Electron-electron attractive interaction in Maxwell-Chern-Simons QED3 at zero temperature

International Nuclear Information System (INIS)

Belich, H.; Ferreira Junior, M.M.; Helayel-Neto, J.A.; Ferreira Junior, M.M.

2001-04-01

One discusses the issue of low-energy electron-electron bound states in the Maxwell-Chern-Simons model coupled to QED 3 with spontaneous breaking of a local U(1)-symmetry. The scattering potential, in the non-relativistic limit, steaming from the electron-electron Moeller scattering, mediated by the Maxwell-Chern-Simons-Proca gauge field and the Higgs scalar, might be attractive by fine-tuning properly the physical parameters of the model. (author)

The renormalization group study of the effective theory of lattice QED

International Nuclear Information System (INIS)

Sugiyama, Y.

1988-01-01

The compact U(1) lattice gauge theory with massless fermions (Lattice QED) is studied through the effective model analytically, using the renormalization group method. The obtained effective model is the local boson field system with non-local interactions. The authors study the existence of non-trivial fixed point and its scaling behavior. This fixed point seems to be tri-critical. Such fixed point is interpreted in terms of the original Lattice QED model, and the results are consistent with the Monte Calro study

Electron-electron attractive interaction in Maxwell-Chern-Simons QED{sub 3} at zero temperature

Energy Technology Data Exchange (ETDEWEB)

Belich, H.; Ferreira Junior, M.M.; Helayel-Neto, J.A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). E-mail: belich@cbpf.br; manojr@cbpf.br; helayel@gft.ucp.br; Ferreira Junior, M.M. [Universidade Catolica de Petropolis, RJ (Brazil). Grupo de Fisica Teorica. E-mail: delcima@gft.ucp.br

2001-04-01

One discusses the issue of low-energy electron-electron bound states in the Maxwell-Chern-Simons model coupled to QED{sub 3} with spontaneous breaking of a local U(1)-symmetry. The scattering potential, in the non-relativistic limit, steaming from the electron-electron Moeller scattering, mediated by the Maxwell-Chern-Simons-Proca gauge field and the Higgs scalar, might be attractive by fine-tuning properly the physical parameters of the model. (author)

Circuit QED with 3D cavities

Energy Technology Data Exchange (ETDEWEB)

Xie, Edwar; Eder, Peter; Fischer, Michael; Goetz, Jan; Deppe, Frank; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Physik-Department, TU Muenchen, 85748 Garching (Germany); Nanosystems Initiative Munich (NIM), 80799 Muenchen (Germany); Haeberlein, Max; Wulschner, Karl Friedrich [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Physik-Department, TU Muenchen, 85748 Garching (Germany); Fedorov, Kirill; Marx, Achim [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany)

2016-07-01

In typical circuit QED systems, on-chip superconducting qubits are coupled to integrated coplanar microwave resonators. Due to the planar geometry, the resonators are often a limiting factor regarding the total coherence of the system. Alternatively, similar hybrid systems can be realized using 3D microwave cavities. Here, we present studies on transmon qubits capacitively coupled to 3D cavities. The internal quality factors of our 3D cavities, machined out of high purity aluminum, are above 1.4 .10{sup 6} at the single photon level and a temperature of 50 mK. For characterization of the sample, we perform dispersive shift measurements up to the third energy level of the qubit. We show simulations and data describing the effect of the transmon geometry on it's capacitive properties. In addition, we present progress towards an integrated quantum memory application.

The parity-preserving massive QED3: Vanishing β-function and no parity anomaly

Directory of Open Access Journals (Sweden)

O.M. Del Cima

2015-11-01

Full Text Available The parity-preserving massive QED3 exhibits vanishing gauge coupling β-function and is parity and infrared anomaly free at all orders in perturbation theory. Parity is not an anomalous symmetry, even for the parity-preserving massive QED3, in spite of some claims about the possibility of a perturbative parity breakdown, called parity anomaly. The proof is done by using the algebraic renormalization method, which is independent of any regularization scheme, based on general theorems of perturbative quantum field theory.

Engineering non-linear resonator mode interactions in circuit QED by continuous driving: Introduction

Science.gov (United States)

Pfaff, Wolfgang; Reagor, Matthew; Heeres, Reinier; Ofek, Nissim; Chou, Kevin; Blumoff, Jacob; Leghtas, Zaki; Touzard, Steven; Sliwa, Katrina; Holland, Eric; Krastanov, Stefan; Frunzio, Luigi; Devoret, Michel; Jiang, Liang; Schoelkopf, Robert

2015-03-01

High-Q microwave resonators show great promise for storing and manipulating quantum states in circuit QED. Using resonator modes as such a resource in quantum information processing applications requires the ability to manipulate the state of a resonator efficiently. Further, one must engineer appropriate coupling channels without spoiling the coherence properties of the resonator. We present an architecture that combines millisecond lifetimes for photonic quantum states stored in a linear resonator with fast measurement provided by a low-Q readout resonator. We demonstrate experimentally how a continuous drive on a transmon can be utilized to generate highly non-classical photonic states inside the high-Q resonator via effective nonlinear resonator mode interactions. Our approach opens new avenues for using modes of long-lived linear resonators in the circuit QED platform for quantum information processing tasks.

Combining NNPDF3.0 and NNPDF2.3QED through the APFEL evolution code

CERN Document Server

Bertone, Valerio

2016-01-01

We present sets of parton distribution functions (PDFs), based on the NNPDF3.0 family, which include the photon PDF from the NNPDF2.3QED sets, and leading-order QED contributions to the DGLAP evolution as implemented in the public code APFEL. The aim is to combine our state-of-the-art determination of quark and gluon PDFs with the so far only direct determination of the photon PDF from LHC data. In addition, the use of APFEL allowed us to employ a solution of the DGLAP equation that, differently from that used for the NNPDF2.3QED sets, includes QED corrections in a more accurate way. We briefly discuss how these sets are constructed and investigate the effect of the inclusion of the QED corrections on PDFs and parton luminosities. Finally, we compare the resulting sets, which we dubbed NNPDF3.0QED, to the older NNPDF2.3QED sets and to all presently available PDF sets that include QED corrections, namely CT14QED and MRST2004QED.

An architecture for integrating planar and 3D cQED devices

Energy Technology Data Exchange (ETDEWEB)

Axline, C.; Reagor, M.; Heeres, R.; Reinhold, P.; Wang, C.; Shain, K.; Pfaff, W.; Chu, Y.; Frunzio, L.; Schoelkopf, R. J. [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States)

2016-07-25

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.

A non-perturbative approach to the Coleman-Weinberg mechanism in massless scalar QED

International Nuclear Information System (INIS)

Malbouisson, A.P.C.; Nogueira, F.S.; Svaiter, N.F.

1995-08-01

We rederived non-perturbatively the Coleman-Weinberg expression for the effective potential for massless scalar QED. Our result is not restricted to small values of the coupling constants. This shows that the Coleman-Weinberg result can be established beyond the range of perturbation theory. Also, we derive it in a manifestly renormalization group invariant way. It is shown that with the derivation given no Landau ghost singularity arises. The finite temperature case is discussed. (author). 13 refs

Circuit QED with 3D cavities

Energy Technology Data Exchange (ETDEWEB)

Xie, Edwar; Baust, Alexander; Zhong, Ling; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Anderson, Gustav; Wang, Lujun; Eder, Peter; Fischer, Michael; Goetz, Jan; Haeberlein, Max; Schwarz, Manuel; Wulschner, Karl Friedrich; Deppe, Frank; Fedorov, Kirill; Huebl, Hans; Menzel, Edwin [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Marx, Achim [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany)

2015-07-01

In typical circuit QED systems on-chip superconducting qubits are coupled to integrated coplanar microwave resonators. Due to the planar geometry, the resonators are often a limiting factor regarding the total coherence of the system. Alternatively, similar hybrid systems can be realized using 3D microwave cavities. Here, we present design considerations for the 3D microwave cavity as well as the superconducting transmon qubit. Moreover, we show experimental data of a high purity aluminum cavity demonstrating quality factors above 1.4 .10{sup 6} at the single photon level and a temperature of 50 mK. Our experiments also demonstrate that the quality factor is less dependent on the power compared to planar resonator geometries. Furthermore, we present strategies for tuning both the cavity and the qubit individually.

Leptonic contributions to the effective electromagnetic coupling at four-loop order in QED

International Nuclear Information System (INIS)

Sturm, Christian

2013-01-01

The running of the effective electromagnetic coupling is for many electroweak observables the dominant correction. It plays an important role for deriving constraints on the Standard Model in the context of electroweak precision measurements. We compute the four-loop QED corrections to the running of the effective electromagnetic coupling and perform a numerical evaluation of the different gauge invariant subsets

Dual QED_3 at “N_F=1/2” is an interacting CFT in the infrared

International Nuclear Information System (INIS)

Roscher, Dietrich; Torres, Emilio; Strack, Philipp

2016-01-01

We study the fate of weakly coupled dual QED_3 in the infrared, that is, a single two-component Dirac fermion coupled to an emergent U(1) gauge field, but without Chern-Simons term. This theory has recently been proposed as a dual description of 2D surfaces of certain topological insulators. Using the renormalization group, we find that the interplay of gauge fluctuations with generated interactions in the four-fermi sector stabilizes an interacting conformal field theory (CFT) with finite four-fermi coupling in the infrared. The emergence of this CFT is due to cancellations in the β-function of the four-fermi coupling special to “N_F=1/2”. We also quantify how a possible “strong” Dirac fermion duality between a free Dirac cone and dual QED_3 would constrain the universal constants of the topological current correlator of the latter.

Leading quantum gravitational corrections to QED

OpenAIRE

Butt, M. S.

2006-01-01

We consider the leading post-Newtonian and quantum corrections to the non-relativistic scattering amplitude of charged spin-1/2 fermions in the combined theory of general relativity and QED. The coupled Dirac-Einstein system is treated as an effective field theory. This allows for a consistent quantization of the gravitational field. The appropriate vertex rules are extracted from the action, and the non-analytic contributions to the 1-loop scattering matrix are calculated in the non-relativi...

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

Science.gov (United States)

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.

Non-markovian effects in semiconductor cavity QED: Role of phonon-mediated processes

DEFF Research Database (Denmark)

Nielsen, Per Kær; Nielsen, Torben Roland; Lodahl, Peter

We show theoretically that the non-Markovian nature of the carrier-phonon interaction influences the dynamical properties of a semiconductor cavity QED system considerably, leading to asymmetries with respect to detuning in carrier lifetimes. This pronounced phonon effect originates from the pola......We show theoretically that the non-Markovian nature of the carrier-phonon interaction influences the dynamical properties of a semiconductor cavity QED system considerably, leading to asymmetries with respect to detuning in carrier lifetimes. This pronounced phonon effect originates from...... the polaritonic quasi-particle nature of the carrier-photon system interacting with the phonon reservoir....

Gauge dependence of the infrared behaviour of massless QED3

International Nuclear Information System (INIS)

Mitra, Indrajit; Ratabole, Raghunath; Sharatchandra, H.S.

2006-01-01

Using the Zumino identities it is shown that in a class of non-local gauges, massless QED 3 has an infrared behaviour of a conformal field theory with a continuously varying anomalous dimension of the fermion. In the usual Lorentz gauge, the fermion propagator falls off exponentially for a large separation, but this apparent fermion mass is a gauge artifact

Measurement of the running of the QED coupling in small-angle Bhabha scattering at LEP

CERN Document Server

Abbiendi, G.; Akesson, P.F.; Alexander, G.; Anagnostou, G.; Anderson, K.J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, Robert M.; Burckhart, H.J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.M.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giacomelli, R.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hill, J.C.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, Niels T.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; ONeale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, Matthias; Schumacher, M.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

2006-01-01

Using the OPAL detector at LEP, the running of the effective QED coupling alpha(t) is measured for space-like momentum transfer through its effect on the angular spectrum of small-angle Bhabha scattering. In an almost ideal QED framework, with very favourable experimental conditions, we obtain: Delta alpha(-6.07GeV^2) - Delta alpha(-1.81GeV^2) = (440 pm 58 pm 43 pm 30) X 10^-5, where the first error is statistical, the second is the experimental systematic and the third is the theoretical uncertainty. This is the strongest direct evidence ever presented that the running of alpha is consistent with Standard Model expectations. The null hypothesis that alpha remains constant within the above interval of -t is excluded with a significance above 5sigma. Similarly, our results are inconsistent at the level of 3sigma with the hypothesis that only leptonic loops contribute to the running, and therefore provide the first clear experimental evidence that hadronic loops also contribute.

Cavity QED experiments with ion Coulomb crystals

DEFF Research Database (Denmark)

Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan

2009-01-01

Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained.......Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained....

Gauge dependence of the infrared behaviour of massless QED{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Mitra, Indrajit [Theory Group, Saha Institute of Nuclear Physics, 1/AF Bidhan-Nagar, Kolkata 700064 (India)]. E-mail: indrajit.mitra@saha.ac.in; Ratabole, Raghunath [The Institute of Mathematical Sciences, CIT Campus, Taramani PO, Chennai 600113 (India)]. E-mail: raghu@imsc.res.in; Sharatchandra, H.S. [The Institute of Mathematical Sciences, CIT Campus, Taramani PO, Chennai 600113 (India)]. E-mail: sharat@imsc.res.in

2006-03-23

Using the Zumino identities it is shown that in a class of non-local gauges, massless QED{sub 3} has an infrared behaviour of a conformal field theory with a continuously varying anomalous dimension of the fermion. In the usual Lorentz gauge, the fermion propagator falls off exponentially for a large separation, but this apparent fermion mass is a gauge artifact.

Magnetic monopole plasma phase in (2+1)d compact quantum electrodynamics with fermionic matter

International Nuclear Information System (INIS)

Armour, Wesley; Hands, Simon; Lucini, Biagio; Kogut, John B.; Strouthos, Costas; Vranas, Pavlos

2011-01-01

We present the first evidence from lattice simulations that the magnetic monopoles in three-dimensional compact quantum electrodynamics (cQED 3 ) with N f =2 and N f =4 four-component fermion flavors are in a plasma phase. The evidence is based mainly on the divergence of the monopole susceptibility (polarizability) with the lattice size at weak gauge couplings. A weak four-Fermi term added to the cQED 3 action enabled simulations with massless fermions. The exact chiral symmetry of the interaction terms forbids symmetry breaking lattice discretization counterterms to appear in the theory's effective action. It is also shown that the scenario of a monopole plasma does not depend on the strength of the four-Fermi coupling. Other observables such as the densities of isolated dipoles and monopoles and the so-called specific heat show that a crossover from a dense monopole plasma to a dilute monopole gas occurs at strong couplings. The implications of our results on the stability of U(1) spin liquids in two spatial dimensions are also discussed.

Measurement of the running of the QED coupling in small angle Bhabha scattering with the OPAL detector

Energy Technology Data Exchange (ETDEWEB)

Guenther, P.

2005-06-01

Using the high precision OPAL Silicon-Tungsten luminometer at LEP, the running of the effective QED coupling {alpha}(t) is measured for space-like momentum transfer 1.81 {<=} -t {<=} 6.07 GeV{sup 2} through its effect on the angular spectrum of small angle Bhabha scattering. In an almost ideal QED framework, with very favourable experimental conditions, we obtain a strong direct evidence that the running of {alpha}(t) is consistent with standard model expectations. The null hypothesis that {alpha} remains constant within the above interval of -t is excluded with a significance above 5{sigma}: {delta}{alpha}(-6.07 GeV{sup 2}) - {delta}{alpha}(-1.81 GeV{sup 2}) = 0.00450 {+-} 0.00079 The hadronic contribution to the running of the coupling has been estimated to be: {delta}{alpha}{sub had}(-6.07 GeV{sup 2}) - {delta}{alpha}{sub had}(-1.81 GeV{sup 2}) = 0.00248 {+-} 0.00079. This result is inconsistent at the level of more than 3{sigma} with the hypothesis that only leptonic loops contribute to the running, and therefore provide the first clear space-like experimental evidence that hadronic loops also contribute. (orig.)

On the classical dynamics of charges in non-commutative QED

International Nuclear Information System (INIS)

Fatollahi, A.H.; Mohammadzadeh, H.

2004-01-01

Following Wong's approach to formulating the classical dynamics of charged particles in non-Abelian gauge theories, we derive the classical equations of motion of a charged particle in U(1) gauge theory on non-commutative space, the so-called non-commutative QED. In the present use of the procedure, it is observed that the definition of the mechanical momenta should be modified. The derived equations of motion manifest the previous statement about the dipole behavior of the charges in non-commutative space. (orig.)

Local and non-local Schroedinger cat states in cavity QED

International Nuclear Information System (INIS)

Haroche, S.

2005-01-01

Full text: I will review recent experiments performed on mesoscopic state superpositions of field states in cavity QED. Proposals to extend these studies to Schroedinger cat states delocalized in two cavities will be discussed. New versions of Bell's inequality tests will probe the non-local behavior of these cats and study their sensitivity to decoherence. (author)

Effective Lagrangian of QED

International Nuclear Information System (INIS)

Kaminski, J.Z.

1981-01-01

A renormalization group equation for the effective Lagrangian of QED is obtained. Starting from this equation, perturbation theory for the renormalization group equation (PTRGE) is developed. The results are in full agreement with the standard perturbation theory. Conjecturing that the asymptotic effective coupling constant is finite, the effective Lagrangian for a strong magnetic field is obtained, which is proportional to the Maxwellian Lagrangian. For the asymptotically free theories the situation is diametrically opposed to QED. In these cases the effective Lagrangian of the Yang-Mills system tends to infinity for very strong external Yang-Mills fields. (Auth.)

Strong Coupling Cavity QED with Gate-Defined Double Quantum Dots Enabled by a High Impedance Resonator

Directory of Open Access Journals (Sweden)

A. Stockklauser

2017-03-01

Full Text Available The strong coupling limit of cavity quantum electrodynamics (QED implies the capability of a matterlike quantum system to coherently transform an individual excitation into a single photon within a resonant structure. This not only enables essential processes required for quantum information processing but also allows for fundamental studies of matter-light interaction. In this work, we demonstrate strong coupling between the charge degree of freedom in a gate-defined GaAs double quantum dot (DQD and a frequency-tunable high impedance resonator realized using an array of superconducting quantum interference devices. In the resonant regime, we resolve the vacuum Rabi mode splitting of size 2g/2π=238  MHz at a resonator linewidth κ/2π=12  MHz and a DQD charge qubit decoherence rate of γ_{2}/2π=40  MHz extracted independently from microwave spectroscopy in the dispersive regime. Our measurements indicate a viable path towards using circuit-based cavity QED for quantum information processing in semiconductor nanostructures.

Atom-field dressed states in slow-light waveguide QED

Science.gov (United States)

Calajó, Giuseppe; Ciccarello, Francesco; Chang, Darrick; Rabl, Peter

2016-03-01

We discuss the properties of atom-photon bound states in waveguide QED systems consisting of single or multiple atoms coupled strongly to a finite-bandwidth photonic channel. Such bound states are formed by an atom and a localized photonic excitation and represent the continuum analog of the familiar dressed states in single-mode cavity QED. Here we present a detailed analysis of the linear and nonlinear spectral features associated with single- and multiphoton dressed states and show how the formation of bound states affects the waveguide-mediated dipole-dipole interactions between separated atoms. Our results provide both a qualitative and quantitative description of the essential strong-coupling processes in waveguide QED systems, which are currently being developed in the optical and microwave regimes.

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

Energy Technology Data Exchange (ETDEWEB)

Jin, Jiasen; Rossini, Davide [CNR, NEST, Scuola Normale Superiore and Istituto di Nanoscienze, Pisa (Italy); Fazio, Rosario [CNR, NEST, Scuola Normale Superiore and Istituto di Nanoscienze, Pisa (Italy); National University of Singapore, Center for Quantum Technologies, Singapore (Singapore)

2015-01-01

We study the zero-temperature phase diagram of a one-dimensional array of QED cavities where, besides the single-photon hopping, an additional coupling between neighboring cavities is mediated by an N-type four-level system. By varying the relative strength of the various couplings, the array is shown to exhibit a variety of quantum phases including a polaritonic Mott insulator, a density-wave and a superfluid phase. Our results have been obtained by means of numerical density-matrix renormalization group calculations. The phase diagram was obtained by analyzing the energy gaps for the polaritons, as well as through a study of two-point correlation functions. (orig.)

Dynamical Properties of Two Coupled Dissipative QED Cavities Driven by Coherent Fields

International Nuclear Information System (INIS)

Hou Bangpin; Sun Weili; Wang Shunjin; Wang Gang

2007-01-01

When two identical QED cavities driven by the coherent fields are located in a uniform environment, in addition to dissipation, there appears an indirect coupling between the two cavities induced by the background fields. We investigate the effects of the coherent fields, the dissipation as well as the incoherent coupling on the following dynamical properties of the system: photon transfer, reversible decoherence, and quantum state transfer, etc. We find that the photons in the cavities do not leak completely into the environment due to the collective coupling between the cavities and the environment, and the photons are transferred irreversibly from the cavity with more photons to the cavity with less ones due to the incoherent coupling so that they are equally distributed among the two cavities. The coherent field pumping on the two cavities increases the mean photons, complements the revived magnitude of the reversible decoherence, but hinders the quantum state transfer between the two cavities. The above phenomena may find applications in quantum communication and other basic fields.

Two-loop QED corrections to the Altarelli-Parisi splitting functions

Energy Technology Data Exchange (ETDEWEB)

Florian, Daniel de [International Center for Advanced Studies (ICAS), UNSAM,Campus Miguelete, 25 de Mayo y Francia (1650) Buenos Aires (Argentina); Sborlini, Germán F.R.; Rodrigo, Germán [Instituto de Física Corpuscular, Universitat de València,Consejo Superior de Investigaciones Científicas,Parc Científic, E-46980 Paterna, Valencia (Spain)

2016-10-11

We compute the two-loop QED corrections to the Altarelli-Parisi (AP) splitting functions by using a deconstructive algorithmic Abelianization of the well-known NLO QCD corrections. We present explicit results for the full set of splitting kernels in a basis that includes the leptonic distribution functions that, starting from this order in the QED coupling, couple to the partonic densities. Finally, we perform a phenomenological analysis of the impact of these corrections in the splitting functions.

Circuit QED lattices: Towards quantum simulation with superconducting circuits

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Sebastian [Institute for Theoretical Physics, ETH Zurich, 8093, Zurich (Switzerland); Koch, Jens [Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208 (United States)

2013-06-15

The Jaynes-Cummings model describes the coupling between photons and a single two-level atom in a simplified representation of light-matter interactions. In circuit QED, this model is implemented by combining microwave resonators and superconducting qubits on a microchip with unprecedented experimental control. Arranging qubits and resonators in the form of a lattice realizes a new kind of Hubbard model, the Jaynes-Cummings-Hubbard model, in which the elementary excitations are polariton quasi-particles. Due to the genuine openness of photonic systems, circuit QED lattices offer the possibility to study the intricate interplay of collective behavior, strong correlations and non-equilibrium physics. Thus, turning circuit QED into an architecture for quantum simulation, i.e., using a well-controlled system to mimic the intricate quantum behavior of another system too daunting for a theorist to tackle head-on, is an exciting idea which has served as theorists' playground for a while and is now also starting to catch on in experiments. This review gives a summary of the most recent theoretical proposals and experimental efforts. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Angular momentum in non-relativistic QED and photon contribution to spin of hydrogen atom

International Nuclear Information System (INIS)

Chen Panying; Ji Xiangdong; Xu Yang; Zhang Yue

2010-01-01

We study angular momentum in non-relativistic quantum electrodynamics (NRQED). We construct the effective total angular momentum operator by applying Noether's theorem to the NRQED lagrangian. We calculate the NRQED matching for the individual components of the QED angular momentum up to one loop. We illustrate an application of our results by the first calculation of the angular momentum of the ground state hydrogen atom carried in radiative photons, α em 3 /18π, which might be measurable in future atomic experiments.

Confining strings in the Abelian-projected SU(3)-gluodynamics. Pt. 2. 4D case with θ-term

International Nuclear Information System (INIS)

Antonov, D.

2001-01-01

The generalization of 4D confining string theory to the SU(3)-inspired case is derived. It describes string representation of the Wilson loop in the SU(3) analogue of compact QED extended by the θ-term. It is shown that although the obtained theory of confining strings differs from that of compact QED, their low-energy limits have the same functional form. This fact leads to the appearance of the string θ-term in the low-energy limit of the SU(3)-inspired confining string theory. In particular, it is shown that in the extreme strong-coupling regime, the crumpling of string world sheets could disappear owing to the string θ-term at θ = π/12. Finally, some characteristic features of the SU(N) case are pointed out. (orig.)

QED3 formulation of vortices in boson condensates and metafluid

International Nuclear Information System (INIS)

Soares, Thales Costa; Spalenza, Wesley; Helayel Neto, Jose Abdalla

2002-01-01

Full text: One consider a system of many non-relativistic particles as a fluid, going from the discrete set of space-time coordinates of each particle to a continuous field. With an interparticle potential that satisfies a number of physically reasonable assumptions, one shows how the Lagrangian describing the motion of the fluid displays an exact local gauge invariance governed by a scalar parameter. The conserved quantity associated to this local symmetry is derived and discussed in the light of planar Electrodynamics, with photons identified as sound waves in the fluid and point-like charges corresponding to vortices with azimuthal circulation. On the other hand, exploiting further the field configurations of planar Electrodynamics, one finds a peculiar source for the electrostatic sector with azimuthal electric field and a string-like scalar potential. This work sets out to attempt at establishing a parallel between this vortex-like electric field configurations in fluid dynamics. Vortices in boson condensates and the fluid dynamics of the condensates are reassessed and translated into electromagnetic fields of planar (Chern-Simons massive) QED. On The other hand, the metafluid equations, once suitable reduced from 3 to 2 space dimensions, are also seen to match field configurations of Maxwell (massless photons) planar QED. (author)

Fermion bag approach to the sign problem in strongly coupled lattice QED with Wilson fermions

OpenAIRE

Chandrasekharan, Shailesh; Li, Anyi

2010-01-01

We explore the sign problem in strongly coupled lattice QED with one flavor of Wilson fermions in four dimensions using the fermion bag formulation. We construct rules to compute the weight of a fermion bag and show that even though the fermions are confined into bosons, fermion bags with negative weights do exist. By classifying fermion bags as either simple or complex, we find numerical evidence that complex bags with positive and negative weights come with almost equal probabilities and th...

Towards bootstrapping QED{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Chester, Shai M.; Pufu, Silviu S. [Joseph Henry Laboratories, Princeton University,Princeton, NJ 08544 (United States)

2016-08-02

We initiate the conformal bootstrap study of Quantum Electrodynamics in 2+1 space-time dimensions (QED{sub 3}) 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.

Simulations of QCD and QED with C* boundary conditions

Science.gov (United States)

Hansen, Martin; Lucini, Biagio; Patella, Agostino; Tantalo, Nazario

2018-03-01

We present exploratory results from dynamical simulations of QCD in isolation, as well as QCD coupled to QED, with C* boundary conditions. In finite volume, the use of C* boundary conditions allows for a gauge invariant and local formulation of QED without zero modes. In particular we show that the simulations reproduce known results and that masses of charged mesons can be extracted in a completely gauge invariant way. For the simulations we use a modified version of the HiRep code. The primary features of the simulation code are presented and we discuss some details regarding the implementation of C* boundary conditions and the simulated lattice action. Preprint: CP3-Origins-2017-046 DNRF90, CERN-TH-2017-214

Quantum Key Distribution Based on a Weak-Coupling Cavity QED Regime

International Nuclear Information System (INIS)

Li Chun-Yan; Li Yan-Song

2011-01-01

We present a quantum key distribution scheme using a weak-coupling cavity QED regime based on quantum dense coding. Hybrid entanglement states of photons and electrons are used to distribute information. We just need to transmit photons without storing them in the scheme. The electron confined in a quantum dot, which is embedded in a microcavity, is held by one of the legitimate users throughout the whole communication process. Only the polarization of a single photon and spin of electron measurements are applied in this protocol, which are easier to perform than collective-Bell state measurements. Linear optical apparatus, such as a special polarizing beam splitter in a circular basis and single photon operations, make it more flexible to realize under current technology. Its efficiency will approach 100% in the ideal case. The security of the scheme is also discussed. (general)

Parton distributions with QED corrections

NARCIS (Netherlands)

Collaboration, The NNPDF; Ball, Richard D.; Bertone, Valerio; Carrazza, Stefano; Debbio, Luigi Del; Forte, Stefano; Guffanti, Alberto; Hartland, Nathan P.; Rojo, Juan

2013-01-01

We present a set of parton distribution functions (PDFs), based on the NNPDF2.3 set, which includes a photon PDF, and QED contributions to parton evolution. We describe the implementation of the combined QCD+QED evolution in the NNPDF framework. We then provide a first determination of the full set

On the problem of unboundedness from below of the spinor QED Hamiltonian

International Nuclear Information System (INIS)

Zastavenko, L.G.

1993-01-01

It is show that the Hamiltonian H QED + H 2 , where H QED is the spinor QED Hamiltonian and H 2 is the positive transversal photon mass term, is unbounded from below if the electromagnetic coupling constant e 2 is small enough, e 2 0 2 , and the transversal photon squared mass parameter M 2 is not large: 0 2 2 (1 - e 2 /e 0 2 )l 2 , here, l is the cut-off parameter; and c and e 0 2 , positive constants which do not depend on any parameters. 7 refs

Constraint on the QED vertex from the mass anomalous dimension γm = 1

International Nuclear Information System (INIS)

Bashir, A.; Pennington, M.R.

1995-10-01

We discuss the structure of the non-perturbative fermion-boson vertex in quenched QED. We show that it is possible to construct a vertex which not only ensures that the fermion propagator is multiplicatively renormalizable, obeys the appropriate Ward-Takahashi identity, reproduces perturbation theory for weak couplings and guarantees that the critical coupling at which the mass is dynamically generated is gauge independent but also makes sure that the value for the anomalous dimension for the mass function is strictly 1, as Holdom and Mahanta have proposed. (author). 8 refs

Power corrections to the HTL effective Lagrangian of QED

Science.gov (United States)

Carignano, Stefano; Manuel, Cristina; Soto, Joan

2018-05-01

We present compact expressions for the power corrections to the hard thermal loop (HTL) Lagrangian of QED in d space dimensions. These are corrections of order (L / T) 2, valid for momenta L ≪ T, where T is the temperature. In the limit d → 3 we achieve a consistent regularization of both infrared and ultraviolet divergences, which respects the gauge symmetry of the theory. Dimensional regularization also allows us to witness subtle cancellations of infrared divergences. We also discuss how to generalize our results in the presence of a chemical potential, so as to obtain the power corrections to the hard dense loop (HDL) Lagrangian.

Zero field Quantum Hall Effect in QED3

International Nuclear Information System (INIS)

Raya, K; Sánchez-Madrigal, S; Raya, A

2013-01-01

We study analytic structure of the fermion propagator in the Quantum Electrodynamics in 2+1 dimensions (QED3) in the Landau gauge, both in perturbation theory and nonperturbatively, by solving the corresponding Schwinger-Dyson equation in rainbow approximation. In the chiral limit, we found many nodal solutions, which could be interpreted as vacuum excitations. Armed with these solutions, we use the Kubo formula and calculate the filling factor for the zero field Quantum Hall Effect

Decoherence in semiconductor cavity QED systems due to phonon couplings

DEFF Research Database (Denmark)

Nielsen, Per Kær; Mørk, Jesper

2014-01-01

We investigate the effect of electron-phonon interactions on the coherence properties of single photons emitted from a semiconductor cavity QED (quantum electrodynamics) system, i.e., a quantum dot embedded in an optical cavity. The degree of indistinguishability, governing the quantum mechanical...

Entangled-photon generation from a quantum dot in cavity QED

International Nuclear Information System (INIS)

Ajiki, Hiroshi; Ishihara, Hajime

2009-01-01

We theoretically study polarization-entangled photon generation from a single quantum dot in a microcavity. Entangled-photon pairs with singlet or triplet Bell states are generated in the resonant-hyperparametric scattering via dressed states in the cavity QED. Although co-polarized non-entangled photons are also generated, the generation is dramatically suppressed in the strong-coupling limit owing to the photon blockade effect. Finite binding energy of biexciton is also important for the generation of photon pairs with high degree of entanglement. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

New Circuit QED system based on Triple-leg Stripline Resonator.

Science.gov (United States)

Kim, Dongmin; Moon, Kyungsun

Conventional circuit QED system consists of a qubit located inside a linear stripline resonator, which has successfully demonstrated a strong coupling between a single photon and a qubit. Here we present a new circuit QED system, where the qubit is coupled to triple-leg stripline resonator (TSR). We have shown that TSR supports two-fold degenerate photon modes among others. By coupling them to a single qubit, we have obtained the dressed states of a coupled system of a single qubit and two-fold degenerate photon modes. By locating two qubits at two legs of TSR, we have studied a potential two-bit gate operation (e.g., CNOT gate) of the system. We will discuss the main advantage of utilizing two-fold degenerate photon modes This work is partially supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF-2016R1D1A1B01013756).

Test of non-commutative QED in the process $e^{+}e^{-} \\to \\gamma \\gamma$ at LEP

CERN Document Server

Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Bloodworth, I.J.; Boeriu, O.; Bock, P.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Buesser, K.; Burckhart, H.J.; Campana, S.; Carnegie, R.K.; Caron, B.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Elfgren, E.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Gagnon, P.; Gary, John William; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Homer, R.J.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kormos, Laura L.; Kramer, T.; Kress, T.; Krieger, P.; von Krogh, J.; Kruger, K.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Layter, J.G.; Leins, A.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, J.; Macpherson, A.; Mader, W.; Marcellini, S.; Martin, A.J.; Masetti, G.; Mashimo, T.; Mattig, Peter; McDonald, W.J.; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Rick, H.; Roney, J.M.; Rosati, S.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schoerner-Sadenius, Thomas; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Siroli, G.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Stephens, K.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Taylor, R.J.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Tricoli, A.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

2003-01-01

Non-communicative QED would lead to deviations from the Standard Model depending on a new energy scale $\\Delta_{NC}$ and a unique direction in space defined by two angles $\\eta$ and $\\xi$. Here in this analysis $\\eta$ is defined as the angle between the unique direction and the rotation axis of the earth. The predictions of such a theory for the process $e^{+} e^{-} \\to \\gamma \\gamma$ are evalued for the specific orientation of the OPAL detector and compared to the measurements. Distributions of the polar and azimuthal scattering angles are used to extract limits on the energy scale $\\Delta_{NC}$ depending on the model parameter $\\eta$. At the 95% confidence level $\\Delta_{NC}$ is found to be larger than 141 GeV for all $\\eta$ and $\\xi$. It is shown that the time dependence of the total cross-section could be used to determine the model parameter $\\xi$ if there were a detectable signal. These are the first limits obtained on non-commutative QED from an $e^{+} e^{-}$ collider experiment.

Impact of the coupling effect and the configuration on a compact rectenna array

Science.gov (United States)

Rivière, J.; Douyere, A.; Luk, J. D. Lan Sun

2014-10-01

This paper proposes an experimental study of the coupling effect of a rectenna array. The rectifying antenna consists of a compact and efficient rectifying circuit in a series topology, coupled with a small metamaterial-inspired antenna. The measurements are investigated in the X plane on the rectenna array's behavior, with series and parallel DC- combining configuration of two and three spaced rectennas from 3 cm to 10 cm. This study shows that the maximum efficiency is reached for the series configuration, with a resistive load of 10 kQ. The optimal distance is not significant for series or parallel configuration. Then, a comparison between a rectenna array with non-optimal mutual coupling and a more traditional patch rectenna is performed. Finally, a practical application is tested to demonstrate the effectiveness of such small rectenna array.

