantum computation. We show that high gate fidelity is possible, given recent dramatic experimental progress in superconducting circuits and photonic-crystal waveguides. The proposed system can be an important building block for future on-chip quantum networks.

  17. QED induced redshift and anomalous microwave emission from dust

    NASA Astrophysics Data System (ADS)

    Prevenslik, Thomas V.

    2015-08-01

    The Planck satellite imaging of CMB polarizations at 353 GHz extrapolated to 160 GHz suggested the AME was caused by dust and not as a relic of gravity waves from Universe expansion. AME stands for anomalous microwave emisssion. Similarly, dust has also been implicated in questioning Universe expansion by exaggerating Hubble redshift measurements. In this regard, QED induced EM radiation in dust NPs may be the commonality by which an expanding Universe may be assessed. QED stands for quantum electrodynamics, EM for electromagnetic, and NPs for nanoparticles. QED radiation is a consequence of QM that denies the atoms in NPs under TIR confinement the heat capacity to allow increases in NP temperature upon absorbing galaxy light. QM stands for quantum mechanics and TIR for total internal reflection.In this paper, the only galaxy light considered are single Lyα photons absorbed in spherical dust NPs. Since NPs have high surface to volume ratios, an absorbed Lyα photon is induced by QED to be totally confined by TIR to the NP surface. Hence, the TIR wavelength λ of the QED photon moving at velocity c/n in the NP surface is λ = 2πa, where c is the speed of light, and n and a are the refractive index and radius of the NP. The boundary between QED induced spinning and redshift depends on the NP material. For amorphous silicate, small NPs with a < 0.040 microns conserve the Lyα photon energy by NP spinning; whereas, the larger NPs having a > 0.040 microns redshift the Lyα photon to produce VIS and near IR galaxy light.Since the TIR mode is tangential to the surface of the NP, the Lyα photon produces circularly polarized light during absorption thereby exerting a momentary torque on the NP. Conserving the Lyα photon energy hc/λ* with the rotational energy ½ Jω2 of the NP gives the spin ω = √ (2 hc/Jλ*). Here, h is Planck’s constant, λ* the Lyα wavelength, J the NP rotational moment of inertia, J = 2 ma2/5, m the NP mass, m = 4πρa3/3, and ρ the NP

  18. NKG2D ligands as therapeutic targets

    PubMed Central

    Spear, Paul; Wu, Ming-Ru; Sentman, Marie-Louise; Sentman, Charles L.

    2013-01-01

    The Natural Killer Group 2D (NKG2D) receptor plays an important role in protecting the host from infections and cancer. By recognizing ligands induced on infected or tumor cells, NKG2D modulates lymphocyte activation and promotes immunity to eliminate ligand-expressing cells. Because these ligands are not widely expressed on healthy adult tissue, NKG2D ligands may present a useful target for immunotherapeutic approaches in cancer. Novel therapies targeting NKG2D ligands for the treatment of cancer have shown preclinical success and are poised to enter into clinical trials. In this review, the NKG2D receptor and its ligands are discussed in the context of cancer, infection, and autoimmunity. In addition, therapies targeting NKG2D ligands in cancer are also reviewed. PMID:23833565

  19. Scheme for implementing the Deutsch-Jozsa algorithm in cavity QED

    SciTech Connect

    Zheng Shibiao

    2004-09-01

    We propose a scheme for realizing the Deutsch-Jozsa algorithm in cavity QED. The scheme is based on the resonant interaction of atoms with a cavity mode. The required experimental techniques are within the scope of what can be obtained in the microwave cavity QED setup. The experimental implementation of the scheme would be an important step toward more complex quantum computation in cavity QED.

  20. One-loop radiative corrections to the QED Casimir energy

    NASA Astrophysics Data System (ADS)

    Moazzemi, Reza; Mojavezi, Amirhosein

    2016-05-01

    In this paper, we investigate one-loop radiative corrections to the Casimir energy in the presence of two perfectly conducting parallel plates for QED theory within the renormalized perturbation theory. In fact, there are three contributions for radiative corrections to the Casimir energy, up to order α . Only the two-loop diagram, which is of order α , has been computed by Bordag et. al (Ann. Phys. 165:192, 1985), approximately. Here, up to this order, we consider corrections due to two one-loop terms, i.e., photonic and fermionic loop corrections resulting from renormalized QED Lagrangian, more precisely. Our results show that only the fermionic loop has a very minor correction and the correction of photonic loop vanishes.

  1. Anomaly-Induced Dynamical Refringence in Strong-Field QED.

    PubMed

    Mueller, N; Hebenstreit, F; Berges, J

    2016-08-01

    We investigate the impact of the Adler-Bell-Jackiw anomaly on the nonequilibrium evolution of strong-field quantum electrodynamics (QED) using real-time lattice gauge theory techniques. For field strengths exceeding the Schwinger limit for pair production, we encounter a highly absorptive medium with anomaly induced dynamical refractive properties. In contrast to earlier expectations based on equilibrium properties, where net anomalous effects vanish because of the trivial vacuum structure, we find that out-of-equilibrium conditions can have dramatic consequences for the presence of quantum currents with distinctive macroscopic signatures. We observe an intriguing tracking behavior, where the system spends longest times near collinear field configurations with maximum anomalous current. Apart from the potential relevance of our findings for future laser experiments, similar phenomena related to the chiral magnetic effect are expected to play an important role for strong QED fields during initial stages of heavy-ion collision experiments. PMID:27541456

  2. Anomaly-Induced Dynamical Refringence in Strong-Field QED

    NASA Astrophysics Data System (ADS)

    Mueller, N.; Hebenstreit, F.; Berges, J.

    2016-08-01

    We investigate the impact of the Adler-Bell-Jackiw anomaly on the nonequilibrium evolution of strong-field quantum electrodynamics (QED) using real-time lattice gauge theory techniques. For field strengths exceeding the Schwinger limit for pair production, we encounter a highly absorptive medium with anomaly induced dynamical refractive properties. In contrast to earlier expectations based on equilibrium properties, where net anomalous effects vanish because of the trivial vacuum structure, we find that out-of-equilibrium conditions can have dramatic consequences for the presence of quantum currents with distinctive macroscopic signatures. We observe an intriguing tracking behavior, where the system spends longest times near collinear field configurations with maximum anomalous current. Apart from the potential relevance of our findings for future laser experiments, similar phenomena related to the chiral magnetic effect are expected to play an important role for strong QED fields during initial stages of heavy-ion collision experiments.

  3. Renormalized strong-coupling quenched QED in four dimensions

    SciTech Connect

    Hawes, F.T.; Sizer, T.; Williams, A.G. |

    1997-03-01

    We study renormalized quenched strong-coupling QED in four dimensions in an arbitrary covariant gauge. Above the critical coupling leading to dynamical chiral symmetry breaking, we show that there is no finite chiral limit. This behavior is found to be independent of the detailed choice of photon-fermion proper vertex in the Dyson-Schwinger equation formalism, provided that the vertex is consistent with the Ward-Takahashi identity and multiplicative renormalizability. We show that the finite solutions previously reported lie in an unphysical regime of the theory with multiple solutions and ultraviolet oscillations in the mass functions. This study is consistent with the assertion that in four dimensions strong coupling QED does not have a continuum limit in the conventional sense. {copyright} {ital 1997} {ital The American Physical Society}

  4. Unitarity and vacuum deformation in QED with critical potential steps

    NASA Astrophysics Data System (ADS)

    Gavrilov, S. P.; Gitman, D. M.; Shishmarev, A. A.

    2016-05-01

    The present article can be considered as a complement to the work of Phys. Rev. D 93, 045002 (2016), where an nonperturbative approach to QED with x -electric critical potential steps was developed. In the beginning, we study conditions when in and out spaces of the QED under consideration are unitarily equivalent. Then, we construct a general density operator with the vacuum initial condition. Such an operator describes a deformation of the initial vacuum state by x -electric critical potential steps. We construct reductions of the deformed state to electron and positron subsystems, calculating the loss of the information in these reductions. We illustrate the general consideration studying the deformation of the quantum vacuum between two capacitor plates. Finally, we calculate the entanglement measures of these reduced matrices as von Neumann entropies.

  5. GATING CIRCUITS

    DOEpatents

    Merrill, L.C.

    1958-10-14

    Control circuits for vacuum tubes are described, and a binary counter having an improved trigger circuit is reported. The salient feature of the binary counter is the application of the input signal to the cathode of each of two vacuum tubes through separate capacitors and the connection of each cathode to ground through separate diodes. The control of the binary counter is achieved in this manner without special pulse shaping of the input signal. A further advantage of the circuit is the simplicity and minimum nuruber of components required, making its use particularly desirable in computer machines.

  6. MULTIPLIER CIRCUIT

    DOEpatents

    Thomas, R.E.

    1959-01-20

    An electronic circuit is presented for automatically computing the product of two selected variables by multiplying the voltage pulses proportional to the variables. The multiplier circuit has a plurality of parallel resistors of predetermined values connected through separate gate circults between a first input and the output terminal. One voltage pulse is applied to thc flrst input while the second voltage pulse is applied to control circuitry for the respective gate circuits. Thc magnitude of the second voltage pulse selects the resistors upon which the first voltage pulse is imprcssed, whereby the resultant output voltage is proportional to the product of the input voltage pulses

  7. Numerical study of dynamical mass generation in QED3

    NASA Astrophysics Data System (ADS)

    Bashir, A.; Huet, A.; Raya, A.

    2006-05-01

    We carry out a numerical study of dynamical generation of fermion masses by solving the Schwinger-Dyson equation for the fermion propagator in three-dimensional quenched Quantum Electrodynamics (QED3) in various gauges. We employ an ansatz for the three-point vertex which satisfies the Ward-Green-Takahashi identity, namely, the Ball-Chiu Vertex. We discuss the advantages of our numerical method over some earlier ones.

  8. TRIPPING CIRCUIT

    DOEpatents

    Lees, G.W.; McCormick, E.D.

    1962-05-22

    A tripping circuit employing a magnetic amplifier for tripping a reactor in response to power level, period, or instrument failure is described. A reference winding and signal winding are wound in opposite directions on the core. Current from an ion chamber passes through both windings. If the current increases at too fast a rate, a shunt circuit bypasses one or the windings and the amplifier output reverses polarity. (AEC)

  9. Perspectives for spintronics in 2D materials

    NASA Astrophysics Data System (ADS)

    Han, Wei

    2016-03-01

    The past decade has been especially creative for spintronics since the (re)discovery of various two dimensional (2D) materials. Due to the unusual physical characteristics, 2D materials have provided new platforms to probe the spin interaction with other degrees of freedom for electrons, as well as to be used for novel spintronics applications. This review briefly presents the most important recent and ongoing research for spintronics in 2D materials.

  10. Annotated Bibliography of EDGE2D Use

    SciTech Connect

    J.D. Strachan and G. Corrigan

    2005-06-24

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables.

  11. Staring 2-D hadamard transform spectral imager

    DOEpatents

    Gentry, Stephen M.; Wehlburg, Christine M.; Wehlburg, Joseph C.; Smith, Mark W.; Smith, Jody L.

    2006-02-07

    A staring imaging system inputs a 2D spatial image containing multi-frequency spectral information. This image is encoded in one dimension of the image with a cyclic Hadamarid S-matrix. The resulting image is detecting with a spatial 2D detector; and a computer applies a Hadamard transform to recover the encoded image.

  12. QEd: Scientific Evidence for Adult Literacy Educators. Number 1 of 5

    ERIC Educational Resources Information Center

    Kruidenier, John R., Ed.

    2007-01-01

    QEd is a five-issue series for the adult education community--literacy educators, paraprofessionals, program directors, and volunteers. QEd brings ideas and information from the expanding scientific research base on how adults learn to read. This first issue tells the story of how researchers are using the high quality, scientific standards that…

  13. NLO QED contributions to top-pair production at hadron colliders

    SciTech Connect

    Hollik, W.; Kollar, M.