On the screening of static electromagnetic fields in hot QED plasmas

International Nuclear Information System (INIS)

Blaizot, J.P.

1995-01-01

The screening of static magnetic and electric fields was studied in massless quantum electrodynamics (QED) and massless scalar electrodynamics (SQED) at temperature T. Various exact relations for the static polarization tensor are first reviewed, and then verified perturbatively to fifth order (in the coupling) in QED and fourth order in SQED, using different resummation techniques. The magnetic and electric screening masses squared, as defined through the pole of the static propagators, are also calculated to fifth order in QED and fourth order in SQED, and their gauge-independence and renormalisation-group invariance is checked. Finally, arguments are provided for the vanishing of the magnetic mass to all orders in perturbation theory. (author) 26 refs

Gauge-invariant dressed fermion propagator in massless QED3

International Nuclear Information System (INIS)

Mitra, Indrajit; Ratabole, Raghunath; Sharatchandra, H.S.

2006-01-01

The infrared behaviour of the gauge-invariant dressed fermion propagator in massless QED 3 is discussed for three choices of dressing. It is found that only the propagator with the isotropic (in three Euclidean dimensions) choice of dressing is acceptable as the physical fermion propagator. It is explained that the negative anomalous dimension of this physical fermion does not contradict any field-theoretical requirement

Gauge covariance of the fermion Schwinger–Dyson equation in QED

Energy Technology Data Exchange (ETDEWEB)

Jia, Shaoyang, E-mail: sjia@email.wm.edu [Physics Department, College of William & Mary, Williamsburg, VA 23187 (United States); Pennington, M.R., E-mail: michaelp@jlab.org [Physics Department, College of William & Mary, Williamsburg, VA 23187 (United States); Theory Center, Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States)

2017-06-10

Any practical application of the Schwinger–Dyson equations to the study of n-point Green's functions in a strong coupling field theory requires truncations. In the case of QED, the gauge covariance, governed by the Landau–Khalatnikov–Fradkin transformations (LKFT), provides a unique constraint on such truncation. By using a spectral representation for the massive fermion propagator in QED, we are able to show that the constraints imposed by the LKFT are linear operations on the spectral densities. We formally define these group operations and show with a couple of examples how in practice they provide a straightforward way to test the gauge covariance of any viable truncation of the Schwinger–Dyson equation for the fermion 2-point function.

Quasiparadoxes of massless QED

International Nuclear Information System (INIS)

Smilga, A.V.

1990-04-01

We show that the limit m e =0 in the conventional QED is not smooth. In contrast to the massless QED the massive QED, however small the mass is, involves finite probability chirality breaking processes. The chirality breaking effects may be observed provided the size of experimental installation is greater than the formation length ∼ E/m 2 . We discuss also the finite cross sections of virtual longitudinal photon production and scattering in massless QED recently found by Gorsky, Ioffe and Khodjamirian and argue that real longitudinal photons do not interact while the limit of zero virtuality is not smooth. (author). 23 refs, 4 figs

Exploring high-intensity QED at ELI

Energy Technology Data Exchange (ETDEWEB)

Heinzl, T. [Plymouth Univ., School of Mathematics and Statistics, Drake Circus, PL4 8AA (United Kingdom); Ilderton, A. [School of Mathematics, Hamilton Building, Trinity College, Dublin (Ireland)

2009-11-15

We give a non-technical overview of quantum electrodynamics (QED) effects arising in the presence of ultra-strong electromagnetic fields highlighting the new prospects provided by a realisation of the ELI laser facility. Vacuum polarization is a genuine QED process describing the probability amplitude of a propagating photon fluctuating into a virtual electron-positron pair. It has measurable effects such as the Lamb shift and charge screening at short distances. Nonlinear Compton scattering that consists of processes of the type: e + ngamma{sub L} -> e' + gamma (where n counting the number of laser photons involved) is an intensity dependent effect that is accessible to experimental observation

Circuit QED with transmon qubits

Energy Technology Data Exchange (ETDEWEB)

Wulschner, Karl Friedrich; Puertas, Javier; Baust, Alexander; Eder, Peter; Fischer, Michael; Goetz, Jan; Haeberlein, Max; Schwarz, Manuel; Xie, Edwar; Zhong, Ling; Deppe, Frank; Fedorov, Kirill; Marx, Achim; Menzel, Edwin; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Huebl, Hans [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Weides, Martin [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany)

2015-07-01

Superconducting quantum bits are basic building blocks for circuit QED systems. Applications in the fields of quantum computation and quantum simulation require long coherence times. We have fabricated and characterized superconducting transmon qubits which are designed to operate at a high ratio of Josephson energy and charging energy. Due to their low sensitivity to charge noise transmon qubits show good coherence properties. We couple transmon qubits to coplanar waveguide resonators and coplanar slotline resonators and characterize the devices at mK-temperatures. From the experimental data we derive the qubit-resonator coupling strength, the qubit relaxation time and calibrate the photon number in the resonator via Stark shifts.

Circuit QED with qutrits: Coupling three or more atoms via virtual-photon exchange

Science.gov (United States)

Zhao, Peng; Tan, Xinsheng; Yu, Haifeng; Zhu, Shi-Liang; Yu, Yang

2017-10-01

We present a model to describe a generic circuit QED system which consists of multiple artificial three-level atoms, namely, qutrits, strongly coupled to a cavity mode. When the state transition of the atoms disobeys the selection rules the process that does not conserve the number of excitations can happen determinatively. Therefore, we can realize coherent exchange interaction among three or more atoms mediated by the exchange of virtual photons. In addition, we generalize the one-cavity-mode mediated interactions to the multicavity situation, providing a method to entangle atoms located in different cavities. Using experimentally feasible parameters, we investigate the dynamics of the model including three cyclic-transition three-level atoms, for which the two lowest energy levels can be treated as qubits. Hence, we have found that two qubits can jointly exchange excitation with one qubit in a coherent and reversible way. In the whole process, the population in the third level of atoms is negligible and the cavity photon number is far smaller than 1. Our model provides a feasible scheme to couple multiple distant atoms together, which may find applications in quantum information processing.

Classical electromagnetic non-minimal coupling for spin 3/2 fields

International Nuclear Information System (INIS)

Villanueva, V. M.; Obregon, O.; Nieto, J. A.

1996-01-01

We obtain a non-minimal electromagnetic coupling for spin 3/2 particles from linearized N=2 Supergravity. This coupling coincides with the one found by Ferrara et al. by demanding g=2 at the tree level. Linearized Einstein field equations plus interaction terms are obtained by squaring the Rarita-Schwinger with this non-minimal coupling by using generalized Poisson brackets

QED effects on individual atomic orbital energies

Science.gov (United States)

Kozioł, Karol; Aucar, Gustavo A.

2018-04-01

Several issues, concerning QED corrections, that are important in precise atomic calculations are presented. The leading QED corrections, self-energy and vacuum polarization, to the orbital energy for selected atoms with 30 ≤ Z ≤ 118 have been calculated. The sum of QED and Breit contributions to the orbital energy is analyzed. It has been found that for ns subshells the Breit and QED contributions are of comparative size, but for np and nd subshells the Breit contribution takes a major part of the QED+Breit sum. It has also, been found that the Breit to leading QED contributions ratio for ns subshells is almost independent of Z. The Z-dependence of QED and Breit+QED contributions per subshell is shown. The fitting coefficients may be used to estimate QED effects on inner molecular orbitals. We present results of our calculations for QED contributions to orbital energy of valence ns-subshell for group 1 and 11 atoms and discuss about the reliability of these numbers by comparing them with experimental first ionization potential data.

Gauge-invariant dressed fermion propagator in massless QED{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Mitra, Indrajit [Theory Group, Saha Institute of Nuclear Physics, 1/AF Bidhan-Nagar, Kolkata 700064 (India)]. E-mail: indrajit.mitra@saha.ac.in; Ratabole, Raghunath [Institute of Mathematical Sciences, C.I.T. Campus, Taramani P.O., Chennai 600113 (India)]. E-mail: raghu@imsc.res.in; Sharatchandra, H.S. [Institute of Mathematical Sciences, C.I.T. Campus, Taramani P.O., Chennai 600113 (India)]. E-mail: sharat@imsc.res.in

2006-04-27

The infrared behaviour of the gauge-invariant dressed fermion propagator in massless QED{sub 3} is discussed for three choices of dressing. It is found that only the propagator with the isotropic (in three Euclidean dimensions) choice of dressing is acceptable as the physical fermion propagator. It is explained that the negative anomalous dimension of this physical fermion does not contradict any field-theoretical requirement.

Theory of superfluorescence-laser crossover in a cavity QED system

Energy Technology Data Exchange (ETDEWEB)

Sezaki, Riku; Ishikawa, Akira; Kobayashi, Kiyoshi [University of Yamanashi, Department of Science for Advanced Materials, Kofu, Yamanashi (Japan); Miyajima, Kensuke [Tokyo University of Science, Department of Applied Physics, Tokyo (Japan)

2017-11-15

Coherent emissions of photons, originating from coherently-coupled polarizations, are created by laser and superfluorescence, but the mechanisms remain obscure to be fully explored in nanophotonics from the application viewpoint to coherent-light sources. In this paper, we present a comprehensive full quantum theory to clarify the crossover between laser and superfluorescence caused by the competition between stimulated and spontaneous emissions in a cavity QED system. As a result, in case of steady-state emission, we show the feasibility of coherent-light emission by superfluorescence different from laser, depending on the quality factor of a cavity QED system. In particular, the coherence generation due to superfluorescence occurs in a shorter timescale in a cavity QED systems with a lower Q factor than laser due to stimulated emission. This result suggests that superfluorescence can be applied to a novel coherent-light source by a mechanism greatly different from laser. (orig.)

Chiral symmetry breaking and confinement in Minkowski space QED2+1

International Nuclear Information System (INIS)

Sauli, V.; Batiz, Z.

2010-01-01

extensions (largely anisotropic and nonrelativistic) of QED3 as an effective theories of the pseudogap insulator/superconducting phase transition. The finite temperature QED3 Euclidean action seems to be enough for the effective description of the phenomena. However the inequivalence between Euclidean and spacelike Minkowski subspace should be kept mind when trying to make some conclusion based on the naive continuation the real time metric. More interestingly, one can expect new outcomes when the similar ideology is applied to the strong coupling even dimensional theories, e.g. to the most successful theory of the strong interaction in the nature: QCD. Note, similar strategy in renormalizable theories is not so straightforward because of presented infinities. In this case, following the experience from QED2+1 here and proposing an approximations in Temporal Euclidean space can offer a simple guide which can be realistic enough to provide reasonable Minkowski space SDEs framework for low energy hadronic physics. (author)

Quenched QED in the chiral limit

International Nuclear Information System (INIS)

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 ψψ), in the quenched limit of euclidean QED, where the number of fermion flavors goes to zero, using the path integral formulation. A cutoff scale, Λ, is introduced into the photon propagator and a new expansion, the open-quotes wormhole expansion,close quotes in powers of Λ 2 /m 2 , where m is the fermion mass, is derived. Graphical rules for the wormhole expansion of left-angle bar ψψ right-angle are described in detail. The author then devises algorithms to generate recursively the graphs at each successive order and to perform the loop momentum integral and γ matrix trace involved in the evaluation of each graph. These algorithms are implemented in Mathmatica and the left-angle bar ψψ right-angle expansion is carried out to order (Λ 2 / m 2 ) 6 . The author employs pade techniques to extrapolate this expansion to the chiral limit (Λ 2 /m 2 → ∞) and looks for a singularity at strong coupling to signal a phase transition. Indications have been found that there may be a phase transition but apparently there are not enough terms in the wormhole expansion to attain stability in our pade analysis. The author therefore cannot conclude that there is a chiral phase transition, although the results are consistent with the existence of one

Electron-electron bound states in Maxwell-Chern-Simons-Proca QED3

International Nuclear Information System (INIS)

Belich, H.; Helayel-Neto, J.A.; Ferreira, M.M. Jr.; Maranhao Univ., Sao Luis, MA

2002-10-01

We start from a parity-breaking MCS QED 3 model with spontaneous breaking of the gauge symmetry as a framework for evaluation of the electron-electron interaction potential and for attainment of numerical values for the e - e - - bound state. Three expressions V eff↓↓ , V eff↓↑ , V eff↓↓ ) are obtained according to the polarization state of the scattered electrons. In an energy scale compatible with condensed matter electronic excitations, these potentials become degenerated. The resulting potential is implemented in the Schroedinger equation and the variational method is applied to carry out the electronic binding energy. The resulting binding energies in the scale of 10-100 meV and a correlation length in the scale of 10 - 30 Angstrom are possible indications that the MCS-QED 3 model adopted may be suitable to address an eventual case of e - e - pairing in the presence of parity-symmetry breakdown. The data analyzed here suggest an energy scale of 10-100 meV to fix the breaking of the U(1)-symmetry. (author)

New Applications of Resummation in Non-Abelian Gauge Theories: QED-QCD Exponentiation for LHC Physics, IR-Improved DGLAP Theory and Resummed Quantum Gravity

International Nuclear Information System (INIS)

Ward, B.F.L.

2006-01-01

We present the elements of three applications of resummation methods in non-Abelian gauge theories: (1), QED-QCD exponentiation and shower/ME matching for LHC physics; (2), IR improvement of DGLAP theory; (3), resummed quantum gravity and the final state of Hawking radiation. In all cases, the extension of the YFS approach, originally introduced for Abelian gauge theory, to non-Abelian gauge theories, QCD and quantum general relativity, leads to new results and solutions which we briefly summarize

Parton distribution functions with QED corrections in the valon model

Science.gov (United States)

Mottaghizadeh, Marzieh; Taghavi Shahri, Fatemeh; Eslami, Parvin

2017-10-01

The parton distribution functions (PDFs) with QED corrections are obtained by solving the QCD ⊗QED DGLAP evolution equations in the framework of the "valon" model at the next-to-leading-order QCD and the leading-order QED approximations. Our results for the PDFs with QED corrections in this phenomenological model are in good agreement with the newly related CT14QED global fits code [Phys. Rev. D 93, 114015 (2016), 10.1103/PhysRevD.93.114015] and APFEL (NNPDF2.3QED) program [Comput. Phys. Commun. 185, 1647 (2014), 10.1016/j.cpc.2014.03.007] in a wide range of x =[10-5,1 ] and Q2=[0.283 ,108] GeV2 . The model calculations agree rather well with those codes. In the latter, we proposed a new method for studying the symmetry breaking of the sea quark distribution functions inside the proton.

Tunable-Range, Photon-Mediated Atomic Interactions in Multimode Cavity QED

Directory of Open Access Journals (Sweden)

Varun D. Vaidya

2018-01-01

Full Text Available Optical cavity QED provides a platform with which to explore quantum many-body physics in driven-dissipative systems. Single-mode cavities provide strong, infinite-range photon-mediated interactions among intracavity atoms. However, these global all-to-all couplings are limiting from the perspective of exploring quantum many-body physics beyond the mean-field approximation. The present work demonstrates that local couplings can be created using multimode cavity QED. This is established through measurements of the threshold of a superradiant, self-organization phase transition versus atomic position. Specifically, we experimentally show that the interference of near-degenerate cavity modes leads to both a strong and tunable-range interaction between Bose-Einstein condensates (BECs trapped within the cavity. We exploit the symmetry of a confocal cavity to measure the interaction between real BECs and their virtual images without unwanted contributions arising from the merger of real BECs. Atom-atom coupling may be tuned from short range to long range. This capability paves the way toward future explorations of exotic, strongly correlated systems such as quantum liquid crystals and driven-dissipative spin glasses.

Agglomeration of powders with a new-coupled vibration-compaction device

Directory of Open Access Journals (Sweden)

Serris Eric

2017-01-01

Full Text Available Inorganic powder recycling should be a crucial process for the “smart factories” in the future. A complex three-phase system (bauxite mixed with ordinary Portland cement and water with a new-coupled vibration-compaction device is studied. The compressive stress of compacts seems to be improved by using this device at low compaction pressure leaving the other characteristics unchanged. The tomographic study of macroscopic porosities shows differences in the pores repartitions inside vibrated and untreated compacts. Classic porosity repartition is shown in the classic compacted bauxite compacts whereas in the vibrated-compacted bauxite exhibits inhomogeneities. Despite this, we find these results quite promising for further investigations.

Polarizability sum rules in QED

International Nuclear Information System (INIS)

Llanta, E.; Tarrach, R.

1978-01-01

The well founded total photoproduction and the, assumed subtraction free, longitudinal photoproduction polarizability sum rules are checked in QED at the lowest non-trivial order. The first one is shown to hold, whereas the second one turns out to need a subtraction, which makes its usefulness for determining the electromagnetic polarizabilities of the nucleons quite doubtful. (Auth.)

The QED Workshop

Energy Technology Data Exchange (ETDEWEB)

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.

Endemic infrared divergences in QED3 at finite temperature

International Nuclear Information System (INIS)

Lo, Pok Man; Swanson, Eric S.

2011-01-01

We demonstrate that massless QED in three dimensions contains endemic infrared divergences. It is argued that these divergences do not affect observables; furthermore, it is possible to choose a gauge that renders the theory finite.

Resonator QED experiments with single {sup 40}Ca{sup +} ions; Resonator-QED-Experimente mit einzelnen {sup 40}Ca{sup +}-Ionen

Energy Technology Data Exchange (ETDEWEB)

Lange, B.

2006-12-20

Combining an optical resonator with an ion trap provides the possibility for QED experiments with single or few particles interacting with a single mode of the electro-magnetic field (Cavity-QED). In the present setup, fluctuations in the count rate on a time scale below 30 seconds were purely determined by the photon statistics due to finite emission and detection efficiency, whereas a marginal drift of the system was noticeable above 200 seconds. To find methods to increase the efficiency of the photon source, investigations were conducted and experimental improvements of the setup implemented in the frame of this thesis. Damping of the resonator field and coupling of ion and field were considered as the most important factors. To reduce the damping of the resonator field, a resonator with a smaller transmissivity of the output mirror was set up. The linear trap used in the experiment allows for the interaction of multiple ions with the resonator field, so that more than one photon may be emitted per pump pulse. This was investigated in this thesis with two ions coupled to the resonator. The cross correlation of the emitted photons was measured with the Hanbury Brown-Twiss method. (orig.)

Nonlinear optics quantum computing with circuit QED.

Science.gov (United States)

Adhikari, Prabin; Hafezi, Mohammad; Taylor, J M

2013-02-08

One approach to quantum information processing is to use photons as quantum bits and rely on linear optical elements for most operations. However, some optical nonlinearity is necessary to enable universal quantum computing. Here, we suggest a circuit-QED approach to nonlinear optics quantum computing in the microwave regime, including a deterministic two-photon phase gate. Our specific example uses a hybrid quantum system comprising a LC resonator coupled to a superconducting flux qubit to implement a nonlinear coupling. Compared to the self-Kerr nonlinearity, we find that our approach has improved tolerance to noise in the qubit while maintaining fast operation.

Optical Search for QED vacuum magnetic birefringence, Axions and photon Regeneration

CERN Multimedia

Pugnat, P; Hryczuk, A; Finger, M; Finger, M; Kral, M

2007-01-01

Since its prediction in 1936 by Euler, Heisenberg and Weisskopf in the earlier development of the Quantum Electrodynamic (QED) theory, the Vacuum Magnetic Birefringence (VMB) is still a challenge for optical metrology techniques. According to QED, the vacuum behaves as an optically active medium in the presence of an external magnetic field. It can be experimentally probed with a linearly polarized laser beam. After propagating through the vacuum submitted to a transverse magnetic field, the polarization of the laser beam will change to elliptical and the parameters of the polarization are directly related to fundamental constants such as the fine structure constant and the electron Compton wavelength. Contributions to the VMB could also arise from the existence of light scalar or pseudo-scalar particles like axions that couple to two photons and this would manifest itself as a sizeable deviation from the initial QED prediction. On one side, the interest in axion search, providing an answer to the strong-CP p...

Dynamics of High-Order Spin-Orbit Couplings about Linear Momenta in Compact Binary Systems*

International Nuclear Information System (INIS)

Huang Li; Wu Xin; Huang Guo-Qing; Mei Li-Jie

2017-01-01

This paper relates to the post-Newtonian Hamiltonian dynamics of spinning compact binaries, consisting of the Newtonian Kepler problem and the leading, next-to-leading and next-to-next-to-leading order spin-orbit couplings as linear functions of spins and momenta. When this Hamiltonian form is transformed to a Lagrangian form, besides the terms corresponding to the same order terms in the Hamiltonian, several additional terms, third post-Newtonian (3PN), 4PN, 5PN, 6PN and 7PN order spin-spin coupling terms, yield in the Lagrangian. That means that the Hamiltonian is nonequivalent to the Lagrangian at the same PN order but is exactly equivalent to the full Lagrangian without any truncations. The full Lagrangian without the spin-spin couplings truncated is integrable and regular. Whereas it is non-integrable and becomes possibly chaotic when any one of the spin-spin terms is dropped. These results are also supported numerically. (paper)

Resonator QED experiments with single 40Ca+ ions

International Nuclear Information System (INIS)

Lange, B.

2006-01-01

Combining an optical resonator with an ion trap provides the possibility for QED experiments with single or few particles interacting with a single mode of the electro-magnetic field (Cavity-QED). In the present setup, fluctuations in the count rate on a time scale below 30 seconds were purely determined by the photon statistics due to finite emission and detection efficiency, whereas a marginal drift of the system was noticeable above 200 seconds. To find methods to increase the efficiency of the photon source, investigations were conducted and experimental improvements of the setup implemented in the frame of this thesis. Damping of the resonator field and coupling of ion and field were considered as the most important factors. To reduce the damping of the resonator field, a resonator with a smaller transmissivity of the output mirror was set up. The linear trap used in the experiment allows for the interaction of multiple ions with the resonator field, so that more than one photon may be emitted per pump pulse. This was investigated in this thesis with two ions coupled to the resonator. The cross correlation of the emitted photons was measured with the Hanbury Brown-Twiss method. (orig.)

Direct measurement of alpha_QED(mZ)at the FCC-ee

CERN Document Server

Janot, Patrick

2016-02-08

When the measurements from the FCC-ee become available, an improved determination of the standard-model "input" parameters will be needed to fully exploit the new precision data towards either constraining or fitting the parameters of beyond-the-standard-model theories. Among these input parameters is the electromagnetic coupling constant estimated at the Z mass scale, alpha_QED(mZ). The measurement of the muon forward- backward asymmetry at the FCC-ee, just below and just above the Z pole, can be used to make a direct determination of alpha_QED(mZ) with an accuracy deemed adequate for an optimal use of the FCC-ee precision data.

Nonperturbative infrared dynamics in three dimensional QED

International Nuclear Information System (INIS)

Gusynin, V.P.

2000-01-01

A non-linear Schwinger-Dyson (SD) equation for the gauge boson propagator of massless QED in 2 + 1 dimensions is studied. It is shown that the nonperturbative solution leads to a non-trivial renormalization-group infrared fixed point quantitatively close to the one found in the leading order of the 1/N expansion, with N the number of fermion flavors

QED with minimal and nonminimal couplings: on the quantum generation of Lorentz violating terms in the pure photon sector

Energy Technology Data Exchange (ETDEWEB)

Gazzola, G.; Fargnoli, H.G.; Sampaio, Marcos; Nemes, M.C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Scarpelli, A.P. Baeta [Departamento de Policia Federal (DPF), Sao Paulo, SP (Brazil). Setor Tecnico-Cientifico

2011-07-01

In this research we consider a modified version of quantum electrodynamics in four dimensions with the coupling between the photon and the fermion composed by two terms: a nonminimal and the minimal one. There are two interesting aspects in this model. First, gauge invariance is restored by the presence of the minimal coupling. Second, the quantum corrections will allow for the possibility of the generation of a Chern-Simons-like term. The fact that the model is gauge invariant allows for a more complete analysis on the value of both the coefficients of the hypothetical CPT odd and CPT even radiatively generated terms. A question that arises involves a possible violation of some Ward-Takahashi identity when radiative corrections are taken into account. In other words, is there an anomaly in the model? We show that, since conventional QED is gauge invariant, there is no room for a non transversal vacuum polarization tensor in the present model. This is study is to be presented in the following order: first we are to present the model; second we do an analysis on the generation of Lorentz violating terms in the pure gauge sector; third we carry out a calculation on gauge invariance grounds to fix the coefficients of the quantum corrections; and lastly the concluding comments. (author)

QED with minimal and nonminimal couplings: on the quantum generation of Lorentz violating terms in the pure photon sector

International Nuclear Information System (INIS)

Gazzola, G.; Fargnoli, H.G.; Sampaio, Marcos; Nemes, M.C.; Scarpelli, A.P. Baeta

2011-01-01

In this research we consider a modified version of quantum electrodynamics in four dimensions with the coupling between the photon and the fermion composed by two terms: a nonminimal and the minimal one. There are two interesting aspects in this model. First, gauge invariance is restored by the presence of the minimal coupling. Second, the quantum corrections will allow for the possibility of the generation of a Chern-Simons-like term. The fact that the model is gauge invariant allows for a more complete analysis on the value of both the coefficients of the hypothetical CPT odd and CPT even radiatively generated terms. A question that arises involves a possible violation of some Ward-Takahashi identity when radiative corrections are taken into account. In other words, is there an anomaly in the model? We show that, since conventional QED is gauge invariant, there is no room for a non transversal vacuum polarization tensor in the present model. This is study is to be presented in the following order: first we are to present the model; second we do an analysis on the generation of Lorentz violating terms in the pure gauge sector; third we carry out a calculation on gauge invariance grounds to fix the coefficients of the quantum corrections; and lastly the concluding comments. (author)

The Hamiltonian of QED. Zero mode

International Nuclear Information System (INIS)

Zastavenko, L.G.

1990-01-01

We start with the standard QED Lagrangian. New derivation of the spinor QED Hamiltonian is given. We have taken into account the zero mode. Our derivation is faultless from the point of view of gauge invariance. It gives important corrections to the standard QED Hamiltonian. Our derivation of the Hamiltonian can be generalized to the case of QCD. 5 refs

Nonperturbative QED vacuum birefringence

Energy Technology Data Exchange (ETDEWEB)

Denisov, V.I.; Dolgaya, E.E.; Sokolov, V.A. [Physics Department, Moscow State University,Moscow, 119991 (Russian Federation)

2017-05-19

In this paper we represent nonperturbative calculation for one-loop Quantum Electrodynamics (QED) vacuum birefringence in presence of strong magnetic field. The dispersion relations for electromagnetic wave propagating in strong magnetic field point to retention of vacuum birefringence even in case when the field strength greatly exceeds Sauter-Schwinger limit. This gives a possibility to extend some predictions of perturbative QED such as electromagnetic waves delay in pulsars neighbourhood or wave polarization state changing (tested in PVLAS) to arbitrary magnetic field values. Such expansion is especially important in astrophysics because magnetic fields of some pulsars and magnetars greatly exceed quantum magnetic field limit, so the estimates of perturbative QED effects in this case require clarification.

Single atoms on demand for cavity QED experiments

International Nuclear Information System (INIS)

Dotsenko, I.

2007-01-01

Cavity quantum electrodynamics (cavity QED) describes electromagnetic fields in a confined space and the radiative properties of atoms in such fields. The simplest example of such system is a single atom interacting with one mode of a high-finesse resonator. Besides observation and exploration of fundamental quantum mechanical effects, this system bears a high potential for applications quantum information science such as, e.g., quantum logic gates, quantum communication and quantum teleportation. In this thesis I present an experiment on the deterministic coupling of a single neutral atom to the mode of a high-finesse optical resonator. In Chapter 1 I describe our basic techniques for trapping and observing single cesium atoms. As a source of single atoms we use a high-gradient magneto-optical trap, which captures the atoms from background gas in a vacuum chamber and cools them down to millikelvin temperatures. The atoms are then transferred without loss into a standing-wave dipole trap, which provides a conservative potential required for experiments on atomic coherence such as quantum information processing and metrology on trapped atoms. Moreover, shifting the standing-wave pattern allows us to deterministically transport the atoms (Chapter 2). In combination with nondestructive fluorescence imaging of individual trapped atoms, this enables us to control their position with submicrometer precision over several millimeters along the dipole trap. The cavity QED system can distinctly display quantum behaviour in the so-called strong coupling regime, i.e., when the coherent atom-cavity coupling rate dominates dissipation in the system. This sets the main requirements on the resonator's properties: small mode volume and high finesse. Chapter 3 is devoted to the manufacturing, assembling, and testing of an ultra-high finesse optical Fabry-Perot resonator, stabilized to the atomic transition. In Chapter 4 I present the transportation of single atoms into the cavity

Single atoms on demand for cavity QED experiments

Energy Technology Data Exchange (ETDEWEB)

Dotsenko, I.

2007-09-06

Cavity quantum electrodynamics (cavity QED) describes electromagnetic fields in a confined space and the radiative properties of atoms in such fields. The simplest example of such system is a single atom interacting with one mode of a high-finesse resonator. Besides observation and exploration of fundamental quantum mechanical effects, this system bears a high potential for applications quantum information science such as, e.g., quantum logic gates, quantum communication and quantum teleportation. In this thesis I present an experiment on the deterministic coupling of a single neutral atom to the mode of a high-finesse optical resonator. In Chapter 1 I describe our basic techniques for trapping and observing single cesium atoms. As a source of single atoms we use a high-gradient magneto-optical trap, which captures the atoms from background gas in a vacuum chamber and cools them down to millikelvin temperatures. The atoms are then transferred without loss into a standing-wave dipole trap, which provides a conservative potential required for experiments on atomic coherence such as quantum information processing and metrology on trapped atoms. Moreover, shifting the standing-wave pattern allows us to deterministically transport the atoms (Chapter 2). In combination with nondestructive fluorescence imaging of individual trapped atoms, this enables us to control their position with submicrometer precision over several millimeters along the dipole trap. The cavity QED system can distinctly display quantum behaviour in the so-called strong coupling regime, i.e., when the coherent atom-cavity coupling rate dominates dissipation in the system. This sets the main requirements on the resonator's properties: small mode volume and high finesse. Chapter 3 is devoted to the manufacturing, assembling, and testing of an ultra-high finesse optical Fabry-Perot resonator, stabilized to the atomic transition. In Chapter 4 I present the transportation of single atoms into the

Compact 3D quantum memory

Science.gov (United States)

Xie, Edwar; Deppe, Frank; Renger, Michael; Repp, Daniel; Eder, Peter; Fischer, Michael; Goetz, Jan; Pogorzalek, Stefan; Fedorov, Kirill G.; Marx, Achim; Gross, Rudolf

2018-05-01

Superconducting 3D microwave cavities offer state-of-the-art coherence times and a well-controlled environment for superconducting qubits. In order to realize at the same time fast readout and long-lived quantum information storage, one can couple the qubit to both a low-quality readout and a high-quality storage cavity. However, such systems are bulky compared to their less coherent 2D counterparts. A more compact and scalable approach is achieved by making use of the multimode structure of a 3D cavity. In our work, we investigate such a device where a transmon qubit is capacitively coupled to two modes of a single 3D cavity. External coupling is engineered so that the memory mode has an about 100 times larger quality factor than the readout mode. Using an all-microwave second-order protocol, we realize a lifetime enhancement of the stored state over the qubit lifetime by a factor of 6 with a fidelity of approximately 80% determined via quantum process tomography. We also find that this enhancement is not limited by fundamental constraints.

Lorentz and CPT violation in QED revisited: A missing analysis

Energy Technology Data Exchange (ETDEWEB)

Del Cima, Oswaldo M., E-mail: wadodelcima@if.uff.b [Universidade Federal Fluminense (UFF), Polo Universitario de Rio das Ostras, Rua Recife s/n, 28890-000, Rio das Ostras, RJ (Brazil); Fonseca, Jakson M., E-mail: jakson.fonseca@ufv.b [Universidade Federal de Vicosa (UFV), Departamento de Fisica, Avenida Peter Henry Rolfs s/n, 36570-000, Vicosa, MG (Brazil); Franco, Daniel H.T., E-mail: daniel.franco@ufv.b [Universidade Federal de Vicosa (UFV), Departamento de Fisica, Avenida Peter Henry Rolfs s/n, 36570-000, Vicosa, MG (Brazil); Piguet, Olivier, E-mail: opiguet@pq.cnpq.b [Universidade Federal do Espirito Santo (UFES), Departamento de Fisica, Campus Universitario de Goiabeiras, 29060-900, Vitoria, ES (Brazil)

2010-05-03

We investigate the breakdown of Lorentz symmetry in QED by a CPT violating interaction term consisting of the coupling of an axial fermion current with a constant vector field b, in the framework of algebraic renormalization - a regularization-independent method. We show, to all orders in perturbation theory, that a CPT-odd and Lorentz violating Chern-Simons-like term, definitively, is not radiatively induced by the axial coupling of the fermions with the constant vector b.

Lorentz and CPT violation in QED revisited: A missing analysis

International Nuclear Information System (INIS)

Del Cima, Oswaldo M.; Fonseca, Jakson M.; Franco, Daniel H.T.; Piguet, Olivier

2010-01-01

We investigate the breakdown of Lorentz symmetry in QED by a CPT violating interaction term consisting of the coupling of an axial fermion current with a constant vector field b, in the framework of algebraic renormalization - a regularization-independent method. We show, to all orders in perturbation theory, that a CPT-odd and Lorentz violating Chern-Simons-like term, definitively, is not radiatively induced by the axial coupling of the fermions with the constant vector b.

Electron-electron bound states in Maxwell-Chern-Simons-Proca QED{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Belich, H.; Helayel-Neto, J.A. [Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil)]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas]. E-mail: belich@cbpf.br; helayel@gft.ucp.br; Del Cima, O.M. [Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil)]. E-mail: delcima@gft.ucp.br; Ferreira, M.M. Jr. [Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil)]|[Maranhao Univ., Sao Luis, MA (Brazil). Dept. de Fisica]. E-mail: manojr@cbpf.br

2002-10-01

We start from a parity-breaking MCS QED{sub 3} model with spontaneous breaking of the gauge symmetry as a framework for evaluation of the electron-electron interaction potential and for attainment of numerical values for the e{sup -}e{sup -} - bound state. Three expressions (V{sub eff{down_arrow}}{sub {down_arrow}}, V{sub eff{down_arrow}}{sub {up_arrow}}, V{sub eff{down_arrow}}{sub {down_arrow}}) are obtained according to the polarization state of the scattered electrons. In an energy scale compatible with condensed matter electronic excitations, these potentials become degenerated. The resulting potential is implemented in the Schroedinger equation and the variational method is applied to carry out the electronic binding energy. The resulting binding energies in the scale of 10-100 meV and a correlation length in the scale of 10 - 30 Angstrom are possible indications that the MCS-QED{sub 3} model adopted may be suitable to address an eventual case of e{sup -}e{sup -} pairing in the presence of parity-symmetry breakdown. The data analyzed here suggest an energy scale of 10-100 meV to fix the breaking of the U(1)-symmetry. (author)

QED radiative corrections under the SANC project

International Nuclear Information System (INIS)

Christova, P.

2003-01-01

Automatic calculations of the QED radiative corrections in the framework of the SANC computer system is described. A collection of the computer programs written in FORM3 language is aimed at compiling a database of analytic results to be used to theoretically support the experiments on high-energy accelerators. Presented here is the scheme of automatic analytical calculations of the QED radiative corrections to the fermionic decays of the Z, H and W boson in the framework of the SANC system

Charged hadrons in local finite-volume QED+QCD with C* boundary conditions

CERN Document Server

Lucini, Biagio; Ramos, Alberto; Tantalo, Nazario

2016-01-01

In order to calculate QED corrections to hadronic physical quantities by means of lattice simulations, a coherent description of electrically-charged states in finite volume is needed. In the usual periodic setup, Gauss's law and large gauge transformations forbid the propagation of electrically-charged states. A possible solution to this problem, which does not violate the axioms of local quantum field theory, has been proposed by Wiese and Polley, and is based on the use of C* boundary conditions. We present a thorough analysis of the properties and symmetries of QED in isolation and QED coupled to QCD, with C* boundary conditions. In particular we learn that a certain class of electrically-charged states can be constructed in this setup in a fully consistent fashion, without relying on gauge fixing. We argue that this class of states covers most of the interesting phenomenological applications in the framework of numerical simulations. We also calculate finite-volume corrections to the mass of stable charg...