    2008-01-01

    Electroweak one-loop calculations for production of top-quark pairs at colliders are completed by providing the missing QED type contributions from real and virtual photons, where also effects from interference between QED and QCD contributions have to be taken into account. Moreover, photon-induced tt production is included as another partonic channel.

  14. Planar Multilayer Circuit Quantum Electrodynamics

    NASA Astrophysics Data System (ADS)

    Minev, Z. K.; Serniak, K.; Pop, I. M.; Leghtas, Z.; Sliwa, K.; Hatridge, M.; Frunzio, L.; Schoelkopf, R. J.; Devoret, M. H.

    2016-04-01

    Experimental quantum information processing with superconducting circuits is rapidly advancing, driven by innovation in two classes of devices, one involving planar microfabricated (2D) resonators, and the other involving machined three-dimensional (3D) cavities. We demonstrate that circuit quantum electrodynamics can be implemented in a multilayer superconducting structure that combines 2D and 3D advantages. We employ standard microfabrication techniques to pattern each layer, and rely on a vacuum gap between the layers to store the electromagnetic energy. Planar qubits are lithographically defined as an aperture in a conducting boundary of the resonators. We demonstrate the aperture concept by implementing an integrated, two-cavity-mode, one-transmon-qubit system.

  15. MULTIPLIER CIRCUIT

    DOEpatents

    Chase, R.L.

    1963-05-01

    An electronic fast multiplier circuit utilizing a transistor controlled voltage divider network is presented. The multiplier includes a stepped potentiometer in which solid state or transistor switches are substituted for mechanical wipers in order to obtain electronic switching that is extremely fast as compared to the usual servo-driven mechanical wipers. While this multiplier circuit operates as an approximation and in steps to obtain a voltage that is the product of two input voltages, any desired degree of accuracy can be obtained with the proper number of increments and adjustment of parameters. (AEC)

  16. Fabrication and characterization of transmon qubits and rectangular waveguide resonators for circuit quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Ha, Dong-Gwang; Park, Jung; Jun, So-Yeon; Song, Woon; Chong, Yonuk

    2013-03-01

    We present our design, fabrication and characterization of superconducting transmon qubits and resonators for circuit quantum electrodynamics (QED). We have made coplanar waveguide resonators and rectangular waveguide resonators. The characteristics of the resonators are well controlled by the design parameters, with the fundamental frequencies in the range of 1 to 8 GHz and the quality factors in the range of 102 to 106, respectively. We measured the resonator characteristics as a function of temperature. The excitation power dependence of the resonator characteristics was also investigated. For transmon qubits, we fabricated 100 nm-scale Al/Al2Ox/Al tunnel junctions with e-beam lithography and double angle evaporation. The junctions were characterized at low temperature down to 10 mK. Furthermore, quantum state measurement and manipulation in circuit QED structure will be discussed.

  17. Circuit QED with hole-spin qubits in Ge/Si nanowire quantum dots

    NASA Astrophysics Data System (ADS)

    Kloeffel, Christoph; Trif, Mircea; Stano, Peter; Loss, Daniel

    2013-12-01

    We propose a setup for universal and electrically controlled quantum information processing with hole spins in Ge/Si core/shell nanowire quantum dots (NW QDs). Single-qubit gates can be driven through electric-dipole-induced spin resonance, with spin-flip times shorter than 100 ps. Long-distance qubit-qubit coupling can be mediated by the cavity electric field of a superconducting transmission line resonator, where we show that operation times below 20 ns seem feasible for the entangling iSWAP gate. The absence of Dresselhaus spin-orbit interaction (SOI) and the presence of an unusually strong Rashba-type SOI enable precise control over the transverse qubit coupling via an externally applied, perpendicular electric field. The latter serves as an on-off switch for quantum gates and also provides control over the g factor, so single- and two-qubit gates can be operated independently. Remarkably, we find that idle qubits are insensitive to charge noise and phonons, and we discuss strategies for enhancing noise-limited gate fidelities.

  18. Dynamical polaron Ansatz: A theoretical tool for the ultrastrong-coupling regime of circuit QED

    NASA Astrophysics Data System (ADS)

    Díaz-Camacho, Guillermo; Bermudez, Alejandro; García-Ripoll, Juan José

    2016-04-01

    In this work we develop a semianalytical variational Ansatz to study the properties of few-photon excitations interacting with a collection of quantum emitters in regimes that go beyond the rotating-wave approximation. This method can be used to approximate both the static and dynamical properties of a superconducting qubit in an open transmission line, including the spontaneous emission spectrum and the resonances in scattering experiments. The approximations are quantitatively accurate for rather strong couplings, as shown by a direct comparison to matrix-product-state numerical methods, and provide also a good qualitative description for stronger couplings well beyond the Markovian regime.

  19. Holonomic quantum computation in the ultrastrong-coupling regime of circuit QED

    NASA Astrophysics Data System (ADS)

    Wang, Yimin; Zhang, Jiang; Wu, Chunfeng; You, J. Q.; Romero, G.

    2016-07-01

    We present an experimentally feasible scheme to implement holonomic quantum computation in the ultrastrong-coupling regime of light-matter interaction. The large anharmonicity and the Z2 symmetry of the quantum Rabi model allow us to build an effective three-level Λ -structured artificial atom for quantum computation. The proposed physical implementation includes two gradiometric flux qubits and two microwave resonators where single-qubit gates are realized by a two-tone driving on one physical qubit, and a two-qubit gate is achieved with a time-dependent coupling between the field quadratures of both resonators. Our work paves the way for scalable holonomic quantum computation in ultrastrongly coupled systems.

  20. Conformal QED d , F-theorem and the ɛ expansion

    NASA Astrophysics Data System (ADS)

    Giombi, Simone; Klebanov, Igor R.; Tarnopolsky, Grigory

    2016-04-01

    We calculate the free energies F for U(1) gauge theories on the d dimensional sphere of radius R. For the theory with free Maxwell action we find the exact result as a function of d; it contains the term \\frac{d-4}{2}{log}R consistent with the lack of conformal invariance in dimensions other than 4. When the U(1) gauge theory is coupled to a sufficient number N f of massless four-component fermions, it acquires an interacting conformal phase, which in d\\lt 4 describes the long distance behavior of the model. The conformal phase can be studied using large N f methods. Generalizing the d = 3 calculation in arXiv:1112.5342, we compute its sphere free energy as a function of d, ignoring the terms of order 1/{N}f and higher. For finite N f , following arXiv:1409.1937 and arXiv:1507.01960, we develop the 4-ε expansion for the sphere free energy of conformal QED d . Its extrapolation to d = 3 shows very good agreement with the large N f approximation for {N}f\\gt 3. For N f at or below some critical value {N}{{crit}}, the {SU}(2{N}f) symmetric conformal phase of QED3 is expected to disappear or become unstable. By using the F-theorem and comparing the sphere free energies in the conformal and broken symmetry phases, we show that {N}{{crit}}≤slant 4. As another application of our results, we calculate the one loop beta function in conformal QED6, where the gauge field has a four-derivative kinetic term. We show that this theory coupled to N f massless fermions is asymptotically free.

  1. Cold atoms in cavity QED for quantum information processing

    NASA Astrophysics Data System (ADS)

    Vernooy, David William

    2000-11-01

    The new field of quantum information science has exploded into virtually every area of modern physics because of the promise it holds for understanding physical limits to communication, computation and more generally the processing of information. Remarkably, this has come concomitantly with stunning successes at integrating laser cooling and trapping techniques with high finesse microresonators. A regime where some of the new theoretical ideas may be experimentally tested in the particular setting of cavity quantum electrodynamics (QED) has now been reached. This thesis contains three inter-related parts. First, work with microspheres as a possible next generation microcavity is presented, including both successful attempts to push the limits of their quality factors in the near infrared and first experimental results at atomic interaction with the mode of the sphere at the one-photon level. The unique properties of these resonators led to some theoretical investigations of the atom-field interaction emphasizing the quantization of the atomic center of mass degrees of freedom. This has been largely unexplored both theoretically and experimentally to this point, yet remains an extremely important aspect of most serious implementations of quantum information processing in the setting of optical cavity QED. Finally, the emphasis of the last part of this thesis is on an attempt at intracavity atomic localization in the laboratory. Results to date include the first ever trapping of single atoms inside a high finesse microresonator. The techniques and capabilities developed en route to this achievement should form the experimental backbone for future work in optical cavity QED.

  2. Inertial solvation in femtosecond 2D spectra

    NASA Astrophysics Data System (ADS)

    Hybl, John; Albrecht Ferro, Allison; Farrow, Darcie; Jonas, David

    2001-03-01

    We have used 2D Fourier transform spectroscopy to investigate polar solvation. 2D spectroscopy can reveal molecular lineshapes beneath ensemble averaged spectra and freeze molecular motions to give an undistorted picture of the microscopic dynamics of polar solvation. The transition from "inhomogeneous" to "homogeneous" 2D spectra is governed by both vibrational relaxation and solvent motion. Therefore, the time dependence of the 2D spectrum directly reflects the total response of the solvent-solute system. IR144, a cyanine dye with a dipole moment change upon electronic excitation, was used to probe inertial solvation in methanol and propylene carbonate. Since the static Stokes' shift of IR144 in each of these solvents is similar, differences in the 2D spectra result from solvation dynamics. Initial results indicate that the larger propylene carbonate responds more slowly than methanol, but appear to be inconsistent with rotational estimates of the inertial response. To disentangle intra-molecular vibrations from solvent motion, the 2D spectra of IR144 will be compared to the time-dependent 2D spectra of the structurally related nonpolar cyanine dye HDITCP.

  3. Light field morphing using 2D features.

    PubMed

    Wang, Lifeng; Lin, Stephen; Lee, Seungyong; Guo, Baining; Shum, Heung-Yeung

    2005-01-01

    We present a 2D feature-based technique for morphing 3D objects represented by light fields. Existing light field morphing methods require the user to specify corresponding 3D feature elements to guide morph computation. Since slight errors in 3D specification can lead to significant morphing artifacts, we propose a scheme based on 2D feature elements that is less sensitive to imprecise marking of features. First, 2D features are specified by the user in a number of key views in the source and target light fields. Then the two light fields are warped view by view as guided by the corresponding 2D features. Finally, the two warped light fields are blended together to yield the desired light field morph. Two key issues in light field morphing are feature specification and warping of light field rays. For feature specification, we introduce a user interface for delineating 2D features in key views of a light field, which are automatically interpolated to other views. For ray warping, we describe a 2D technique that accounts for visibility changes and present a comparison to the ideal morphing of light fields. Light field morphing based on 2D features makes it simple to incorporate previous image morphing techniques such as nonuniform blending, as well as to morph between an image and a light field. PMID:15631126

  4. Internal Photoemission Spectroscopy of 2-D Materials

    NASA Astrophysics Data System (ADS)

    Nguyen, Nhan; Li, Mingda; Vishwanath, Suresh; Yan, Rusen; Xiao, Shudong; Xing, Huili; Cheng, Guangjun; Hight Walker, Angela; Zhang, Qin

    Recent research has shown the great benefits of using 2-D materials in the tunnel field-effect transistor (TFET), which is considered a promising candidate for the beyond-CMOS technology. The on-state current of TFET can be enhanced by engineering the band alignment of different 2D-2D or 2D-3D heterostructures. Here we present the internal photoemission spectroscopy (IPE) approach to determine the band alignments of various 2-D materials, in particular SnSe2 and WSe2, which have been proposed for new TFET designs. The metal-oxide-2-D semiconductor test structures are fabricated and characterized by IPE, where the band offsets from the 2-D semiconductor to the oxide conduction band minimum are determined by the threshold of the cube root of IPE yields as a function of photon energy. In particular, we find that SnSe2 has a larger electron affinity than most semiconductors and can be combined with other semiconductors to form near broken-gap heterojunctions with low barrier heights which can produce a higher on-state current. The details of data analysis of IPE and the results from Raman spectroscopy and spectroscopic ellipsometry measurements will also be presented and discussed.

  5. 2D materials for nanophotonic devices

    NASA Astrophysics Data System (ADS)

    Xu, Renjing; Yang, Jiong; Zhang, Shuang; Pei, Jiajie; Lu, Yuerui

    2015-12-01

    Two-dimensional (2D) materials have become very important building blocks for electronic, photonic, and phononic devices. The 2D material family has four key members, including the metallic graphene, transition metal dichalcogenide (TMD) layered semiconductors, semiconducting black phosphorous, and the insulating h-BN. Owing to the strong quantum confinements and defect-free surfaces, these atomically thin layers have offered us perfect platforms to investigate the interactions among photons, electrons and phonons. The unique interactions in these 2D materials are very important for both scientific research and application engineering. In this talk, I would like to briefly summarize and highlight the key findings, opportunities and challenges in this field. Next, I will introduce/highlight our recent achievements. We demonstrated atomically thin micro-lens and gratings using 2D MoS2, which is the thinnest optical component around the world. These devices are based on our discovery that the elastic light-matter interactions in highindex 2D materials is very strong. Also, I would like to introduce a new two-dimensional material phosphorene. Phosphorene has strongly anisotropic optical response, which creates 1D excitons in a 2D system. The strong confinement in phosphorene also enables the ultra-high trion (charged exciton) binding energies, which have been successfully measured in our experiments. Finally, I will briefly talk about the potential applications of 2D materials in energy harvesting.

  6. Circuit Training.

    ERIC Educational Resources Information Center

    Nelson, Jane B.

    1998-01-01

    Describes a research-based activity for high school physics students in which they build an LC circuit and find its resonant frequency of oscillation using an oscilloscope. Includes a diagram of the apparatus and an explanation of the procedures. (DDR)

  7. Dynamics of momentum entanglement in lowest-order QED

    SciTech Connect

    Lamata, L.; Leon, J.; Solano, E.

    2006-01-15

    We study the dynamics of momentum entanglement generated in the lowest-order QED interaction between two massive spin-(1/2) charged particles, which grows in time as the two fermions exchange virtual photons. We observe that the degree of generated entanglement between interacting particles with initial well-defined momentum can be infinite. We explain this divergence in the context of entanglement theory for continuous variables, and show how to circumvent this apparent paradox. Finally, we discuss two different possibilities of transforming momentum into spin entanglement, through dynamical operations or through Lorentz boosts.

  8. Sequential generation of matrix-product states in cavity QED

    SciTech Connect

    Schoen, C.; Hammerer, K.; Wolf, M. M.; Cirac, J. I.; Solano, E.

    2007-03-15

    We study the sequential generation of entangled photonic and atomic multiqubit states in the realm of cavity QED. We extend the work of C. Schoen et al. [Phys. Rev. Lett. 95, 110503 (2005)], where it was shown that all states generated in a sequential manner can be classified efficiently in terms of matrix-product states. In particular, we consider two scenarios: photonic multiqubit states sequentially generated at the cavity output of a single-photon source and atomic multiqubit states generated by their sequential interaction with the same cavity mode.

  9. Renormalization of high-energy Lorentz-violating QED

    SciTech Connect

    Anselmi, Damiano; Taiuti, Martina

    2010-04-15

    We study a QED extension that is unitary, CPT invariant, and super-renormalizable, but violates Lorentz symmetry at high energies, and contains higher-dimension operators (LVQED). Divergent diagrams are only one- and two-loop. We compute the one-loop renormalizations at high and low energies and analyze the relation between them. It emerges that the powerlike divergences of the low-energy theory are multiplied by arbitrary constants, inherited by the high-energy theory, and therefore can be set to zero at no cost, bypassing the hierarchy problem.

  10. QED (quantum-electrodynamical) theory of excess spontaneous emission noise

    SciTech Connect

    Milonni, P.W.

    1990-01-01

    The results of a quantum-electrodynamical theory of excess spontaneous emission noise in lossy resonators will be presented. The Petermann K factor'' does not enter into the spontaneous emission rate of a single atom in the cavity. The QED theory allows different interpretations of the K factor, and we use this fact to justify semiclassical analyses and to provide in one example a simple derivation of K in terms of the amplification of the quantum vacuum field entering the resonator through its mirrors. 17 refs.

  11. Two-photon entanglement in multiqubit bidirectional-waveguide QED

    NASA Astrophysics Data System (ADS)

    Mirza, Imran M.; Schotland, John C.

    2016-07-01

    We study entanglement generation and control in bidirectional-waveguide QED driven by a two-photon Gaussian wave packet. In particular, we focus on how increasing the number of qubits affects the overall average pairwise entanglement in the system. We also investigate how the presence of a second photon can introduce nonlinearities, thereby manipulating the generated entanglement. In addition, we show that, through the introduction of chirality and small decay rates, entanglement can be stored and enhanced up to factors of 2 and 3, respectively. Finally, we analyze the influence of finite detunings and time-delays on the generated entanglement.

  12. Observation of Cavity QED in thick dielectric films

    NASA Astrophysics Data System (ADS)

    Sarabi, Bahman; Ramanayaka, A. N.; Gladchenko, S.; Stoutimore, M. J. A.; Khalil, M. S.; Osborn, K. D.

    2013-03-01

    Cavity QED in amorphous dielectrics is investigated by measuring five linear superconducting resonators with thick dielectric films and capacitor volumes ranging from 80 μm3 to 5000 μm3. In the smallest volume dielectrics we observe additional resonances which may be explained by CQED, despite the dielectric volume which is many orders of magnitude larger than Josephson junction barrier volumes. In addition to the volume dependence of the CQED resonances, we will report on the stability of the resonances in time and the phase noise. This research allows new fundamental studies on TLS phenomena in meso-volume amorphous dielectrics.

  13. General QED/QCD aspects of simple systems

    SciTech Connect

    Telegdi, V.L.; Brodsky, S.J.

    1989-09-01

    This paper discusses the following topics: renormalization theory; the Kinoshita-Lee-Nauenberg theorem; the Yennie-Frautschi-Suura relation; scale invariance at large momentum transfer; scaling and scaling violation at large momentum transfers; low-energy theorem in Compton scattering; does the perturbation series in QED converge; renormalization of the weak angle /Theta//sub w/; the Nambu-Bethe-Salpeter (NBS) equation; the decay rate of /sup 3/S, positronium; radiative corrections to QCD Born cross section; and progress on the relativistic 2-body equation.

  14. Long range correlations by local dissipation in lattice waveguide QED

    NASA Astrophysics Data System (ADS)

    Royer, Baptiste; Grimsmo, Arne L.; Blais, Alexandre

    In waveguide QED, superconducting qubits acting as artificial atoms are coupled to 1D superconducting transmission lines playing the role of common bath for the qubits. By controlling their effective separation and coupling to the transmission line, it is possible to engineer various types of dissipation-induced interactions between the qubits. In this talk, we consider the situation where multiple superconducting qubits are coupled to a lattice of superconducting transmission lines. We show that this can lead to the creation of highly entangled dark states using local dissipation only. Using tensor networks techniques, we study such large-scale highly-correlated systems.

  15. Simple QED- and QCD-like models at finite density

    NASA Astrophysics Data System (ADS)

    Pawlowski, Jan M.; Stamatescu, Ion-Olimpiu; Zielinski, Christian

    2015-07-01

    In this paper we discuss one-dimensional models reproducing some features of quantum electrodynamics and quantum chromodynamics at nonzero density and temperature. Since a severe sign problem makes a numerical treatment of QED and QCD at high density difficult, such models help to explore various effects peculiar to the full theory. Studying them gives insights into the large density behavior of the Polyakov loop by taking both bosonic and fermionic degrees of freedom into account, although in one dimension only the implementation of a global gauge symmetry is possible. For these models we evaluate the respective partition functions and discuss several observables as well as the Silver Blaze phenomenon.

  16. Realizing quantum controlled phase flip through cavity QED

    NASA Astrophysics Data System (ADS)

    Xiao, Yun-Feng; Lin, Xiu-Min; Gao, Jie; Yang, Yong; Han, Zheng-Fu; Guo, Guang-Can

    2004-10-01

    We propose a scheme to realize quantum controlled phase flip (CPF) between two rare-earth ions embedded in the respective microsphere cavity via interacting with a single-photon pulse in sequence. The numerical simulations illuminate that the CPF gate between ions is robust and scalable with extremely high fidelity and low error rate. Our scheme is more applicable than other schemes presented before based on current laboratory cavity-QED technology, and it is possible to be used as an applied unit gate in future quantum computation and quantum communication.

  17. Multiqubit entanglement in bidirectional-chiral-waveguide QED

    NASA Astrophysics Data System (ADS)

    Mirza, Imran M.; Schotland, John C.

    2016-07-01

    We study the generation of transient entanglement induced by a single-photon Gaussian wave packet in multiatom bidirectional-waveguide QED. In particular, we investigate the effect of increasing the number of atoms on the average pairwise entanglement. We demonstrate, by selecting smaller decay rates and in chiral-waveguide settings, that both entanglement survival times and maximum generated entanglement can be increased by at least a factor of ˜3 /2 , independent of the number of atoms. In addition, we analyze the influence of detuning and delays on the robustness of the generated entanglement. There are potential applications of our results in entanglement-based multiqubit quantum networks.

  18. Robust Josephson-Kondo screening cloud in circuit quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Snyman, Izak; Florens, Serge

    2015-08-01

    We investigate the entanglement properties of a standard circuit-QED setup that consists of a Cooper pair box coupled to a long chain of Josephson junctions. We calculate the static charge polarization at finite distances along the device. Our calculations reveal a deep connection to the Kondo screening cloud, together with robust correlations that are difficult to measure in a condensed matter context. We also find weak sensitivity of these Kondo signatures to the actual parameters and design of the device, demonstrating the universality of the Josephson entanglement cloud.

  19. Superconducting circuit probe for analog quantum simulators

    NASA Astrophysics Data System (ADS)

    Du, Liang-Hui; You, J. Q.; Tian, Lin

    2015-07-01

    Analog quantum simulators can be used to study quantum correlation in novel many-body systems by emulating the Hamiltonian of these systems. One essential question in quantum simulation is to probe the properties of an emulated many-body system. Here we present a circuit QED scheme for probing such properties by measuring the spectrum of a superconducting resonator coupled to a quantum simulator. We first study a general framework of this approach and show that the spectrum of the resonator is directly related to the correlation function of the coupling operator between the resonator and the simulator. We then apply this scheme to a simulator of the transverse field Ising model implemented with superconducting qubits, where the resonance peaks in the resonator spectrum correspond to the frequencies of the elementary excitations. The effects of resonator damping, qubit decoherence, and resonator backaction are also discussed. This setup can be used to probe a broad range of many-body models.

  20. Entanglement distillation in circuit quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Oppliger, Markus; Heinsoo, Johannes; Salathe, Yves; Potocnik, Anton; Mondal, Mintu; Wallraff, Andreas; Paraoanu, Gheorghe Sorin

    Entanglement is an essential resource for quantum information processing, such as quantum error correction, quantum teleportation and quantum communication. Such algorithms perform optimally with maximally entangled states. In practice entangled quantum states are very fragile due to a wide range of decoherence mechanisms. When two parties share degraded entangled states they are still able to generate an entangled state with higher fidelity using local operations and classical communication. This process is commonly referred to as entanglement distillation. Here we demonstrate distillation of highly entangled Bell states from two copies of less entangled states on a four transmon qubit device realized in the circuit-QED architecture. We characterize the output state for different degrees of entanglement at the input with quantum state tomography. A clear improvement of the entanglement measures is observed at the output.

  1. Matrix models of 2d gravity

    SciTech Connect

    Ginsparg, P.

    1991-01-01

    These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.

  2. Matrix models of 2d gravity

    SciTech Connect

    Ginsparg, P.

    1991-12-31

    These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.