Variational techniques in non-perturbative QCD

CERN Document Server

Kovner, Alex; Kovner, Alex

2004-01-01

We review attempts to apply the variational principle to understand the vacuum of non-abelian gauge theories. In particular, we focus on the method explored by Ian Kogan and collaborators, which imposes exact gauge invariance on the trial Gaussian wave functional prior to the minimization of energy. We describe the application of the method to a toy model -- confining compact QED in 2+1 dimensions -- where it works wonderfully and reproduces all known non-trivial results. We then follow its applications to pure Yang-Mills theory in 3+1 dimensions at zero and finite temperature. Among the results of the variational calculation are dynamical mass generation and the analytic description of the deconfinement phase transition.

Leading quantum gravitational corrections to scalar QED

OpenAIRE

Bjerrum-Bohr, N. E. J.

2002-01-01

We consider the leading post-Newtonian and quantum corrections to the non-relativistic scattering amplitude of charged scalars in the combined theory of general relativity and scalar QED. The combined theory is treated as an effective field theory. This allows for a consistent quantization of the gravitational field. The appropriate vertex rules are extracted from the action, and the non-analytic contributions to the 1-loop scattering matrix are calculated in the non-relativistic limit. The n...

Non-compact left ventricle/hypertrabeculated left ventricle

International Nuclear Information System (INIS)

Restrepo, Gustavo; Castano, Rafael; Marmol, Alejandro

2005-01-01

Non-compact left ventricle/hypertrabeculated left ventricle is a myocardiopatie produced by an arrest of the normal left ventricular compaction process during the early embryogenesis. It is associated to cardiac anomalies (congenital cardiopaties) as well as to extracardial conditions (neurological, facial, hematologic, cutaneous, skeletal and endocrinological anomalies). This entity is frequently unnoticed, being diagnosed only in centers with great experience in the diagnosis and treatment of myocardiopathies. Many cases of non-compact left ventricle have been initially misdiagnosed as hypertrophic myocardiopatie, endocardial fibroelastosis, dilated cardiomyopatie, restrictive cardiomyopathy and endocardial fibrosis. It is reported the case of a 74 years old man with a history of chronic arterial hypertension and diabetes mellitus, prechordial chest pain and mild dyspnoea. An echocardiogram showed signs of non-compact left ventricle with prominent trabeculations and deep inter-trabecular recesses involving left ventricular apical segment and extending to the lateral and inferior walls. Literature on this topic is reviewed

The QED contribution to J/{psi} plus light hadrons production at B-factories

Energy Technology Data Exchange (ETDEWEB)

He, Zhi-Guo [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Wang, Jian-Xiong [Chinese Academy of Science, Beijing (China). Inst. of High Energy Physics; Chinese Academy of Science, Beijing (China). Theoretical Physics Center for Science Facilities

2013-01-15

To understand the direct J/{psi}+X{sub non-c} {sub anti} {sub c} production mechanism in e{sup +}e{sup -} annihilation, in this work, we propose to measure the inclusive J/{psi} plus light hadrons (LH) production at B-factories and present a detailed study on its QED production due to {psi}(2S) feed-down, where the {psi}(2S) are produced in e{sup +}e{sup -}{yields}{psi}(2S)+{gamma} and e{sup +}e{sup -}{yields}{psi}(2S) +f anti f, f = lepton, lightquark, and QED contribution to direct J/{psi}+q anti q production with q = u, d, s quark. We find that the QED contribution is huge in the whole phase space region, but can be reduced largely and is in the same order as the QCD contribution when a suitable cut on the angel {theta}{sub J/{psi}} between J/{psi} and the e{sup +}e{sup -} beam is made. In this way, the cross section of J/{psi} + LH QCD production % which was predicted theoretical at next-to-leading order QCD together with relativistic correction, can be obtained by subtracting the QED contribution from the experimental measurement on inclusive J/{psi} plus light hadrons. To help to remove the QED background, we also calculate the angular and momentum distribution of J/{psi} in the QED contribution.

Experimentally simulating the dynamics of quantum light and matter at ultrastrong coupling using circuit QED (1) - implementation and matter dynamics -

Science.gov (United States)

Kounalakis, M.; Langford, N. K.; Sagastizabal, R.; Dickel, C.; Bruno, A.; Luthi, F.; Thoen, D. J.; Endo, A.; Dicarlo, L.

The field dipole coupling of quantum light and matter, described by the quantum Rabi model, leads to exotic phenomena when the coupling strength g becomes comparable or larger than the atom and photon frequencies ωq , r. In this ultra-strong coupling regime, excitations are not conserved, leading to collapse-revival dynamics in atom and photon parity and Schrödinger-cat-like atom-photon entanglement. We realize a quantum simulation of the Rabi model using a transmon qubit coupled to a resonator. In this first part, we describe our analog-digital approach to implement up to 90 symmetric Trotter steps, combining single-qubit gates with the Jaynes-Cummings interaction naturally present in our circuit QED system. Controlling the phase of microwave pulses defines a rotating frame and enables simulation of arbitrary parameter regimes of the Rabi model. We demonstrate measurements of qubit parity dynamics showing revivals at g /ωr > 0 . 8 for ωq = 0 and characteristic dynamics for nondegenerate ωq from g / 4 to g. Funding from the EU FP7 Project ScaleQIT, an ERC Grant, the Dutch Research Organization NWO, and Microsoft Research.

The lattice spinor QED Hamiltonian critique of the continuous space approach

International Nuclear Information System (INIS)

Sidorov, A.V.; Zastavenko, L.G.

1993-01-01

We give the irreproachable, from the point of view of gauge invariance, derivation of the lattice spinor QED Hamiltonian. Our QED Hamiltonian is manifestly gauge invariant. We point out important defects of the continuous space formulation of the QED that make, in our opinion, the lattice QED obviously preferable to the continuous space QED. We state that it is impossible to give a continuous space QED formulation which is compatible with the condition of gauge invariance. 17 refs

QED at high energies

International Nuclear Information System (INIS)

Gastmans, R.

1980-01-01

This chapter demonstrates that to establish the validity of QED at the level of a few percent requires knowledge of the cross sections of the QED processes to the same accuracy. Discusses the virtual radiative corrections to the processes. Calculates the vertex correction effect to illustrate the technique. Examines the hadronic vacuum polarization because of its numerical significance. Calculates the effects of soft real photon bremsstrahlung, and shows that they cancel infrared divergences introduced by the virtual corrections. Outlines the analytical work and introduces the dimensional regularization of the infrared divergences as for the virtual photon case. Describes the calculation of the cross section for the bremsstrahlung processes in the ultra-relativistic limit. Shows the surprising simplicity of these cross sections. Discusses the phase space and the choice of integration variables in which the selection criteria must be expressed. Concludes with a comparison of some of the latest experiments on these QED reactions

MRI in the diagnosis of non-compacted ventricular Myocardium (NCVM) compared to echocardiography

International Nuclear Information System (INIS)

Weiss, F.; Habermann, C.R.; Sievers, J.; Weil, J.; Adam, G.; Lilje, C.; Razek, W.

2003-01-01

Purpose: To report the detection of con-compacted ventricular myocardium (NVCM) with MRI compared to echocardiography in 8 patients. Material and methods: Non-compaction of the ventricular myocardium is a congenital disorder characterized by an altered structure of the myocardial wall resulting from an intrauterine arrest in endomyocardial embryogenesis. The morphological findings consist of a prominent meshwork of multiple myocardial trabeculations and deep intertrabecular recesses, communicating with the left ventricular cavity. 8 consecutive patients (mean age 7.3 years) with clinical and echocardiographic signs of NCVM were examined by MRI (1.5 T, Vision, Siemens) in short axis and 2- and 4-chamber views, using T 1 -weighted TSE and Cine-GRE in 6 patients and true FISP sequences in 2 patients. MRI and echocardiography were evaluated for visibility, signs of NCVM and involvement of myocardial wall segments. Thickness was measured for non-compacted and compacted myocardium and the non-compacted to compacted (N/C) ratio calculated. Results: MRI diagnosed 6 of 8 patients of having NCVM. Myocardial thickness as measured by echocardiography and MRI showed a good correlation in compacted myocardium (r = 0.82) and no correlation in non-compacted myocardium (r = 0.4). In 2 cases, non-compacted myocardium was detected, but echocardiography did not reach the N/C ratio > 2 as required to diagnose NCVM in accordance with the criteria found in the literature. Both patients were also misdiagnosed by MRI performed with Cine-GRE. MRI reached a N/C ratio > 2 in only three patients. Newer TruFisp sequences showed no definite advantages. Extent of non-compaction could be visualized correctly with MRI. (orig.) [de

Equivariant volumes of non-compact quotients and instanton counting

OpenAIRE

Martens, Johan

2006-01-01

Motivated by Nekrasov's instanton counting, we discuss a method for calculating equivariant volumes of non-compact quotients in symplectic and hyper-K\\"ahler geometry by means of the Jeffrey-Kirwan residue-formula of non-abelian localization. In order to overcome the non-compactness, we use varying symplectic cuts to reduce the problem to a compact setting, and study what happens in the limit that recovers the original problem. We implement this method for the ADHM construction of the moduli ...

Algebraic Bethe ansatz for U(1) invariant integrable models: Compact and non-compact applications

International Nuclear Information System (INIS)

Martins, M.J.; Melo, C.S.

2009-01-01

We apply the algebraic Bethe ansatz developed in our previous paper [C.S. Melo, M.J. Martins, Nucl. Phys. B 806 (2009) 567] to three different families of U(1) integrable vertex models with arbitrary N bond states. These statistical mechanics systems are based on the higher spin representations of the quantum group U q [SU(2)] for both generic and non-generic values of q as well as on the non-compact discrete representation of the SL(2,R) algebra. We present for all these models the explicit expressions for both the on-shell and the off-shell properties associated to the respective transfer matrices eigenvalue problems. The amplitudes governing the vectors not parallel to the Bethe states are shown to factorize in terms of elementary building blocks functions. The results for the non-compact SL(2,R) model are argued to be derived from those obtained for the compact systems by taking suitable N→∞ limits. This permits us to study the properties of the non-compact SL(2,R) model starting from systems with finite degrees of freedom.

Algebraic Bethe ansatz for U(1) invariant integrable models: Compact and non-compact applications

Science.gov (United States)

Martins, M. J.; Melo, C. S.

2009-10-01

We apply the algebraic Bethe ansatz developed in our previous paper [C.S. Melo, M.J. Martins, Nucl. Phys. B 806 (2009) 567] to three different families of U(1) integrable vertex models with arbitrary N bond states. These statistical mechanics systems are based on the higher spin representations of the quantum group U[SU(2)] for both generic and non-generic values of q as well as on the non-compact discrete representation of the SL(2,R) algebra. We present for all these models the explicit expressions for both the on-shell and the off-shell properties associated to the respective transfer matrices eigenvalue problems. The amplitudes governing the vectors not parallel to the Bethe states are shown to factorize in terms of elementary building blocks functions. The results for the non-compact SL(2,R) model are argued to be derived from those obtained for the compact systems by taking suitable N→∞ limits. This permits us to study the properties of the non-compact SL(2,R) model starting from systems with finite degrees of freedom.

N = 1 super-Chern-Simons coupled to parity-preserving matter from Atiyah-Ward space-time

International Nuclear Information System (INIS)

Andrade, M.A. de; Cima, O.M. Del; Colatto, L.P.

1995-06-01

In this letter, we present the Parkes-Siegel formulation for the massive Abelian N=1 super-QED 2+2 coupled to a self-dual supermultiplet, by introducing a chiral multiplier superfield. We show that after carrying out a suitable dimensional reduction from (2+2) to (1+2) dimensions, and performing some necessary truncations, the simple supersymmetric extension of the π3 QED 1+2 coupled to a Chern-Simons term naturally comes out. (author). 15 refs

Status and prospects of (g-2)μ and ΔαQED

International Nuclear Information System (INIS)

Teubner, Thomas

2008-01-01

A brief review of the status of the anomalous magnetic moment of the muon, (g-2) μ , and the running of the electromagnetic coupling, α QED (q 2 ), is given. The discrepancy between the Standard Model prediction of g-2 and the measurement from BNL is discussed. The prospects for further improvements in the determination of the vacuum polarisation contributions are outlined.

QED fermi fields as operator-valued distributions and anomalies

International Nuclear Information System (INIS)

Grange, P.; Werner, E.

2005-01-01

The treatment of fields as operator-valued distributions (OPVD) is recalled with the emphasis on the importance of causality following the work of Epstein and Glaser. Gauge-invariant theories demand the extension of the usual translation operation on OPVD, thereby leading to a generalized QED formulation. At D = 2 the solvability of the Schwinger model is totally preserved. At D = 4 the paracompactness property of the Euclidean manifold permits the use of test functions which are a decomposition of unity and thereby provides a natural justification and extension of the non-perturbative heat kernel method (Fujikawa) for Abelian anomalies. On the Minkowski manifold the specific role of causality in the restauration of gauge invariance (and mass generation for QED 2 is exemplified in a simple way. (author)

Quantum Simulation of the Ultrastrong-Coupling Dynamics in Circuit Quantum Electrodynamics

Directory of Open Access Journals (Sweden)

D. Ballester

2012-05-01

Full Text Available We propose a method to get experimental access to the physics of the ultrastrong- and deep-strong-coupling regimes of light-matter interaction through the quantum simulation of their dynamics in standard circuit QED. The method makes use of a two-tone driving scheme, using state-of-the-art circuit-QED technology, and can be easily extended to general cavity-QED setups. We provide examples of ultrastrong- and deep-strong-coupling quantum effects that would be otherwise inaccessible.

QED corrections to the Altarelli-Parisi splitting functions

Energy Technology Data Exchange (ETDEWEB)

Florian, Daniel de [Universidad de Buenos Aires, Departamento de Fisica and IFIBA, FCEyN, Capital Federal (Argentina); UNSAM, International Center for Advanced Studies (ICAS), Buenos Aires (Argentina); Sborlini, German F.R.; Rodrigo, German [Universitat de Valencia - Consejo Superior de Investigaciones Cientificas, Instituto de Fisica Corpuscular, Paterna, Valencia (Spain)

2016-05-15

We discuss the combined effect of QED and QCD corrections to the evolution of parton distributions. We extend the available knowledge of the Altarelli-Parisi splitting functions to one order higher in QED, and we provide explicit expressions for the splitting kernels up to O(α α{sub S}). The results presented in this article allow one to perform a parton distribution function analysis reaching full NLO QCD-QED combined precision. (orig.)

QED revisited

International Nuclear Information System (INIS)

Hueffel, H.

2003-01-01

Full text: We perform the stochastic quantization of scalar as well as of fermionic QED based on a generalization of the stochastic gauge fixing scheme and its geometrical interpretation. It is shown that the stochastic quantization scheme agrees exactly with the usual path integral formulation. (author)

The QED coupling at the Z pole and jet studies of small x dynamics

International Nuclear Information System (INIS)

Outhwaite, J.

2000-12-01

In the first half of this thesis, motivated by significant progress in both theoretical and empirical studies of e + e - annihilation into hadrons, we perform a reevaluation of the running of the QED coupling to the Z-pole, paying particular attention to the hadronic contribution to vacuum polarization. We use a comprehensive collection of the presently available data and perturbative QCD expressions. This new determination of the running of the coupling is then used as input into a global fit to electroweak data to estimate a preferred value of the Standard Model Higgs boson. An estimate is obtained of M H = 110 GeV, marginally above the zone excluded by direct searches at LEP2. We then investigate the potential for further constraining the hadronic contribution to the vacuum polarization function through mechanisms incorporating analytic continuation from the timelike domain of s > 0 around a large semicircle into the spacelike domain of s c = 1.4. In the latter half of the thesis, we examine forward jet and pion production in electron - proton deep inelastic scattering in the small x region of the HERA collider at DESY. We demonstrate the imposition of physically motivated dominant subleading corrections to all orders on the leading logarithmic BFKL equation, and that this leads to stable phenomenological predictions. We compare the calculations of differential cross-section distributions incorporating the higher order effects with the experimental profiles for a single jet, an identified π 0 and dijets in the very forward region and investigate the sensitivity of the calculation to residual parametric freedom. (author)

Electronic bound states in parity-preserving QED3 applied to high-Tc cuprate superconductors

International Nuclear Information System (INIS)

Christiansen, H.R.; Cima, O.M. Del; Ferreira Junior, M.M.; Maranhao Univ., Sao Luis, MA; Helayel-Neto, J.A.; Centro Brasileiro de Pesquisas Fisicas

2001-08-01

We consider a parity-preserving QED 3 model with spontaneous breaking of the gauge symmetry as a framework for the evaluation of the electron-electron interaction potential underlying high-T e superconductivity. The fact that resulting potential, - C s K o (Mr), is non-confining and weak (in the sense of Kato) strongly suggests the mechanism of pair-condensation. This potential, compatible with an s-wave order parameters, is then applied to the Schrodinger equation for the sake of numerical calculations, thereby enforcing the existence of bound states. The results worked out by means of our theoretical framework are checked by considering a number of phenomenological data extracted from different copper oxide superconductors. The agreement may motivate a deeper analysis of our model viewing an application to quasi-planar cuprate superconductors. The data analyzed here suggest an energy scale of 1-10 meV for the breaking of the U(1)-symmetry. (author)

Experimentally simulating the dynamics of quantum light and matter at ultrastrong coupling using circuit QED (2) - light dynamics and light-matter entanglement -

Science.gov (United States)

Sagastizabal, R.; Langford, N. K.; Kounalakis, M.; Dickel, C.; Bruno, A.; Luthi, F.; Thoen, D. J.; Endo, A.; Dicarlo, L.

Light-matter interaction can lead to large photon build-up and hybrid atom-photon entanglement in the ultrastrong coupling (USC) regime, where the coupling strength becomes comparable to the eigenenergies of the system. Accessing the cavity degree of freedom, however, is an outstanding challenge in natural USC systems. In this talk, we directly probe light field dynamics in the USC regime using a digital simulation of the quantum Rabi model in a planar circuit QED chip with a transmon moderately coupled to a resonator. We produce high-accuracy USC light-matter dynamics, using second-order Trotterisation and up to 90 Trotter steps. We probe the average photon number, photon parity and perform Wigner tomography of the simulated field. Finally, we combine tomography of the resonator with qubit measurements to evidence the Schrödinger-cat-like atom-photon entanglement which is a key signature of light-matter dynamics in the USC regime. Funding from the EU FP7 Project ScaleQIT, the ERC Synergy Grant QC-lab, the Netherlands Organization of Scientic Research (NWO), and Microsoft Research.

Perturbative renormalization of QED via flow equations

International Nuclear Information System (INIS)

Keller, G.; Kopper, C.

1991-01-01

We prove the perturbative renormalizability of euclidean QED 4 with a small photon mass in the framework of effective lagrangians due to Wilson and Polchinski. In particular we show that the QED identities, which become violated by our momentum space regularization at intermediate stages, are restored in the renormalized theory. (orig.)

Lessons from non-Abelian plasma instabilities in two spatial dimensions

International Nuclear Information System (INIS)

Arnold, Peter; Leang, P.-S.

2007-01-01

Plasma instabilities can play a fundamental role in quark-gluon plasma equilibration in the high energy (weak coupling) limit. Early simulations of the evolution of plasma instabilities in non-Abelian gauge theory, performed in one spatial dimension, found behavior qualitatively similar to traditional QED plasmas. Later simulations of the fully three-dimensional theory found different behavior, unlike traditional QED plasmas. To shed light on the origin of this difference, we study the intermediate case of two spatial dimensions. Depending on how the 'two-dimensional' theory is formulated, we can obtain either behavior

Existence of Green's functions in perturbative Q.E.D

International Nuclear Information System (INIS)

Seneor, R.

1976-01-01

A report is made on some work done in collaboration with P. Blanchard which shows how, in the framework developped by H.Epstein and V.Glaser, one can prove the existence of Green's functions in quantum electrodynamics (Q.E.D.). The proof can be extended, in principle, to any theory involving massive and non massive particles. (Auth.)

Implementation of Traveling Odd Schrödinger Cat States in Circuit-QED

Directory of Open Access Journals (Sweden)

Jaewoo Joo

2016-10-01

Full Text Available We propose a realistic scheme of generating a traveling odd Schrödinger cat state and a generalized entangled coherent state in circuit quantum electrodynamics (circuit-QED. A squeezed vacuum state is used as the initial resource of nonclassical states, which can be created through a Josephson traveling-wave parametric amplifier, and travels through a transmission line. Because a single-photon subtraction from the squeezed vacuum gives an odd Schrödinger cat state with very high fidelity, we consider a specific circuit-QED setup consisting of the Josephson amplifier creating the traveling resource in a line, a beam-splitter coupling two transmission lines, and a single photon detector located at the end of the other line. When a single microwave photon is detected by measuring the excited state of a superconducting qubit in the detector, a heralded cat state is generated with high fidelity in the opposite line. For example, we show that the high fidelity of the outcome with the ideal cat state can be achieved with appropriate squeezing parameters theoretically. As its extended setup, we suggest that generalized entangled coherent states can be also built probabilistically and that they are useful for microwave quantum information processing for error-correctable qudits in circuit-QED.

Perturbative renormalization of QED via flow equations

Energy Technology Data Exchange (ETDEWEB)

Keller, G. (Max-Planck-Inst. fuer Physik, Werner-Heisenberg-Inst., Munich (Germany)); Kopper, C. (Max-Planck-Inst. fuer Physik, Werner-Heisenberg-Inst., Munich (Germany) Inst. fuer Theoretische Physik, Univ. Goettingen (Germany))

1991-12-19

We prove the perturbative renormalizability of euclidean QED{sub 4} with a small photon mass in the framework of effective lagrangians due to Wilson and Polchinski. In particular we show that the QED identities, which become violated by our momentum space regularization at intermediate stages, are restored in the renormalized theory. (orig.).

Hammering towards QED

Directory of Open Access Journals (Sweden)

Jasmin C. Blanchette

2016-01-01

Full Text Available This paper surveys the emerging methods to automate reasoning over large libraries developed with formal proof assistants. We call these methods hammers. They give the authors of formal proofs a strong "one-stroke" tool for discharging difficult lemmas without the need for careful and detailed manual programming of proof search.The main ingredients underlying this approach are efficient automatic theorem provers that can cope with hundreds of axioms, suitable translations of richer logics to their formalisms, heuristic and learning methods that select relevant facts from large libraries, and methods that reconstruct the automatically found proofs inside the proof assistants.We outline the history of these methods, explain the main issues and techniques, and show their strength on several large benchmarks. We also discuss the relation of this technology to the QED Manifesto and consider its implications for QED-style efforts.

Confinement and dynamical chiral symmetry breaking in QED3

International Nuclear Information System (INIS)

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

2008-01-01

We establish that QED3 can possess a critical number of flavors, N f 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 f 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

Electroweak effective couplings for future precision experiments

International Nuclear Information System (INIS)

Jegerlehner, F.

2011-01-01

The leading hadronic effects in electroweak theory derive from vacuum polarization which are non-perturbative hadronic contributions to the running of the gauge couplings, the electromagnetic α em (s)and the SU(2) L coupling α 2 (s). I will report on my recent package alphaQED, which besides the effective fine structure constant α em (s) also allows for a fairly precise calculation of the SU(2) L gauge coupling α 2 (s). I will briefly review the role, future requirements and possibilities. Applied together with the R had package by Harlander and Steinhauser, the package allows to calculate all SM running couplings as well as running sin 2 Θ versions with state-of-the-art accuracy.

Electroweak effective couplings for future precision experiments

International Nuclear Information System (INIS)

Jegerlehner, F.; Humboldt-Universitaet, Berlin

2011-07-01

The leading hadronic effects in electroweak theory derive from vacuum polarization which are non-perturbative hadronic contributions to the running of the gauge couplings, the electromagnetic α em (s) and the SU(2) L coupling α 2 (s). I report on my recent package alphaQED [1], which besides the effective fine structure constant α em (s) also allows for a fairly precise calculation of the SU(2) L gauge coupling α 2 (s). I will briefly review the role, future requirements and possibilities. Applied together with the Rhad package by Harlander and Steinhauser [2], the package allows to calculate all SM running couplings as well as running sin 2 Θ versions with state-of-the-art accuracy. (orig.)

Finite size effects and chiral symmetry breaking in quenched three-dimensional QED

International Nuclear Information System (INIS)

Hands, S.; Kogut, J.B.

1990-01-01

Finite size effects and the chiral condensate are studied in three-dimensional QED by the Lanczos and the conjugate-gradient algorithms. Very substantial finite size effects are observed, but studies on L 3 lattices with L ranging from 8 to 80 indicate the development of a non-vanishing chiral condensate in the continuum limit of the theory. The systematics of the finite size effects and the fermion mass dependence in the conjugate-gradient algorithm are clarified in this extensive study. (orig.)

Electric Resistance Tests on Compacted Clay Material under Dynamic Load Coupled with Dry-Wet Cycling

Directory of Open Access Journals (Sweden)

Zheng Lu

2018-01-01

Full Text Available The study of compacted clay material under dynamic load coupled with dry-wet cycling is one of the most important areas in the field of transportation. In this paper, experiments in terms of compacted clay under dynamic load coupled with dry-wet cycling are performed, and synchronous resistivity tests are also conducted. According to the test results, the influences of cumulative plastic strain, dry-wet cycles, and amplitudes on the soil resistivity are analyzed. Then a new damage factor based on resistivity is proposed to evaluate the long-term performance of compacted clay material. The result of research shows that the evolution of the soil resistivity can be divided into two stages, which has a contrary tendency with that of cumulative plastic strain. The dry-wet cycles and amplitudes have a significant effect on the damage of the compacted soil, which indicates that the dry-wet cycling of compacted soil materials should not be ignored in road engineering, especially in rainy and humid areas.

Leading quantum gravitational corrections to scalar QED

International Nuclear Information System (INIS)

Bjerrum-Bohr, N.E.J.

2002-01-01

We consider the leading post-Newtonian and quantum corrections to the non-relativistic scattering amplitude of charged scalars in the combined theory of general relativity and scalar QED. The combined theory is treated as an effective field theory. This allows for a consistent quantization of the gravitational field. The appropriate vertex rules are extracted from the action, and the non-analytic contributions to the 1-loop scattering matrix are calculated in the non-relativistic limit. The non-analytical parts of the scattering amplitude, which are known to give the long range, low energy, leading quantum corrections, are used to construct the leading post-Newtonian and quantum corrections to the two-particle non-relativistic scattering matrix potential for two charged scalars. The result is discussed in relation to experimental verifications

Compact Printed Arrays with Embedded Coupling Mitigation for Energy-Efficient Wireless Sensor Networking

Directory of Open Access Journals (Sweden)

Constantine G. Kakoyiannis

2010-01-01

Full Text Available Wireless sensors emerged as narrowband, resource-constrained devices to provide monitoring services over a wide life span. Future applications of sensor networks are multimedia-driven and include sensor mobility. Thus, sensors must combine small size, large bandwidth, and diversity capabilities. Compact arrays, offering transmit/receive diversity, suffer from strong mutual coupling (MC, which causes lower antenna efficiency, loss of bandwidth, and signal correlation. An efficient technique to reduce coupling in compact arrays is described herein: a defect was inserted in the ground plane (GNDP area between each pair of elements. The defect disturbed the GNDP currents and offered multidecibel coupling suppression, bandwidth recovery, and reduction of in-band correlation. Minimal pattern distortion was estimated. Computational results were supported by measurements. The bandwidth of unloaded arrays degraded gracefully from 38% to 28% with decreasing interelement distance (0.25 to 0.10. Defect-loaded arrays exhibited active impedance bandwidths 37–45%, respectively. Measured coupling was reduced by 15–20 dB.

Gauge equivalence of σ models with non-compact Grassmannian manifolds

International Nuclear Information System (INIS)

Kundu, A.

1986-01-01

The gauge equivalence (GE) of σ models associated with non-compact Grassmannian manifolds is investigated with emphasis on the necessary restrictions for the choice of gauge elements in such cases. The importance of GE in solving a non-linear system with the help of inverse scattering data of its gauge related counterpart is demonstrated. The gauge relations between generalised Landau-Lifshitz (LL) and non-linear Schroedinger (NLS) type equations and also between non-linear σ models and generalised 'sine-sinh-Gordon' equations for non-compact SU(p,q)/S(U(u,v) x U(s,t)) manifolds are established. Using H-gauge invariance of LL the GE is extended to some higher-order specific non-linear systems. The gauge connection among various LL and NLS equations are schematically represented. Along with the recovery of earlier results important new results, some with significant non-compact structures, are discovered. (author)

Quantum Bayesian rule for weak measurements of qubits in superconducting circuit QED

International Nuclear Information System (INIS)

Wang, Peiyue; Qin, Lupei; Li, Xin-Qi

2014-01-01

Compared with the quantum trajectory equation (QTE), the quantum Bayesian approach has the advantage of being more efficient to infer a quantum state under monitoring, based on the integrated output of measurements. For weak measurement of qubits in circuit quantum electrodynamics (cQED), properly accounting for the measurement backaction effects within the Bayesian framework is an important problem of current interest. Elegant work towards this task was carried out by Korotkov in ‘bad-cavity’ and weak-response limits (Korotkov 2011 Quantum Bayesian approach to circuit QED measurement (arXiv:1111.4016)). In the present work, based on insights from the cavity-field states (dynamics) and the help of an effective QTE, we generalize the results of Korotkov to more general system parameters. The obtained Bayesian rule is in full agreement with Korotkov's result in limiting cases and as well holds satisfactory accuracy in non-limiting cases in comparison with the QTE simulations. We expect the proposed Bayesian rule to be useful for future cQED measurement and control experiments. (paper)

Signals for Non-Cummutative Interactions at Linear Colliders

International Nuclear Information System (INIS)

Rizzo, Thomas G.

2001-01-01

Recent theoretical results have demonstrated that non-commutative geometries naturally appear within the context of string/M-theory. One consequence of this possibility is that QED takes on a non-abelian nature due to the introduction of 3- and 4-point functions. In addition, each QED vertex acquires a momentum dependent phase factor. We parameterize the effects of non-commutative space-time co-ordinates and show that they lead to observable signatures in several 2 → 2 QED processes in e + e - collisions. In particular, we examine pair annihilation, Moller and Bhabha scattering, as well as γγ → γγ scattering and show that non-commutative scales of order a TeV can be probed at high energy linear colliders

Signals for Non-Cummutative Interactions at Linear Colliders

Energy Technology Data Exchange (ETDEWEB)

Rizzo, Thomas G.

2001-07-23

Recent theoretical results have demonstrated that non-commutative geometries naturally appear within the context of string/M-theory. One consequence of this possibility is that QED takes on a non-abelian nature due to the introduction of 3- and 4-point functions. In addition, each QED vertex acquires a momentum dependent phase factor. We parameterize the effects of non-commutative space-time co-ordinates and show that they lead to observable signatures in several 2 {yields} 2 QED processes in e{sup +}e{sup -} collisions. In particular, we examine pair annihilation, Moller and Bhabha scattering, as well as {gamma}{gamma} {yields} {gamma}{gamma} scattering and show that non-commutative scales of order a TeV can be probed at high energy linear colliders.

An introduction about precise measurements of QED γ structure functions

International Nuclear Information System (INIS)

Courau, A.

1989-11-01

Pure QED processes are theoretically exactly computable. However precise measurements and theoretical expectations of QED γ structure functions within a given experimental acceptance are not so trivial. Yet such a study is quite interesting. It supplies on the one hand a good QED test and, on the other hand, a good exercise for testing the procedure used for the determination of the hadronic γ structure functions

Hardware-efficient fermionic simulation with a cavity-QED system

Science.gov (United States)

Zhu, Guanyu; Subaşı, Yiǧit; Whitfield, James D.; Hafezi, Mohammad

2018-03-01

In digital quantum simulation of fermionic models with qubits, non-local maps for encoding are often encountered. Such maps require linear or logarithmic overhead in circuit depth which could render the simulation useless, for a given decoherence time. Here we show how one can use a cavity-QED system to perform digital quantum simulation of fermionic models. In particular, we show that highly nonlocal Jordan-Wigner or Bravyi-Kitaev transformations can be efficiently implemented through a hardware approach. The key idea is using ancilla cavity modes, which are dispersively coupled to a qubit string, to collectively manipulate and measure qubit states. Our scheme reduces the circuit depth in each Trotter step of the Jordan-Wigner encoding by a factor of N2, comparing to the scheme for a device with only local connectivity, where N is the number of orbitals for a generic two-body Hamiltonian. Additional analysis for the Fermi-Hubbard model on an N × N square lattice results in a similar reduction. We also discuss a detailed implementation of our scheme with superconducting qubits and cavities.

Critical number of flavors in QED

International Nuclear Information System (INIS)

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

2011-01-01

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

No parity anomaly in massless QED3: A BPHZL approach

International Nuclear Information System (INIS)

Del Cima, O.M.; Franco, D.H.T.; Piguet, O.; Schweda, M.

2009-01-01

In this Letter we call into question the perturbatively parity breakdown at 1-loop for the massless QED 3 frequently claimed in the literature. As long as perturbative quantum field theory is concerned, whether a parity anomaly owing to radiative corrections exists or not shall be definitely proved by using a renormalization method independent of any regularization scheme. Such a problem has been investigated in the framework of BPHZL renormalization method, by adopting the Lowenstein-Zimmermann subtraction scheme. The 1-loop parity-odd contribution to the vacuum-polarization tensor is explicitly computed in the framework of the BPHZL renormalization method. It is shown that a Chern-Simons term is generated at that order induced through the infrared subtractions - which violate parity. We show then that, what is called 'parity anomaly', is in fact a parity-odd counterterm needed for restauring parity.

Comparative study of numerical schemes of TVD3, UNO3-ACM and optimized compact scheme

Science.gov (United States)

Lee, Duck-Joo; Hwang, Chang-Jeon; Ko, Duck-Kon; Kim, Jae-Wook

1995-01-01

Three different schemes are employed to solve the benchmark problem. The first one is a conventional TVD-MUSCL (Monotone Upwind Schemes for Conservation Laws) scheme. The second scheme is a UNO3-ACM (Uniformly Non-Oscillatory Artificial Compression Method) scheme. The third scheme is an optimized compact finite difference scheme modified by us: the 4th order Runge Kutta time stepping, the 4th order pentadiagonal compact spatial discretization with the maximum resolution characteristics. The problems of category 1 are solved by using the second (UNO3-ACM) and third (Optimized Compact) schemes. The problems of category 2 are solved by using the first (TVD3) and second (UNO3-ACM) schemes. The problem of category 5 is solved by using the first (TVD3) scheme. It can be concluded from the present calculations that the Optimized Compact scheme and the UN03-ACM show good resolutions for category 1 and category 2 respectively.