  3. Brittle damage models in DYNA2D

    SciTech Connect

    Faux, D.R.

    1997-09-01

    DYNA2D is an explicit Lagrangian finite element code used to model dynamic events where stress wave interactions influence the overall response of the system. DYNA2D is often used to model penetration problems involving ductile-to-ductile impacts; however, with the advent of the use of ceramics in the armor-anti-armor community and the need to model damage to laser optics components, good brittle damage models are now needed in DYNA2D. This report will detail the implementation of four brittle damage models in DYNA2D, three scalar damage models and one tensor damage model. These new brittle damage models are then used to predict experimental results from three distinctly different glass damage problems.

  4. 2-d Finite Element Code Postprocessor

    Energy Science and Technology Software Center (ESTSC)

    1996-07-15

    ORION is an interactive program that serves as a postprocessor for the analysis programs NIKE2D, DYNA2D, TOPAZ2D, and CHEMICAL TOPAZ2D. ORION reads binary plot files generated by the two-dimensional finite element codes currently used by the Methods Development Group at LLNL. Contour and color fringe plots of a large number of quantities may be displayed on meshes consisting of triangular and quadrilateral elements. ORION can compute strain measures, interface pressures along slide lines, reaction forcesmore » along constrained boundaries, and momentum. ORION has been applied to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.« less

  5. 2D electronic materials for army applications

    NASA Astrophysics Data System (ADS)

    O'Regan, Terrance; Perconti, Philip

    2015-05-01

    The record electronic properties achieved in monolayer graphene and related 2D materials such as molybdenum disulfide and hexagonal boron nitride show promise for revolutionary high-speed and low-power electronic devices. Heterogeneous 2D-stacked materials may create enabling technology for future communication and computation applications to meet soldier requirements. For instance, transparent, flexible and even wearable systems may become feasible. With soldier and squad level electronic power demands increasing, the Army is committed to developing and harnessing graphene-like 2D materials for compact low size-weight-and-power-cost (SWAP-C) systems. This paper will review developments in 2D electronic materials at the Army Research Laboratory over the last five years and discuss directions for future army applications.

  6. Additive Manufacturing of Hybrid Circuits

    NASA Astrophysics Data System (ADS)

    Sarobol, Pylin; Cook, Adam; Clem, Paul G.; Keicher, David; Hirschfeld, Deidre; Hall, Aaron C.; Bell, Nelson S.

    2016-07-01

    There is a rising interest in developing functional electronics using additively manufactured components. Considerations in materials selection and pathways to forming hybrid circuits and devices must demonstrate useful electronic function; must enable integration; and must complement the complex shape, low cost, high volume, and high functionality of structural but generally electronically passive additively manufactured components. This article reviews several emerging technologies being used in industry and research/development to provide integration advantages of fabricating multilayer hybrid circuits or devices. First, we review a maskless, noncontact, direct write (DW) technology that excels in the deposition of metallic colloid inks for electrical interconnects. Second, we review a complementary technology, aerosol deposition (AD), which excels in the deposition of metallic and ceramic powder as consolidated, thick conformal coatings and is additionally patternable through masking. Finally, we show examples of hybrid circuits/devices integrated beyond 2-D planes, using combinations of DW or AD processes and conventional, established processes.

  7. Chemical Approaches to 2D Materials.

    PubMed

    Samorì, Paolo; Palermo, Vincenzo; Feng, Xinliang

    2016-08-01

    Chemistry plays an ever-increasing role in the production, functionalization, processing and applications of graphene and other 2D materials. This special issue highlights a selection of enlightening chemical approaches to 2D materials, which nicely reflect the breadth of the field and convey the excitement of the individuals involved in it, who are trying to translate graphene and related materials from the laboratory into a real, high-impact technology. PMID:27478083

  8. Extended 2D generalized dilaton gravity theories

    NASA Astrophysics Data System (ADS)

    de Mello, R. O.

    2008-09-01

    We show that an anomaly-free description of matter in (1+1) dimensions requires a deformation of the 2D relativity principle, which introduces a non-trivial centre in the 2D Poincaré algebra. Then we work out the reduced phase space of the anomaly-free 2D relativistic particle, in order to show that it lives in a noncommutative 2D Minkowski space. Moreover, we build a Gaussian wave packet to show that a Planck length is well defined in two dimensions. In order to provide a gravitational interpretation for this noncommutativity, we propose to extend the usual 2D generalized dilaton gravity models by a specific Maxwell component, which guages the extra symmetry associated with the centre of the 2D Poincaré algebra. In addition, we show that this extension is a high energy correction to the unextended dilaton theories that can affect the topology of spacetime. Further, we couple a test particle to the general extended dilaton models with the purpose of showing that they predict a noncommutativity in curved spacetime, which is locally described by a Moyal star product in the low energy limit. We also conjecture a probable generalization of this result, which provides strong evidence that the noncommutativity is described by a certain star product which is not of the Moyal type at high energies. Finally, we prove that the extended dilaton theories can be formulated as Poisson Sigma models based on a nonlinear deformation of the extended Poincaré algebra.

  9. Quantum repeater based on cavity QED evolutions and coherent light

    NASA Astrophysics Data System (ADS)

    Gonţa, Denis; van Loock, Peter

    2016-05-01

    In the framework of cavity QED, we propose a quantum repeater scheme that uses coherent light and chains of atoms coupled to optical cavities. In contrast to conventional repeater schemes, in our scheme there is no need for an explicit use of two-qubit quantum logical gates by exploiting solely the cavity QED evolution. In our previous work (Gonta and van Loock in Phys Rev A 88:052308, 2013), we already proposed a quantum repeater in which the entanglement between two neighboring repeater nodes was distributed using controlled displacements of input coherent light, while the produced low-fidelity entangled pairs were purified using ancillary (four-partite) entangled states. In the present work, the entanglement distribution is realized using a sequence of controlled phase shifts and displacements of input coherent light. Compared to previous coherent-state-based distribution schemes for two-qubit entanglement, our scheme here relies only upon a simple discrimination of two coherent states with opposite signs, which can be performed in a quantum mechanically optimal fashion via a beam splitter and two on-off detectors. For the entanglement purification, we employ a method that avoids the use of extra entangled ancilla states. Our repeater scheme exhibits reasonable fidelities and repeater rates providing an attractive platform for long-distance quantum communication.

  10. Chiral current generation in QED by longitudinal photons

    NASA Astrophysics Data System (ADS)

    Acosta Avalo, J. L.; Pérez Rojas, H.

    2016-08-01

    We report the generation of a pseudovector electric current having imbalanced chirality in an electron-positron strongly magnetized gas in QED. It propagates along the external applied magnetic field B as a chiral magnetic effect in QED. It is triggered by a perturbative electric field parallel to B, associated to a pseudovector longitudinal mode propagating along B. An electromagnetic chemical potential was introduced, but our results remain valid even when it vanishes. A nonzero fermion mass was assumed, which is usually considered vanishing in the literature. In the quantum field theory formalism at finite temperature and density, an anomaly relation for the axial current was found for a medium of massive fermions. It bears some analogy to the Adler-Bell-Jackiw anomaly. From the expression for the chiral current in terms of the photon self-energy tensor in a medium, it is obtained that electrons and positrons scattered by longitudinal photons (inside the light cone) contribute to the chiral current, as well as the to pair creation due to longitudinal photons (out of light cone). In the static limit, an electric pseudovector current is obtained in the lowest Landau level.

  11. Investigating the QED vacuum with ultra-intense laser fields

    NASA Astrophysics Data System (ADS)

    King, B.; Di Piazza, A.

    2014-05-01

    In view of the increasingly stronger available laser fields it is becoming feasible to employ them to probe the nonlinear dielectric properties of the vacuum as predicted by quantum electrodynamics (QED) and to test QED in the presence of intense laser beams. First, we discuss vacuum-polarization effects that arise in the collision of a high-energy proton beam with a strong laser field. In addition, we investigate the process of light-by-light diffraction mediated by the virtual electron-positrons of the vacuum. A strong laser beam "diffracts" a probe laser field due to vacuum polarization effects, and changes its polarization. This change of the polarization is shown to be in principle measurable. Also, the possibility of generating harmonics by exploiting vacuum-polarization effects in the collision in vacuum of two ultra-strong laser beams is discussed. Moreover, when two strong parallel laser beams collide with a probe electromagnetic field, each photon of the probe may interact through the "polarized" quantum vacuum with the photons of the other two fields. Analogously to "ordinary" double-slit set-ups involving matter, the vacuum-scattered probe photons produce a diffraction pattern, which is the envisaged observable to measure the quantum interaction between the probe and strong field photons. We have shown that the diffraction pattern becomes visible in a few operating hours, if the strong fields have an intensity exceeding 1024W/cm2.

  12. QED vacuum fluctuations and induced electric dipole moment of the neutron

    SciTech Connect

    Dominguez, C. A.; Falomir, H.; Ipinza, M.; Loewe, M.; Kohler, S.; Rojas, J. C.

    2009-08-01

    Quantum fluctuations in the QED vacuum generate nonlinear effects, such as peculiar induced electromagnetic fields. In particular, we show here that an electrically neutral particle, possessing a magnetic dipole moment, develops an induced electric dipole-type moment with unusual angular dependence, when immersed in a quasistatic, constant external electric field. The calculation of this effect is done in the framework of the Euler-Heisenberg effective QED Lagrangian, corresponding to the weak field asymptotic expansion of the effective action to one-loop order. It is argued that the neutron might be a good candidate to probe this signal of nonlinearity in QED.

  13. Focal plane readout for 2-D LWIR application implemented with current mode background suppression per pixel

    NASA Astrophysics Data System (ADS)

    Woo, Doo Hyung; Kang, Sang Gu; Lee, Hee Chul

    2004-02-01

    In this paper, a readout technique involving current mode background suppression is studied for 2-dimensional infrared focal plane arrays (IR FPA"s). This technique has a current memory per pixel, and the suppression current can be optimized per pixel element. Capacitive transimpedende amplifier (CTIA) and feedback amplifier structure are adopted for input circuit and background suppression circuit, respectively. Feedback amplifier structure can minimize skimming error due to channel length modulation. The area size of the pixel circuit is generally limited in the case of 2-D application. So, the amplifier used in the CTIA input circuit adopts timesharing for background suppression. To further improve the area limitation, a half circuit of the CTIA is shared in row circuit out of the pixel array. Because of the leakage of the current memory, the skimming data of the current memory in the pixel array is stored in SRAM array through ADC, and is refreshed periodically with SRAM data through DAC. The readout circuit was fabricated using 0.6um 2-poly 3-metal CMOS process for 64 x 64 LWIR HgCdTe IR array with the pixel size of 50um x 50um. The measurement performance of the skimming circuit exhibits about only 3% error for 100nA background current. The simulation results exhibit that skimming error can be reduced further to 0.3% when the ratioed current mirror scheme and/or multi step refresh scheme is adopted.

  14. 2D-Crystal-Based Functional Inks.

    PubMed

    Bonaccorso, Francesco; Bartolotta, Antonino; Coleman, Jonathan N; Backes, Claudia

    2016-08-01

    The possibility to produce and process graphene, related 2D crystals, and heterostructures in the liquid phase makes them promising materials for an ever-growing class of applications as composite materials, sensors, in flexible optoelectronics, and energy storage and conversion. In particular, the ability to formulate functional inks with on-demand rheological and morphological properties, i.e., lateral size and thickness of the dispersed 2D crystals, is a step forward toward the development of industrial-scale, reliable, inexpensive printing/coating processes, a boost for the full exploitation of such nanomaterials. Here, the exfoliation strategies of graphite and other layered crystals are reviewed, along with the advances in the sorting of lateral size and thickness of the exfoliated sheets together with the formulation of functional inks and the current development of printing/coating processes of interest for the realization of 2D-crystal-based devices. PMID:27273554

  15. 2D microwave imaging reflectometer electronics

    SciTech Connect

    Spear, A. G.; Domier, C. W. Hu, X.; Muscatello, C. M.; Ren, X.; Luhmann, N. C.; Tobias, B. J.