Strong-field QED processes in short laser pulses. One- and two-photon Compton scattering

Energy Technology Data Exchange (ETDEWEB)

Seipt, Daniel

2012-12-20

The purpose of this thesis is to advance the understanding of strong-field QED processes in short laser pulses. The processes of non-linear one-photon and two-photon Compton scattering are studied, that is the scattering of photons in the interaction of relativistic electrons with ultra-short high-intensity laser pulses. These investigations are done in view of the present and next generation of ultra-high intensity optical lasers which are supposed to achieve unprecedented intensities of the order of 10{sup 24} W/cm{sup 2} and beyond, with pulse lengths in the order of some femtoseconds. The ultra-high laser intensity requires a non-perturbative description of the interaction of charged particles with the laser field to allow for multi-photon interactions, which is beyond the usual perturbative expansion of QED organized in powers of the fine structure constant. This is achieved in strong-field QED by employing the Furry picture and non-perturbative solutions of the Dirac equation in the presence of a background laser field as initial and final state wave functions, as well as the laser dressed Dirac-Volkov propagator. The primary objective is a realistic description of scattering processes with regard to the finite laser pulse duration beyond the common approximation of infinite plane waves, which is made necessary by the ultra-short pulse length of modern high-intensity lasers. Non-linear finite size effects are identified, which are a result of the interplay between the ultra-high intensity and the ultra-short pulse length. In particular, the frequency spectra and azimuthal photon emission spectra are studied emphasizing the differences between pulsed and infinite laser fields. The proper description of the finite temporal duration of the laser pulse leads to a regularization of unphysical infinities (due to the infinite plane-wave description) of the laser-dressed Dirac-Volkov propagator and in the second-order strong-field process of two-photon Compton

An introduction to QED

International Nuclear Information System (INIS)

Martin, A.D.

1984-01-01

The lecture concerns quantum electrodynamics (QED), the relativistic quantum theory of electromagnetic interactions. Antiparticles, electrodynamics of spinless particles, the dirac equation and electrodynamics of spin 1/2 particles are discussed in detail. (U.K.)

Oblique photon expansion of QED structure functions

International Nuclear Information System (INIS)

Chahine, C.

1986-01-01

In the oblique photon expansion, the collinear part of photon emission is summed up to all orders in perturbation theory. The number of oblique or non-collinear photons is the expansion order. Unlike in perturbation theory, every term of the expansion is both infrared finite and gauge invariant. The zero oblique photon contribution to the electromagnetic structure tensor in QED is computed in detail. The behaviors of the structure functions F1 and F2 are discussed in the soft and ultra-soft limits

Leading-order hadronic contributions to aμ and αQED from Nf=2+1+1 twisted mass fermions

International Nuclear Information System (INIS)

Feng, Xu; Hotzel, Grit; Renner, Dru B.

2012-11-01

We present the first four-flavour lattice calculation of the leading-order hadronic vacuum-polarisation contribution to the anomalous magnetic moment of the muon, a hvp μ , and the hadronic running of the QED coupling constant, Δα hvp QED (Q 2 ). In the heavy sector a mixed-action setup is employed. The bare quark masses are determined from matching the K- and D-meson masses to their physical values. Several light quark masses are used in order to yield a controlled extrapolation to the physical pion mass by utilising a recently proposed improved method. We demonstrate that this method also works in the four-flavour case.

Non-minimally coupled tachyonic inflation in warped string background

International Nuclear Information System (INIS)

Chingangbam, Pravabati; Panda, Sudhakar; Deshamukhya, Atri

2005-01-01

We show that the non-minimal coupling of tachyon field to the scalar curvature, as proposed by Piao et al, with the chosen coupling parameter does not produce the effective potential where the tachyon field can roll down from T=0 to large T along the slope of the potential. We find a correct choice of the parameters which ensures this requirement and support slow-roll inflation. However, we find that the cosmological parameter found from the analysis of the theory are not in the range obtained from observations. We then invoke warped compactification and varying dilaton field over the compact manifold, as proposed by Raeymaekers, to show that in such a setup the observed parameter space can be ensured. (author)

Strong Coupling of Microwave Photons to Antiferromagnetic Fluctuations in an Organic Magnet

Science.gov (United States)

Mergenthaler, Matthias; Liu, Junjie; Le Roy, Jennifer J.; Ares, Natalia; Thompson, Amber L.; Bogani, Lapo; Luis, Fernando; Blundell, Stephen J.; Lancaster, Tom; Ardavan, Arzhang; Briggs, G. Andrew D.; Leek, Peter J.; Laird, Edward A.

2017-10-01

Coupling between a crystal of di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium radicals and a superconducting microwave resonator is investigated in a circuit quantum electrodynamics (circuit QED) architecture. The crystal exhibits paramagnetic behavior above 4 K, with antiferromagnetic correlations appearing below this temperature, and we demonstrate strong coupling at base temperature. The magnetic resonance acquires a field angle dependence as the crystal is cooled down, indicating anisotropy of the exchange interactions. These results show that multispin modes in organic crystals are suitable for circuit QED, offering a platform for their coherent manipulation. They also utilize the circuit QED architecture as a way to probe spin correlations at low temperature.

Quasiparticle lifetimes and infrared physics in QED and QCD plasmas

Energy Technology Data Exchange (ETDEWEB)

Blaizot, J.P. [CEA-Saclay, Gif-sur-Yvette (France)

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}.

Diagnosis of Non-compacted Myocardium of the Left Ventricle in Children

Directory of Open Access Journals (Sweden)

I.B. Yershova

2014-05-01

Full Text Available The authors presented a review of published literature data on rare congenital abnormalities in children — a non-compacted myocardium of the left ventricle, which refers to unclassified cardiomyopathy. This pathology by the American Heart Association classification relates to genetic cardiomyopathy. Non-compacted myocardium of the left ventricle in children develops due to violation of myocardial induration of the fetus in utero. Diagnosis of the disease is difficult due to the lack of specific clinical signs. The authors also presented a clinical case of non-compacted left ventricular myocardium in 6-year-old girl.

Does the Higgs mechanism favour electron-electron bound states in Maxwell-Chern-Simons QED3?

International Nuclear Information System (INIS)

Belich, Humberto; Helayeel-Neto, Jose Abdalla; Ferreira Junior, Manoel Messias

2000-01-01

Full text follows: We show that low-energy electron-electron bound states appear in the Maxwell-Chern-Simons (MCS) planar QED. In spite of the repulsive interaction mediated by the MCS gauge field, a net attractive interaction stems due to the Higgs mechanism through an Yukawa-type interaction. The spontaneous breaking of a local U(1)-symmetry is realized by a γ 6 -type potential. We conclude, by using the Schroedinger equation associated to the net attractive scattering potential, that electron-electron bound states arise in the model. Therefore, the Higgs mechanism overcomes the difficulties found out by Girotti et al. (Phys. Rev. Lett. 69 (1992) 2623) in searching for bound states in the MCS planar QED. (author)

On-chip broadband ultra-compact optical couplers and polarization splitters based on off-centered and non-symmetric slotted Si-wire waveguides

Science.gov (United States)

Haldar, Raktim; Mishra, V.; Dutt, Avik; Varshney, Shailendra K.

2016-10-01

In this work, we propose novel schemes to design on-chip ultra-compact optical directional couplers (DC) and broadband polarization beam splitters (PBS) based on off-centered and asymmetric dielectric slot waveguides, respectively. Slot dimensions and positions are optimized to achieve maximum coupling coefficients between two symmetric and non-symmetric slotted Si wire waveguides through overlap integral method. We observe >88% of enhancement in the coupling coefficients when the size-optimized slots are placed in optimal positions, with respect to the same waveguides with no slot. When the waveguides are parallel, in that case, a coupling length as short as 1.73 μm is accomplished for TM mode with the off-centered and optimized slots. This scheme enables us to design optical DC with very small footprint, L c ∼ 0.9 μm in the presence of S-bends. We also report a compact (L c ∼ 1.1 μm) on-chip broadband PBS with hybrid slots. Extinction ratios of 13 dB and 22.3 dB are realized with very low insertion loss (0.055 dB and 0.008 dB) for TM and TE modes at 1.55 μm, respectively. The designed PBS exhibits a bandwidth of 78 nm for the TM mode (C-and partial L-bands) and >100 nm for the TE mode (S + C + L wavelength bands). Such on-chip devices can be used to design compact photonic interconnects and quantum information processing units efficiently. We have also investigated the fabrication tolerances of the proposed devices and described the fabrication steps to realize such hybrid devices. Our results are in good agreement with 3D FDTD simulations.

QED corrections to the 4p-4d transition energies of copperlike heavy ions

International Nuclear Information System (INIS)

Chen, M. H.; Cheng, K. T.; Johnson, W. R.; Sapirstein, J.

2006-01-01

Quantum electrodynamic (QED) corrections to 4p-4d transition energies of several copperlike ions with Z=70-92 are calculated nonperturbatively in strong external fields to all orders in binding corrections. Dirac-Kohn-Sham potentials are used to account for screening and core-relaxation effects. For the 4p 1/2 -4d 3/2 transition in copperlike bismuth, thorium, and uranium, results are in good agreement with empirical QED corrections deduced from differences between transition energies obtained from recent high-precision electron-beam ion-trap measurements and those calculated with the relativistic many-body perturbation theory (RMBPT). These comparisons provide sensitive tests of QED corrections for high-angular-momentum states in many-electron heavy ions and illustrate the importance of core-relaxation corrections. Comparisons are also made with other theories and with experiments on the 4s-4p transition energies of high-Z Cu-like ions as accuracy checks of the present RMBPT and QED calculations

Second post-Newtonian Lagrangian dynamics of spinning compact binaries

Energy Technology Data Exchange (ETDEWEB)

Huang, Li; Wu, Xin [Nanchang University, Department of Physics and Institute of Astronomy, Nanchang (China); Ma, DaZhu [Hubei University for Nationalities, School of Science, Enshi (China)

2016-09-15

The leading-order spin-orbit coupling is included in a post-Newtonian Lagrangian formulation of spinning compact binaries, which consists of the Newtonian term, first post-Newtonian (1PN) and 2PN non-spin terms and 2PN spin-spin coupling. This leads to a 3PN spin-spin coupling occurring in the derived Hamiltonian. The spin-spin couplings are mainly responsible for chaos in the Hamiltonians. However, the 3PN spin-spin Hamiltonian is small and has different signs, compared with the 2PN spin-spin Hamiltonian equivalent to the 2PN spin-spin Lagrangian. As a result, the probability of the occurrence of chaos in the Lagrangian formulation without the spin-orbit coupling is larger than that in the Lagrangian formulation with the spin-orbit coupling. Numerical evidences support this claim. (orig.)

Nonlinear QED effects in X-ray emission of pulsars

Energy Technology Data Exchange (ETDEWEB)

Shakeri, Soroush [Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Haghighat, Mansour [Department of Physics, Shiraz University, Shiraz 71946-84795 (Iran, Islamic Republic of); Xue, She-Sheng, E-mail: Soroush.Shakeri@ph.iut.ac.ir, E-mail: m.haghighat@shirazu.ac.ir, E-mail: xue@icra.it [ICRANet, Piazzale della Repubblica 10, 65122, Pescara (Italy)

2017-10-01

In the presence of strong magnetic fields near pulsars, the QED vacuum becomes a birefringent medium due to nonlinear QED interactions. Here, we explore the impact of the effective photon-photon interaction on the polarization evolution of photons propagating through the magnetized QED vacuum of a pulsar. We solve the quantum Boltzmann equation within the framework of the Euler-Heisenberg Lagrangian to find the evolution of the Stokes parameters. We find that linearly polarized X-ray photons propagating outward in the magnetosphere of a rotating neutron star can acquire high values for the circular polarization parameter. Meanwhile, it is shown that the polarization characteristics of photons besides photon energy depend strongly on parameters of the pulsars such as magnetic field strength, inclination angle and rotational period. Our results are clear predictions of QED vacuum polarization effects in the near vicinity of magnetic stars which can be tested with the upcoming X-ray polarimetric observations.

High order QED corrections in Z physics

International Nuclear Information System (INIS)

Marck, S.C. van der.

1991-01-01

In this thesis a number of calculations of higher order QED corrections are presented, all applying to the standard LEP/SLC processes e + e - → f-bar f, where f stands for any fermion. In cases where f≠ e - , ν e , the above process is only possible via annihilation of the incoming electron positron pair. At LEP/SLC this mainly occurs via the production and the subsequent decay of a Z boson, i.e. the cross section is heavily dominated by the Z resonance. These processes and the corrections to them, treated in a semi-analytical way, are discussed (ch. 2). In the case f = e - (Bhabha scattering) the process can also occur via the exchange of a virtual photon in the t-channel. Since the latter contribution is dominant at small scattering angles one has to exclude these angles if one is interested in Z physics. Having excluded that region one has to recalculate all QED corrections (ch. 3). The techniques introduced there enables for the calculation the difference between forward and backward scattering, the forward backward symmetry, for the cases f ≠ e - , ν e (ch. 4). At small scattering angles, where Bhabha scattering is dominated by photon exchange in the t-channel, this process is used in experiments to determine the luminosity of the e + e - accelerator. hence an accurate theoretical description of this process at small angles is of vital interest to the overall normalization of all measurements at LEP/SLC. Ch. 5 gives such a description in a semi-analytical way. The last two chapters discuss Monte Carlo techniques that are used for the cases f≠ e - , ν e . Ch. 6 describes the simulation of two photon bremsstrahlung, which is a second order QED correction effect. The results are compared with results of the semi-analytical treatment in ch. 2. Finally ch. 7 reviews several techniques that have been used to simulate higher order QED corrections for the cases f≠ e - , ν e . (author). 132 refs.; 10 figs.; 16 tabs

Quantum Simulation with Circuit-QED Lattices: from Elementary Building Blocks to Many-Body Theory

Science.gov (United States)

Zhu, Guanyu

Recent experimental and theoretical progress in superconducting circuits and circuit QED (quantum electrodynamics) has helped to develop high-precision techniques to control, manipulate, and detect individual mesoscopic quantum systems. A promising direction is hence to scale up from individual building blocks to form larger-scale quantum many-body systems. Although realizing a scalable fault-tolerant quantum computer still faces major barriers of decoherence and quantum error correction, it is feasible to realize scalable quantum simulators with state-of-the-art technology. From the technological point of view, this could serve as an intermediate stage towards the final goal of a large-scale quantum computer, and could help accumulating experience with the control of quantum systems with a large number of degrees of freedom. From the physical point of view, this opens up a new regime where condensed matter systems can be simulated and studied, here in the context of strongly correlated photons and two-level systems. In this thesis, we mainly focus on two aspects of circuit-QED based quantum simulation. First, we discuss the elementary building blocks of the quantum simulator, in particular a fluxonium circuit coupled to a superconducting resonator. We show the interesting properties of the fluxonium circuit as a qubit, including the unusual structure of its charge matrix elements. We also employ perturbation theory to derive the effective Hamiltonian of the coupled system in the dispersive regime, where qubit and the photon frequencies are detuned. The observables predicted with our theory, including dispersive shifts and Kerr nonlinearity, are compared with data from experiments, such as homodyne transmission and two-tone spectroscopy. These studies also relate to the problem of detection in a circuit-QED quantum simulator. Second, we study many-body physics of circuit-QED lattices, serving as quantum simulators. In particular, we focus on two different

Development of a high-pressure compaction system for non-combustible solid waste

International Nuclear Information System (INIS)

Yogo, S.; Hata, T.; Torita, K.; Yamamoto, K.; Karita, Y.

1989-01-01

In recent years, nuclear power plants in Japan have been in search of a means to reduce the volume of non-combustible solid wastes and therefore the application of a high-pressure compaction system has been in demand. Most non-combustible solid wastes have been packed in 200-litre drums for storage and the situation requires a high-pressure compaction system designed exclusively for 200-litre drums. The authors have developed a high-pressure compaction system which compresses 200-litre drums filled with non-combustible solid wastes and packs them into new woo-litre drums efficiently. This paper reports the outline of this high-pressure compaction system and the results of the full-scale verification tests

QED, QCD en pratique

OpenAIRE

Aurenche , P; Guillet , J.-Ph; Pilon , E

2016-01-01

3rd cycle; Ces notes sont une introduction à l'application de l'électrodynamique quantique (QED) et de la chromodynamiques quantique (QCD) aux réactions de diffusion à hautes énergies. Le premier thème abordé est celui des divergences ultraviolettes et de la renormalisation à une boucle, avec comme conséquence pour QCD la liberté asymptotique. Le deuxième thème est celui des divergences infrarouges et colinéaires qui dans QCD sont traitées dans le cadre du modèle des partons avec l'introducti...

On C{sub J} and C{sub T} in conformal QED

Energy Technology Data Exchange (ETDEWEB)

Giombi, Simone; Tarnopolsky, Grigory [Princeton University, Department of Physics,Jadwin Hall, Washington Road, Princeton NJ 08544 (United States); Klebanov, Igor R. [Princeton University, Department of Physics,Jadwin Hall, Washington Road, Princeton NJ 08544 (United States); Princeton Center for Theoretical Science, Princeton University,Jadwin Hall, Washington Road, Princeton NJ 08544 (United States)

2016-08-26

QED with a large number N of massless fermionic degrees of freedom has a conformal phase in a range of space-time dimensions. We use a large N diagrammatic approach to calculate the leading corrections to C{sub T}, the coefficient of the two-point function of the stress-energy tensor, and C{sub J}, the coefficient of the two-point function of the global symmetry current. We present explicit formulae as a function of d and check them versus the expectations in 2 and 4−ϵ dimensions. Using our results in higher even dimensions we find a concise formula for C{sub T} of the conformal Maxwell theory with higher derivative action F{sub μν}(−∇{sup 2}){sup (d/2)−2}F{sup μν}. In d=3, QED has a topological symmetry current, and we calculate the correction to its two-point function coefficient, C{sub J}{sup top}. We also show that some RG flows involving QED in d=3 obey C{sub T}{sup UV}>C{sub T}{sup IR} and discuss possible implications of this inequality for the symmetry breaking at small values of N.

The coupled process laboratory test of highly compacted bentonite

International Nuclear Information System (INIS)

Shen Zhenyao; Li Guoding; Li Shushen; Wang Chengzu

2004-01-01

Highly compacted bentonite blocks have been heated and hydrated in the laboratory in order to simulate the thermo-hydro-mechanical (THM) coupled processes of buffer material in a high-level radioactive waste (HLW) repository. The experiment facility, which is composed of experiment barrel, heated system, high pressure water input system, temperature measure system, water content measure system and swelling stress system, is introduced in this paper. The steps of the THM coupled experiment are also given out in detail. There are total 10 highly compacted bentonite blocks used in this test. Experimental number 1-4 are the tests with the heater and the hydrated process, which temperature distribution vs. time and final moisture distribution are measured. Experimental number 5-8 are the tests with the heater and without the hydrated process, which temperature distribution vs. time and final moisture distribution are measured. Experimental number 9-10 are the tests with the heater and the hydrated process, which temperature distribution vs. time, final moisture distribution and the swelling stress distribution at some typical points vs. time are measured. The maximum test time is nearly 20 days and the minimum test time is only 8 hours. The results show that the temperature field is little affected by hydration process and stress condition, but moisture transport and stress distribution are a little affected by the thermal gradient. The results also show that the water head difference is the mainly driving force of hydration process and the swelling stress is mainly from hydration process. It will great help to understand better about heat and mass transfer in porous media and the THM coupled process in actual HLW disposal. (author)

2D massless QED Hall half-integer conductivity and graphene

International Nuclear Information System (INIS)

Martínez, A Pérez; Querts, E Rodriguez; Rojas, H Pérez; Gaitan, R; Rodriguez-Romo, S

2011-01-01

Starting from the photon self-energy tensor in a magnetized medium, the 3D complete antisymmetric form of the conductivity tensor is found in the static limit of a fermion system C-non-invariant under fermion–antifermion exchange. The massless relativistic 2D fermion limit in QED is derived by using the compactification along the dimension parallel to the magnetic field. In the static limit and at zero temperature, the main features of the quantum Hall effect (QHE) are obtained: the half-integer QHE and the minimum value proportional to e 2 /h for the Hall conductivity. For typical values of graphene the plateaus of the Hall conductivity are also reproduced. (paper)

Electronic bound states in parity-preserving QED{sub 3} applied to high-T{sub c} cuprate superconductors

Energy Technology Data Exchange (ETDEWEB)

Christiansen, H.R. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas]. E-mail: hugo@cbpf.br; Cima, O.M. Del [Universidade Catolica de Petropolis, RJ (Brazil). Grupo de Fisica Teorica]. E-mail: delcima@gft.ucp.br; Ferreira Junior, M.M. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas]|[Maranhao Univ., Sao Luis, MA (Brazil). Dept. de Fisica]. E-mail: manojr@cbpf.br; Helayel-Neto, J.A. [Universidade Catolica de Petropolis, RJ (Brazil). Grupo de Fisica Teorica]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Coordenacao de Teoria de Campos e Particulas]. E-mail: helayel@gft.ucp.br

2001-08-01

We consider a parity-preserving QED{sub 3} model with spontaneous breaking of the gauge symmetry as a framework for the evaluation of the electron-electron interaction potential underlying high-T{sub e} superconductivity. The fact that resulting potential, - C{sub s} K{sub o} (Mr), is non-confining and weak (in the sense of Kato) strongly suggests the mechanism of pair-condensation. This potential, compatible with an s-wave order parameters, is then applied to the Schrodinger equation for the sake of numerical calculations, thereby enforcing the existence of bound states. The results worked out by means of our theoretical framework are checked by considering a number of phenomenological data extracted from different copper oxide superconductors. The agreement may motivate a deeper analysis of our model viewing an application to quasi-planar cuprate superconductors. The data analyzed here suggest an energy scale of 1-10 meV for the breaking of the U(1)-symmetry. (author)

QED contributions to electron g-2

Science.gov (United States)

Laporta, Stefano

2018-05-01

In this paper I briefly describe the results of the numerical evaluation of the mass-independent 4-loop contribution to the electron g-2 in QED with 1100 digits of precision. In particular I also show the semi-analytical fit to the numerical value, which contains harmonic polylogarithms of eiπ/3, e2iπ/3 and eiπ/2 one-dimensional integrals of products of complete elliptic integrals and six finite parts of master integrals, evaluated up to 4800 digits. I give also some information about the methods and the program used.

Familial occurrence of isolated non-compaction cardiomyopathy

NARCIS (Netherlands)

Lorsheyd, Anouk; Cramer, Maarten-Jan M.; Velthuis, Birgitta K.; Vonken, Evert-Jan P.; van der Smagt, Jasper; van Tintelen, Peter; Hauer, Richard N. W.

2006-01-01

Background and aims: Isolated left ventricular non-compaction cardiomyopathy (LVNC) may have an autosomal dominant or X-linked recessive inheritance. We focus on the familial occurrence of LVNC after misdiagnosing this disorder in symptomatic patients in two families. After identification of the

Critical behavior of the compact 3D U(1) theory in the limit of zero spatial coupling

International Nuclear Information System (INIS)

Borisenko, O; Gravina, M; Papa, A

2008-01-01

Critical properties of the compact three-dimensional U(1) lattice gauge theory are explored at finite temperatures on an asymmetric lattice. For vanishing value of the spatial gauge coupling one obtains an effective two-dimensional spin model which describes the interaction between Polyakov loops. We study numerically the effective spin model for N t = 1,4,8 on lattices with spatial extent ranging from L = 64 to 256. Our results indicate that the finite temperature U(1) lattice gauge theory belongs to the universality class of the two-dimensional XY model, thus supporting the Svetitsky–Yaffe conjecture

Cardiovascular magnetic resonance findings in a pediatric population with isolated left ventricular non-compaction

Directory of Open Access Journals (Sweden)

Uribe Sergio

2012-01-01

Full Text Available Abstract Background Isolated Left Ventricular Non-compaction (LVNC is an uncommon disorder characterized by the presence of increased trabeculations and deep intertrabecular recesses. In adults, it has been found that Ejection Fraction (EF decreases significantly as non-compaction severity increases. In children however, there are a few data describing the relation between anatomical characteristics of LVNC and ventricular function. We aimed to find correlations between morphological features and ventricular performance in children and young adolescents with LVNC using Cardiovascular Magnetic Resonance (CMR. Methods 15 children with LVNC (10 males, mean age 9.7 y.o., range 0.6 - 17 y.o., underwent a CMR scan. Different morphological measures such as the Compacted Myocardial Mass (CMM, Non-Compaction (NC to the Compaction (C distance ratio, Compacted Myocardial Area (CMA and Non-Compacted Myocardial Area (NCMA, distribution of NC, and the assessment of ventricular wall motion abnormalities were performed to investigate correlations with ventricular performance. EF was considered normal over 53%. Results The distribution of non-compaction in children was similar to published adult data with a predilection for apical, mid-inferior and mid-lateral segments. Five patients had systolic dysfunction with decreased EF. The number of affected segments was the strongest predictor of systolic dysfunction, all five patients had greater than 9 affected segments. Basal segments were less commonly affected but they were affected only in these five severe cases. Conclusion The segmental pattern of involvement of non-compaction in children is similar to that seen in adults. Systolic dysfunction in children is closely related to the number of affected segments.

Quantum revolution. [Vol.] 2: QED: the jewel of physics

International Nuclear Information System (INIS)

Venkataraman, G.

1994-01-01

Events leading to the plague or crisis of infinities in the field of quantum mechanics are surveyed in brief. How that crisis was contained by formulation of quantum electrodynamics (QED) theory is narrated in this volume. Contributions of Tomanoga, Schwinger and Feynman to the QED theory are discussed. The story of quantum mechanics is brought up to fifties. (M.G.B.)

Implementation of quantum partial search with superconducting quantum interference device qudits in cavity QED

International Nuclear Information System (INIS)

Li Hong-Yi; Wu Chun-Wang; Chen Yu-Bo; Lin Yuan-Gen; Chen Ping-Xing; Li Cheng-Zu

2013-01-01

We present a method to implement the quantum partial search of the database separated into any number of blocks with qudits, D-level quantum systems. Compared with the partial search using qubits, our method needs fewer iteration steps and uses the carriers of the information more economically. To illustrate how to realize the idea with concrete physical systems, we propose a scheme to carry out a twelve-dimensional partial search of the database partitioned into three blocks with superconducting quantum interference devices (SQUIDs) in cavity QED. Through the appropriate modulation of the amplitudes of the microwave pulses, the scheme can overcome the non-identity of the cavity—SQUID coupling strengths due to the parameter variations resulting from the fabrication processes. Numerical simulation under the influence of the cavity and SQUID decays shows that the scheme could be achieved efficiently within current state-of-the-art technology

Higher Order QED Contributions to the Atomic Structure at Strong Central Fields

International Nuclear Information System (INIS)

Mokler, P H

2007-01-01

An accurate determination of the precise structure of highly charged, very heavy ions is crucial for understanding QED at strong fields. The experimental advances in the spectroscopy of very heavy, highly charged ions-in particular H-, He- and Li-like species-are reviewed: Presently the ground state Lamb shift for H-like U ions is measured on a 1% level of accuracy; the screening terms in two-electron QED have just been touched by experiments for He-like U; and two-loop QED terms have been determined with ultimate accuracy for Li-like heavy species. The different approaches on QED measurements in strong fields will be discussed and the results compared to theory

No parity anomaly in massless QED{sub 3}: A BPHZL approach

Energy Technology Data Exchange (ETDEWEB)

Del Cima, O.M. [Universidade Federal Fluminense (UFF), Polo Universitario de Rio das Ostras (PURO), Departamento de Ciencia e Tecnologia, Rua Recife s/n, 28890-000, Rio das Ostras, RJ (Brazil)], E-mail: wadodelcima@if.uff.br; Franco, D.H.T. [Universidade Federal de Vicosa (UFV), Departamento de Fisica - Campus Universitario, Avenida Peter Henry Rolfs s/n, 36570-000, Vicosa, MG (Brazil)], E-mail: dhtfranco@gmail.com; Piguet, O. [Universidade Federal do Espirito Santo (UFES), CCE, Departamento de Fisica, Campus Universitario de Goiabeiras, 29060-900, Vitoria, ES (Brazil)], E-mail: opiguet@pq.cnpq.br; Schweda, M. [Institut fuer Theoretische Physik, Technische Universitaet Wien (TU-Wien), Wiedner Hauptstrasse 8-10, A-1040, Vienna (Austria)], E-mail: mschweda@tph.tuwien.ac.at

2009-09-14

In this Letter we call into question the perturbatively parity breakdown at 1-loop for the massless QED{sub 3} frequently claimed in the literature. As long as perturbative quantum field theory is concerned, whether a parity anomaly owing to radiative corrections exists or not shall be definitely proved by using a renormalization method independent of any regularization scheme. Such a problem has been investigated in the framework of BPHZL renormalization method, by adopting the Lowenstein-Zimmermann subtraction scheme. The 1-loop parity-odd contribution to the vacuum-polarization tensor is explicitly computed in the framework of the BPHZL renormalization method. It is shown that a Chern-Simons term is generated at that order induced through the infrared subtractions - which violate parity. We show then that, what is called 'parity anomaly', is in fact a parity-odd counterterm needed for restauring parity.

A note on non-compact Cauchy surfaces

International Nuclear Information System (INIS)

Kim, Do-Hyung

2008-01-01

It is shown that if a spacetime has a non-compact Cauchy surface Σ, then its causal structure is completely determined by the class of compact subsets of Σ of the forms J - (p) intersection Σ and J + (p) intersection Σ. Since the causal structure determines its metric structure up to a conformal factor, this implies that the sets J - (p) intersection Σ and J + (p) intersection Σ determine the conformal structure of a globally hyperbolic spacetime. In this way, we can encode the conformal structure of the spacetime into its Cauchy surface and we get another method for reconstructing spacetime. (comments, replies and notes)

QED as the tensionless limit of the spinning string with contact interaction

Energy Technology Data Exchange (ETDEWEB)

Edwards, James P., E-mail: J.P.Edwards@durham.ac.uk; Mansfield, Paul, E-mail: P.R.W.Mansfield@durham.ac.uk

2015-06-30

QED with spinor matter is argued to correspond to the tensionless limit of spinning strings with contact interactions. The strings represent electric lines of force with charges at their ends. The interaction is constructed from a delta-function on the world-sheet which, although off-shell, decouples from the world-sheet metric. Integrating out the string degrees of freedom with fixed boundary generates the super-Wilson loop that couples spinor matter to electromagnetism in the world-line formalism. World-sheet and world-line, but not spacetime, supersymmetry underpin the model.

Simplicity in the structure of QED and gravity amplitudes

Energy Technology Data Exchange (ETDEWEB)

Badger, Simon [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Bjerrum-Bohr, N.E.J. [Institute for Advanced Study, Princeton, NJ (United States). School of Natural Sciences; Vanhove, Pierre [Institut des Hautes Etudes Scientifiques IHES, Bures sur Yvette (France); CEA, IPhT, CNRS, URA, Gif-sur-Yvette, (France). Inst. de Physique Theorique

2008-11-15

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 'notriangle' property found in the case of maximal 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. (orig.)

Simplicity in the structure of QED and gravity amplitudes

International Nuclear Information System (INIS)

Badger, Simon; Bjerrum-Bohr, N.E.J.; Vanhove, Pierre; CEA, IPhT, CNRS, URA, Gif-sur-Yvette,

2008-11-01

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 'notriangle' property found in the case of maximal 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. (orig.)

Azimuthal asymmetry in processes of nonlinear QED for linearly polarized photon

International Nuclear Information System (INIS)

Bajer, V.N.; Mil'shtejn, A.I.

1994-01-01

Cross sections of nonlinear QED processes (photon-photon scattering, photon splitting in a Coulomb field, and Delbrueck scattering) are considered for linearly polarized initial photon. The cross sections have sizeable azimuthal asymmetry. 15 refs.; 3 figs

QED effects induced harmonics generation in extreme intense laser foil interaction

Science.gov (United States)

Yu, J. Y.; Yuan, T.; Liu, W. Y.; Chen, M.; Luo, W.; Weng, S. M.; Sheng, Z. M.

2018-04-01

A new mechanism of harmonics generation (HG) induced by quantum electrodynamics (QED) effects in extreme intense laser foil interaction is found and investigated by particle-in-cell (PIC) simulations. When two laser pulses with identical intensities of 1.6× {10}24 {{W}} {{{cm}}}-2 are counter-incident on a thin foil target, harmonics emission is observed in their reflected electromagnetic waves. Such harmonics radiation is excited due to transversely oscillating electric currents coming from the vibration of QED effect generated {e}-{e}+ pairs. The effects of laser intensity and polarization were studied. By distinguishing the cascade depth of generated photons and pairs, the influence of QED cascades on HG was analyzed. Although the current HG is not an efficient way for radiation source applications, it may provide a unique way to detect the QED processes in the near future ultra-relativistic laser solid interactions.

Avoidance of a Landau pole by flat contributions in QED

Energy Technology Data Exchange (ETDEWEB)

Klaczynski, Lutz, E-mail: lutz.klaczynski@gmx.de [Department of Physics, Humboldt University Berlin, 12489 Berlin (Germany); Kreimer, Dirk, E-mail: kreimer@mathematik.hu-berlin.de [Alexander von Humboldt Chair in Mathematical Physics, Humboldt University, Berlin 12489 (Germany)

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.

The standard model on non-commutative space-time

International Nuclear Information System (INIS)

Calmet, X.; Jurco, B.; Schupp, P.; Wohlgenannt, M.; Wess, J.

2002-01-01

We consider the standard model on a non-commutative space and expand the action in the non-commutativity parameter θ μν . No new particles are introduced; the structure group is SU(3) x SU(2) x U(1). We derive the leading order action. At zeroth order the action coincides with the ordinary standard model. At leading order in θ μν we find new vertices which are absent in the standard model on commutative space-time. The most striking features are couplings between quarks, gluons and electroweak bosons and many new vertices in the charged and neutral currents. We find that parity is violated in non-commutative QCD. The Higgs mechanism can be applied. QED is not deformed in the minimal version of the NCSM to the order considered. (orig.)

The covariant-evolution-operator method in bound-state QED

International Nuclear Information System (INIS)

Lindgren, Ingvar; Salomonson, Sten; Aasen, Bjoern

2004-01-01

The methods of quantum-electrodynamical (QED) calculations on bound atomic systems are reviewed with emphasis on the newly developed covariant-evolution-operator method. The aim is to compare that method with other available methods and also to point out possibilities to combine that with standard many-body perturbation theory (MBPT) in order to perform accurate numerical QED calculations, including quasi-degeneracy, also for light elements, where the electron correlation is relatively strong. As a background, the time-independent many-body perturbation theory (MBPT) is briefly reviewed, particularly the method with extended model space. Time-dependent perturbation theory is discussed in some detail, introducing the time-evolution operator and the Gell-Mann-Low relation, generalized to an arbitrary model space. Three methods of treating the bound-state QED problem are discussed. The standard S-matrix formulation, which is restricted to a degenerate model space, is discussed only briefly. Two methods applicable also to the quasi-degenerate problem are treated in more detail, the two-times Green's-function and the covariant-evolution-operator techniques. The treatment is concentrated on the latter technique, which has been developed more recently and which has not been discussed in more detail before. A comparison of the two-times Green's-function and the covariant-evolution-operator techniques, which have great similarities, is performed. In the appendix a simple procedure is derived for expressing the evolution-operator diagrams of arbitrary order. The possibilities of merging QED in the covariant evolution-operator formulation with MBPT in a systematic way is indicated. With such a technique it might be feasible to perform accurate QED calculations also on light elements, which is presently not possible with the techniques available

Non-compaction cardiomyopathy – an unusual cause of heart failure

Directory of Open Access Journals (Sweden)

Jure Dolenc

2011-03-01

Full Text Available Introduction: Non-compaction cardiomyopathy is a rare inborn anomaly caused by disorder of endomyocardial morphogenesis. The diagnosis is based on echocardiographic criteria. The prevalence in the adult population is not known. The symptoms are atypical. Three main groups of clinical signs exist: heart failure, thromobembolic events and arrhythmias. In the group of patients with reduced left ventricular function the prognosis is poor and the treatment options are limited. Patients and methods: In the recent 10 years, 7 patients with non-compaction cardiomyopathy were diagnosed at the Department of Cardiology of the University Medical Centre Ljubljana. Results: All seven patients were males, their mean age at the last follow-up being 39 ± 20.3 years (range 20 to 70 years. Five patients were diagnosed in adulthood. All of them fulfilled the echocardiographic diagnostic criteria of noncompaction cardiomyopathy. Five patients had depressed function of both ventricles, two patients had isolated left ventricular dysfunction. Three patients had decreased left ventricular ejection fraction, six patients showed left ventricular diastolic dysfunction. Only three patients had normal physical capacity. Two patients presented with clinical signs of overt heart failure. During follow-up, one patient died from heart failure. We observed thromboembolic events in one patient. Three patients suffered from nonsustained ventricular tachycardias and two patients had rhythm conduction abnormalities. Conclusions: Non-compaction cardiomyopathy is a rare disorder. We observed all common complications in our group of patients. The majority of patients displayed dysfunction of the affected ventricle and the dysfunction was more pronounced in older patients. Treatment of complications is an important factor in long-term survival of these patients.