    2014-11-15

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

  16. 2D microwave imaging reflectometer electronics

    NASA Astrophysics Data System (ADS)

    Spear, A. G.; Domier, C. W.; Hu, X.; Muscatello, C. M.; Ren, X.; Tobias, B. J.; Luhmann, N. C.

    2014-11-01

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

  17. Optical modulators with 2D layered materials

    NASA Astrophysics Data System (ADS)

    Sun, Zhipei; Martinez, Amos; Wang, Feng

    2016-04-01

    Light modulation is an essential operation in photonics and optoelectronics. With existing and emerging technologies increasingly demanding compact, efficient, fast and broadband optical modulators, high-performance light modulation solutions are becoming indispensable. The recent realization that 2D layered materials could modulate light with superior performance has prompted intense research and significant advances, paving the way for realistic applications. In this Review, we cover the state of the art of optical modulators based on 2D materials, including graphene, transition metal dichalcogenides and black phosphorus. We discuss recent advances employing hybrid structures, such as 2D heterostructures, plasmonic structures, and silicon and fibre integrated structures. We also take a look at the future perspectives and discuss the potential of yet relatively unexplored mechanisms, such as magneto-optic and acousto-optic modulation.

  18. Large Area Synthesis of 2D Materials

    NASA Astrophysics Data System (ADS)

    Vogel, Eric

    Transition metal dichalcogenides (TMDs) have generated significant interest for numerous applications including sensors, flexible electronics, heterostructures and optoelectronics due to their interesting, thickness-dependent properties. Despite recent progress, the synthesis of high-quality and highly uniform TMDs on a large scale is still a challenge. In this talk, synthesis routes for WSe2 and MoS2 that achieve monolayer thickness uniformity across large area substrates with electrical properties equivalent to geological crystals will be described. Controlled doping of 2D semiconductors is also critically required. However, methods established for conventional semiconductors, such as ion implantation, are not easily applicable to 2D materials because of their atomically thin structure. Redox-active molecular dopants will be demonstrated which provide large changes in carrier density and workfunction through the choice of dopant, treatment time, and the solution concentration. Finally, several applications of these large-area, uniform 2D materials will be described including heterostructures, biosensors and strain sensors.

  19. 2D microwave imaging reflectometer electronics.

    PubMed

    Spear, A G; Domier, C W; Hu, X; Muscatello, C M; Ren, X; Tobias, B J; Luhmann, N C

    2014-11-01

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program. PMID:25430247

  20. New Approach for 2D Readout of GEM Detectors

    SciTech Connect

    Hasell, Douglas K

    2011-10-29

    Detectors based on Gas Electron Multiplication (GEM) technology are becoming more and more widely used in nuclear and high energy physics and are being applied in astronomy, medical physics, industry, and homeland security. GEM detectors are thin, low mass, insensitive to magnetic fields, and can currently provide position resolutions down to {approx}50 microns. However, the designs for reconstructing the position, in two dimensions (2D), of the charged particles striking a GEM detector are often complicated to fabricate and expensive. The objective of this proposal is to investigate a simpler procedure for producing the two dimensional readout layer of GEM detectors using readily available printed circuit board technology which can be tailored to the detector requirements. We will use the established GEM laboratory and facilities at M.I.T. currently employed in developing GEM detectors for the STAR forward tracking upgrade to simplify the testing and evaluation of the new 2D readout designs. If this new design proves successful it will benefit future nuclear and high energy physics experiments already being planned and will similarly extend and simplify the application of GEM technology to other branches of science, medicine, and industry. These benefits would be not only in lower costs for fabrication but also it increased flexibility for design and application.

  1. Local currents in a 2D topological insulator

    NASA Astrophysics Data System (ADS)

    Dang, Xiaoqian; Burton, J. D.; Tsymbal, Evgeny Y.

    2015-12-01

    Symmetry protected edge states in 2D topological insulators are interesting both from the fundamental point of view as well as from the point of view of potential applications in nanoelectronics as perfectly conducting 1D channels and functional elements of circuits. Here using a simple tight-binding model and the Landauer-Büttiker formalism we explore local current distributions in a 2D topological insulator focusing on effects of non-magnetic impurities and vacancies as well as finite size effects. For an isolated edge state, we show that the local conductance decays into the bulk in an oscillatory fashion as explained by the complex band structure of the bulk topological insulator. We demonstrate that although the net conductance of the edge state is topologically protected, impurity scattering leads to intricate local current patterns. In the case of vacancies we observe vortex currents of certain chirality, originating from the scattering of current-carrying electrons into states localized at the edges of hollow regions. For finite size strips of a topological insulator we predict the formation of an oscillatory band gap in the spectrum of the edge states, the emergence of Friedel oscillations caused by an open channel for backscattering from an impurity and antiresonances in conductance when the Fermi energy matches the energy of the localized state created by an impurity.

  2. Circuit Connectors

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The U-shaped wire devices in the upper photo are Digi-Klipsm; aids to compact packaging of electrical and electronic devices. They serve as connectors linking the circuitry of one circuit board with another in multi-board systems. Digi-Klips were originally developed for Goddard Space Flight Center to meet a need for lightweight, reliable connectors to replace hand-wired connections formerly used in spacecraft. They are made of beryllium copper wire, noted for its excellent conductivity and its spring-like properties, which assure solid electrical contact over a long period of time.

  3. Inkjet printing of 2D layered materials.

    PubMed

    Li, Jiantong; Lemme, Max C; Östling, Mikael

    2014-11-10

    Inkjet printing of 2D layered materials, such as graphene and MoS2, has attracted great interests for emerging electronics. However, incompatible rheology, low concentration, severe aggregation and toxicity of solvents constitute critical challenges which hamper the manufacturing efficiency and product quality. Here, we introduce a simple and general technology concept (distillation-assisted solvent exchange) to efficiently overcome these challenges. By implementing the concept, we have demonstrated excellent jetting performance, ideal printing patterns and a variety of promising applications for inkjet printing of 2D layered materials. PMID:25169938

  4. Measurement of 2D birefringence distribution

    NASA Astrophysics Data System (ADS)

    Noguchi, Masato; Ishikawa, Tsuyoshi; Ohno, Masahiro; Tachihara, Satoru

    1992-10-01

    A new measuring method of 2-D birefringence distribution has been developed. It has not been an easy job to get a birefringence distribution in an optical element with conventional ellipsometry because of its lack of scanning means. Finding an analogy between the rotating analyzer method in ellipsometry and the phase-shifting method in recently developed digital interferometry, we have applied the phase-shifting algorithm to ellipsometry, and have developed a new method that makes the measurement of 2-D birefringence distribution easy and possible. The system contains few moving parts, assuring reliability, and measures a large area of a sample at one time, making the measuring time very short.

  5. The 2D lingual appliance system.

    PubMed

    Cacciafesta, Vittorio

    2013-09-01

    The two-dimensional (2D) lingual bracket system represents a valuable treatment option for adult patients seeking a completely invisible orthodontic appliance. The ease of direct or simplified indirect bonding of 2D lingual brackets in combination with low friction mechanics makes it possible to achieve a good functional and aesthetic occlusion, even in the presence of a severe malocclusion. The use of a self-ligating bracket significantly reduces chair-side time for the orthodontist, and the low-profile bracket design greatly improves patient comfort. PMID:24005953

  6. LOGIC CIRCUIT

    DOEpatents

    Strong, G.H.; Faught, M.L.

    1963-12-24

    A device for safety rod counting in a nuclear reactor is described. A Wheatstone bridge circuit is adapted to prevent de-energizing the hopper coils of a ball backup system if safety rods, sufficient in total control effect, properly enter the reactor core to effect shut down. A plurality of resistances form one arm of the bridge, each resistance being associated with a particular safety rod and weighted in value according to the control effect of the particular safety rod. Switching means are used to switch each of the resistances in and out of the bridge circuit responsive to the presence of a particular safety rod in its effective position in the reactor core and responsive to the attainment of a predetermined velocity by a particular safety rod enroute to its effective position. The bridge is unbalanced in one direction during normal reactor operation prior to the generation of a scram signal and the switching means and resistances are adapted to unbalance the bridge in the opposite direction if the safety rods produce a predetermined amount of control effect in response to the scram signal. The bridge unbalance reversal is then utilized to prevent the actuation of the ball backup system, or, conversely, a failure of the safety rods to produce the predetermined effect produces no unbalance reversal and the ball backup system is actuated. (AEC)

  7. Induced Chern-Simons-like action in Lorentz-violating massless QED

    SciTech Connect

    Brito, F. A.; Grigorio, L. S.; Guimaraes, M. S.; Wotzasek, C.; Passos, E.

    2008-12-15

    In the present work, we study different aspects of Lorentz and CPT symmetry violation in extended massless QED. By following the observation that the 2+1-dimensional Maxwell-Chern-Simons theory can be originated from the 3+1-dimensional Chern-Simons-like action, we also focus on the fermion sector to relate the 3+1 dimensional extended massless QED to 2+1-dimensional massive QED. We take advantage of this to state that the Chern-Simons-like action in extended massless QED can be induced with its coefficient being well defined and finite just as its 2+1 counterpart. We make use of three different regularization schemes by inducting the Chern-Simons-like term in 3+1 dimensions to support the conjecture.

  8. New QED calculations for processes in strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Leahy, D.; Semionova, L.

    2000-09-01

    The results of some new QED calculations are presented. We consider two-photon emission by electrons, and determine magnetic field, spin and polarization dependence of the transition rates. We utilize the electron wave functions of Sokolov and Ternov (1968, Synchrotron Radiation, Berlin: Akademie), rather than those of Johnson and Lippmann (1949, Physical Review D, 76, 828). As pointed out by Graziani (1993, Astrophysical Journal, 412, 351), use of the former wave functions is necessary to obtain results valid outside the weak field limit. The results are of particular interest for processes in magnetars, for which the magnetic field is near, or can exceed, the critical value (Bcr=4.414×1013 G). .

  9. Confinement and dynamical chiral symmetry breaking in QED3

    SciTech Connect

    Bashir, A.; Raya, A.; Cloeet, I. C.; Roberts, C. D.

    2008-11-15

    We establish that QED3 can possess a critical number of flavors, N{sub f}{sup c}, associated with dynamical chiral symmetry breaking if, and only if, the fermion wave function renormalization and photon vacuum polarization are homogeneous functions at infrared momenta when the fermion mass function vanishes. The Ward identity entails that the fermion-photon vertex possesses the same property and ensures a simple relationship between the homogeneity degrees of each of these functions. Simple models for the photon vacuum polarization and fermion-photon vertex are used to illustrate these observations. The existence and value of N{sub f}{sup c} are contingent upon the precise form of the vertex but any discussion of gauge dependence is moot. We introduce an order parameter for confinement. Chiral symmetry restoration and deconfinement are coincident owing to an abrupt change in the analytic properties of the fermion propagator when a nonzero scalar self-energy becomes insupportable.

  10. Confinement and dynamical chiral symmetry breaking in QED3.

    SciTech Connect

    Bashir, A.; Raya, A.; Cloet, I. C.; Roberts, C. D.; Univ. Michoacana de San Nicolas de Hidalgo

    2008-01-01

    We establish that QED3 can possess a critical number of flavors, Nfc, associated with dynamical chiral symmetry breaking if, and only if, the fermion wave function renormalization and photon vacuum polarization are homogeneous functions at infrared momenta when the fermion mass function vanishes. The Ward identity entails that the fermion-photon vertex possesses the same property and ensures a simple relationship between the homogeneity degrees of each of these functions. Simple models for the photon vacuum polarization and fermion-photon vertex are used to illustrate these observations. The existence and value of Nfc are contingent upon the precise form of the vertex but any discussion of gauge dependence is moot. We introduce an order parameter for confinement. Chiral symmetry restoration and deconfinement are coincident owing to an abrupt change in the analytic properties of the fermion propagator when a nonzero scalar self-energy becomes insupportable.

  11. Gauge dependence in QED amplitudes in expanding de Sitter space

    NASA Astrophysics Data System (ADS)

    Nicolaevici, Nistor

    2016-04-01

    We consider first-order transition amplitudes in external fields in QED in the expanding de Sitter space and point out that they are gauge dependent quantities. We examine the gauge variations of the amplitudes assuming a decoupling of the interaction at large times, which allows to conclude that the source of the problem lies in the fact that the frequencies of the modes in the infinite future become independent of the comoving momenta. We show that a possibility to assure the gauge invariance of the external field amplitudes is to restrict to potentials which vanish sufficiently fast at infinite times, and briefly discuss a number of options in the face of the possible gauge invariance violation in the full interacting theory.

  12. Quasiparticle lifetimes and infrared physics in QED and QCD plasmas

    SciTech Connect

    Blaizot, J.P.

    1997-09-22

    The perturbative calculation of the lifetime of fermion excitations in a QED plasma at high temperature is plagued with infrared divergences which are not eliminated by the screening corrections. The physical processes responsible for these divergences are the collisions involving the exchange of longwavelength, quasistatic, magnetic photons, which are not screened by plasma effects. The leading divergences can be resummed in a non-perturbative treatment based on a generalization of the Bloch-Nordsieck model at finite temperature. The resulting expression of the fermion propagator is free of infrared problems, and exhibits a non-exponential damping at large times: S{sub R}(t) {approx} exp(-{alpha}T t ln{omega}{sub p}t), where {omega}{sub p} = eT/3 is the plasma frequency and {alpha} = e{sup 2}/4{pi}.

  13. Baby universes in 2d quantum gravity

    NASA Astrophysics Data System (ADS)

    Ambjørn, Jan; Jain, Sanjay; Thorleifsson, Gudmar

    1993-06-01

    We investigate the fractal structure of 2d quantum gravity, both for pure gravity and for gravity coupled to multiple gaussian fields and for gravity coupled to Ising spins. The roughness of the surfaces is described in terms of baby universes and using numerical simulations we measure their distribution which is related to the string susceptibility exponent γstring.

  14. QED calculations in heavy many-electron atoms and one-electron quasi-molecules

    NASA Astrophysics Data System (ADS)

    Tupitsyn, I. I.; Safronova, M. S.; Kozlov, M. G.; Porsev, S. G.; Shabaev, V. M.

    2016-05-01

    Construction of simple one-electron approach to one-loop QED operator is an important task for the relativistic quantum theory of atoms and molecules. In this work we used two modifications of the model QED potential approach to calculations of the Lamb shift in many-electron atoms and one-electron quasi-molecules. The model potential is constructed as a sum of local and nonlocal (separable) potentials. The nonlocal part of the model potential was introduced to reproduce exactly the diagonal elements and also off-diagonal elements of the one-loop ab initio QED operator. The one-particle model QED operator was introduced in the Dirac-Fock and CI+MBPT relativistic calculations of the heavy and super-heavy atoms and in the calculations of the diatomic quasi-molecules. The comparison of the data obtained in different approaches to the one-loop QED operator is presented. Model QED potential is applied to calculate Lamb shift in the U91+- U92+ dimer. The results are compared with Ref..

  15. Entangling distant resonant exchange qubits via circuit quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Srinivasa, Vanita; Taylor, Jacob M.; Tahan, Charles

    Enabling modularity within a quantum information processing device relies on robust entanglement of coherent qubits at macroscopic distances. To address this challenge, we investigate theoretically a hybrid quantum system consisting of spatially separated resonant exchange qubits, defined in three-electron semiconductor triple quantum dots, that are coupled via a superconducting transmission line resonator. By analyzing three specific approaches drawn from circuit quantum electrodynamics and Hartmann-Hahn double resonance techniques for implementing resonator-mediated two-qubit entangling gates in both dispersive and resonant regimes, we show that methods for entangling superconducting qubits map directly to resonant exchange qubits. We also calculate the rate of relaxation via phonons for resonant exchange qubits in silicon triple dots and show that such an implementation is particularly well-suited to achieving the strong coupling regime. Our approach combines the robustness of encoded spin qubits in silicon with the rapid and robust long-range entanglement provided by circuit QED systems.

  16. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology

    PubMed Central

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-01-01

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct “beyond graphene” domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials. PMID:26861346

  17. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology.

    PubMed

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-01-01

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials. PMID:26861346

  18. Commutation circuit for an HVDC circuit breaker

    DOEpatents

    Premerlani, William J.

    1981-01-01

    A commutation circuit for a high voltage DC circuit breaker incorporates a resistor capacitor combination and a charging circuit connected to the main breaker, such that a commutating capacitor is discharged in opposition to the load current to force the current in an arc after breaker opening to zero to facilitate arc interruption. In a particular embodiment, a normally open commutating circuit is connected across the contacts of a main DC circuit breaker to absorb the inductive system energy trapped by breaker opening and to limit recovery voltages to a level tolerable by the commutating circuit components.

  19. Commutation circuit for an HVDC circuit breaker

    DOEpatents

    Premerlani, W.J.

    1981-11-10

    A commutation circuit for a high voltage DC circuit breaker incorporates a resistor capacitor combination and a charging circuit connected to the main breaker, such that a commutating capacitor is discharged in opposition to the load current to force the current in an arc after breaker opening to zero to facilitate arc interruption. In a particular embodiment, a normally open commutating circuit is connected across the contacts of a main DC circuit breaker to absorb the inductive system energy trapped by breaker opening and to limit recovery voltages to a level tolerable by the commutating circuit components. 13 figs.

  20. Stochastic Inversion of 2D Magnetotelluric Data

    SciTech Connect

    Chen, Jinsong

    2010-07-01

    The algorithm is developed to invert 2D magnetotelluric (MT) data based on sharp boundary parametrization using a Bayesian framework. Within the algorithm, we consider the locations and the resistivity of regions formed by the interfaces are as unknowns. We use a parallel, adaptive finite-element algorithm to forward simulate frequency-domain MT responses of 2D conductivity structure. Those unknown parameters are spatially correlated and are described by a geostatistical model. The joint posterior probability distribution function is explored by Markov Chain Monte Carlo (MCMC) sampling methods. The developed stochastic model is effective for estimating the interface locations and resistivity. Most importantly, it provides details uncertainty information on each unknown parameter. Hardware requirements: PC, Supercomputer, Multi-platform, Workstation; Software requirements C and Fortan; Operation Systems/version is Linux/Unix or Windows

  1. Static & Dynamic Response of 2D Solids

    Energy Science and Technology Software Center (ESTSC)

    1996-07-15

    NIKE2D is an implicit finite-element code for analyzing the finite deformation, static and dynamic response of two-dimensional, axisymmetric, plane strain, and plane stress solids. The code is fully vectorized and available on several computing platforms. A number of material models are incorporated to simulate a wide range of material behavior including elasto-placicity, anisotropy, creep, thermal effects, and rate dependence. Slideline algorithms model gaps and sliding along material interfaces, including interface friction, penetration and single surfacemore » contact. Interactive-graphics and rezoning is included for analyses with large mesh distortions. In addition to quasi-Newton and arc-length procedures, adaptive algorithms can be defined to solve the implicit equations using the solution language ISLAND. Each of these capabilities and more make NIKE2D a robust analysis tool.« less

  2. Stochastic Inversion of 2D Magnetotelluric Data

    Energy Science and Technology Software Center (ESTSC)

    2010-07-01

    The algorithm is developed to invert 2D magnetotelluric (MT) data based on sharp boundary parametrization using a Bayesian framework. Within the algorithm, we consider the locations and the resistivity of regions formed by the interfaces are as unknowns. We use a parallel, adaptive finite-element algorithm to forward simulate frequency-domain MT responses of 2D conductivity structure. Those unknown parameters are spatially correlated and are described by a geostatistical model. The joint posterior probability distribution function ismore » explored by Markov Chain Monte Carlo (MCMC) sampling methods. The developed stochastic model is effective for estimating the interface locations and resistivity. Most importantly, it provides details uncertainty information on each unknown parameter. Hardware requirements: PC, Supercomputer, Multi-platform, Workstation; Software requirements C and Fortan; Operation Systems/version is Linux/Unix or Windows« less

  3. Explicit 2-D Hydrodynamic FEM Program

    Energy Science and Technology Software Center (ESTSC)

    1996-08-07

    DYNA2D* is a vectorized, explicit, two-dimensional, axisymmetric and plane strain finite element program for analyzing the large deformation dynamic and hydrodynamic response of inelastic solids. DYNA2D* contains 13 material models and 9 equations of state (EOS) to cover a wide range of material behavior. The material models implemented in all machine versions are: elastic, orthotropic elastic, kinematic/isotropic elastic plasticity, thermoelastoplastic, soil and crushable foam, linear viscoelastic, rubber, high explosive burn, isotropic elastic-plastic, temperature-dependent elastic-plastic. Themore » isotropic and temperature-dependent elastic-plastic models determine only the deviatoric stresses. Pressure is determined by one of 9 equations of state including linear polynomial, JWL high explosive, Sack Tuesday high explosive, Gruneisen, ratio of polynomials, linear polynomial with energy deposition, ignition and growth of reaction in HE, tabulated compaction, and tabulated.« less

  4. Schottky diodes from 2D germanane

    NASA Astrophysics Data System (ADS)

    Sahoo, Nanda Gopal; Esteves, Richard J.; Punetha, Vinay Deep; Pestov, Dmitry; Arachchige, Indika U.; McLeskey, James T.

    2016-07-01

    We report on the fabrication and characterization of a Schottky diode made using 2D germanane (hydrogenated germanene). When compared to germanium, the 2D structure has higher electron mobility, an optimal band-gap, and exceptional stability making germanane an outstanding candidate for a variety of opto-electronic devices. One-atom-thick sheets of hydrogenated puckered germanium atoms have been synthesized from a CaGe2 framework via intercalation and characterized by XRD, Raman, and FTIR techniques. The material was then used to fabricate Schottky diodes by suspending the germanane in benzonitrile and drop-casting it onto interdigitated metal electrodes. The devices demonstrate significant rectifying behavior and the outstanding potential of this material.

  5. Flexible phosphorene devices and circuits

    NASA Astrophysics Data System (ADS)

    Zhu, Weinan; Yogeesh, Maruthi N.; Akinwande, Deji

    2015-05-01

    Two-dimensional (2D) semiconductors with high carrier mobilities and sizeable bandgap are desirable for future high-speed and low power mechanically flexible nanoelectronics. In this work, we report encapsulated bottom-gated black phosphorus (BP) field-effect transistors (FETs) on flexible polyimide affording maximum carrier mobility of about 310cm2/V•s and current on/off ratio exceeding 103. Essential circuits of flexible electronic systems enabled by the device ambipolar functionality, high-mobility and current saturation are demonstrated in this work, including digital inverter, frequency doubler, and analog amplifiers featuring a voltage gain of ~8.7, which is the state-of-the-art value for flexible 2D semiconductor based amplifiers. In addition, we demonstrate the single FET based flexible BP amplitude-modulated (AM) demodulator, an active stage in radio receivers.

  6. Compact 2-D graphical representation of DNA

    NASA Astrophysics Data System (ADS)

    Randić, Milan; Vračko, Marjan; Zupan, Jure; Novič, Marjana

    2003-05-01

    We present a novel 2-D graphical representation for DNA sequences which has an important advantage over the existing graphical representations of DNA in being very compact. It is based on: (1) use of binary labels for the four nucleic acid bases, and (2) use of the 'worm' curve as template on which binary codes are placed. The approach is illustrated on DNA sequences of the first exon of human β-globin and gorilla β-globin.