Large N dynamics in QED in a magnetic field

International Nuclear Information System (INIS)

Gusynin, V.P.; Miransky, V.A.; Shovkovy, I.A.

2003-01-01

The expression for the dynamical mass of fermions in QED in a magnetic field is obtained for a large number of the fermion flavor N in the framework of 1/N expansion. The existence of a threshold value N thr , dividing the theories with essentially different dynamics, is established. For the number of flavors N thr , the dynamical mass is very sensitive to the value of the coupling constant α b , related to the magnetic scale μ=√(vertical bar eB vertical bar). For N of the order of N thr or larger, a dynamics similar to that in the Nambu-Jona-Lasinio model with a cutoff of the order of √(vertical bar eB vertical bar) and the dimensional coupling constant G∼1/(N vertical bar eB vertical bar) takes place. In this case, the value of the dynamical mass is essentially α b independent (the dynamics with an infrared stable fixed point). The value of N thr separates a weak coupling dynamics (with α-tilde b ≡Nα b b > or approx. 1) and is of the order of 1/α b

Perturbative expansion of Chern-Simons theory with non-compact gauge group

International Nuclear Information System (INIS)

Bar-Natan, D.; Witten, E.

1991-01-01

Naive imitation of the usual formulas for compact gauge group in quantizing three dimensional Chern-Simons gauge theory with non-compact gauge group leads to formulas that are wrong or unilluminating. In this paper, an appropriate modification is described, which puts the perturbative expansion in a standard manifestly 'unitary' format. The one loop contributions (which differ from naive extrapolation from the case of compact gauge group) are computed, and their topological invariance is verified. (orig.)

Infrared behaviour of massless QED in space-time dimensions 2

International Nuclear Information System (INIS)

Mitra, Indrajit; Ratabole, Raghunath; Sharatchandra, H.S.

2005-01-01

We show that the logarithmic infrared divergences in electron self-energy and vertex function of massless QED in 2+1 dimensions can be removed at all orders of 1/N by an appropriate choice of a non-local gauge. Thus the infrared behaviour given by the leading order in 1/N is not modified by higher order corrections. Our analysis gives a computational scheme for the Amati-Testa model, resulting in a non-trivial conformal invariant field theory for all space-time dimensions 2< d<4

Infrared behaviour of massless QED in space-time dimensions 2

Energy Technology Data Exchange (ETDEWEB)

Mitra, Indrajit [The Institute of Mathematical Sciences, C.I.T. Campus, Taramani P.O., Chennai 600113 (India) and Theory Group, Saha Institute of Nuclear Physics, 1/AF Bidhan-Nagar, Kolkata 700064 (India)]. E-mail: indra@theory.saha.ernet.in; Ratabole, Raghunath [The Institute of Mathematical Sciences, C.I.T. Campus, Taramani P.O., Chennai 600113 (India)]. E-mail: raghu@imsc.res.in; Sharatchandra, H.S. [The Institute of Mathematical Sciences, C.I.T. Campus, Taramani P.O., Chennai 600113 (India)]. E-mail: sharat@imsc.res.in

2005-04-07

We show that the logarithmic infrared divergences in electron self-energy and vertex function of massless QED in 2+1 dimensions can be removed at all orders of 1/N by an appropriate choice of a non-local gauge. Thus the infrared behaviour given by the leading order in 1/N is not modified by higher order corrections. Our analysis gives a computational scheme for the Amati-Testa model, resulting in a non-trivial conformal invariant field theory for all space-time dimensions 2

Design and Simulation of a Compact UWB MIMO Antenna with Mutual Coupling Reduction

Directory of Open Access Journals (Sweden)

Narges Malekpoor

2016-01-01

Full Text Available In this paper, A compact multiple-input-multiple-output (MIMO antenna with a small size of 26×31mm2 is proposed for portable ultrawideband (UWB applications. The antenna consists of two square-monopole antenna with microstrip-fed by a 50- Ω printed on one side of the substrate. To enhance isolation and increase impedance bandwidth, two long ground stubs are added to the ground plane on the other side. Simulation is used to study the antenna performance in terms of reflection coefficients at the two input ports, coupling between the two input ports, radiation pattern, realized peak gain, efficiency and envelope correlation coefficient. Results show that the MIMO antenna has an impedance bandwidth ( for S22< -10 dB of larger than 3.1–10.6 GHz, low mutual coupling ( for S21< 3 dB of less than -16 dB, and a low envelope correlation coefficient of less than 0.003 across the frequency band, making it a good candidate for portable UWB applications.

QED loop effects in the spacetime background of a Schwarzschild black hole

Science.gov (United States)

Emelyanov, Viacheslav A.

2017-12-01

The black-hole evaporation implies that the quantum-field propagators in a local Minkowski frame acquire a correction, which gives rise to this process. The modification of the propagators causes, in turn, non-trivial local effects due to the radiative/loop diagrams in non-linear QFTs. In particular, there should be imprints of the evaporation in QED, if one goes beyond the tree-level approximation. Of special interest in this respect is the region near the black-hole horizon, which, already at tree level, appears to show highly non-classical features, e.g., negative energy density and energy flux into the black hole.

Nonsequential multiphoton double ionization of He in intense laser - a QED approach

International Nuclear Information System (INIS)

Bhattacharyya, S.; Mazumder, Mina; Chakrabarti, J.; Faisal, F.H.M.

2010-01-01

The non-sequential muItiphoton double ionization (NSDI) of He in intense laser field is not yet completely understood, more so for spin resolved currents. We are tempted to use QED and Feynman diagram to obtain spin polarized currents. Hartree-Fock (HF) ground-state correlated wave function of He atom is considered in circularly polarized laser. In QED approach one of the electrons is directly ionized by photon absorption while the second electron is shaken off due to the change in the internal potential of the atom. In He-atom the two ionized electrons can only be in the singlet spin state. Spin-symmetric and spin-flip transitions are eventually possible for the direct and the shake-off electrons. In an ensemble of (HF type) He-atoms the ionized Volkov electrons may acquire 4 pairs of momenta indicating e-e correlation in the final state. Coulomb correction is taken care off through the Sommerfeld factor

Non-Supramenable Groups Acting on Locally Compact Spaces

DEFF Research Database (Denmark)

Kellerhals, Julian; Monod, Nicolas; Rørdam, Mikael

2013-01-01

Supramenability of groups is characterised in terms of invariant measures on locally compact spaces. This opens the door to constructing interesting crossed product $C^*$-algebras for non-supramenable groups. In particular, stable Kirchberg algebras in the UCT class are constructed using crossed ...

Leading-order hadronic contributions to a{sub {mu}} and {alpha}{sub QED} from N{sub f}=2+1+1 twisted mass fermions

Energy Technology Data Exchange (ETDEWEB)

Feng, Xu [High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki (Japan); Hotzel, Grit [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Petschlies, Marcus [The Cyprus Institute, Nicosia (Cyprus); Renner, Dru B. [Jefferson Lab, Newport News, VA (United States)

2012-11-15

We present the first four-flavour lattice calculation of the leading-order hadronic vacuum-polarisation contribution to the anomalous magnetic moment of the muon, a{sup hvp}{sub {mu}}, and the hadronic running of the QED coupling constant, {Delta}{alpha}{sup hvp}{sub QED}(Q{sup 2}). In the heavy sector a mixed-action setup is employed. The bare quark masses are determined from matching the K- and D-meson masses to their physical values. Several light quark masses are used in order to yield a controlled extrapolation to the physical pion mass by utilising a recently proposed improved method. We demonstrate that this method also works in the four-flavour case.

Leading order hadronic contributions to a{sub {mu}} and {alpha}{sub QED} from N{sub f} = 2 + 1 + 1 twisted mass fermions

Energy Technology Data Exchange (ETDEWEB)

Xu Feng, Grit Hotzel, Karl Jansen, Marcus Petschlies, Dru B. Renner

2012-12-01

We present the first four-flavour lattice calculation of the leading-order hadronic vacuum polarisation contribution to the anomalous magnetic moment of the muon, a{sub {mu}}{sup hvp}, and the hadronic running of the QED coupling constant, {Delta}{alpha}{sup hvp}{sub QED}(Q{sup 2}). In the heavy sector a mixed-action setup is employed. The bare quark masses are determined from matching the K- and D-meson masses to their physical values. Several light quark masses are used in order to yield a controlled extrapolation to the physical pion mass by utilising a recently proposed improved method. We demonstrate that this method also works in the four-flavour case.

Leading-order hadronic contributions to a{sub μ} and α{sub QED} from N{sub f}=2+1+1 twisted mass fermions

Energy Technology Data Exchange (ETDEWEB)

Feng, Xu [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); Hotzel, Grit [Humboldt-Universitaet zu Berlin, Institut fuer Physik, Berlin (Germany); Jansen, Karl [NIC, DESY, Zeuthen (Germany); Petschlies, Marcus [The Cyprus Institute, Nicosia (Cyprus); Renner, Dru [Jefferson Lab, Newport News (United States)

2013-07-01

We present the first four-flavour lattice calculation of the leading-order hadronic vacuum-polarisation contribution to the anomalous magnetic moment of the muon, a{sub μ}{sup hvp}, and the hadronic running of the QED coupling constant, Δ α{sub QED}{sup hvp} (Q{sup 2}). In the heavy sector a mixed-action setup is employed. The bare quark masses are determined from matching the K- and D-meson masses to their physical values. Several light quark masses are used in order to yield a controlled extrapolation to the physical pion mass by utilising a recently proposed improved method. We demonstrate that this method also works in the four-flavour case.

Symplectic matrix, gauge invariance and Dirac brackets for super-QED

Energy Technology Data Exchange (ETDEWEB)

Alves, D.T. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Cheb-Terrab, E.S. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Mathematics

1999-08-01

The calculation of Dirac brackets (DB) using a symplectic matrix approach but in a Hamiltonian framework is discussed, and the calculation of the DB for the supersymmetric extension of QED (super-QED) is shown. The relation between the zero-mode of the pre-symplectic matrix and the gauge transformations admitted by the model is verified. A general description to construct Lagrangians linear in the velocities is also presented. (author)

General QED/QCD aspects of simple systems

International Nuclear Information System (INIS)

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 Θ w ; the Nambu-Bethe-Salpeter (NBS) equation; the decay rate of 3 S, positronium; radiative corrections to QCD Born cross section; and progress on the relativistic 2-body equation

Strong-coupling of WSe2 in ultra-compact plasmonic nanocavities at room temperature.

Science.gov (United States)

Kleemann, Marie-Elena; Chikkaraddy, Rohit; Alexeev, Evgeny M; Kos, Dean; Carnegie, Cloudy; Deacon, Will; de Pury, Alex Casalis; Große, Christoph; de Nijs, Bart; Mertens, Jan; Tartakovskii, Alexander I; Baumberg, Jeremy J

2017-11-03

Strong coupling of monolayer metal dichalcogenide semiconductors with light offers encouraging prospects for realistic exciton devices at room temperature. However, the nature of this coupling depends extremely sensitively on the optical confinement and the orientation of electronic dipoles and fields. Here, we show how plasmon strong coupling can be achieved in compact, robust, and easily assembled gold nano-gap resonators at room temperature. We prove that strong-coupling is impossible with monolayers due to the large exciton coherence size, but resolve clear anti-crossings for greater than 7 layer devices with Rabi splittings exceeding 135 meV. We show that such structures improve on prospects for nonlinear exciton functionalities by at least 10 4 , while retaining quantum efficiencies above 50%, and demonstrate evidence for superlinear light emission.

The standard model on non-commutative space-time

Energy Technology Data Exchange (ETDEWEB)

Calmet, X.; Jurco, B.; Schupp, P.; Wohlgenannt, M. [Sektion Physik, Universitaet Muenchen (Germany); Wess, J. [Sektion Physik, Universitaet Muenchen (Germany); Max-Planck-Institut fuer Physik, Muenchen (Germany)

2002-03-01

We consider the standard model on a non-commutative space and expand the action in the non-commutativity parameter {theta}{sup {mu}}{sup {nu}}. No new particles are introduced; the structure group is SU(3) x SU(2) x U(1). We derive the leading order action. At zeroth order the action coincides with the ordinary standard model. At leading order in {theta}{sup {mu}}{sup {nu}} we find new vertices which are absent in the standard model on commutative space-time. The most striking features are couplings between quarks, gluons and electroweak bosons and many new vertices in the charged and neutral currents. We find that parity is violated in non-commutative QCD. The Higgs mechanism can be applied. QED is not deformed in the minimal version of the NCSM to the order considered. (orig.)

Running coupling constant of a gauge theory in the framework of the Schwinger-Dyson equation: Infrared behavior of three-dimensional quantum electrodynamics

International Nuclear Information System (INIS)

Kondo, K.

1997-01-01

We discuss how to define and obtain the running coupling of a gauge theory in the approach of the Schwinger-Dyson (SD) equation, in order to perform a nonperturbative study of the theory. For this purpose, we introduce the nonlocally generalized gauge fixing into the SD equation, which is used to define the running coupling constant (this method is applicable only to a gauge theory). Some advantages and the validity of this approach are exemplified in QED 3 . This confirms the slowing down of the rate of decrease of the running coupling and the existence of the nontrivial infrared fixed point (in the normal phase) of QED 3 , claimed recently by Aitchison and Mavromatos, without so many of their approximations. We also argue that the conventional approach is recovered by applying the (inverse) Landau-Khalatnikov transformation to the nonlocal gauge result. copyright 1997 The American Physical Society

The Gribov problem in noncommutative QED

Energy Technology Data Exchange (ETDEWEB)

Canfora, Fabrizio [Centro de Estudios Científicos (CECS),Casilla 1469, Valdivia (Chile); Kurkov, Maxim A. [Dipartimento di Matematica, Università di Napoli Federico II,Monte S. Angelo, Via Cintia, 80126 Napoli (Italy); CMCC-Universidade Federal do ABC,Santo André, S.P. (Brazil); INFN, Sezione di Napoli,Monte S. Angelo, Via Cintia, 80126 Napoli (Italy); Rosa, Luigi; Vitale, Patrizia [Dipartimento di Fisica, Università di Napoli Federico II,Monte S. Angelo, Via Cintia, 80126 Napoli (Italy); INFN, Sezione di Napoli,Monte S. Angelo, Via Cintia, 80126 Napoli (Italy)

2016-01-04

It is shown that in the noncommutative version of QED (NCQED) Gribov copies induced by the noncommutativity of space-time appear in the Landau gauge. This is a genuine effect of noncommutative geometry which disappears when the noncommutative parameter vanishes.

Cavity QED with single trapped Ca+-ions

International Nuclear Information System (INIS)

Mundt, A.B.

2003-02-01

This thesis reports on the design and setup of a vacuum apparatus allowing the investigation of cavity QED effects with single trapped 40 Ca + ions. The weak coupling of ion and cavity in the 'bad cavity limit' may serve to inter--convert stationary and flying qubits. The ion is confined in a miniaturized Paul trap and cooled via the Doppler effect to the Lamb--Dicke regime. The extent of the atomic wave function is less than 30 nm. The ion is enclosed by a high finesse optical cavity. The technically--involved apparatus allows movement of the trap relative to the cavity and the trapped ion can be placed at any position in the standing wave. By means of a transfer lock the cavity can be resonantly stabilized with the S 1/2 ↔ D 5/2 quadrupole transition at 729 nm (suitable as a qubit) without light at that wavelength being present in the cavity. The coupling of the cavity field to the S 1/2 ↔ D 5/2 quadrupole transition is investigated with various techniques in order to determine the spatial dependence as well as the temporal dynamics. The orthogonal coupling of carrier and first--order sideband transitions at field nodes and antinodes is explored. The coherent interaction of the ion and the cavity field is confirmed by exciting Rabi oscillations with short resonant pulses injected into the cavity. Finally, first experimental steps towards the observation of cavity enhanced spontaneous emission have been taken. (author)

The Effect of Mutual Coupling on a High Altitude Platform Diversity System Using Compact Antenna Arrays

Directory of Open Access Journals (Sweden)

Tommy Hult

2010-01-01

Full Text Available We analyze the destructive effects of mutual coupling and spatial correlation between the separate antenna elements on a combined diversity system consisting of multiple HAPs (High-Altitude Platforms employing various compact MIMO (Multiple-Input Multiple-Output antenna array configurations, in order to enhance the mutual information in HAP communication links. In addition, we assess the influence of the separation angle between HAPs on system performance, and determine the optimal separation angles that maximize the total mutual information of the system for various compact MIMO antennas. Simulation results show that although the mutual information is degraded by mutual coupling and spatial correlation, the proposed HAP diversity system still provides better performance compared to a nondiversity system for all tested scenarios.

Hybrid Circuit QED with Electrons on Helium

Science.gov (United States)

Yang, Ge

Electrons on helium (eHe) is a 2-dimensional system that forms naturally at the interface between superfluid helium and vacuum. It has the highest measured electron mobility, and long predicted spin coherence time. In this talk, we will first review various quantum computer architecture proposals that take advantage of these exceptional properties. In particular, we describe how electrons on helium can be combined with superconducting microwave circuits to take advantage of the recent progress in the field of circuit quantum electrodynamics (cQED). We will then demonstrate how to reliably trap electrons on these devices hours at a time, at millikelvin temperatures inside a dilution refrigerator. The coupling between the electrons and the microwave resonator exceeds 1 MHz, and can be reproduced from the design geometry using our numerical simulation. Finally, we will present our progress on isolating individual electrons in such circuits, to build single-electron quantum dots with electrons on helium.

Developing magnonic architectures in circuit QED

Science.gov (United States)

Karenowska, Alexy; van Loo, Arjan; Morris, Richard; Kosen, Sandoko

The development of low-temperature experiments aimed at exploring and exploiting magnonic systems at the quantum level is rapidly becoming a highly active and innovative area of microwave magnetics research. Magnons are easily excited over the microwave frequency range typical of established solid-state quantum circuit technology, and couple readily to electromagnetic fields. These facts, in combination with the highly tunable dispersion of the excitations, make them a particularly interesting proposition in the context of quantum device design. In this talk, we survey recent progress made in our group in the area of the hybridization of planar superconducting circuit technology (circuit-QED) with magnon systems. We discuss the technical requirements of successful experiments, including the choice of suitable materials. We go on to describe the results of investigations including the study spin-wave propagation in magnetic waveguides at the single magnon level, the investigation of magnon modes in spherical magnetic resonators, and the development of systems incorporating Josephson-junction based qubits. The authors would like to acknowledge funding by the EPSRC through Grant EP/K032690/1.

Bern-Kosower rule for scalar QED

International Nuclear Information System (INIS)

Daikouji, K.; Shino, M.; Sumino, Y.

1996-01-01

We derive a full Bern-Kosower-type rule for scalar QED starting from quantum field theory: we derive a set of rules for calculating S-matrix elements for any processes at any order of the coupling constant. A gauge-invariant set of diagrams in general is first written in the world line path-integral expression. Then we integrate over x(τ), and the resulting expression is given in terms of a correlation function on the world line left-angle x(τ)x(τ ' )right-angle. Simple rules to decompose the correlation function into basic elements are obtained. A gauge transformation known as the integration by parts technique can be used to reduce the number of independent terms before integration over proper-time variables. The surface terms can be omitted provided the external scalars are on shell. Also, we clarify correspondence to the conventional Feynman rule, which enabled us to avoid any ambiguity coming from the infinite dimensionality of the path-integral approach. copyright 1996 The American Physical Society

A semi perturbative method for QED

OpenAIRE

Jora, Renata; Schechter, Joseph

2014-01-01

We compute the QED beta function using a new method of functional integration. It turns out that in this procedure the beta function contains only the first two orders coefficients and thus corresponds to a new renormalization scheme, long time supposed to exist.

QED radiative corrections to the pionium life time

International Nuclear Information System (INIS)

Kuraev, Eh.A.

1997-01-01

The lowest order QED radiative corrections to the cross section of the recharged process of transition of two neutral ones and to the pionium lifetime are calculated in frame of scalar QED. It is argued that the ultraviolet cut-off of the loop momentum is to be chosen of order of ρ-meson mass. This fact permits to perform the calculation in frames of Effective Chiral Lagrangian theory with vector-meson dominance. The Coulomb factor corresponding to interaction in the initial state, shown, is to be removed to avoid the double counting. Resulting value of the radiative correction to the pionium lifetime is 0.25%

Left Ventricle Non compaction: Physiopathology and Findings by Magnetic Resonance

International Nuclear Information System (INIS)

Parra R, Rodrigo; Cadavid Lina

2009-01-01

A Left ventricular non compaction (LVNC) has recently been classified as a primary cardiomyopathy with a genetic origin. It is morphologically characterized by numerous prominent trabeculations and deep inter trabecular recesses. LVNC is probably secondary to an arrest in the normal process of myocardial compaction during fetal life. LVNC may be an isolated finding in the absence of any coexisting cardiac anomaly or may be associated with other congenital heart anomalies or neuromuscular disorders. LVNC includes both asymptomatic and symptomatic patients with severe heart failure, systemic embolism, arrhythmia or sudden death. Diagnosis has moved from autopsy to recognition during life by non-invasive means: echocardiography and more recently cardiac magnetic resonance imaging.

Influence of coupling phenomena on the transport through compacted clays

Energy Technology Data Exchange (ETDEWEB)

Rosanne, M.; Koudina, N.; Adler, P.M. [IPGP, Paris (France); Tevissen, E. [ANDRA, Dept. Etude-Experimentation et Calcul, Chatenay Malabry (France)

2001-07-01

Our principal motivation was to study the influence of the coupling phenomena on transport through compacted clays. Coupled transports may occur when a pressure gradient {nabla}P, and electrical field E and a concentration gradient {nabla}C interact. These three gradients induce three fluxes. A flow is generated characterized by the seepage velocity U; a solute flux J{sub L} and a current density I are generated. Close to equilibrium, when the gradients are not to large, the problem is linear and the fluxes are linear functions of the gradients. A first series of experiments was performed with argillite to determine the diagonal properties, i.e., permeability, conductivity, and diffusion coefficient. In a second series of experiments, the voltage resulting from an imposed concentration gradient between two reservoirs separated by a clay sample was systematically measured; this corresponds to the coefficient L{sub 13}. (orig.)

Compact Quantum Random Number Generator with Silicon Nanocrystals Light Emitting Device Coupled to a Silicon Photomultiplier

Science.gov (United States)

Bisadi, Zahra; Acerbi, Fabio; Fontana, Giorgio; Zorzi, Nicola; Piemonte, Claudio; Pucker, Georg; Pavesi, Lorenzo

2018-02-01

A small-sized photonic quantum random number generator, easy to be implemented in small electronic devices for secure data encryption and other applications, is highly demanding nowadays. Here, we propose a compact configuration with Silicon nanocrystals large area light emitting device (LED) coupled to a Silicon photomultiplier to generate random numbers. The random number generation methodology is based on the photon arrival time and is robust against the non-idealities of the detector and the source of quantum entropy. The raw data show high quality of randomness and pass all the statistical tests in national institute of standards and technology tests (NIST) suite without a post-processing algorithm. The highest bit rate is 0.5 Mbps with the efficiency of 4 bits per detected photon.

Remnants of semiclassical bistability in the few-photon regime of cavity QED.

Science.gov (United States)

Kerckhoff, Joseph; Armen, Michael A; Mabuchi, Hideo

2011-11-21

Broadband homodyne detection of the light transmitted by a Fabry-Perot cavity containing a strongly-coupled (133)Cs atom is used to probe the dynamic optical response in a regime where semiclassical theory predicts bistability but strong quantum corrections should apply. While quantum fluctuations destabilize true equilibrium bistability, our observations confirm the existence of metastable states with finite lifetimes and a hysteretic response is apparent when the optical drive is modulated on comparable timescales. Our experiment elucidates remnant semiclassical behavior in the attojoule (~10 photon) regime of single-atom cavity QED, of potential significance for ultra-low power photonic signal processing. © 2011 Optical Society of America

Bloch-wave engineered submicron-diameter quantum-dot micropillars for cavity QED experiments

DEFF Research Database (Denmark)

Gregersen, Niels; Lermer, Matthias; Reitzenstein, Stephan

2013-01-01

The semiconductor micropillar is attractive for cavity QED experiments. For strong coupling, the figure of merit is proportional to Q/√V, and a design combining a high Q and a low mode volume V is thus desired. However, for the standard submicron diameter design, poor mode matching between the ca...... the cavity and the DBR Bloch mode limits the Q. We present a novel adiabatic design where Bloch-wave engineering is employed to improve the mode matching, allowing the demonstration of a record-high vacuum Rabi splitting of 85 μeV and a Q of 13600 for a 850 nm diameter micropillar....

Recursive relations for processes with n photons of noncommutative QED

International Nuclear Information System (INIS)

Jafari, Abolfazl

2007-01-01

Recursion relations are derived in the sense of Berends-Giele for the multi-photon processes of noncommutative QED. The relations concern purely photonic processes as well as the processes with two fermions involved, both for arbitrary number of photons at tree level. It is shown that despite of the dependence of noncommutative vertices on momentum, in contrast to momentum-independent color factors of QCD, the recursion relation method can be employed for multi-photon processes of noncommutative QED

QED Theory of the Nuclear Magnetic Shielding in Hydrogenlike Ions

International Nuclear Information System (INIS)

Yerokhin, V. A.; Pachucki, K.; Harman, Z.; Keitel, C. H.

2011-01-01

The shielding of the nuclear magnetic moment by the bound electron in hydrogenlike ions is calculated ab initio with inclusion of relativistic, nuclear, and quantum electrodynamics (QED) effects. The QED correction is evaluated to all orders in the nuclear binding strength parameter and, independently, to the first order in the expansion in this parameter. The results obtained lay the basis for the high-precision determination of nuclear magnetic dipole moments from measurements of the g factor of hydrogenlike ions.

Meson-meson scattering in lattice QED2+1

International Nuclear Information System (INIS)

Fiebig, H.R.; Woloshyn, R.M.

1993-01-01

Scattering phase shifts of a meson-meson system in staggered 3-dimensional lattice QED are computed. The main task of the simulation is to obtain a discrete set of two-body energy levels. These are extracted from a 4-point time correlation matrix and then used to obtain scattering phase shifts. The results for the l = 0 and l = 2 partial waves are consistent with short-range repulsion and intermediate-range attraction of the residual meson-meson interaction. (orig.)

Relativistic and QED corrections to the g factor of Li-like ions

International Nuclear Information System (INIS)

Glazov, D.A.; Shabaev, V.M.; Volotka, A.V.; Tupitsyn, I.I.; Yerokhin, V.A.; Plunien, G.; Soff, G.

2004-01-01

Calculations of various corrections to the g factor of Li-like ions are presented, which result in a significant improvement of the theoretical accuracy in the region Z=6-92. The configuration-interaction Dirac-Fock method is employed for the evaluation of the interelectronic-interaction correction of order 1/Z 2 and higher. This correction is combined with the 1/Z interelectronic-interaction term derived within a rigorous QED approach. The one-electron QED correction of first order in α is obtained by employing our recent results for the self-energy term and by evaluating the vacuum-polarization contribution. The screening of QED corrections is taken into account to the leading orders in αZ and 1/Z

CERN LEP2 constraint on 4D QED having a dynamically generated spatial dimension

International Nuclear Information System (INIS)

Cho, G.-C.; Izumi, Etsuko; Sugamoto, Akio

2002-01-01

We study 4D QED in which one spatial dimension is dynamically generated from the 3D action, following the mechanism proposed by Arkani-Hamed, Cohen, and Georgi. In this model, the generated fourth dimension is discretized by an interval parameter a. We examine the phenomenological constraint on the parameter a coming from collider experiments on the QED process e + e - →γγ. It is found that the CERN e + e - collider LEP2 experiments give the constraint of 1/a > or approx. 461 GeV. The expected bound on the same parameter a at a future e + e - linear collider is briefly discussed

Quantum Private Comparison via Cavity QED

International Nuclear Information System (INIS)

Ye Tian-Yu

2017-01-01

The first quantum private comparison (QPC) protocol via cavity quantum electrodynamics (QED) is proposed in this paper by making full use of the evolution law of atom via cavity QED, where the third party (TP) is allowed to misbehave on his own but cannot conspire with either of the two users. The proposed protocol adopts two-atom product states rather than entangled states as the initial quantum resource, and only needs single-atom measurements for two users. Both the unitary operations and the quantum entanglement swapping operation are not necessary for the proposed protocol. The proposed protocol can compare the equality of one bit from each user in each round comparison with one two-atom product state. The proposed protocol can resist both the outside attack and the participant attack. Particularly, it can prevent TP from knowing two users’ secrets. Furthermore, the qubit efficiency of the proposed protocol is as high as 50%. (paper)

Compact Quantum Random Number Generator with Silicon Nanocrystals Light Emitting Device Coupled to a Silicon Photomultiplier

Directory of Open Access Journals (Sweden)

Zahra Bisadi

2018-02-01

Full Text Available A small-sized photonic quantum random number generator, easy to be implemented in small electronic devices for secure data encryption and other applications, is highly demanding nowadays. Here, we propose a compact configuration with Silicon nanocrystals large area light emitting device (LED coupled to a Silicon photomultiplier to generate random numbers. The random number generation methodology is based on the photon arrival time and is robust against the non-idealities of the detector and the source of quantum entropy. The raw data show high quality of randomness and pass all the statistical tests in national institute of standards and technology tests (NIST suite without a post-processing algorithm. The highest bit rate is 0.5 Mbps with the efficiency of 4 bits per detected photon.

Hopf-algebraic renormalization of QED in the linear covariant gauge

Energy Technology Data Exchange (ETDEWEB)

Kißler, Henry, E-mail: kissler@physik.hu-berlin.de

2016-09-15

In the context of massless quantum electrodynamics (QED) with a linear covariant gauge fixing, the connection between the counterterm and the Hopf-algebraic approach to renormalization is examined. The coproduct formula of Green’s functions contains two invariant charges, which give rise to different renormalization group functions. All formulas are tested by explicit computations to third loop order. The possibility of a finite electron self-energy by fixing a generalized linear covariant gauge is discussed. An analysis of subdivergences leads to the conclusion that such a gauge only exists in quenched QED.

Finite field-energy of a point charge in QED

International Nuclear Information System (INIS)

Costa, Caio V; Gitman, Dmitry M; Shabad, Anatoly E

2015-01-01

We consider a simple nonlinear (quartic in the fields) gauge-invariant modification of classical electrodynamics, to show that it possesses a regularizing ability sufficient to make the field energy of a point charge finite. The model is exactly solved in the class of static central-symmetric electric fields. Collation with quantum electrodynamics (QED) results in the total field energy of a point elementary charge about twice the electron mass. The proof of the finiteness of the field energy is extended to include any polynomial selfinteraction, thereby the one that stems from the truncated expansion of the Euler–Heisenberg local Lagrangian in QED in powers of the field strength. (paper)

Low-loss compact multilayer silicon nitride platform for 3D photonic integrated circuits.

Science.gov (United States)

Shang, Kuanping; Pathak, Shibnath; Guan, Binbin; Liu, Guangyao; Yoo, S J B

2015-08-10

We design, fabricate, and demonstrate a silicon nitride (Si(3)N(4)) multilayer platform optimized for low-loss and compact multilayer photonic integrated circuits. The designed platform, with 200 nm thick waveguide core and 700 nm interlayer gap, is compatible for active thermal tuning and applicable to realizing compact photonic devices such as arrayed waveguide gratings (AWGs). We achieve ultra-low loss vertical couplers with 0.01 dB coupling loss, multilayer crossing loss of 0.167 dB at 90° crossing angle, 50 μm bending radius, 100 × 2 μm(2) footprint, lateral misalignment tolerance up to 400 nm, and less than -52 dB interlayer crosstalk at 1550 nm wavelength. Based on the designed platform, we demonstrate a 27 × 32 × 2 multilayer star coupler.

Controlled teleportation of a multipartite quantum state via driven QED cavity

International Nuclear Information System (INIS)

Cao Haijing; Song Heshan

2007-01-01

We propose a scheme for teleporting a multipartite quantum state via driven QED cavity technologies. The combined state of Bell states is employed as a quantum channel. By adopting QED cavity technologies, our scheme does not involve the Bell-state measurements and can be perfectly realized by communicators' single particle measurements, possible C-not transformation and classical communication. The probability of successful teleportation can reach 1.0. The theoretical scheme is experimentally feasible via current technologies

Diagrammatic cancellations and the gauge dependence of QED

Energy Technology Data Exchange (ETDEWEB)

Kißler, Henry, E-mail: kissler@physik.hu-berlin.de [Department of Mathematical Sciences, University of Liverpool, L69 7ZL, Liverpool (United Kingdom); Department of Mathematics, Humboldt-Universität zu Berlin, Rudower Chaussee 25, D-12489 Berlin (Germany); Kreimer, Dirk, E-mail: kreimer@math.hu-berlin.de [Department of Mathematics, Humboldt-Universität zu Berlin, Rudower Chaussee 25, D-12489 Berlin (Germany)

2017-01-10

This letter examines diagrammatic cancellations for Quantum Electrodynamics (QED) in the general linear gauge. These cancellations combine Feynman graphs of various topologies and provide a method to reconstruct the gauge dependence of the electron propagator from the result of a particular gauge by means of a linear Dyson–Schwinger equation. We use this method in combination with dimensional regularization to demonstrate how the 3-loop ε-expansion in the Feynman gauge determines the ε-expansions for all gauge parameter dependent terms to 4 loops.

[Rare cause of heart failure in an elderly woman in Djibouti: left ventricular non compaction].

Science.gov (United States)

Massoure, P L; Lamblin, G; Bertani, A; Eve, O; Kaiser, E

2011-10-01

The purpose of this report is to describe the first case of left ventricular non compaction diagnosed in Djibouti. The patient was a 74-year-old Djiboutian woman with symptomatic heart failure. Echocardiography is the key tool for assessment of left ventricular non compaction. This rare cardiomyopathy is probably underdiagnosed in Africa.

Circuit QED: generation of two-transmon-qutrit entangled states via resonant interaction

Science.gov (United States)

Ye, Xi-Mei; Zheng, Zhen-Fei; Lu, Dao-Ming; Yang, Chui-Ping

2018-04-01

We present a way to create entangled states of two superconducting transmon qutrits based on circuit QED. Here, a qutrit refers to a three-level quantum system. Since only resonant interaction is employed, the entanglement creation can be completed within a short time. The degree of entanglement for the prepared entangled state can be controlled by varying the weight factors of the initial state of one qutrit, which allows the prepared entangled state to change from a partially entangled state to a maximally entangled state. Because a single cavity is used, only resonant interaction is employed, and none of identical qutrit-cavity coupling constant, measurement, and auxiliary qutrit is needed, this proposal is easy to implement in experiments. The proposal is quite general and can be applied to prepare a two-qutrit partially or maximally entangled state with two natural or artificial atoms of a ladder-type level structure, coupled to an optical or microwave cavity.

Multi-coupling dynamic model and 3d simulation program for in-situ leaching of uranium mining

International Nuclear Information System (INIS)

Tan Kaixuan; Zeng Sheng; Sang Xiao; Sun Bing

2010-01-01

The in-situ leaching of uranium mining is a very complicated non-linear dynamic system, which involves couplings and positive/negative feedback among many factors and processes. A comprehensive, coupled multi-factors and processes dynamic model and simulation method was established to study the in-situ leaching of uranium mining. The model accounts for most coupling among various processes as following: (1) rock texture mechanics and its evolution, (2)the incremental stress rheology of rock deformation, (3) 3-D viscoelastic/ plastic multi-deformation processes, (4) hydrofracturing, (5) tensorial (anisotropic) fracture and rock permeability, (6) water-rock interactions and mass-transport (both advective and diffusive), (7) dissolution-induced chemical compaction, (8) multi-phase fluid flow. A 3-D simulation program was compiled based on Fortran and C++. An example illustrating the application of this model to simulating acidification, production and terminal stage of in situ leaching of uranium mining is presented for the some mine in Xinjiang, China. This model and program can be used for theoretical study, mine design, production management, the study of contaminant transport and restoration in groundwater of in-situ leaching of uranium mining. (authors)

The non-linear coupled spin 2-spin 3 Cotton equation in three dimensions

Energy Technology Data Exchange (ETDEWEB)

Linander, Hampus; Nilsson, Bengt E.W. [Department of Physics, Theoretical PhysicsChalmers University of Technology, S-412 96 Göteborg (Sweden)

2016-07-05

In the context of three-dimensional conformal higher spin theory we derive, in the frame field formulation, the full non-linear spin 3 Cotton equation coupled to spin 2. This is done by solving the corresponding Chern-Simons gauge theory system of equations, that is, using F=0 to eliminate all auxiliary fields and thus expressing the Cotton equation in terms of just the spin 3 frame field and spin 2 covariant derivatives and tensors (Schouten). In this derivation we neglect the spin 4 and higher spin sectors and approximate the star product commutator by a Poisson bracket. The resulting spin 3 Cotton equation is complicated but can be related to linearized versions in the metric formulation obtained previously by other authors. The expected symmetry (spin 3 “translation”, “Lorentz” and “dilatation”) properties are verified for Cotton and other relevant tensors but some perhaps unexpected features emerge in the process, in particular in relation to the non-linear equations. We discuss the structure of this non-linear spin 3 Cotton equation but its explicit form is only presented here, in an exact but not completely refined version, in appended files obtained by computer algebra methods. Both the frame field and metric formulations are provided.

Simulations of relativistic quantum plasmas using real-time lattice scalar QED

Science.gov (United States)

Shi, Yuan; Xiao, Jianyuan; Qin, Hong; Fisch, Nathaniel J.

2018-05-01

Real-time lattice quantum electrodynamics (QED) provides a unique tool for simulating plasmas in the strong-field regime, where collective plasma scales are not well separated from relativistic-quantum scales. As a toy model, we study scalar QED, which describes self-consistent interactions between charged bosons and electromagnetic fields. To solve this model on a computer, we first discretize the scalar-QED action on a lattice, in a way that respects geometric structures of exterior calculus and U(1)-gauge symmetry. The lattice scalar QED can then be solved, in the classical-statistics regime, by advancing an ensemble of statistically equivalent initial conditions in time, using classical field equations obtained by extremizing the discrete action. To demonstrate the capability of our numerical scheme, we apply it to two example problems. The first example is the propagation of linear waves, where we recover analytic wave dispersion relations using numerical spectrum. The second example is an intense laser interacting with a one-dimensional plasma slab, where we demonstrate natural transition from wakefield acceleration to pair production when the wave amplitude exceeds the Schwinger threshold. Our real-time lattice scheme is fully explicit and respects local conservation laws, making it reliable for long-time dynamics. The algorithm is readily parallelized using domain decomposition, and the ensemble may be computed using quantum parallelism in the future.

Ultra-compact and wide-spectrum-range thermo-optic switch based on silicon coupled photonic crystal microcavities

International Nuclear Information System (INIS)

Zhang, Xingyu; Chung, Chi-Jui; Pan, Zeyu; Yan, Hai; Chakravarty, Swapnajit; Chen, Ray T.

2015-01-01

We design, fabricate, and experimentally demonstrate a compact thermo-optic gate switch comprising a 3.78 μm-long coupled L0-type photonic crystal microcavities on a silicon-on-insulator substrate. A nanohole is inserted in the center of each individual L0 photonic crystal microcavity. Coupling between identical microcavities gives rise to bonding and anti-bonding states of the coupled photonic molecules. The coupled photonic crystal microcavities are numerically simulated and experimentally verified with a 6 nm-wide flat-bottom resonance in its transmission spectrum, which enables wider operational spectrum range than microring resonators. An integrated micro-heater is in direct contact with the silicon core to efficiently drive the device. The thermo-optic switch is measured with an optical extinction ratio of 20 dB, an on-off switching power of 18.2 mW, a thermo-optic tuning efficiency of 0.63 nm/mW, a rise time of 14.8 μs, and a fall time of 18.5 μs. The measured on-chip loss on the transmission band is as low as 1 dB

The two-photon self-energy and other QED radiative corrections

International Nuclear Information System (INIS)

Zschocke, S.

2001-07-01

One of the main issues in current nuclear physics is the precise measurement of the Lamb shift of strongly bound electrons in quantum electrodynamic (QED) tests in strong fields in highly charged ions. The currently performed high-precision measurements require extreme accuracy in the theoretical calculation of Lamb shift. This requires consideration of all α and α 2 order QED corrections as well as of precisely all orders in Zα. In the past years most of these QED corrections have been calculated both in 1st order and in 2nd order interference theory. As yet however, it has not been possible to assess the contribution of the two-photon self-energy, which has therefore been the greatest uncertainty factor in predicting Lamb shift in hydrogen-like systems. This study examines the contribution of these processes to Lamb shift. It also provides the first ever derivation of renormalized terms of two-photon vacuum polarisation and self-energy vacuum polarisation. Until now it has only been possible to evaluate these contributions by way of an Uehling approximation [de

A Cavity QED Implementation of Deutsch-Jozsa Algorithm

OpenAIRE

Guerra, E. S.

2004-01-01

The Deutsch-Jozsa algorithm is a generalization of the Deutsch algorithm which was the first algorithm written. We present schemes to implement the Deutsch algorithm and the Deutsch-Jozsa algorithm via cavity QED.

Non-minimally coupled tachyon and inflation

International Nuclear Information System (INIS)

Piao Yunsong; Huang Qingguo; Zhang Xinmin; Zhang Yuanzhong

2003-01-01

In this Letter, we consider a model of tachyon with a non-minimal coupling to gravity and study its cosmological effects. Regarding inflation, we show that only for a specific coupling of tachyon to gravity this model satisfies observations and solves various problems which exist in the single and multi tachyon inflation models. But noting in the string theory the coupling coefficient of tachyon to gravity is of order g s , which in general is very small, we can hardly expect that the non-minimally coupling of tachyon to gravity could provide a reasonable tachyon inflation scenario. Our work may be a meaningful try for the cosmological effect of tachyon non-minimally coupled to gravity

Resilience of the quantum Rabi model in circuit QED

International Nuclear Information System (INIS)

Manucharyan, Vladimir E; Baksic, Alexandre; Ciuti, Cristiano

2017-01-01

In circuit quantum electrodynamics (circuit QED), an artificial ‘circuit atom’ can couple to a quantized microwave radiation much stronger than its real atomic counterpart. The celebrated quantum Rabi model describes the simplest interaction of a two-level system with a single-mode boson field. When the coupling is large enough, the bare multilevel structure of a realistic circuit atom cannot be ignored even if the circuit is strongly anharmonic. We explored this situation theoretically for flux (fluxonium) and charge (Cooper pair box) type multi-level circuits tuned to their respective flux/charge degeneracy points. We identified which spectral features of the quantum Rabi model survive and which are renormalized for large coupling. Despite significant renormalization of the low-energy spectrum in the fluxonium case, the key quantum Rabi feature—nearly-degenerate vacuum consisting of an atomic state entangled with a multi-photon field—appears in both types of circuits when the coupling is sufficiently large. Like in the quantum Rabi model, for very large couplings the entanglement spectrum is dominated by only two, nearly equal eigenvalues, in spite of the fact that a large number of bare atomic states are actually involved in the atom-resonator ground state. We interpret the emergence of the two-fold degeneracy of the vacuum of both circuits as an environmental suppression of flux/charge tunneling due to their dressing by virtual low-/high-impedance photons in the resonator. For flux tunneling, the dressing is nothing else than the shunting of a Josephson atom with a large capacitance of the resonator. Suppression of charge tunneling is a manifestation of the dynamical Coulomb blockade of transport in tunnel junctions connected to resistive leads. (paper)

Radiation fluid stars in the non-minimally coupled Y(R)F{sup 2} gravity

Energy Technology Data Exchange (ETDEWEB)

Sert, Oezcan [Pamukkale University, Department of Mathematics, Faculty of Arts and Sciences, Denizli (Turkey)

2017-02-15

We propose a non-minimally coupled gravity model in Y(R)F{sup 2} form to describe the radiation fluid stars which have the radiative equation of state between the energy density ρ and the pressure p given by ρ = 3p. Here F{sup 2} is the Maxwell invariant and Y(R) is a function of the Ricci scalar R. We give the gravitational and electromagnetic field equations in differential form notation taking the infinitesimal variations of the model. We look for electrically charged star solutions to the field equations under the constraint eliminating complexity of the higher order terms in the field equations. We determine the non-minimally coupled function Y(R) and the corresponding model which admits new exact solutions in the interior of the star and the Reissner-Nordstrom solution at the exterior region. Using the vanishing pressure condition at the boundary together with the continuity conditions of the metric functions and the electric charge, we find the mass-radius ratio, charge-radius ratio, and the gravitational surface redshift depending on the parameter of the model for the radiation fluid star. We derive general restrictions for the ratios and redshift of the charged compact stars. We obtain a slightly smaller upper mass-radius ratio limit than the Buchdahl bound 4/9 and a smaller upper redshift limit than the bound of the standard general relativistic stars. (orig.)

QED coherence in matter

CERN Document Server

Preparata, Giuliano

1995-01-01

Up until now the dominant view of condensed matter physics has been that of an "electrostatic MECCANO" (erector set, for Americans). This book is the first systematic attempt to consider the full quantum-electrodynamical interaction (QED), thus greatly enriching the possible dynamical mechanisms that operate in the construction of the wonderful variety of condensed matter systems, including life itself.A new paradigm is emerging, replacing the "electrostatic MECCANO" with an "electrodynamic NETWORK," which builds condensed matter through the long range (as opposed to the "short range" nature o

QED blue-sheet effects inside black holes

International Nuclear Information System (INIS)

Burko, L.M.

1997-01-01

The interaction of the unboundedly blueshifted photons of the cosmic microwave background radiation with a physical object falling towards the inner horizon of a Reissner-Nordstroem black hole is analyzed. To evaluate this interaction we consider the QED effects up to the second order in the perturbation expansion. We then extrapolate the QED effects up to a cutoff, which we introduce at the Planckian level. (Our results are not sensitive to the cutoff energy.) We find that the energy absorbed by an infalling observer is finite, and for typical parameters would not lead to a catastrophic heating. However, this interaction would almost certainly be fatal for a human being, or other living organisms of similar size. On the other hand, we find that smaller objects may survive the interaction. Our results do not provide support for the idea that the Cauchy horizon is to be regarded as the boundary of spacetime. copyright 1997 The American Physical Society

A Test of QED in Electron-Positron Annihilation at Energies around the Z Mass

CERN Document Server

Spartiotis, C

1992-01-01

A study of the reaction e+ e- -t 11( /) at center-of-mass energies around the mass of the z 0 boson(91.2Ge V) has been performed. The total and differential cross sections have been measured cor- responding to an integrated luminosity of 14.42pb- 1 . The results are in good agreement with QED predictions. Lower limits were set , at 95% confidence level, on the QED cutoff parameters of A+ >130 GeV, A_ >112 GeV and on the mass of an excited elec- tron of me* > 120 Ge V. z 0 rare decays with photonic signatures in the final state were also searched for. Upper limits, at 953 confi- dence level, for the branching ratio of z 0 decaying into 7ro/ /11, TJI and /// are 1.2 x 10-4, 1.7 x 10-4, 3.3 x 10- 5 respectively.

Three-point Green's function of massless QED in position space to lowest order

International Nuclear Information System (INIS)

Mitra, Indrajit

2009-01-01

The transverse part of the three-point Green's function of massless QED is determined to the lowest order in position space. Taken together with the evaluation of the longitudinal part in Mitra (2008) (J. Phys. A: Math. Theor. 41 315401), this gives a relation for QED which is analogous to the star-triangle relation. We relate our result to conformal-invariant three-point functions

Chiral symmetry breaking is permitted in supersymmetric QED

International Nuclear Information System (INIS)

Walker, M.

2000-01-01

Full text: A chirally symmetric theory will generally have a chirally symmetric and a chirally asymmetric solution for the dressed fermionic propagator. It has been claimed that no chirally asymmetric solution for the fermionic propagator exists in supersymmetric QED. This result in the superfield formalism uses a gauge dependent argument whose validity has since been questioned. We present an analogous analysis using the component formalism which demonstrates that chiral symmetry breaking is permitted in this theory. We open the presentation with a brief introduction to supersymmetry, supersymmetric QED, and the superfield formalism. We describe chiral symmetry breaking and the Dyson-Schwinger equation used to analyse it. The derivation of the erroneous theorem claiming the lack of an a chiral propagator is outlined and its flaws discussed. We finish with the equivalent derivation in component fields and our contradictory result

Compact solitary waves in linearly elastic chains with non-smooth on-site potential

Energy Technology Data Exchange (ETDEWEB)

Gaeta, Giuseppe [Dipartimento di Matematica, Universita di Milano, Via Saldini 50, 20133 Milan (Italy); Gramchev, Todor [Dipartimento di Matematica e Informatica, Universita di Cagliari, Via Ospedale 72, 09124 Cagliari (Italy); Walcher, Sebastian [Lehrstuhl A Mathematik, RWTH Aachen, 52056 Aachen (Germany)

2007-04-27

It was recently observed by Saccomandi and Sgura that one-dimensional chains with nonlinear elastic interaction and regular on-site potential can support compact solitary waves, i.e. travelling solitary waves with strictly compact support. In this paper, we show that the same applies to chains with linear elastic interaction and an on-site potential which is continuous but non-smooth at minima. Some different features arise; in particular, the speed of compact solitary waves is not uniquely fixed by the equation. We also discuss several generalizations of our findings.

Compactibility of atomized high-speed steel and steel 3 powders

International Nuclear Information System (INIS)

Kulak, L.D.; Gavrilenko, A.P.; Pikozh, A.P.; Kuz'menko, N.N.

1985-01-01

Spherical powders and powders of lammellar-scaly shape of high-speed R6M5K5 steel and steel 3 produced by the method of centrifugal atomization of a rotating billet under conditions of cold pressing in steel moulds are studied for thier compactability. Compacting pressure dependnences are establsihed for density of cold-pressed compacts of spherical and scaly powders. The powders of lammellar-scaly shape both of high-speed steel and steel 3 are found to possess better compactibility within a wide range of pressures as compared to powders of spherical shape. Compacts of the lammellar-scaly powders possess also higher mechanical strength

Supersymmetry and cotangent bundle over non-compact exceptional Hermitian symmetric space

International Nuclear Information System (INIS)

Arai, Masato; Baba, Kurando

2015-01-01

We construct N=2 supersymmetric nonlinear sigma models on the cotangent bundles over the non-compact exceptional Hermitian symmetric spaces M=E 6(−14) /SO(10)×U(1) and E 7(−25) /E 6 ×U(1). In order to construct them we use the projective superspace formalism which is an N=2 off-shell superfield formulation in four-dimensional space-time. This formalism allows us to obtain the explicit expression of N=2 supersymmetric nonlinear sigma models on the cotangent bundles over any Hermitian symmetric spaces in terms of the N=1 superfields, once the Kähler potentials of the base manifolds are obtained. We derive the N=1 supersymmetric nonlinear sigma models on the Kähler manifolds M. Then we extend them into the N=2 supersymmetric models with the use of the result in arXiv:1211.1537 developed in the projective superspace formalism. The resultant models are the N=2 supersymmetric nonlinear sigma models on the cotangent bundles over the Hermitian symmetric spaces M. In this work we complete constructing the cotangent bundles over all the compact and non-compact Hermitian symmetric spaces.

Study of Multiphoton Final States and Tests of QED in $e^+ e^-$ collisions at $\\sqrt{s}$ up to 209 GeV

CERN Document Server

Achard, P.; Aguilar-Benitez, M.; Alcaraz, J.; Alemanni, G.; Allaby, J.; Aloisio, A.; Alviggi, M.G.; Anderhub, H.; Andreev, Valery P.; Anselmo, F.; Arefev, A.; Azemoon, T.; Aziz, T.; Bagnaia, P.; Bajo, A.; Baksay, G.; Baksay, L.; Baldew, S.V.; Banerjee, S.; Banerjee, Sw.; Barczyk, A.; Barillere, R.; Bartalini, P.; Basile, M.; Batalova, N.; Battiston, R.; Bay, A.; Becattini, F.; Becker, U.; Behner, F.; Bellucci, L.; Berbeco, R.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biasini, M.; Biglietti, M.; Biland, A.; Blaising, J.J.; Blyth, S.C.; Bobbink, G.J.; Bohm, A.; Boldizsar, L.; Borgia, B.; Bottai, S.; Bourilkov, D.; Bourquin, M.; Braccini, S.; Branson, J.G.; Brochu, F.; Burger, J.D.; Burger, W.J.; Cai, X.D.; Capell, M.; Cara Romeo, G.; Carlino, G.; Cartacci, A.; Casaus, J.; Cavallari, F.; Cavallo, N.; Cecchi, C.; Cerrada, M.; Chamizo, M.; Chang, Y.H.; Chemarin, M.; Chen, A.; Chen, G.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chiefari, G.; Cifarelli, L.; Cindolo, F.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Costantini, S.; de la Cruz, B.; Cucciarelli, S.; van Dalen, J.A.; de Asmundis, R.; Deglon, P.; Debreczeni, J.; Degre, A.; Deiters, K.; della Volpe, D.; Delmeire, E.; Denes, P.; DeNotaristefani, F.; De Salvo, A.; Diemoz, M.; Dierckxsens, M.; Dionisi, C.; Dittmar, M.; Doria, A.; Dova, M.T.; Duchesneau, D.; Echenard, B.; Eline, A.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Ewers, A.; Extermann, P.; Falagan, M.A.; Falciano, S.; Favara, A.; Fay, J.; Fedin, O.; Felcini, M.; Ferguson, T.; Fesefeldt, H.; Fiandrini, E.; Field, J.H.; Filthaut, F.; Fisher, P.H.; Fisher, W.; Fisk, I.; Forconi, G.; Freudenreich, K.; Furetta, C.; Galaktionov, Iouri; Ganguli, S.N.; Garcia-Abia, Pablo; Gataullin, M.; Gentile, S.; Giagu, S.; Gong, Z.F.; Grenier, Gerald Jean; Grimm, O.; Gruenewald, M.W.; Guida, M.; van Gulik, R.; Gupta, V.K.; Gurtu, A.; Gutay, L.J.; Haas, D.; Hatzifotiadou, D.; Hebbeker, T.; Herve, Alain; Hirschfelder, J.; Hofer, H.; Hohlmann, M.; Holzner, G.; Hou, S.R.; Hu, Y.; Jin, B.N.; Jones, Lawrence W.; de Jong, P.; Josa-Mutuberria, I.; Kafer, D.; Kaur, M.; Kienzle-Focacci, M.N.; Kim, J.K.; Kirkby, Jasper; Kittel, W.; Klimentov, A.; Konig, A.C.; Kopal, M.; Koutsenko, V.; Kraber, M.; Kraemer, R.W.; Krenz, W.; Kruger, A.; Kunin, A.; Ladron de Guevara, P.; Laktineh, I.; Landi, G.; Lebeau, M.; Lebedev, A.; Lebrun, P.; Lecomte, P.; Lecoq, P.; Le Coultre, P.; Le Goff, J.M.; Leiste, R.; Levtchenko, P.; Li, C.; Likhoded, S.; Lin, C.H.; Lin, W.T.; Linde, F.L.; Lista, L.; Liu, Z.A.; Lohmann, W.; Longo, E.; Lu, Y.S.; Lubelsmeyer, K.; Luci, C.; Luminari, L.; Lustermann, W.; Ma, W.G.; Malgeri, L.; Malinin, A.; Mana, C.; Mangeol, D.; Mans, J.; Martin, J.P.; Marzano, F.; Mazumdar, K.; McNeil, R.R.; Mele, S.; Merola, L.; Meschini, M.; Metzger, W.J.; Mihul, A.; Milcent, H.; Mirabelli, G.; Mnich, J.; Mohanty, G.B.; Muanza, G.S.; Muijs, A.J.M.; Musicar, B.; Musy, M.; Nagy, S.; Natale, S.; Napolitano, M.; Nessi-Tedaldi, F.; Newman, H.; Niessen, T.; Nisati, A.; Kluge, Hannelies; Ofierzynski, R.; Organtini, G.; Palomares, C.; Pandoulas, D.; Paolucci, P.; Paramatti, R.; Passaleva, G.; Patricelli, S.; Paul, Thomas Cantzon; Pauluzzi, M.; Paus, C.; Pauss, F.; Pedace, M.; Pensotti, S.; Perret-Gallix, D.; Petersen, B.; Piccolo, D.; Pierella, F.; Pioppi, M.; Piroue, P.A.; Pistolesi, E.; Plyaskin, V.; Pohl, M.; Pojidaev, V.; Pothier, J.; Prokofev, D.O.; Prokofiev, D.; Quartieri, J.; Rahal-Callot, G.; Rahaman, M.A.; Raics, P.; Raja, N.; Ramelli, R.; Rancoita, P.G.; Ranieri, R.; Raspereza, A.; Razis, P.; Ren, D.; Rescigno, M.; Reucroft, S.; Riemann, S.; Riles, Keith; Roe, B.P.; Romero, L.; Rosca, A.; Rosier-Lees, S.; Roth, Stefan; Rosenbleck, C.; Roux, B.; Rubio, J.A.; Ruggiero, G.; Rykaczewski, H.; Sakharov, A.; Saremi, S.; Sarkar, S.; Salicio, J.; Sanchez, E.; Sanders, M.P.; Schafer, C.; Schegelsky, V.; Schmidt-Kaerst, S.; Schmitz, D.; Schopper, H.; Schotanus, D.J.; Schwering, G.; Sciacca, C.; Servoli, L.; Shevchenko, S.; Shivarov, N.; Shoutko, V.; Shumilov, E.; Shvorob, A.; Siedenburg, T.; Son, D.; Spillantini, P.; Steuer, M.; Stickland, D.P.; Stoyanov, B.; Straessner, A.; Sudhakar, K.; Sultanov, G.; Sun, L.Z.; Sushkov, S.; Suter, H.; Swain, J.D.; Szillasi, Z.; Tang, X.W.; Tarjan, P.; Tauscher, L.; Taylor, L.; Tellili, B.; Teyssier, D.; Timmermans, Charles; Ting, Samuel C.C.; Ting, S.M.; Tonwar, S.C.; Toth, J.; Tully, C.; Tung, K.L.; Ulbricht, J.; Valente, E.; Van de Walle, R.T.; Veszpremi, V.; Vesztergombi, G.; Vetlitsky, I.; Vicinanza, D.; Viertel, G.; Villa, S.; Vivargent, M.; Vlachos, S.; Vodopianov, I.; Vogel, H.; Vogt, H.; Vorobev, I.; Vorobyov, A.A.; Wadhwa, M.; Wallraff, W.; Wang, X.L.; Wang, Z.M.; Weber, M.; Wienemann, P.; Wilkens, H.; Wynhoff, S.; Xia, L.; Xu, Z.Z.; Yamamoto, J.; Yang, B.Z.; Yang, C.G.; Yang, H.J.; Yang, M.; Yeh, S.C.; Zalite, A.; Zalite, Yu.; Zhang, Z.P.; Zhao, J.; Zhu, G.Y.; Zhu, R.Y.; Zhuang, H.L.; Zichichi, A.; Zilizi, G.; Zimmermann, B.; Zoller, M.

2002-01-01

The process e+ e- -> n gamma with n>=2 is studied at centre-of-mass energies ranging from \\root(s)=192 to 208 GeV. The data sample corresponds to a total integrated luminosity of 427 1/pb. The total and differential cross sections are found to be in agreement with the QED expectations. Using all the data collected with the L3 detector above the Z pole, limits on deviations from QED, excited electrons, contact interactions, extra space dimensions and excited spin-3/2 leptons are set.

Watt-level wireless power transmission to multiple compact receivers

International Nuclear Information System (INIS)

Garraud, A; Munzer, D J; Althar, M; Garraud, N; Arnold, D P

2015-01-01

This paper reports an electrodynamic wireless power transmission (EWPT) system using a low-frequency (300 Hz) magnetic field to transmit watt-scale power levels to multiple compact receivers. As compared to inductively or resonantly coupled coils, EWPT facilitates transmission to multiple non-interacting receivers with little restriction on their orientation. A single 3.0 cm 3 receiver achieves 1.25 W power transmission with 8% efficiency at a distance of 1 cm (350 mW/cm 3 power density) from the transmitter. The same prototype achieves 9 mW at a distance of 9 cm. Moreover, we demonstrate simultaneous recharge of two wearable devices, using two receivers located in arbitrary positions and orientations. (paper)

Invariant differential operators for non-compact Lie groups: an introduction

International Nuclear Information System (INIS)

Dobrev, V.K.

2015-01-01

In the present paper we review the progress of the project of classification and construction of invariant differential operators for non-compact semisimple Lie groups. Our starting points is the class of algebras, which we called earlier 'conformal Lie algebras' (CLA), which have very similar properties to the conformal algebras of Minkowski space-time, though our aim is to go beyond this class in a natural way. For this we introduced recently the new notion of parabolic relation between two non-compact semisimple Lie algebras G and G' that have the same complexification and possess maximal parabolic subalgebras with the same complexification. In the present paper we consider in detail the orthogonal algebras so(p,q) all of which are parabolically related to the conformal algebra so(n,2) with p+q=n+2, the parabolic subalgebras including the Lorentz subalgebra so(n-1,1) and its analogs so(p-1,q-1)

3D Simulation of Self-Compacting Concrete Flow Based on MRT-LBM

Directory of Open Access Journals (Sweden)

Liu-Chao Qiu

2018-01-01

Full Text Available A three-dimensional multiple-relaxation-time lattice Boltzmann method (MRT-LBM with a D3Q27 discrete velocity model is applied for simulation of self-compacting concrete (SCC flows. In the present study, the SCC is assumed as a non-Newtonian fluid, and a modified Herschel–Bulkley model is used as constitutive mode. The mass tracking algorithm was used for modeling the liquid-gas interface. Two numerical examples of the slump test and enhanced L-box test were performed, and the calculated results are compared with available experiments in literatures. The numerical results demonstrate the capability of the proposed MRT-LBM in modeling of self-compacting concrete flows.

Spontaneous Scalarization of Black Holes and Compact Stars from a Gauss-Bonnet Coupling.

Science.gov (United States)

Silva, Hector O; Sakstein, Jeremy; Gualtieri, Leonardo; Sotiriou, Thomas P; Berti, Emanuele

2018-03-30

We identify a class of scalar-tensor theories with coupling between the scalar and the Gauss-Bonnet invariant that exhibit spontaneous scalarization for both black holes and compact stars. In particular, these theories formally admit all of the stationary solutions of general relativity, but these are not dynamically preferred if certain conditions are satisfied. Remarkably, black holes exhibit scalarization if their mass lies within one of many narrow bands. We find evidence that scalarization can occur in neutron stars as well.

Exploring photonic topological insulator states in a circuit-QED lattice

Science.gov (United States)

Li, Jing-Ling; Shan, Chuan-Jia; Zhao, Feng

2018-04-01

We propose a simple protocol to explore the topological properties of photonic integer quantum Hall states in a one-dimensional circiut-QED lattice. By periodically modulating the on-site photonic energies in such a lattice, we demonstrate that this one-dimensional lattice model can be mapped into a two-dimensional integer quantum Hall insulator model. Based on the lattice-based cavity input-output theory, we show that both the photonic topological protected edge states and topological invariants can be clearly measured from the final steady state of the resonator lattice after taking into account cavity dissipation. Interestingly, we also find that the measurement signals associated with the above topological features are quite unambitious even in five coupled dissipative resonators. Our work opens up a new prospect of exploring topological states with a small-size dissipative quantum artificial lattice, which is quite attractive to the current quantum optics community.

Two-channel interaction models in cavity QED

International Nuclear Information System (INIS)

Wang, L.

1993-01-01

The authors introduce four fully quantized models of light-matter interactions in optical or microwave cavities. These are the first exactly soluble models in cavity quantum electrodynamics (cavity QED) that provide two transition channels for the flipping of atomic states. In these models a loss-free cavity is assumed to support three or four quantized field modes, which are coupled to a single atom. The atom exchanges photons with the cavity, in either the Raman configuration including both Stokes and anti-Stokes modes, or through two-photon cascade processes. The authors obtain the effective Hamiltonians for these models by adiabatically eliminating an off-resonant intermediate atomic level, and discuss their novel properties in comparison to the existing one-channel Jaynes-Cummings models. They give a detailed description of a method to find exact analytic solutions for the eigenfunctions and eigenvalues for the Hamiltonians of four models. These are also valid when the AC Stark shifts are included. It is shown that the eigenvalues can be expressed in very simple terms, and formulas for normalized eigenvectors are also given, as well as discussions of some of their simple properties. Heisenberg picture equations of motions are derived for several operators with solutions provided in a couple of cases. The dynamics of the systems with both Fock state and coherent state fields are demonstrated and discussed using the model's two key variables, the atomic inversion and the expectation value of photon number. Clear evidences of high efficiency mode-mixing are seen in both the Raman and cascade configurations, and different kinds of collapses and revivals are encountered in the atomic inversions. Effects of several factors like the AC Stark shift and variations in the complex coupling constants are also illustrated

High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED.

Science.gov (United States)

Ullmann, Johannes; Andelkovic, Zoran; Brandau, Carsten; Dax, Andreas; Geithner, Wolfgang; Geppert, Christopher; Gorges, Christian; Hammen, Michael; Hannen, Volker; Kaufmann, Simon; König, Kristian; Litvinov, Yuri A; Lochmann, Matthias; Maaß, Bernhard; Meisner, Johann; Murböck, Tobias; Sánchez, Rodolfo; Schmidt, Matthias; Schmidt, Stefan; Steck, Markus; Stöhlker, Thomas; Thompson, Richard C; Trageser, Christian; Vollbrecht, Jonas; Weinheimer, Christian; Nörtershäuser, Wilfried

2017-05-16

Electrons bound in highly charged heavy ions such as hydrogen-like bismuth 209 Bi 82+ experience electromagnetic fields that are a million times stronger than in light atoms. Measuring the wavelength of light emitted and absorbed by these ions is therefore a sensitive testing ground for quantum electrodynamical (QED) effects and especially the electron-nucleus interaction under such extreme conditions. However, insufficient knowledge of the nuclear structure has prevented a rigorous test of strong-field QED. Here we present a measurement of the so-called specific difference between the hyperfine splittings in hydrogen-like and lithium-like bismuth 209 Bi 82+,80+ with a precision that is improved by more than an order of magnitude. Even though this quantity is believed to be largely insensitive to nuclear structure and therefore the most decisive test of QED in the strong magnetic field regime, we find a 7-σ discrepancy compared with the theoretical prediction.

QED effects in the pseudoscalar meson sector

Energy Technology Data Exchange (ETDEWEB)

Horsley, R. [School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD (United Kingdom); Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe, Hyogo, 650-0047 (Japan); Perlt, H. [Institut für Theoretische Physik, Universität Leipzig, Brüderstrasse 16, Leipzig, 04109 (Germany); Pleiter, D. [Jülich Supercomputer Centre, Forschungszentrum Jülich, Jülich, 52425 (Germany); Institut für Theoretische Physik, Universität Regensburg, Regensburg, 93040 (Germany); Rakow, P.E.L. [Theoretical Physics Division, Department of Mathematical Sciences, University of Liverpool, Peach Street , Liverpool, L69 3BX (United Kingdom); Schierholz, G. [Deutsches Elektronen-Synchrotron DESY, Hamburg, 22603 (Germany); Schiller, A. [Institut für Theoretische Physik, Universität Leipzig, Brüderstrasse 16, Leipzig, 04109 (Germany); Stokes, R. [CSSM, Department of Physics, University of Adelaide, Adelaide, SA, 5005 (Australia); Stüben, H. [Regionales Rechenzentrum, Universität Hamburg, Hamburg, 20146 (Germany); Young, R.D.; Zanotti, J.M. [CSSM, Department of Physics, University of Adelaide, Adelaide, SA, 5005 (Australia); Collaboration: the QCDSF and UKQCD collaboration

2016-04-15

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{sup +}–π{sup 0} splitting and also look at other isospin violating mass differences. We have presented results for these isospin splittings in http://arxiv.org/abs/1508.06401. 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 (MS)-bar , in which Dashen’s theorem for neutral mesons is violated.

General coupled mode theory in non-Hermitian waveguides.

Science.gov (United States)

Xu, Jing; Chen, Yuntian

2015-08-24

In the presence of loss and gain, the coupled mode equation on describing the mode hybridization of various waveguides or cavities, or cavities coupled to waveguides becomes intrinsically non-Hermitian. In such non-Hermitian waveguides, the standard coupled mode theory fails. We generalize the coupled mode theory with a properly defined inner product based on reaction conservation. We apply our theory to the non-Hermitian parity-time symmetric waveguides, and obtain excellent agreement with results obtained by finite element fullwave simulations. The theory presented here is typically formulated in space to study coupling between waveguides, which can be transformed into time domain by proper reformulation to study coupling between non-Hermitian resonators. Our theory has the strength of studying non-Hermitian optical systems with inclusion of the full vector fields, thus is useful to study and design non-Hermitian devices that support asymmetric and even nonreciprocal light propagations.

High-flux cold rubidium atomic beam for strongly-coupled cavity QED

Energy Technology Data Exchange (ETDEWEB)

Roy, Basudev [Indian Institute of Science Education and Research, Kolkata (India); University of Maryland, MD (United States); Scholten, Michael [University of Maryland, MD (United States)

2012-08-15

This paper presents a setup capable of producing a high-flux continuous beam of cold rubidium atoms for cavity quantum electrodynamics experiments in the region of strong coupling. A 2D{sup +} magneto-optical trap (MOT), loaded with rubidium getters in a dry-film-coated vapor cell, fed a secondary moving-molasses MOT (MM-MOT) at a rate greater than 2 x 10{sup 10} atoms/s. The MM-MOT provided a continuous beam with a tunable velocity. This beam was then directed through the waist of a cavity with a length of 280 μm, resulting in a vacuum Rabi splitting of more than ±10 MHz. The presence of a sufficient number of atoms in the cavity mode also enabled splitting in the polarization perpendicular to the input. The cavity was in the strong coupling region, with an atom-photon dipole coupling coefficient g of 7 MHz, a cavity mode decay rate κ of 3 MHz, and a spontaneous emission decay rate γ of 6 MHz.

Loop expansion in massless three-dimensional QED

International Nuclear Information System (INIS)

Guendelman, E.I.; Radulovic, Z.M.