  7. 2D materials: Graphene and others

    NASA Astrophysics Data System (ADS)

    Bansal, Suneev Anil; Singh, Amrinder Pal; Kumar, Suresh

    2016-05-01

    Present report reviews the recent advancements in new atomically thick 2D materials. Materials covered in this review are Graphene, Silicene, Germanene, Boron Nitride (BN) and Transition metal chalcogenides (TMC). These materials show extraordinary mechanical, electronic and optical properties which make them suitable candidates for future applications. Apart from unique properties, tune-ability of highly desirable properties of these materials is also an important area to be emphasized on.

  8. Layer Engineering of 2D Semiconductor Junctions.

    PubMed

    He, Yongmin; Sobhani, Ali; Lei, Sidong; Zhang, Zhuhua; Gong, Yongji; Jin, Zehua; Zhou, Wu; Yang, Yingchao; Zhang, Yuan; Wang, Xifan; Yakobson, Boris; Vajtai, Robert; Halas, Naomi J; Li, Bo; Xie, Erqing; Ajayan, Pulickel

    2016-07-01

    A new concept for junction fabrication by connecting multiple regions with varying layer thicknesses, based on the thickness dependence, is demonstrated. This type of junction is only possible in super-thin-layered 2D materials, and exhibits similar characteristics as p-n junctions. Rectification and photovoltaic effects are observed in chemically homogeneous MoSe2 junctions between domains of different thicknesses. PMID:27136275

  9. 2dF mechanical engineering

    NASA Astrophysics Data System (ADS)

    Smith, Greg; Lankshear, Allan

    1998-07-01

    2dF is a multi-object instrument mounted at prime focus at the AAT capable of spectroscopic analysis of 400 objects in a single 2 degree field. It also prepares a second 2 degree 400 object field while the first field is being observed. At its heart is a high precision robotic positioner that places individual fiber end magnetic buttons on one of two field plates. The button gripper is carried on orthogonal gantries powered by linear synchronous motors and contains a TV camera which precisely locates backlit buttons to allow placement in user defined locations to 10 (mu) accuracy. Fiducial points on both plates can also be observed by the camera to allow repeated checks on positioning accuracy. Field plates rotate to follow apparent sky rotation. The spectrographs both analyze light from the 200 observing fibers each and back- illuminate the 400 fibers being re-positioned during the observing run. The 2dF fiber position and spectrograph system is a large and complex instrument located at the prime focus of the Anglo Australian Telescope. The mechanical design has departed somewhat from the earlier concepts of Gray et al, but still reflects the audacity of those first ideas. The positioner is capable of positioning 400 fibers on a field plate while another 400 fibers on another plate are observing at the focus of the telescope and feeding the twin spectrographs. When first proposed it must have seemed like ingenuity unfettered by caution. Yet now it works, and works wonderfully well. 2dF is a system which functions as the result of the combined and coordinated efforts of the astronomers, the mechanical designers and tradespeople, the electronic designers, the programmers, the support staff at the telescope, and the manufacturing subcontractors. The mechanical design of the 2dF positioner and spectrographs was carried out by the mechanical engineering staff of the AAO and the majority of the manufacture was carried out in the AAO workshops.

  10. Realistic and efficient 2D crack simulation

    NASA Astrophysics Data System (ADS)

    Yadegar, Jacob; Liu, Xiaoqing; Singh, Abhishek

    2010-04-01

    Although numerical algorithms for 2D crack simulation have been studied in Modeling and Simulation (M&S) and computer graphics for decades, realism and computational efficiency are still major challenges. In this paper, we introduce a high-fidelity, scalable, adaptive and efficient/runtime 2D crack/fracture simulation system by applying the mathematically elegant Peano-Cesaro triangular meshing/remeshing technique to model the generation of shards/fragments. The recursive fractal sweep associated with the Peano-Cesaro triangulation provides efficient local multi-resolution refinement to any level-of-detail. The generated binary decomposition tree also provides efficient neighbor retrieval mechanism used for mesh element splitting and merging with minimal memory requirements essential for realistic 2D fragment formation. Upon load impact/contact/penetration, a number of factors including impact angle, impact energy, and material properties are all taken into account to produce the criteria of crack initialization, propagation, and termination leading to realistic fractal-like rubble/fragments formation. The aforementioned parameters are used as variables of probabilistic models of cracks/shards formation, making the proposed solution highly adaptive by allowing machine learning mechanisms learn the optimal values for the variables/parameters based on prior benchmark data generated by off-line physics based simulation solutions that produce accurate fractures/shards though at highly non-real time paste. Crack/fracture simulation has been conducted on various load impacts with different initial locations at various impulse scales. The simulation results demonstrate that the proposed system has the capability to realistically and efficiently simulate 2D crack phenomena (such as window shattering and shards generation) with diverse potentials in military and civil M&S applications such as training and mission planning.

  11. TACO (2D AND 3D). Taco

    SciTech Connect

    Mason, W.E.

    1983-03-01

    A set of finite element codes for the solution of nonlinear, two-dimensional (TACO2D) and three-dimensional (TACO3D) heat transfer problems. Performs linear and nonlinear analyses of both transient and steady state heat transfer problems. Has the capability to handle time or temperature dependent material properties. Materials may be either isotropic or orthotropic. A variety of time and temperature dependent boundary conditions and loadings are available including temperature, flux, convection, radiation, and internal heat generation.

  12. Tomosynthesis imaging with 2D scanning trajectories

    NASA Astrophysics Data System (ADS)

    Khare, Kedar; Claus, Bernhard E. H.; Eberhard, Jeffrey W.

    2011-03-01

    Tomosynthesis imaging in chest radiography provides volumetric information with the potential for improved diagnostic value when compared to the standard AP or LAT projections. In this paper we explore the image quality benefits of 2D scanning trajectories when coupled with advanced image reconstruction approaches. It is intuitively clear that 2D trajectories provide projection data that is more complete in terms of Radon space filling, when compared with conventional tomosynthesis using a linearly scanned source. Incorporating this additional information for obtaining improved image quality is, however, not a straightforward problem. The typical tomosynthesis reconstruction algorithms are based on direct inversion methods e.g. Filtered Backprojection (FBP) or iterative algorithms that are variants of the Algebraic Reconstruction Technique (ART). The FBP approach is fast and provides high frequency details in the image but at the same time introduces streaking artifacts degrading the image quality. The iterative methods can reduce the image artifacts by using image priors but suffer from a slow convergence rate, thereby producing images lacking high frequency details. In this paper we propose using a fast converging optimal gradient iterative scheme that has advantages of both the FBP and iterative methods in that it produces images with high frequency details while reducing the image artifacts. We show that using favorable 2D scanning trajectories along with the proposed reconstruction method has the advantage of providing improved depth information for structures such as the spine and potentially producing images with more isotropic resolution.

  13. MAGNUM-2D computer code: user's guide

    SciTech Connect

    England, R.L.; Kline, N.W.; Ekblad, K.J.; Baca, R.G.

    1985-01-01

    Information relevant to the general use of the MAGNUM-2D computer code is presented. This computer code was developed for the purpose of modeling (i.e., simulating) the thermal and hydraulic conditions in the vicinity of a waste package emplaced in a deep geologic repository. The MAGNUM-2D computer computes (1) the temperature field surrounding the waste package as a function of the heat generation rate of the nuclear waste and thermal properties of the basalt and (2) the hydraulic head distribution and associated groundwater flow fields as a function of the temperature gradients and hydraulic properties of the basalt. MAGNUM-2D is a two-dimensional numerical model for transient or steady-state analysis of coupled heat transfer and groundwater flow in a fractured porous medium. The governing equations consist of a set of coupled, quasi-linear partial differential equations that are solved using a Galerkin finite-element technique. A Newton-Raphson algorithm is embedded in the Galerkin functional to formulate the problem in terms of the incremental changes in the dependent variables. Both triangular and quadrilateral finite elements are used to represent the continuum portions of the spatial domain. Line elements may be used to represent discrete conduits. 18 refs., 4 figs., 1 tab.

  14. Engineering light outcoupling in 2D materials.

    PubMed

    Lien, Der-Hsien; Kang, Jeong Seuk; Amani, Matin; Chen, Kevin; Tosun, Mahmut; Wang, Hsin-Ping; Roy, Tania; Eggleston, Michael S; Wu, Ming C; Dubey, Madan; Lee, Si-Chen; He, Jr-Hau; Javey, Ali

    2015-02-11

    When light is incident on 2D transition metal dichalcogenides (TMDCs), it engages in multiple reflections within underlying substrates, producing interferences that lead to enhancement or attenuation of the incoming and outgoing strength of light. Here, we report a simple method to engineer the light outcoupling in semiconducting TMDCs by modulating their dielectric surroundings. We show that by modulating the thicknesses of underlying substrates and capping layers, the interference caused by substrate can significantly enhance the light absorption and emission of WSe2, resulting in a ∼11 times increase in Raman signal and a ∼30 times increase in the photoluminescence (PL) intensity of WSe2. On the basis of the interference model, we also propose a strategy to control the photonic and optoelectronic properties of thin-layer WSe2. This work demonstrates the utilization of outcoupling engineering in 2D materials and offers a new route toward the realization of novel optoelectronic devices, such as 2D LEDs and solar cells. PMID:25602462

  15. 2D superconductivity by ionic gating

    NASA Astrophysics Data System (ADS)

    Iwasa, Yoshi

    2D superconductivity is attracting a renewed interest due to the discoveries of new highly crystalline 2D superconductors in the past decade. Superconductivity at the oxide interfaces triggered by LaAlO3/SrTiO3 has become one of the promising routes for creation of new 2D superconductors. Also, the MBE grown metallic monolayers including FeSe are also offering a new platform of 2D superconductors. In the last two years, there appear a variety of monolayer/bilayer superconductors fabricated by CVD or mechanical exfoliation. Among these, electric field induced superconductivity by electric double layer transistor (EDLT) is a unique platform of 2D superconductivity, because of its ability of high density charge accumulation, and also because of the versatility in terms of materials, stemming from oxides to organics and layered chalcogenides. In this presentation, the following issues of electric filed induced superconductivity will be addressed; (1) Tunable carrier density, (2) Weak pinning, (3) Absence of inversion symmetry. (1) Since the sheet carrier density is quasi-continuously tunable from 0 to the order of 1014 cm-2, one is able to establish an electronic phase diagram of superconductivity, which will be compared with that of bulk superconductors. (2) The thickness of superconductivity can be estimated as 2 - 10 nm, dependent on materials, and is much smaller than the in-plane coherence length. Such a thin but low resistance at normal state results in extremely weak pinning beyond the dirty Boson model in the amorphous metallic films. (3) Due to the electric filed, the inversion symmetry is inherently broken in EDLT. This feature appears in the enhancement of Pauli limit of the upper critical field for the in-plane magnetic fields. In transition metal dichalcogenide with a substantial spin-orbit interactions, we were able to confirm the stabilization of Cooper pair due to its spin-valley locking. This work has been supported by Grant-in-Aid for Specially

  16. A simple tachometer circuit

    NASA Technical Reports Server (NTRS)

    Dimeff, J.

    1972-01-01

    Electric circuit to measure frequency of repetitive sinusoidal or rectangular wave is presented. Components of electric circuit and method of operation are explained. Application of circuit as tachometer for automobile is discussed.

  17. Photomultiplier blanking circuit

    NASA Technical Reports Server (NTRS)

    Mcclenahan, J. O.

    1972-01-01

    Circuit for protecting photomultiplier equipment from current surges which occur when exposed to brilliant illumination is discussed. Components of circuit and details of operation are provided. Circuit diagram to show action of blanking pulse on zener diode is included.

  18. QED Estimates of the 1990-91 Schools and Staffing Survey: Deriving and Comparing QED School Estimates with CCD Estimates. Working Paper Series.

    ERIC Educational Resources Information Center

    Holt, Albert; Scanlon, Brian R.