1983-01-01

It is shown how the loop expansion in massless three-dimensional QED can be made finite, up to three loops, by absorbing the infrared divergences in a gauge-fixing term. The same method removes leading and first subleading singularities to all orders of perturbation theory, and all singularities of the fermion self-energy to four loops

Neutron stars in non-linear coupling models

International Nuclear Information System (INIS)

Taurines, Andre R.; Vasconcellos, Cesar A.Z.; Malheiro, Manuel; Chiapparini, Marcelo

2001-01-01

We present a class of relativistic models for nuclear matter and neutron stars which exhibits a parameterization, through mathematical constants, of the non-linear meson-baryon couplings. For appropriate choices of the parameters, it recovers current QHD models found in the literature: Walecka, ZM and ZM3 models. We have found that the ZM3 model predicts a very small maximum neutron star mass, ∼ 0.72M s un. A strong similarity between the results of ZM-like models and those with exponential couplings is noted. Finally, we discuss the very intense scalar condensates found in the interior of neutron stars which may lead to negative effective masses. (author)

Neutron stars in non-linear coupling models

Energy Technology Data Exchange (ETDEWEB)

Taurines, Andre R.; Vasconcellos, Cesar A.Z. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil); Malheiro, Manuel [Universidade Federal Fluminense, Niteroi, RJ (Brazil); Chiapparini, Marcelo [Universidade do Estado, Rio de Janeiro, RJ (Brazil)

2001-07-01

We present a class of relativistic models for nuclear matter and neutron stars which exhibits a parameterization, through mathematical constants, of the non-linear meson-baryon couplings. For appropriate choices of the parameters, it recovers current QHD models found in the literature: Walecka, ZM and ZM3 models. We have found that the ZM3 model predicts a very small maximum neutron star mass, {approx} 0.72M{sub s}un. A strong similarity between the results of ZM-like models and those with exponential couplings is noted. Finally, we discuss the very intense scalar condensates found in the interior of neutron stars which may lead to negative effective masses. (author)

QED vacuum loops and inflation

Energy Technology Data Exchange (ETDEWEB)

Fried, H.M. [Brown University, Department of Physics, Providence, RI (United States); Gabellini, Y. [UMR 6618 CNRS, Institut Non Lineaire de Nice, Valbonne (France)

2015-03-01

A QED-based model of a new version of vacuum energy has recently been suggested, which leads to a simple, finite, one parameter representation of dark energy. An elementary, obvious, but perhaps radical generalization is then able to describe both dark energy and inflation in the same framework of vacuum energy. One further, obvious generalization then leads to a relation between inflation and the big bang, to the automatic inclusion of dark matter, and to a possible understanding of the birth (and death) of a universe. (orig.)

QED vacuum loops and inflation

International Nuclear Information System (INIS)

Fried, H.M.; Gabellini, Y.

2015-01-01

A QED-based model of a new version of vacuum energy has recently been suggested, which leads to a simple, finite, one parameter representation of dark energy. An elementary, obvious, but perhaps radical generalization is then able to describe both dark energy and inflation in the same framework of vacuum energy. One further, obvious generalization then leads to a relation between inflation and the big bang, to the automatic inclusion of dark matter, and to a possible understanding of the birth (and death) of a universe. (orig.)

Inflationary models with non-minimally derivative coupling

International Nuclear Information System (INIS)

Yang, Nan; Fei, Qin; Gong, Yungui; Gao, Qing

2016-01-01

We derive the general formulae for the scalar and tensor spectral tilts to the second order for the inflationary models with non-minimally derivative coupling without taking the high friction limit. The non-minimally kinetic coupling to Einstein tensor brings the energy scale in the inflationary models down to be sub-Planckian. In the high friction limit, the Lyth bound is modified with an extra suppression factor, so that the field excursion of the inflaton is sub-Planckian. The inflationary models with non-minimally derivative coupling are more consistent with observations in the high friction limit. In particular, with the help of the non-minimally derivative coupling, the quartic power law potential is consistent with the observational constraint at 95% CL. (paper)

Hamiltonian formulation of QED in the superaxial gauge

International Nuclear Information System (INIS)

Girotti, H.O.; Rothe, H.J.

A Hamiltonian formulation of QED in a fully fixed axial gauge is presented. The equal-time commutators for all field variables are computed and are shown to lead to the correct equations of motion. The constraints and gauge conditions hold as strong operator relations. (Author) [pt

APFEL : A PDF Evolution Library with QED corrections

NARCIS (Netherlands)

Bertone, Valerio; Carrazza, Stefano; Rojo, Juan

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

Quantum Logic Network for Cloning a State Near a Given One Based on Cavity QED

International Nuclear Information System (INIS)

Da-Wei, Zhang; Xiao-Qiang, Shao; Ai-Dong, Zhu

2008-01-01

A quantum logic network is constructed to simulate a cloning machine which copies states near a given one. Meanwhile, a scheme for implementing this cloning network based on the technique of cavity quantum electrodynamics (QED) is presented. It is easy to implement this network of cloning machine in the framework of cavity QED and feasible in the experiment. (general)

Large gauge symmetries and asymptotic states in QED

Energy Technology Data Exchange (ETDEWEB)

Gabai, Barak; Sever, Amit [School of Physics and Astronomy, Tel Aviv University,Ramat Aviv 69978 (Israel)

2016-12-19

Large Gauge Transformations (LGT) are gauge transformations that do not vanish at infinity. Instead, they asymptotically approach arbitrary functions on the conformal sphere at infinity. Recently, it was argued that the LGT should be treated as an infinite set of global symmetries which are spontaneously broken by the vacuum. It was established that in QED, the Ward identities of their induced symmetries are equivalent to the Soft Photon Theorem. In this paper we study the implications of LGT on the S-matrix between physical asymptotic states in massive QED. In appose to the naively free scattering states, physical asymptotic states incorporate the long range electric field between asymptotic charged particles and were already constructed in 1970 by Kulish and Faddeev. We find that the LGT charge is independent of the particles’ momenta and may be associated to the vacuum. The soft theorem’s manifestation as a Ward identity turns out to be an outcome of not working with the physical asymptotic states.

Measurements of the QED Structure of the Photon

CERN Document Server

Abbiendi, G.; Alexander, G.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Blobel, V.; Bloodworth, I.J.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; de Roeck, A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Doucet, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A.A.; Fiedler, F.; Fierro, M.; Fleck, I.; Folman, R.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Hargrove, C.K.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hobson, P.R.; Hoch, M.; Hocker, James Andrew; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klier, A.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lazic, D.; Lee, A.M.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oreglia, M.J.; Orito, S.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Poli, B.; Polok, J.; Przybycien, M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schmitt, S.; Schoning, A.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, David M.; Strohmer, R.; Surrow, B.; Talbot, S.D.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Ueda, I.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.

1999-01-01

The structure of both quasi-real and highly virtual photons is investigated using the reaction e+e- -> e+e-mu+mu-, proceeding via the exchange of two photons. The results are based on the complete OPAL dataset taken at e+e- centre-of-mass energies close to the mass of the Z boson. The QED structure function F_2^gamma and the differential cross-section dsigdx for quasi-real photons are obtained as functions of the fractional momentum x from the muon momentum which is carried by the struck muon in the quasi-real photon for values of Q**2 ranging from 1.5 to 400 GeV**2. The differential cross-section dsigdx for highly virtual photons is measured for 1.5 P**2. Based on azimuthal correlations the QED structure functions F_A^gamma and F_B^gamma for quasi-real photons are determined for an average Q**2 of 5.4 GeV**2.

Coupling of an ICRF compact loop antenna to H-mode plasmas in DIII-D

International Nuclear Information System (INIS)

Mayberry, M.J.; Baity, F.W.; Hoffman, D.J.; Luxon, J.L.; Owens, T.L.; Prater, R.

1987-01-01

Low power coupling tests have been carried out with a prototype ICRF compact loop antenna on the DIII-D tokamak. During neutral-beam-heated L-mode discharges the antenna loading is typically R≅1-2Ω for an rf frequency of 32 MHz (B/sub T/ = 21 kG, ω = 2Ω/sub D/(0)). When a transition into the H-mode regime of improved confinement occurs, the loading drops to R≅0.5-1.0Ω. During ELMs, transient increases in loading up to several Ohms are observed. The apparent sensitivity of ICRF antenna coupling to changes in the edge plasma profiles associated with the H-mode regime could have important implications for the design of future high power systems

Non-destructive system to evaluate critical properties of asphalt compaction : [research brief].

Science.gov (United States)

2013-12-01

The Wisconsin Highway Research Program sponsored a two-stage investigation to develop a non-destructive system to evaluate critical compaction properties and characteristics of asphalt pavements during the densification process. Stage One activities ...

Simulations and Experiments of Dynamic Granular Compaction in Non-ideal Geometries

Science.gov (United States)

Homel, Michael; Herbold, Eric; Lind, John; Crum, Ryan; Hurley, Ryan; Akin, Minta; Pagan, Darren; LLNL Team

2017-06-01

Accurately describing the dynamic compaction of granular materials is a persistent challenge in computational mechanics. Using a synchrotron x-ray source we have obtained detailed imaging of the evolving compaction front in synthetic olivine powder impacted at 300 - 600 m / s . To facilitate imaging, a non-traditional sample geometry is used, producing multiple load paths within the sample. We demonstrate that (i) commonly used models for porous compaction may produce inaccurate results for complex loading, even if the 1 - D , uniaxial-strain compaction response is reasonable, and (ii) the experimental results can be used along with simulations to determine parameters for sophisticated constitutive models that more accurately describe the strength, softening, bulking, and poroelastic response. Effects of experimental geometry and alternative configurations are discussed. Our understanding of the material response is further enhanced using mesoscale simulations that allow us to relate the mechanisms of grain fracture, contact, and comminution to the macroscale continuum response. Numerical considerations in both continuum and mesoscale simulations are described. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LDRD#16-ERD-010. LLNL-ABS-725113.

Localization of supersymmetric field theories on non-compact hyperbolic three-manifolds

Energy Technology Data Exchange (ETDEWEB)

Assel, Benjamin; Martelli, Dario; Murthy, Sameer; Yokoyama, Daisuke [Department of Mathematics, King’s College London,The Strand, London WC2R 2LS (United Kingdom)

2017-03-17

We study supersymmetric gauge theories with an R-symmetry, defined on non-compact, hyperbolic, Riemannian three-manifolds, focusing on the case of a supersymmetry-preserving quotient of Euclidean AdS{sub 3}. We compute the exact partition function in these theories, using the method of localization, thus reducing the problem to the computation of one-loop determinants around a supersymmetric locus. We evaluate the one-loop determinants employing three different techniques: an index theorem, the method of pairing of eigenvalues, and the heat kernel method. Along the way, we discuss aspects of supersymmetry in manifolds with a conformal boundary, including supersymmetric actions and boundary conditions.

A Tightly Coupled Non-Equilibrium Magneto-Hydrodynamic Model for Inductively Coupled RF Plasmas

Science.gov (United States)

2016-02-29

development a tightly coupled magneto-hydrodynamic model for Inductively Coupled Radio- Frequency (RF) Plasmas. Non Local Thermodynamic Equilibrium (NLTE...for Inductively Coupled Radio-Frequency (RF) Plasmas. Non Local Thermodynamic Equilibrium (NLTE) effects are described based on a hybrid State-to-State...Inductively Coupled Plasma (ICP) torches have wide range of possible applications which include deposition of metal coatings, synthesis of ultra-fine powders

Noncommutative QED and anomalous dipole moments

International Nuclear Information System (INIS)

Riad, I.F.; Sheikh-Jabbari, M.M.

2000-09-01

We study QED on noncommutative spaces, NCQED. In particular we present the detailed calculation for the noncommutative electron-photon vertex and show that the Ward identity is satisfied. We discuss that in the noncommutative case moving electron will show electric dipole effects. In addition, we work out the electric and magnetic dipole moments up to one loop level. For the magnetic moment we show that noncommutative electron has an intrinsic (spin independent) magnetic moment. (author)

Gauge fixing problem in the conformal QED

International Nuclear Information System (INIS)

Ichinose, Shoichi

1986-01-01

The gauge fixing problem in the conformal (spinor and scalar) QED is examined. For the analysis, we generalize Dirac's manifestly conformal-covariant formalism. It is shown that the (vector and matter) fields must obey a certain mixed (conformal and gauge) type of transformation law in order to fix the local gauge symmetry preserving the conformal invariance in the Lagrangian. (orig.)

QED contribution to the color-singlet J/ψ production in Υ decay near the endpoint

International Nuclear Information System (INIS)

Liu Xiaohui

2010-01-01

A recent study indicates that the α 2 α s 2 order QED processes of Υ→J/ψ+X decay are compatible with those of QCD processes. However, in the endpoint region, the nonrelativistic QED calculation breaks down since the collinear degrees of freedom are missing under the framework of this effective theory. In this paper we apply the soft-collinear effective theory (SCET) to study the color-singlet QED process at the kinematic limit. Within this approach we are able to sum the kinematic logarithms by running operators using the renormalization group equations of soft-collinear effective theory, which will lead to a dramatic change in the momentum distribution near the endpoint and the spectrum shape consistent with the experimental results.

Coupling non-gravitational fields with simplicial spacetimes

International Nuclear Information System (INIS)

McDonald, Jonathan R; Miller, Warner A

2010-01-01

The inclusion of source terms in discrete gravity is a long-standing problem. Providing a consistent coupling of source to the lattice in the Regge calculus (RC) yields a robust unstructured spacetime mesh applicable to both numerical relativity and quantum gravity. RC provides a particularly insightful approach to this problem with its purely geometric representation of spacetime. The simplicial building blocks of RC enable us to represent all matter and fields in a coordinate-free manner. We provide an interpretation of RC as a discrete exterior calculus framework into which non-gravitational fields naturally couple with the simplicial lattice. Using this approach we obtain a consistent mapping of the continuum action for non-gravitational fields to the Regge lattice. In this paper we apply this framework to scalar, vector and tensor fields. In particular we reconstruct the lattice action for (1) the scalar field, (2) Maxwell field tensor and (3) Dirac particles. The straightforward application of our discretization techniques to these three fields demonstrates a universal implementation of the coupling source to the lattice in RC.

Renormalization of QED with planar binary trees

International Nuclear Information System (INIS)

Brouder, C.

2001-01-01

The Dyson relations between renormalized and bare photon and electron propagators Z 3 anti D(q)=D(q) and Z 2 anti S(q)=S(q) are expanded over planar binary trees. This yields explicit recursive relations for the terms of the expansions. When all the trees corresponding to a given power of the electron charge are summed, recursive relations are obtained for the finite coefficients of the renormalized photon and electron propagators. These relations significantly decrease the number of integrals to carry out, as compared to the standard Feynman diagram technique. In the case of massless quantum electrodynamics (QED), the relation between renormalized and bare coefficients of the perturbative expansion is given in terms of a Hopf algebra structure. (orig.)

QED Effects in Molecules: Test on Rotational Quantum States of H2

Science.gov (United States)

Salumbides, E. J.; Dickenson, G. D.; Ivanov, T. I.; Ubachs, W.

2011-07-01

Quantum electrodynamic effects have been systematically tested in the progression of rotational quantum states in the XΣg+1, v=0 vibronic ground state of molecular hydrogen. High-precision Doppler-free spectroscopy of the EFΣg+1-XΣg+1 (0,0) band was performed with 0.005cm-1 accuracy on rotationally hot H2 (with rotational quantum states J up to 16). QED and relativistic contributions to rotational level energies as high as 0.13cm-1 are extracted, and are in perfect agreement with recent calculations of QED and high-order relativistic effects for the H2 ground state.

Classical Electron Model with QED Corrections

OpenAIRE

Lenk, Ron

2010-01-01

In this article we build a metric for a classical general relativistic electron model with QED corrections. We calculate the stress-energy tensor for the radiative corrections to the Coulomb potential in both the near-field and far-field approximations. We solve the three field equations in both cases by using a perturbative expansion to first order in alpha (the fine-structure constant) while insisting that the usual (+, +, -, -) structure of the stress-energy tensor is maintained. The resul...

Preparation of ultra-thin and high-quality WO{sub 3} compact layers and comparision of WO{sub 3} and TiO{sub 2} compact layer thickness in planar perovskite solar cells

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jincheng; Shi, Chengwu, E-mail: shicw506@foxmail.com; Chen, Junjun; Wang, Yanqing; Li, Mingqian

2016-06-15

In this paper, the ultra-thin and high-quality WO{sub 3} compact layers were successfully prepared by spin-coating-pyrolysis method using the tungsten isopropoxide solution in isopropanol. The influence of WO{sub 3} and TiO{sub 2} compact layer thickness on the photovoltaic performance of planar perovskite solar cells was systematically compared, and the interface charge transfer and recombination in planar perovskite solar cells with TiO{sub 2} compact layer was analyzed by electrochemical impedance spectroscopy. The results revealed that the optimum thickness of WO{sub 3} and TiO{sub 2} compact layer was 15 nm and 60 nm. The planar perovskite solar cell with 15 nm WO{sub 3} compact layer gave a 9.69% average and 10.14% maximum photoelectric conversion efficiency, whereas the planar perovskite solar cell with 60 nm TiO{sub 2} compact layer achieved a 11.79% average and 12.64% maximum photoelectric conversion efficiency. - Graphical abstract: The planar perovskite solar cell with 15 nm WO{sub 3} compact layer gave a 9.69% average and 10.14% maximum photoelectric conversion efficiency, whereas the planar perovskite solar cell with 60 nm TiO{sub 2} compact layer achieved a 11.79% average and 12.64% maximum photoelectric conversion efficiency. Display Omitted - Highlights: • Preparation of ultra-thin and high-quality WO{sub 3} compact layers. • Perovskite solar cell with 15 nm-thick WO{sub 3} compact layer achieved PCE of 10.14%. • Perovskite solar cell with 60 nm-thick TiO{sub 2} compact layer achieved PCE of 12.64%.

Phase transition of light in cavity QED lattices.

Science.gov (United States)

Schiró, M; Bordyuh, M; Oztop, B; Türeci, H E

2012-08-03

Systems of strongly interacting atoms and photons, which can be realized wiring up individual cavity QED systems into lattices, are perceived as a new platform for quantum simulation. While sharing important properties with other systems of interacting quantum particles, here we argue that the nature of light-matter interaction gives rise to unique features with no analogs in condensed matter or atomic physics setups. By discussing the physics of a lattice model of delocalized photons coupled locally with two-level systems through the elementary light-matter interaction described by the Rabi model, we argue that the inclusion of counterrotating terms, so far neglected, is crucial to stabilize finite-density quantum phases of correlated photons out of the vacuum, with no need for an artificially engineered chemical potential. We show that the competition between photon delocalization and Rabi nonlinearity drives the system across a novel Z(2) parity symmetry-breaking quantum criticality between two gapped phases that share similarities with the Dicke transition of quantum optics and the Ising critical point of quantum magnetism. We discuss the phase diagram as well as the low-energy excitation spectrum and present analytic estimates for critical quantities.

Test of QED in e+e- → γγ at LEP

International Nuclear Information System (INIS)

Adeva, B.; Adriani, O.; Aguilar-Benitez, M.; Akbari, H.; Alcaraz, J.; Aloisio, A.; Alverson, G.; Alviggi, M.G.; An, Q.; Anderhub, H.; Anderson, A.L.; Andreev, V.P.; Angelov, T.; Antonov, L.; Antreasyan, D.; Arce, P.; Arefiev, A.; Azemoon, T.; Aziz, T.; Baba, P.V.K.S.; Bagnaia, P.; Bakken, J.A.; Baksay, L.; Ball, R.C.; Banerjee, S.; Bao, J.; Barone, L.; Bay, A.; Becker, U.; Behrens, J.; Beingessner, S.; Bencze, G.L.; Berdugo, J.; Berges, P.; Bertucci, B.; Betev, B.L.; Biland, A.; Bizzarri, R.; Blaising, J.J.; Bloemeke, P.; Blumenfeld, B.; Bobbink, G.J.; Bocciolini, M.; Boehlen, W.; Boehm, A.; Boehringer, T.; Borgia, B.; Borilkov, D.; Bourquin, M.; Boutigny, D.; Branson, J.G.; Brock, I.C.; Bryant, F.; Buisson, C.; Bujak, A.; Burger, J.D.; Burq, J.P.; Busenitz, J.; Cai, X.D.; Camps, C.; Capell, M.; Carbonara, F.; Carmianti, F.; Cartacci, A.M.; Cerrada, M.; Cesaroni, F.; Chang, Y.H.; Chaturvedi, U.K.; Chemarin, M.; Chen, A.; Chen, C.; Chen, G.M.; Chen, H.F.; Chen, H.S.; Chen, M.; Chen, M.L.; Chiefari, G.; Chien, C.Y.; Civinini, C.; Clare, I.; Clare, R.; Coignet, G.; Colino, N.; Commichau, V.; Conforto, G.; Contin, A.; Crijns, F.; Cui, X.Y.; Dai, T.S.; D'Alessandro, R.; De Asmudis, R.; Degre, A.; Deiters, K.; Denes, E.; Denes, P.; De Notaristefani, F.; Dhina, M.; DiBitonto, D.; Diemoz, M.; Diez-Hedo, F.; Dimitrov, H.R.; Dionisi, C.; Dittus, F.; Dolin, R.; Drago, E.; Driever, T.; Duchesneau, D.; Duinker, P.; Duran, I.; El Mamouni, H.; Engler, A.; Eppling, F.J.; Erne, F.C.; Extermann, P.; Fabretti, R.; Faber, G.; Falciano, S.; Fan, Q.; Fan, S.J.; Fabre, M.; Fay, J.; Fehlmann, J.; Fenker, H.; Ferguson, T.; Fernandez, G.; Ferroni, F.; Fesefeldt, H.; Field, J.; Finocchiaro, G.; Fisher, P.H.; Forconi, G.; Foreman, T.; Freudenreich, K.; Friebel, W.; Fukushima, M.; Gailloud, M.; Galaktionov, Yu.; Gallo, E.; Ganguli, S.N.; Garcia-Abia, P.; Gau, S.S.; Gentile, S.; Glaubman, M.; Goldfarb, S.; Gong, Z.F.; Gonzalez, E.; Gordeev, A.; Goettlicher, P.; Goujon, D.; Gratta, G.; Grinnell, C.; Gruenewald, M.; Guanziroli, M.; Gurtu, A.; Gustafson, H.R.; Gutay, L.J.; Haan, H.; Hancke, S.; Hangarter, K.; Harris, M.; Hasan, A.; He, C.F.; Hebbeker, T.; Herbert, M.; Herten, G.; Herten, U.; Herve, A.; Hilgers, K.; Hofer, H.; Hoorani, H.; Hsu, L.S.; Hu, G.; Hu, G.Q.; Ille, B.; Ilyas, M.M.; Innocente, V.; Isiksal, E.; Jagel, E.; Jin, B.N.; Jones, L.W.; Khan, R.A.; Kamyshkov, Yu.; Karyotakis, Y.; Kaur, M.; Khokhar, S.; Khoze, V.; Kirkby, D.; Kittel, W.; Klimentov, A.; Koenig, A.C.; Kornadt, O.; Koutsenko, V.; Kraemer, R.W.; Kramer, T.; Kratsev, V.R.; Krenz, W.; Krizmanic, J.; Kuhn, A.; Kumar, K.S.; Kumar, V.; Kunin, A.; Laak, A. van; Lalieu, V.; Landi, G.; Lanius, K.; Lange, W.; Lanske, D.; Lanzano, S.; Lebrun, P.

1990-01-01

We have measured the cross-section of the reaction e + e - →γγ at center of mass energies around the Z 0 mass. The results are in good agreement with QED predictions. For the QED cutoff parameters the limit of Λ + >103 GeV and Λ - >118 GeV are found. For the decays Z 0 →γγ, Z 0 →π 0 γ, Z 0 →ηγ and Z 0 →γγγ we find upper limits of 2.9x10 -4 , 2.9x10 -4 , 4.1x10 -4 and 1.2x10 -4 , respectively. All limits are at 95% CL. (orig.)

Condensation phenomena in two-flavor scalar QED at finite chemical potential

CERN Document Server

Schmidt, Alexander; Gattringer, Christof

2014-01-01

We study condensation in two-flavored, scalar QED with non-degenerate masses at finite chemical potential. The conventional formulation of the theory has a sign problem at finite density which can be solved using an exact reformulation of the theory in terms of dual variables. We perform a Monte Carlo simulation in the dual representation and observe a condensation at a critical chemical potential $\\mu_c$. After determining the low-energy spectrum of the theory we try to establish a connection between $\\mu_c$ and the mass of the lightest excitation of the system, which are naively expected to be equal. It turns out, however, that the relation of the critical chemical potential to the mass spectrum in this case is non-trivial: Taking into account the form of the condensate and making some simplifying assumptions we suggest an adequate explanation which is supported by numerical results.

Implementing quantum information splitting using a five-partite cluster state in cavity QED

International Nuclear Information System (INIS)

Ye Liu; Song Qingmin; Li Aixia

2010-01-01

We propose an explicit scheme for splitting up quantum information into parts using five-atom cluster states in cavity quantum electrodynamics (QED). It is found that the quantum information splitting of an arbitrary two-atomic state can be realized by using the five-atom cluster state. During the process, the cavity fields are excited only virtually. The scheme is insensitive to cavity decay. Therefore, the scheme can be experimentally realized using a range of current cavity QED techniques. The schemes considered here are also secure against certain eavesdropping attacks.

New uncertainties in QCD–QED rescaling factors using quadrature ...

Indian Academy of Sciences (India)

mf ). This is true for heavier quarks ... mass scale down to the physical quark mass scale is parametrised by the QCD–. QED rescaling factors ηf ... It will be an important numerical exercise to estimate the uncertainties in ηf using the quadrature ...

(g-2){sub μ} at four loops in QED

Energy Technology Data Exchange (ETDEWEB)

Marquard, Peter [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Smirnov, Alexander V. [Moscow State Univ. (Russian Federation). Research Computing Center; Smirnov, Vladimir A. [Moscow State Univ. (Russian Federation). Skobeltsyn Inst. of Nuclear Physics; Steinhauser, Matthias; Wellmann, David [Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany). Inst. fuer Theoretische Teilchenphysik

2017-08-15

We review the four-loop QED corrections to the anomalous magnetic moment of the muon. The fermionic contributions with closed electron and tau contributions are discussed. Furthermore, we report on a new independent calculation of the universal four-loop contribution and compare with existing results.

QED approach to the nuclear spin-spin coupling tensor

International Nuclear Information System (INIS)

Romero, Rodolfo H.; Aucar, Gustavo A.

2002-01-01

A quantum electrodynamical approach for the calculation of the nuclear spin-spin coupling tensor of nuclear-magnetic-resonance spectroscopy is given. Quantization of radiation fields within the molecule is considered and expressions for the magnetic field in the neighborhood of a nucleus are calculated. Using a generalization of time-dependent response theory, an effective spin-spin interaction is obtained from the coupling of nuclear magnetic moments to a virtual quantized magnetic field. The energy-dependent operators obtained reduce to usual classical-field expressions at suitable limits

Multipartite quantum correlations among atoms in QED cavities

Science.gov (United States)

Batle, J.; Farouk, A.; Tarawneh, O.; Abdalla, S.

2018-02-01

We study the nonlocality dynamics for two models of atoms in cavity quantum electrodynamics (QED); the first model contains atoms in a single cavity undergoing nearest-neighbor interactions with no initial correlation, and the second contains atoms confined in n different and noninteracting cavities, all of which were initially prepared in a maximally correlated state of n qubits corresponding to the atomic degrees of freedom. The nonlocality evolution of the states in the second model shows that the corresponding maximal violation of a multipartite Bell inequality exhibits revivals at precise times, defining, nonlocality sudden deaths and nonlocality sudden rebirths, in analogy with entanglement. These quantum correlations are provided analytically for the second model to make the study more thorough. Differences in the first model regarding whether the array of atoms inside the cavity is arranged in a periodic or open fashion are crucial to the generation or redistribution of quantum correlations. This contribution paves the way to using the nonlocality multipartite correlation measure for describing the collective complex behavior displayed by slightly interacting cavity QED arrays.

Determination of the integrated luminosity at HERA using elastic QED Compton events

International Nuclear Information System (INIS)

Aaron, F.D.; Andreev, V.

2012-04-01

A measurement of the integrated luminosity at the ep collider HERA is presented, exploiting the elastic QED Compton process ep→eγp. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of 2.3%. The measurement is found to be compatible with the corresponding result obtained using the Bethe-Heitler process.

Determination of the Integrated Luminosity at HERA using Elastic QED Compton Events

CERN Document Server

Aaron, F.D.; Andreev, V.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Bruncko, D.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cvach, J.; Dainton, J.B.; Daum, K.; Delcourt, B.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Egli, S.; Eliseev, A.; Elsen, E.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Habib, S.; Haidt, D.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, H.; Kapichine, M.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Kogler, R.; Kostka, P.; Kramer, M.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Lopez-Fernandez, R.; Lubimov, V.; Malinovski, E.; Martyn, H.U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Ruiz Tabasco, J.E.; Rusakov, S.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sykora, T.; Thompson, P.D.; Tran, T.H.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zlebcik, R.; Zohrabyan, H.; Zomer, F.

2012-10-10

A measurement of the integrated luminosity at the ep collider HERA is presented, exploiting the elastic QED Compton process ep \\rightarrow ep. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of 2.3%. The measurement is found to be compatible with the corresponding result obtained using the Bethe-Heitler process.

Compact four-channel terahertz demultiplexer based on directional coupling photonic crystal

Science.gov (United States)

Jiu-Sheng, Li; Han, Liu; Le, Zhang

2015-09-01

Electromagnetic polarization conveys valuable information for signal processing. Manipulation of terahertz wavelength demultiplexer exhibits tremendous potential in developing application of terahertz science and technology. We propose an approach to separate efficiently four frequencies terahertz waves based on three cascaded directional coupling two-dimensional photonic crystal waveguides. Both plane wave expansion method and finite-difference time-domain method are used to calculate and analyze the characteristics of the proposed device. The simulation results show that the designed terahertz wavelength demultiplexer can split four different wavelengths of terahertz wave into different propagation directions with high transmittance and low crosstalk. The present device is very compact and the total size is 6.8×10.6 mm2. This enables the terahertz wavelength demultiplexer to be used in terahertz wave system and terahertz wave integrated circuit fields.

Causal theory in (2+1)-dimensional Qed

International Nuclear Information System (INIS)

Scharf, G.; Wreszinski, W.F.

1994-01-01

The program of constructing the S-matrix by means of causality in quantum field theory goes back to Stueckelberg and Bogoliubov. Epstein and Glaser proposed an axiomatic construct where ultraviolet divergences do not appear, leading directly to the renormalized perturbation series. They have shown that in the causal theory the UV problem is a consequence of incorrect distribution splitting. This paper studies the causal theory in (2+1)D Qed

Superadiabatic holonomic quantum computation in cavity QED

Science.gov (United States)

Liu, Bao-Jie; Huang, Zhen-Hua; Xue, Zheng-Yuan; Zhang, Xin-Ding

2017-06-01

Adiabatic quantum control is a powerful tool for quantum engineering and a key component in some quantum computation models, where accurate control over the timing of the involved pulses is not needed. However, the adiabatic condition requires that the process be very slow and thus limits its application in quantum computation, where quantum gates are preferred to be fast due to the limited coherent times of the quantum systems. Here, we propose a feasible scheme to implement universal holonomic quantum computation based on non-Abelian geometric phases with superadiabatic quantum control, where the adiabatic manipulation is sped up while retaining its robustness against errors in the timing control. Consolidating the advantages of both strategies, our proposal is thus both robust and fast. The cavity QED system is adopted as a typical example to illustrate the merits where the proposed scheme can be realized in a tripod configuration by appropriately controlling the pulse shapes and their relative strength. To demonstrate the distinct performance of our proposal, we also compare our scheme with the conventional adiabatic strategy.

Experimentation at LEP: weak-electromagnetic interference, QED and two-photon physics

International Nuclear Information System (INIS)

Davier, M.

1979-01-01

The energy range opened by LEP will permit a clean and direct study of the weak interaction. Of particular importance are those effects resulting from the interference between the weak and the electromagnetic (EM) currents: it is shown that they give access to the basic couplings which can be measured unambiguously. The paper is in three parts. The first and major section deals with the weak interaction experiments. Most of the calculations and estimates rely on the Weinberg-Salam model as a realistic guide of what might happen. The second section is devoted to 2γ processes. On one hand they constitute an interesting physics study which has been assessed both from theory and experiment and appears promising. On the other hand, they can generate background to many annihilation channels and this aspect has been studied in detail. The last section presents a brief look at short distance tests of Quantum Electrodynamics (QED) - a restricted, but important area of research at LEP. (Auth.)

Plateau inflation from random non-minimal coupling

International Nuclear Information System (INIS)

Broy, Benedict J.; Roest, Diederik

2016-06-01

A generic non-minimal coupling can push any higher-order terms of the scalar potential sufficiently far out in field space to yield observationally viable plateau inflation. We provide analytic and numerical evidence that this generically happens for a non-minimal coupling strength ξ of the order N 2 e . In this regime, the non-minimally coupled field is sub-Planckian during inflation and is thus protected from most higher-order terms. For larger values of ξ, the inflationary predictions converge towards the sweet spot of PLANCK. The latter includes ξ≅10 4 obtained from CMB normalization arguments, thus providing a natural explanation for the inflationary observables measured.

Noether symmetry for non-minimally coupled fermion fields

International Nuclear Information System (INIS)

Souza, Rudinei C de; Kremer, Gilberto M

2008-01-01

A cosmological model where a fermion field is non-minimally coupled with the gravitational field is studied. By applying Noether symmetry the possible functions for the potential density of the fermion field and for the coupling are determined. Cosmological solutions are found showing that the non-minimally coupled fermion field behaves as an inflaton describing an inflationary scenario, whereas the minimally coupled fermion field describes a decelerated period, behaving as a standard matter field

The Role of Zero-Modes in the Canonical Quantization of Heavy-Fermion QED in Light-Cone Coordinates

OpenAIRE

Brown, Robert W.; Jun, Jin Woo; Shvartsman, Shmaryu M.; Taylor, Cyrus C.

1993-01-01

Four-dimensional heavy-fermion QED is studied in light-cone coordinates with (anti-)periodic field boundary conditions. We carry out a consistent light-cone canonical quantization of this model using the Dirac algorithm for a system with first- and second-class constraints. To examine the role of the zero modes, we consider the quantization procedure in {the }zero-mode {and the non-zero-mode} sectors separately. In both sectors we obtain the physical variables and their canonical commutation ...

Simulating lattice fermions by microcanonically averaging out the nonlocal dependence of the fermionic action

International Nuclear Information System (INIS)

Azcoiti, V.; Cruz, A.; Di Carlo, G.; Grillo, A.F.; Vladikas, A.

1991-01-01

We attempt to increase the efficiency of simulations of dynamical fermions on the lattice by calculating the fermionic determinant just once for all the values of the theory's gauge coupling and flavor number. Our proposal is based on the determination of an effective fermionic action by the calculation of the fermionic determinant averaged over configurations at fixed gauge energy. The feasibility of our method is justified by the observed volume dependence of the fluctuations of the logarithm of the determinant. The algorithm we have used in order to calculate the fermionic determinant, based on the determination of all the eigenvalues of the fermionic matrix at zero mass, also enables us to obtain results at any fermion mass, with a single fermionic simulation. We test the method by simulating compact lattice QED, finding good agreement with other standard calculations. New results on the phase transition of compact QED with massless fermions on 6 4 and 8 4 lattices are also presented

Non-compact random generalized games and random quasi-variational inequalities

OpenAIRE

Yuan, Xian-Zhi

1994-01-01

In this paper, existence theorems of random maximal elements, random equilibria for the random one-person game and random generalized game with a countable number of players are given as applications of random fixed point theorems. By employing existence theorems of random generalized games, we deduce the existence of solutions for non-compact random quasi-variational inequalities. These in turn are used to establish several existence theorems of noncompact generalized random ...