    This study examines the magnitude of the difference between estimates from the 1990-91 Schools and Staffing Survey (SASS) using a Common Core of Data (CCD) definition of a school and a Quality Education Data (QED) definition of a school. The 1990-91 SASS sample design allows for the development of school and administrator estimates using either…

  19. GBL-2D Version 1.0: a 2D geometry boolean library.

    SciTech Connect

    McBride, Cory L. (Elemental Technologies, American Fort, UT); Schmidt, Rodney Cannon; Yarberry, Victor R.; Meyers, Ray J.

    2006-11-01

    This report describes version 1.0 of GBL-2D, a geometric Boolean library for 2D objects. The library is written in C++ and consists of a set of classes and routines. The classes primarily represent geometric data and relationships. Classes are provided for 2D points, lines, arcs, edge uses, loops, surfaces and mask sets. The routines contain algorithms for geometric Boolean operations and utility functions. Routines are provided that incorporate the Boolean operations: Union(OR), XOR, Intersection and Difference. A variety of additional analytical geometry routines and routines for importing and exporting the data in various file formats are also provided. The GBL-2D library was originally developed as a geometric modeling engine for use with a separate software tool, called SummitView [1], that manipulates the 2D mask sets created by designers of Micro-Electro-Mechanical Systems (MEMS). However, many other practical applications for this type of software can be envisioned because the need to perform 2D Boolean operations can arise in many contexts.

  20. 2D stepping drive for hyperspectral systems

    NASA Astrophysics Data System (ADS)

    Endrödy, Csaba; Mehner, Hannes; Grewe, Adrian; Sinzinger, Stefan; Hoffmann, Martin

    2015-07-01

    We present the design, fabrication and characterization of a compact 2D stepping microdrive for pinhole array positioning. The miniaturized solution enables a highly integrated compact hyperspectral imaging system. Based on the geometry of the pinhole array, an inch-worm drive with electrostatic actuators was designed resulting in a compact (1 cm2) positioning system featuring a step size of about 15 µm in a 170 µm displacement range. The high payload (20 mg) as required for the pinhole array and the compact system design exceed the known electrostatic inch-worm-based microdrives.

  1. A scalable 2-D parallel sparse solver

    SciTech Connect

    Kothari, S.C.; Mitra, S.

    1995-12-01

    Scalability beyond a small number of processors, typically 32 or less, is known to be a problem for existing parallel general sparse (PGS) direct solvers. This paper presents a parallel general sparse PGS direct solver for general sparse linear systems on distributed memory machines. The algorithm is based on the well-known sequential sparse algorithm Y12M. To achieve efficient parallelization, a 2-D scattered decomposition of the sparse matrix is used. The proposed algorithm is more scalable than existing parallel sparse direct solvers. Its scalability is evaluated on a 256 processor nCUBE2s machine using Boeing/Harwell benchmark matrices.

  2. Periodically sheared 2D Yukawa systems

    SciTech Connect

    Kovács, Anikó Zsuzsa; Hartmann, Peter; Donkó, Zoltán

    2015-10-15

    We present non-equilibrium molecular dynamics simulation studies on the dynamic (complex) shear viscosity of a 2D Yukawa system. We have identified a non-monotonic frequency dependence of the viscosity at high frequencies and shear rates, an energy absorption maximum (local resonance) at the Einstein frequency of the system at medium shear rates, an enhanced collective wave activity, when the excitation is near the plateau frequency of the longitudinal wave dispersion, and the emergence of significant configurational anisotropy at small frequencies and high shear rates.

  3. ENERGY LANDSCAPE OF 2D FLUID FORMS

    SciTech Connect

    Y. JIANG; ET AL

    2000-04-01

    The equilibrium states of 2D non-coarsening fluid foams, which consist of bubbles with fixed areas, correspond to local minima of the total perimeter. (1) The authors find an approximate value of the global minimum, and determine directly from an image how far a foam is from its ground state. (2) For (small) area disorder, small bubbles tend to sort inwards and large bubbles outwards. (3) Topological charges of the same sign repel while charges of opposite sign attract. (4) They discuss boundary conditions and the uniqueness of the pattern for fixed topology.

  4. Interparticle Attraction in 2D Complex Plasmas

    NASA Astrophysics Data System (ADS)

    Kompaneets, Roman; Morfill, Gregor E.; Ivlev, Alexei V.

    2016-03-01

    Complex (dusty) plasmas allow experimental studies of various physical processes occurring in classical liquids and solids by directly observing individual microparticles. A major problem is that the interaction between microparticles is generally not molecularlike. In this Letter, we propose how to achieve a molecularlike interaction potential in laboratory 2D complex plasmas. We argue that this principal aim can be achieved by using relatively small microparticles and properly adjusting discharge parameters. If experimentally confirmed, this will make it possible to employ complex plasmas as a model system with an interaction potential resembling that of conventional liquids.

  5. A Novel Crosstalk Suppression Method of the 2-D Networked Resistive Sensor Array

    PubMed Central

    Wu, Jianfeng; Wang, Lei; Li, Jianqing; Song, Aiguo

    2014-01-01

    The 2-D resistive sensor array in the row–column fashion suffered from the crosstalk problem for parasitic parallel paths. Firstly, we proposed an Improved Isolated Drive Feedback Circuit with Compensation (IIDFCC) based on the voltage feedback method to suppress the crosstalk. In this method, a compensated resistor was specially used to reduce the crosstalk caused by the column multiplexer resistors and the adjacent row elements. Then, a mathematical equivalent resistance expression of the element being tested (EBT) of this circuit was analytically derived and verified by the circuit simulations. The simulation results show that the measurement method can greatly reduce the influence on the EBT caused by parasitic parallel paths for the multiplexers' channel resistor and the adjacent elements. PMID:25046011

  6. Dynamical Masses and Confinement in QED{sub 3}

    SciTech Connect

    Raya, Alfredo; Madrigal, Sanchez

    2008-07-02

    Dynamical Chiral Symmetry Breaking (DCSB) and Confinement are two crucial features of QCD which are responsible for the nature of the hadronic spectrum. A simpler model which exhibits both is quantum electrodynamics in (2+1) space-time dimensions, QED{sub 3}. A long standing debate in this model is the existence of a critical number of fermion families, N{sub c}, above which DCSB ceases to take place. This was established from the solutions of the Schwinger-Dyson equations (SDEs), in the leading order of the 1/N expansion in the Landau gauge. Confinement has also been found to be absent in this scenario. In this work, we study the stability of the solutions to the said SDEs under a variation of gauge while still working with the bare vertex. We find that the Landau gauge is the only gauge which exhibits the above mentioned results. Away from this gauge, DCSB takes place for an arbitrarily large N and confinement is reinstated. Attempting to understand this apparent inconsistency, we argue that in order to maintain the gauge covariance of the results, full vertex has to be employed in other gauges and/or constraints like the Landau-Khalatnikov-Fradkin transformations must be employed in going from Landau gauge to other gauges.

  7. Avoidance of a Landau pole by flat contributions in QED

    SciTech Connect

    Klaczynski, Lutz; Kreimer, Dirk

    2014-05-15

    We consider massless Quantum Electrodynamics in the momentum scheme and carry forward an approach based on Dyson–Schwinger equations to approximate both the β-function and the renormalized photon self-energy (Yeats, 2011). Starting from the Callan–Symanzik equation, we derive a renormalization group (RG) recursion identity which implies a non-linear ODE for the anomalous dimension and extract a sufficient but not necessary criterion for the existence of a Landau pole. This criterion implies a necessary condition for QED to have no such pole. Solving the differential equation exactly for a toy model case, we integrate the corresponding RG equation for the running coupling and find that even though the β-function entails a Landau pole it exhibits a flat contribution capable of decreasing its growth, in other cases possibly to the extent that such a pole is avoided altogether. Finally, by applying the recursion identity, we compute the photon propagator and investigate the effect of flat contributions on both spacelike and timelike photons. -- Highlights: •We present an approach to approximate both the β-function and the photon self-energy. •We find a sufficient criterion for the self-energy to entail the existence of a Landau pole. •We study non-perturbative ‘flat’ contributions that emerge within the context of our approach. •We discuss a toy model and how it is affected by flat contributions.

  8. From aether impulse to QED: Sommerfeld and the Bremsstrahlen theory

    NASA Astrophysics Data System (ADS)

    Eckert, Michael

    2015-08-01

    The radiation that is due to the braking of charged particles has been in the focus of theoretical physics since the discovery of X-rays by the end of the 19th century. The impact of cathode rays in the anti-cathode of an X-ray tube that resulted in the production of X-rays led to the view that X-rays are aether impulses spreading from the site of the impact. In 1909, Arnold Sommerfeld calculated from Maxwell's equations the angular distribution of electromagnetic radiation due to the braking of electrons. He thereby coined the notion of "Bremsstrahlen." In 1923, Hendrik A. Kramers provided a quantum theoretical explanation of this process by means of Bohr's correspondence principle. With the advent of quantum mechanics the theory of bremsstrahlung became a target of opportunity for theorists like Yoshikatsu Sugiura, Robert Oppenheimer, and-again-Sommerfeld, who presented in 1931 a comprehensive treatise on this subject. Throughout the 1930s, Sommerfeld's disciples in Munich and elsewhere extended and improved the bremsstrahlen theory. Hans Bethe and Walter Heitler, in particular, in 1934 presented a theory that was later regarded as "the most important achievement of QED in the 1930s" (Freeman Dyson). From a historical perspective the bremsstrahlen problem may be regarded as a probe for the evolution of theories in response to revolutionary changes in the underlying principles.

  9. WFR-2D: an analytical model for PWAS-generated 2D ultrasonic guided wave propagation

    NASA Astrophysics Data System (ADS)

    Shen, Yanfeng; Giurgiutiu, Victor

    2014-03-01

    This paper presents WaveFormRevealer 2-D (WFR-2D), an analytical predictive tool for the simulation of 2-D ultrasonic guided wave propagation and interaction with damage. The design of structural health monitoring (SHM) systems and self-aware smart structures requires the exploration of a wide range of parameters to achieve best detection and quantification of certain types of damage. Such need for parameter exploration on sensor dimension, location, guided wave characteristics (mode type, frequency, wavelength, etc.) can be best satisfied with analytical models which are fast and efficient. The analytical model was constructed based on the exact 2-D Lamb wave solution using Bessel and Hankel functions. Damage effects were inserted in the model by considering the damage as a secondary wave source with complex-valued directivity scattering coefficients containing both amplitude and phase information from wave-damage interaction. The analytical procedure was coded with MATLAB, and a predictive simulation tool called WaveFormRevealer 2-D was developed. The wave-damage interaction coefficients (WDICs) were extracted from harmonic analysis of local finite element model (FEM) with artificial non-reflective boundaries (NRB). The WFR-2D analytical simulation results were compared and verified with full scale multiphysics finite element models and experiments with scanning laser vibrometer. First, Lamb wave propagation in a pristine aluminum plate was simulated with WFR-2D, compared with finite element results, and verified by experiments. Then, an inhomogeneity was machined into the plate to represent damage. Analytical modeling was carried out, and verified by finite element simulation and experiments. This paper finishes with conclusions and suggestions for future work.

  10. Microwave Assisted 2D Materials Exfoliation

    NASA Astrophysics Data System (ADS)

    Wang, Yanbin

    Two-dimensional materials have emerged as extremely important materials with applications ranging from energy and environmental science to electronics and biology. Here we report our discovery of a universal, ultrafast, green, solvo-thermal technology for producing excellent-quality, few-layered nanosheets in liquid phase from well-known 2D materials such as such hexagonal boron nitride (h-BN), graphite, and MoS2. We start by mixing the uniform bulk-layered material with a common organic solvent that matches its surface energy to reduce the van der Waals attractive interactions between the layers; next, the solutions are heated in a commercial microwave oven to overcome the energy barrier between bulk and few-layers states. We discovered the minutes-long rapid exfoliation process is highly temperature dependent, which requires precise thermal management to obtain high-quality inks. We hypothesize a possible mechanism of this proposed solvo-thermal process; our theory confirms the basis of this novel technique for exfoliation of high-quality, layered 2D materials by using an as yet unknown role of the solvent.