Determination of the integrated luminosity at HERA using elastic QED Compton events

International Nuclear Information System (INIS)

Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Vazdik, Y.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H.; Barrelet, E.; Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Habib, S.; Haidt, D.; Kleinwort, C.; Kraemer, M.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Pandurovic, M.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D.; Bruncko, D.; Cerny, V.; Ferencei, J.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Fedotov, A.; Lubimov, V.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Ceccopieri, F.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Roosen, R.; Staykova, Z.; Mechelen, P. van; Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R.; Chekelian, V.; Grindhammer, G.; Kiesling, C.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Daum, K.; Meyer, H.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C.; Dobre, M.; Kogler, R.; Nowak, K.; Dodonov, V.; Povh, B.; Dossanov, A.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Feltesse, J.; Perez, E.; Schoeffel, L.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Grab, C.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Herrera, G.; Lopez-Fernandez, R.; Huber, F.; Pirumov, H.; Sauter, M.; Schoening, A.; Joensson, L.; Jung, H.; Kapichine, M.; Morozov, A.; Nikitin, D.; Palichik, V.; Spaskov, V.; Landon, M.P.J.; Rizvi, E.; Traynor, D.; Martyn, H.U.; Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P.; Soloviev, Y.; Stella, B.; Sykora, T.; Tsakov, I.; Wegener, D.

2012-01-01

A measurement of the integrated luminosity at the ep collider HERA is presented, exploiting the elastic QED Compton process ep→eγp. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of 2.3 %. The measurement is found to be compatible with the corresponding result obtained using the Bethe-Heitler process. (orig.)

Determination of the integrated luminosity at HERA using elastic QED Compton events

Energy Technology Data Exchange (ETDEWEB)

Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)

2012-04-15

A measurement of the integrated luminosity at the ep collider HERA is presented, exploiting the elastic QED Compton process ep{yields}e{gamma}p. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of 2.3%. The measurement is found to be compatible with the corresponding result obtained using the Bethe-Heitler process.

Strategies for real-time position control of a single atom in cavity QED

International Nuclear Information System (INIS)

Lynn, T W; Birnbaum, K; Kimble, H J

2005-01-01

Recent realizations of single-atom trapping and tracking in cavity QED open the door for feedback schemes which actively stabilize the motion of a single atom in real time. We present feedback algorithms for cooling the radial component of motion for a single atom trapped by strong coupling to single-photon fields in an optical cavity. Performance of various algorithms is studied through simulations of single-atom trajectories, with full dynamical and measurement noise included. Closed loop feedback algorithms compare favourably to open loop 'switching' analogues, demonstrating the importance of applying actual position information in real time. The high optical information rate in current experiments enables real-time tracking that approaches the standard quantum limit for broadband position measurements, suggesting that realistic active feedback schemes may reach a regime where measurement backaction appreciably alters the motional dynamics

Effects of toroidal coupling on the non-linear evolution of tearing modes and on the stochastisation of the magnetic field topology in plasmas

International Nuclear Information System (INIS)

Edery, D.; Pellat, R.; Soule, J.L.

1981-01-01

The resistive MHD equations have been handled in toroidal geometry following the tokamak ordering, in order to obtain a simplified set of non-linear equations. This system of equations is compact, closed, consistent and exact to the first two orders in the expansion in the inverse aspect ratio. Studies of the non-linear evolution of tearing modes in the real geometry of tokamak discharges are now in progress, and quite significant results have been obtained from the numerical code REVE of Fontenay based on our above model. From the analytical results, strong linear coupling between neighbouring modes is expected as is demonstrated by the numerical results in the linear, and non-linear regimes. Moreover, coupling exhibits a stochastic structure of the magnetic field lines, the threshold of which is seen to be easily computed by a simple analytical criterion. (orig.)

First-principles approach to the dynamic magnetoelectric couplings for the non-reciprocal directional dichroism in BiFeO3

Science.gov (United States)

Lee, Jun Hee; Kézsmáki, István; Fishman, Randy S.

2016-04-01

Due to the complicated magnetic and crystallographic structures of BiFeO3, its magnetoelectric (ME) couplings and microscopic model Hamiltonian remain poorly understood. By employing a first-principles approach, we uncover all possible ME couplings associated with the spin-current (SC) and exchange-striction (ES) polarizations, and construct an appropriate Hamiltonian for the long-range spin-cycloid in BiFeO3. First-principles calculations are used to understand the microscopic origins of the ME couplings. We find that inversion symmetries broken by ferroelectric and antiferroelectric distortions induce the SC and the ES polarizations, which cooperatively produce the dynamic ME effects in BiFeO3. A model motivated by first principles reproduces the absorption difference of counter-propagating light beams called non-reciprocal directional dichroism. The current paper focuses on the spin-driven (SD) polarizations produced by a dynamic electric field, i.e. the dynamic ME couplings. Due to the inertial properties of Fe, the dynamic SD polarizations differ significantly from the static SD polarizations. Our systematic approach can be generally applied to any multiferroic material, laying the foundation for revealing hidden ME couplings on the atomic scale and for exploiting optical ME effects in the next generation of technological devices such as optical diodes. This manuscript has been written by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan.

ZnTiO3 ceramic nanopowder microstructure changes during compaction

Directory of Open Access Journals (Sweden)

Labus N.

2013-01-01

Full Text Available ZnTiO3 nanopowder as a constitutive component in compact production was primarily characterized. Scanning electron micrographs of as received powder were recorded. Mercury porosimetry and nitrogen adsorption were also performed on loose powder. Particle size distribution in a water powder suspension was determined with a laser particle size analyser. Compaction was performed on different pressures in a range from 100 to 400 MPa using the uniaxial double sided compaction technique without binder and lubricant. Micrographs of compacted specimens were obtained using scanning electron microscopy and atomic force microscopy. Pore size distribution was also determined by mercury porosimetry and nitrogen adsorption. Results revealed that with increasing pressure during compaction interagglomerate pores diminish in size until they reach some critical diameter related to the intra-agglomerate pore size.

First-principles approach to the dynamic magnetoelectric couplings for the non-reciprocal directional dichroism in BiFeO3

International Nuclear Information System (INIS)

Lee, Jun Hee; Fishman, Randy S; Kézsmáki, István

2016-01-01

Due to the complicated magnetic and crystallographic structures of BiFeO 3 , its magnetoelectric (ME) couplings and microscopic model Hamiltonian remain poorly understood. By employing a first-principles approach, we uncover all possible ME couplings associated with the spin-current (SC) and exchange-striction (ES) polarizations, and construct an appropriate Hamiltonian for the long-range spin-cycloid in BiFeO 3 . First-principles calculations are used to understand the microscopic origins of the ME couplings. We find that inversion symmetries broken by ferroelectric and antiferroelectric distortions induce the SC and the ES polarizations, which cooperatively produce the dynamic ME effects in BiFeO 3 . A model motivated by first principles reproduces the absorption difference of counter-propagating light beams called non-reciprocal directional dichroism. The current paper focuses on the spin-driven (SD) polarizations produced by a dynamic electric field, i.e. the dynamic ME couplings. Due to the inertial properties of Fe, the dynamic SD polarizations differ significantly from the static SD polarizations. Our systematic approach can be generally applied to any multiferroic material, laying the foundation for revealing hidden ME couplings on the atomic scale and for exploiting optical ME effects in the next generation of technological devices such as optical diodes. (paper)

On the equivalence of massive qed with renormalizable and in unitary gauge

International Nuclear Information System (INIS)

Abdalla, E.

1978-03-01

In the framework of BPHZ renormalization procedure, we discuss the equivalence between 4-dimensional renormalizable massive quantum electrodynamics (Stueckelberg lagrangian), and massive QED in the unitary gauge

Low energy gauge couplings in grand unified theories and high precision physics

International Nuclear Information System (INIS)

Lynn, B.W.

1993-09-01

I generalize the leading log relations between low energy SU(3) QCD , SU(2) rvec I and U(l) Y effective gauge couplings to include all one-loop threshold effects of matter fields in oblique vector self energy quantum corrections for both supersymmetric and non-supersymmetric SU(5) grand unified theories. These always involve an exactly conserved current from the unbroken SU(3) QCD x U(L) QED subgroup; this fact strongly constrains any non-decoupling of heavy states as well as the generic character of threshold effects. Relations between low energy gauge couplings depend on the details of the spectra of both the superheavy and low mass sectors; I display the common origin of the logs appropriate to superheavy matter states, which can be found with well known renormalization group techniques, and the combination of logs and polynomials appropriate for light matter states, which cannot. Relations between any two or all three low energy effective gauge couplings do not depend on the top quark or standard model Higgs' masses. Neither do they depend on neutral color singlet states such as other neutral color singlet Higgs' or higgsinos, neutrinos, zinos or photinos. Further, they do not depend on degenerate SU(5) matter representations, of either spin 0 or spin 1/2 of any mass; matter representations of SU(5) can affect such relations only if there is mass splitting within them. The b quark splitting from the τ and ν τ can affect the relation between gauge couplings for |q 2 | → m b 2 as can hadronic resonances and multi-hadron states for lower |q 2 |. New mass-split representations of light states, such as occur in supersymmetric theories, can also affect such relations

Low energy gauge couplings in grand unified theories and high precision physics

Energy Technology Data Exchange (ETDEWEB)

Lynn, B.W. [Stanford Univ., CA (United States). Dept. of Physics]|[Superconducting Super Collider Lab., Dallas, TX (United States)

1993-09-01

I generalize the leading log relations between low energy SU(3){sub QCD}, SU(2){sub {rvec I}} and U(l){sub Y} effective gauge couplings to include all one-loop threshold effects of matter fields in oblique vector self energy quantum corrections for both supersymmetric and non-supersymmetric SU(5) grand unified theories. These always involve an exactly conserved current from the unbroken SU(3){sub QCD} {times} U(L){sub QED} subgroup; this fact strongly constrains any non-decoupling of heavy states as well as the generic character of threshold effects. Relations between low energy gauge couplings depend on the details of the spectra of both the superheavy and low mass sectors; I display the common origin of the logs appropriate to superheavy matter states, which can be found with well known renormalization group techniques, and the combination of logs and polynomials appropriate for light matter states, which cannot. Relations between any two or all three low energy effective gauge couplings do not depend on the top quark or standard model Higgs` masses. Neither do they depend on neutral color singlet states such as other neutral color singlet Higgs` or higgsinos, neutrinos, zinos or photinos. Further, they do not depend on degenerate SU(5) matter representations, of either spin 0 or spin 1/2 of any mass; matter representations of SU(5) can affect such relations only if there is mass splitting within them. The b quark splitting from the {tau} and {nu}{sub {tau}} can affect the relation between gauge couplings for {vert_bar}q{sub 2}{vert_bar} {yields} m{sub b}{sup 2} as can hadronic resonances and multi-hadron states for lower {vert_bar}q{sub 2}{vert_bar}. New mass-split representations of light states, such as occur in supersymmetric theories, can also affect such relations.

Chiral current generation in QED by longitudinal photons

Energy Technology Data Exchange (ETDEWEB)

Acosta Avalo, J.L., E-mail: jlacosta@instec.cu [Instituto Superior de Tecnologías y Ciencias Aplicadas (INSTEC), Ave Salvador Allende, No. 1110, Vedado, La Habana 10400 (Cuba); Pérez Rojas, H., E-mail: hugo@icimaf.cu [Instituto de Cibernética, Matemática y Física (ICIMAF), Calle E esq 15, No. 309, Vedado, La Habana 10400 (Cuba)

2016-08-15

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.

Chiral current generation in QED by longitudinal photons

Directory of Open Access Journals (Sweden)

J.L. Acosta Avalo

2016-08-01

Full Text Available 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.

Non-statistical behavior of coupled optical systems

International Nuclear Information System (INIS)

Perez, G.; Pando Lambruschini, C.; Sinha, S.; Cerdeira, H.A.

1991-10-01

We study globally coupled chaotic maps modeling an optical system, and find clear evidence of non-statistical behavior: the mean square deviation (MSD) of the mean field saturates with respect to increase in the number of elements coupled, after a critical value, and its distribution is clearly non-Gaussian. We also find that the power spectrum of the mean field displays well defined peaks, indicating a subtle coherence among different elements, even in the ''turbulent'' phase. This system is a physically realistic model that may be experimentally realizable. It is also a higher dimensional example (as each individual element is given by a complex map). Its study confirms that the phenomena observed in a wide class of coupled one-dimensional maps are present here as well. This gives more evidence to believe that such non-statistical behavior is probably generic in globally coupled systems. We also investigate the influence of parametric fluctuations on the MSD. (author). 10 refs, 7 figs, 1 tab

Improved ring potential of QED at finite temperature and in the presence of weak and strong magnetic fields

International Nuclear Information System (INIS)

Sadooghi, N.; Anaraki, K. Sohrabi

2008-01-01

Using the general structure of the vacuum polarization tensor Π μν (k 0 ,k) in the infrared (IR) limit, k 0 →0, the ring contribution to the QED effective potential at finite temperature and the nonzero magnetic field is determined beyond the static limit, (k 0 →0, k→0). The resulting ring potential is then studied in weak and strong magnetic field limits. In the weak magnetic field limit, at high temperature and for α→0, the improved ring potential consists of a term proportional to T 4 α 5/2 , in addition to the expected T 4 α 3/2 term arising from the static limit. Here, α is the fine structure constant. In the limit of the strong magnetic field, where QED dynamics is dominated by the lowest Landau level, the ring potential includes a novel term consisting of dilogarithmic function (eB)Li 2 (-(2α/π)(eB/m 2 )). Using the ring improved (one-loop) effective potential including the one-loop effective potential and ring potential in the IR limit, the dynamical chiral symmetry breaking of QED is studied at finite temperature and in the presence of the strong magnetic field. The gap equation, the dynamical mass and the critical temperature of QED in the regime of the lowest Landau level dominance are determined in the improved IR as well as in the static limit. For a given value of the magnetic field, the improved ring potential is shown to be more efficient in decreasing the critical temperature arising from the one-loop effective potential.

Continuum limit of QED2 on a lattice

International Nuclear Information System (INIS)

Weingarten, D.H.; Challifour, J.L.

1979-01-01

A path integral is defined for the vacuum expectation values of Euclidean QED 2 on a periodic lattice. Wilson's expression is used for the coupling between fermion and gauge fields. The action for the gauge field by itself is assumed to be a quadratic in place of Wilson's periodic action. The integral over the fermion field is carried out explicitly to obtain a Matthews--Salam formula for vacuum expectation values. For a combination of gauge and fermion fields G on a lattice with spacing proportional to N -+ , Nelement ofZ + , the Matthews--Salam formula for the vacuum expectation /sub N/ has the form /sub n/=∫ dμW/sub N/(G, f), where dμ is an N-independent measure on a random electromagnetic field f and W/sub N/(G,f) is an N-dependent function of f determined by G. For a class of G we prove that as N→infinity, W/sub N/(G,f) has a limit W (G,f) except possibly for a set of f of measure zero. In subsequent articles it will be shown that ∫ dμW (G,f) exists and lim/sub N/→infinity /sub N/ =∫ dμW

Soft thermal contributions to 3-loop gauge coupling

Science.gov (United States)

Laine, M.; Schicho, P.; Schröder, Y.

2018-05-01

We analyze 3-loop contributions to the gauge coupling felt by ultrasoft ("magnetostatic") modes in hot Yang-Mills theory. So-called soft/hard terms, originating from dimension-six operators within the soft effective theory, are shown to cancel 1097/1098 of the IR divergence found in a recent determination of the hard 3-loop contribution to the soft gauge coupling. The remaining 1/1098 originates from ultrasoft/hard contributions, induced by dimension-six operators in the ultrasoft effective theory. Soft 3-loop contributions are likewise computed, and are found to be IR divergent, rendering the ultrasoft gauge coupling non-perturbative at relative order O({α}s^{3/2}) . We elaborate on the implications of these findings for effective theory studies of physical observables in thermal QCD.

AGR-1 Fuel Compact 6-3-2 Post-Irradiation Examination Results

Energy Technology Data Exchange (ETDEWEB)

Paul demkowicz; jason Harp; Scott Ploger

2012-12-01

Destructive post-irradiation examination was performed on fuel Compact 6-3-2, which was irradiated in the AGR-1 experiment to a final compact average burnup of 11.3% FIMA and a time-average, volume-average temperature of 1070°C. The analysis of this compact was focused on characterizing the extent of fission product release from the particles and examining particles to determine the condition of the kernels and coating layers. The work included deconsolidation of the compact and leach-burn-leach analysis, visual inspection and gamma counting of individual particles, measurement of fuel burnup by several methods, metallurgical preparation of selected particles, and examination of particle cross-sections with optical microscopy. A single particle with a defective SiC layer was identified during deconsolidation-leach-burn-leach analysis, which is in agreement with previous measurements showing elevated cesium in the Capsule 6 graphite fuel holder associated with this fuel compact. The fraction of the compact europium inventory released from the particles and retained in the matrix was relatively high (approximately 6E-3), indicating release from intact particle coatings. The Ag-110m inventory in individual particles exhibited a very broad distribution, with some particles retaining =80% of the predicted inventory and others retaining less than 25%. The average degree of Ag-110m retention in 60 gamma counted particles was approximately 50%. This elevated silver release is in agreement with analysis of silver on the Capsule 6 components, which indicated an average release of 38% of the Capsule 6 inventory from the fuel compacts. In spite of the relatively high degree of silver release from the particles, virtually none of the Ag-110m released was found in the compact matrix, and presumably migrated out of the compact and was deposited on the irradiation capsule components. Release of all other fission products from the particles appears to be less than a single

Unbounded dynamics and compact invariant sets of one Hamiltonian system defined by the minimally coupled field

Energy Technology Data Exchange (ETDEWEB)

Starkov, Konstantin E., E-mail: kstarkov@ipn.mx

2015-06-12

In this paper we study some features of global dynamics for one Hamiltonian system arisen in cosmology which is formed by the minimally coupled field; this system was introduced by Maciejewski et al. in 2007. We establish that under some simple conditions imposed on parameters of this system all trajectories are unbounded in both of time directions. Further, we present other conditions for system parameters under which we localize the domain with unbounded dynamics; this domain is defined with help of bounds for values of the Hamiltonian level surface parameter. We describe the case when our system possesses periodic orbits which are found explicitly. In the rest of the cases we get some localization bounds for compact invariant sets. - Highlights: • Domain with unbounded dynamics is localized. • Equations for periodic orbits are given in one level set. • Localizations for compact invariant sets are got.

Quality factor of a transmission line coupled coplanar waveguide resonator

Energy Technology Data Exchange (ETDEWEB)

Besedin, Ilya [National University for Science and Technology (MISiS), Moscow (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation); Menushenkov, Alexey P. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation)

2018-12-15

We investigate analytically the coupling of a coplanar waveguide resonator to a coplanar waveguide feedline. Using a conformal mapping technique we obtain an expression for the characteristic mode impedances and coupling coefficients of an asymmetric multi-conductor transmission line. Leading order terms for the external quality factor and frequency shift are calculated. The obtained analytical results are relevant for designing circuit-QED quantum systems and frequency division multiplexing of superconducting bolometers, detectors and similar microwave-range multi-pixel devices. (orig.)

An interesting case of cryptogenic stroke in a young man due to left ventricular non-compaction: role of cardiac MRI in the accurate diagnosis.

Science.gov (United States)

Kannan, Arun; Das, Anindita; Janardhanan, Rajesh

2014-06-24

A 28-year-old man arrived for an outpatient cardiac MRI (CMR) study to evaluate cardiac structure. At the age of 24 the patient presented with acute onset expressive aphasia and was diagnosed with ischaemic stroke. Echocardiography at that time was reported as 'apical wall thickening consistent with apical hypertrophic cardiomyopathy'. CMR revealed a moderately dilated left ventricle with abnormal appearance of the left ventricular (LV) apical segments. Further evaluation was consistent with a diagnosis of LV non-compaction (LVNC) cardiomyopathy with a ratio of non-compacted to compacted myocardium measuring 3. There was extensive delayed hyperenhancement signal involving multiple segments representing a significant myocardial scar which is shown to have a prognostic role. Our patient, with no significant cerebrovascular risk factors, would likely have had an embolic stroke. This case demonstrates the role of CMR in accurately diagnosing LVNC in a patient with young stroke where prior echocardiography was non-diagnostic. 2014 BMJ Publishing Group Ltd.

Compact stars in vector-tensor-Horndeski theory of gravity

Energy Technology Data Exchange (ETDEWEB)

Momeni, Davood; Myrzakulov, Kairat; Myrzakulov, Ratbay [Eurasian National University, Department of General and Theoretical Physics, Eurasian International Center for Theoretical Physics, Astana (Kazakhstan); Faizal, Mir [University of British Columbia-Okanagan, Irving K. Barber School of Arts and Sciences, Kelowna, BC (Canada); University of Lethbridge, Department of Physics and Astronomy, Lethbridge, AB (Canada)

2017-01-15

In this paper, we will analyze a theory of modified gravity, in which the field content of general relativity will be increased to include a vector field. We will use the Horndeski formalism to non-minimally couple this vector field to the metric. As we will be using the Horndeski formalism, this theory will not contain Ostrogradsky ghost degree of freedom. We will analyze compact stars using this vector-tensor-Horndeski theory. (orig.)

A note of topological pressure for non-compact sets of a factor map

International Nuclear Information System (INIS)

Li, Qian; Chen, Ercai; Zhou, Xiaoyao

2013-01-01

Using the notion of topological pressure for non-compact sets, we prove a relation for two topological pressures with a factor map. We also provide an application in symbolic dynamics and conformal repellers. These results are generalized to the cases of BS-dimensions

The Nielsen identities for the two-point functions of QED and QCD

International Nuclear Information System (INIS)

Breckenridge, J.C.; Sasketchewan Univ., Saskatoon, SK; Lavelle, M.J.; Steele, T.G.; Sasketchewan Univ., Saskatoon, SK

1995-01-01

We consider the Nielsen identities for the two-point functions of full QCD and QED in the class of Lorentz gauges. For pedagogical reasons the identities are first derived in QED to demonstrate the gauge independence of the photon self-energy, and of the electron mass shell. In QCD we derive the general identity and hence the identities for the quark, gluon and ghost propagators. The explicit contributions to the gluon and ghost identities are calculated to one-loop order, and then we show that the quark identity requires that in on-shell schemes the quark mass renormalisation must be gauge independent. Furthermore, we obtain formal solutions for the gluon self-energy and ghost propagator in terms of the gauge dependence of other, independent Green functions. (orig.)

Testing Non-commutative QED, Constructing Non-commutative MHD

OpenAIRE

Guralnik, Z.; Jackiw, R.; Pi, S. Y.; Polychronakos, A. P.

2001-01-01

The effect of non-commutativity on electromagnetic waves violates Lorentz invariance: in the presence of a background magnetic induction field b, the velocity for propagation transverse to b differs from c, while propagation along b is unchanged. In principle, this allows a test by the Michelson-Morley interference method. We also study non-commutativity in another context, by constructing the theory describing a charged fluid in a strong magnetic field, which forces the fluid particles into ...

A tightly coupled non-equilibrium model for inductively coupled radio-frequency plasmas

International Nuclear Information System (INIS)

Munafò, A.; Alfuhaid, S. A.; Panesi, M.; Cambier, J.-L.

2015-01-01

The objective of the present work is the development of a tightly coupled magneto-hydrodynamic model for inductively coupled radio-frequency plasmas. Non Local Thermodynamic Equilibrium (NLTE) effects are described based on a hybrid State-to-State approach. A multi-temperature formulation is used to account for thermal non-equilibrium between translation of heavy-particles and vibration of molecules. Excited electronic states of atoms are instead treated as separate pseudo-species, allowing for non-Boltzmann distributions of their populations. Free-electrons are assumed Maxwellian at their own temperature. The governing equations for the electro-magnetic field and the gas properties (e.g., chemical composition and temperatures) are written as a coupled system of time-dependent conservation laws. Steady-state solutions are obtained by means of an implicit Finite Volume method. The results obtained in both LTE and NLTE conditions over a broad spectrum of operating conditions demonstrate the robustness of the proposed coupled numerical method. The analysis of chemical composition and temperature distributions along the torch radius shows that: (i) the use of the LTE assumption may lead to an inaccurate prediction of the thermo-chemical state of the gas, and (ii) non-equilibrium phenomena play a significant role close the walls, due to the combined effects of Ohmic heating and macroscopic gradients

Physical pictures of symmetry breaking in quenched QED4

International Nuclear Information System (INIS)

Kogut, J.B.; Argonne National Lab., IL

1989-01-01

We discuss 'collapse of the wavefunction' as the phenomenon underlying chiral symmetry breaking in quenched QED4. The 1/r singularity in the 'collapsed' qanti q wavefunction causes 'catalyzed symmetry breaking' which is the field theoretic analog of 'monopole induced proton decay'. The evasion of mean field exponents by the quenched theory's chiral phase transition is emphasized. (orig.)

Strong coupling in F-theory and geometrically non-Higgsable seven-branes

Directory of Open Access Journals (Sweden)

James Halverson

2017-06-01

Full Text Available Geometrically non-Higgsable seven-branes carry gauge sectors that cannot be broken by complex structure deformation, and there is growing evidence that such configurations are typical in F-theory. We study strongly coupled physics associated with these branes. Axiodilaton profiles are computed using Ramanujan's theories of elliptic functions to alternative bases, showing explicitly that the string coupling is O(1 in the vicinity of the brane; that it sources nilpotent SL(2,Z monodromy and therefore the associated brane charges are modular; and that essentially all F-theory compactifications have regions with order one string coupling. It is shown that non-perturbative SU(3 and SU(2 seven-branes are related to weakly coupled counterparts with D7-branes via deformation-induced Hanany–Witten moves on (p,q string junctions that turn them into fundamental open strings; only the former may exist for generic complex structure. D3-brane near these and the Kodaira type II seven-branes probe Argyres–Douglas theories. The BPS states of slightly deformed theories are shown to be dyonic string junctions.

Four-dimensional aether-like Lorentz-breaking QED revisited and problem of ambiguities

Energy Technology Data Exchange (ETDEWEB)

Baeta Scarpelli, A.P. [Setor Tecnico-Cientifico, Departamento de Policia Federal, Rua Hugo D' Antola, 95, Lapa, Sao Paulo (Brazil); Mariz, T. [Universidade Federal de Alagoas, Instituto de Fisica, Maceio, Alagoas (Brazil); Nascimento, J.R.; Petrov, A.Yu. [Universidade Federal da Paraiba, Departamento de Fisica, Caixa Postal 5008, Joao Pessoa, Paraiba (Brazil)

2013-08-15

In this paper, we consider the perturbative generation of the CPT-even aether-like Lorentz-breaking term in the extended Lorentz-breaking QED within different approaches and discuss its ambiguities. (orig.)

Four-dimensional aether-like Lorentz-breaking QED revisited and problem of ambiguities

International Nuclear Information System (INIS)

Baeta Scarpelli, A.P.; Mariz, T.; Nascimento, J.R.; Petrov, A.Yu.

2013-01-01

In this paper, we consider the perturbative generation of the CPT-even aether-like Lorentz-breaking term in the extended Lorentz-breaking QED within different approaches and discuss its ambiguities. (orig.)

OpenQ∗D simulation code for QCD+QED

DEFF Research Database (Denmark)

Campos, Isabel; Fritzsch, Patrick; Hansen, Martin

2018-01-01

The openQ∗D code for the simulation of QCD+QED with C∗ boundary conditions is presented. This code is based on openQCD-1.6, from which it inherits the core features that ensure its efficiency: the locally-deflated SAP-preconditioned GCR solver, the twisted-mass frequency splitting of the fermion....... An alpha version of this code is publicly available and can be downloaded from http://rcstar.web.cern.ch/....

Effect of magnetic coupling on non-radiative relaxation time of Fe3+ sites on LaAl1-xFexO3 pigments

Science.gov (United States)

Novatski, A.; Somer, A.; Maranha, F. G.; de Souza, E. C. F.; Andrade, A. V. C.; Antunes, S. R. M.; Borges, C. P. F.; Dias, D. T.; Medina, A. N.; Astrath, N. G. C.

2018-02-01

Inorganic pigments of the system LaAl1-xFexO3 were prepared by the Pechini and the Solid State Reaction (SSR) methods. Magnetic interactions and non-radiative relaxation time were analyzed by means of phase-resolved photoacoustic spectroscopy and electron paramagnetic resonance (EPR) techniques. EPR results show a change in the magnetic behavior from paramagnetic (x = 0.2 and 0.4) to antiferromagnetic (x = 1.0), which is believed to be a result of the SSR preparation method. Trends in the optical absorption bands of the Fe3+ are attributed to their electronic transitions, and the increase in the band's intensity at 480 and 550 nm was assigned to the increase in the magnetic coupling between Fe-Fe. The phase-resolved method is capable of distinguishing between the two preparation methods, and it is possible to infer that SSR modifies the magnetic coupling of Fe-Fe with x.

One-Step Generation of Multiqubit Greenberger-Horne-Zeilinger States in a Driven Circuit QED System

International Nuclear Information System (INIS)

Huang Jinsong; Nie Wei; Wei Lianfu

2011-01-01

We propose an efficient scheme to generate multiqubit Greenberger-Horne-Zeilinger (GHZ) states by one-step quantum operation in a driven circuit quantum electrodynamics (QED) system. Our proposal is based on a unitary evolution exp[-iλS 2 x ], with S x being the collective spin operator in x direction and λ a controllable parameter, induced by driving the resonator. The quantum operation avoids resonator-field decay and may achieve the GHZ states with ideal success probability. The feasibility with the experimentally-demonstrated circuit QED system is also discussed. (general)

Bosonic construction of the Lie algebras of some non-compact groups appearing in supergravity theories and their oscillator-like unitary representations

International Nuclear Information System (INIS)

Guenaydin, M.; Saclioglu, C.

1981-06-01

We give a construction of the Lie algebras of the non-compact groups appearing in four dimensional supergravity theories in terms of boson operators. Our construction parallels very closely their emergence in supergravity and is an extension of the well-known construction of the Lie algebras of the non-compact groups Sp(2n,IR) and SO(2n) from boson operators transforming like a fundamental representation of their maximal compact subgroup U(n). However this extension is non-trivial only for n >= 4 and stops at n = 8 leading to the Lie algebras of SU(4) x SU(1,1), SU(5,1), SO(12) and Esub(7(7)). We then give a general construction of an infinite class of unitary irreducible representations of the respective non-compact groups (except for Esub(7(7)) and SO(12) obtained from the extended construction). We illustrate our construction with the examples of SU(5,1) and SO(12). (orig.)

A Coherence Preservation Control Strategy in Cavity QED Based on Classical Quantum Feedback

Directory of Open Access Journals (Sweden)

Ming Li

2013-01-01

Full Text Available For eliminating the unexpected decoherence effect in cavity quantum electrodynamics (cavity QED, the transfer function of Rabi oscillation is derived theoretically using optical Bloch equations. In particular, the decoherence in cavity QED from the atomic spontaneous emission is especially considered. A feedback control strategy is proposed to preserve the coherence through Rabi oscillation stabilization. In the scheme, a classical quantum feedback channel for the quantum information acquisition is constructed via the quantum tomography technology, and a compensation system based on the root locus theory is put forward to suppress the atomic spontaneous emission and the associated decoherence. The simulation results have proved its effectiveness and superiority for the coherence preservation.

Testing of QED-Theory and Precise Measurements of the Rydberg Series for the He-Like Multicharged Ions

Energy Technology Data Exchange (ETDEWEB)

Pal' chikov, V. G. [VNIIFTRI, Mendeleevo, National Research Institute for Physical-Technical and Radiotechnical Measurements - (Russian Federation)], E-mail: vitpal@mail.ru

2001-01-15

The wavelengths of the 1snp{sup 1}P{sub 1}-1s{sup 21}S{sub 0} transitions in He-like Mg XI, F VIII (n= 4-8) and Al XII (n=6,9) have been calculated in the framework of the 1/Z expansion method including relativistic effects and QED contributions. It is found that QED corrections to the ground-state ionization energy are significant at the present level of experimental accuracy.

Multi-flavor massless QED{sub 2} at finite densities via Lefschetz thimbles

Energy Technology Data Exchange (ETDEWEB)

Tanizaki, Yuya [RIKEN BNL Research Center, Brookhaven National Laboratory,Upton, NY 11973-5000 (United States); Tachibana, Motoi [Department of Physics, Saga University,Saga 840-8502 (Japan)

2017-02-15

We consider multi-flavor massless (1+1)-dimensional QED with chemical potentials at finite spatial length and the zero-temperature limit. Its sign problem is solved using the mean-field calculation with complex saddle points.

Isolated left ventricular non-compaction cardiomyopathy associated with polymorphous ventricular tachycardia mimicking torsades de pointes

Directory of Open Access Journals (Sweden)

Oana Dickinson

2013-02-01

Full Text Available Left ventricular non-compaction (LVNC cardiomyopathy is a rare congenital disorder, classified by the American Heart Association as a primary genetic cardiomyopathy and characterized by multiple trabeculations within the left ventricle. LVNC cardiomyopathy has been associated with 3 major clinical manifestations: heart failure, atrial and ventricular arrhythmias and thromboembolic events, including stroke. In this case report, we describe a female patient with apparently isolated LVNC in whom pause-dependent polymorphic ventricular tachycardia suggesting torsades de pointes occurred in the presence of a normal QT interval.

Hydrogen atom spectrum and the Lamb shift in noncommutative QED

International Nuclear Information System (INIS)

Chaichian, M. . Helsinki Institute of Physics, Helsinki; Tureanu, A. . Helsinki Institute of Physics, Helsinki; FI)

2000-10-01

We have calculated the energy levels of the hydrogen atom and as well the Lamb shift within the noncommutative quantum electrodynamics theory. The results show deviations from the usual QED both on the classical and on the quantum levels. On both levels, the deviations depend on the parameter of space/space noncommutativity. (author)

Invariant differential operators for non-compact Lie groups: the SO* (12) case

Science.gov (United States)

Dobrev, V. K.

2015-04-01

In the present paper we continue the project of systematic construction of invariant differential operators on the example of the non-compact algebra so* (12). We give the main multiplets of indecomposable elementary representations. Due to the recently established parabolic relations the multiplet classification results are valid also for the algebra so(6, 6) with suitably chosen maximal parabolic subalgebra.

Coupled 3D neutronic and thermohydraulic calculations for a compact fuel element with disperse UMo fuel at FRM II

International Nuclear Information System (INIS)

Breitkreutz, H.; Roehrmoser, A.; Petry, W.

2010-01-01

The newly developed X 2 program system is intended to be used for high-detail 3D calculations on compact research reactor cores. Using this system, the efforts to calculate scenarios for a new fuel element for FRM II using disperse UMo (8wt% Mo, 50% enrichment) are continued. By now, a radial symmetric core model with averaged built-in components for the D 2 O tank is used. Two different scenarios are compared: The minimum fuel density of 7.5 g U/cm 3 and 8.0 g U/cm 3 with 60 days cycle length. In addition, two 'flux loss compensating' scenarios based on 8.0 g U/cm 3 with 10% higher power/longer reactor cycles are regarded. (author)

Artificial boundary conditions for certain evolution PDEs with cubic nonlinearity for non-compactly supported initial data

Science.gov (United States)

Vaibhav, V.

2011-04-01

The paper addresses the problem of constructing non-reflecting boundary conditions for two types of one dimensional evolution equations, namely, the cubic nonlinear Schrödinger (NLS) equation, ∂tu+Lu-iχ|u|2u=0 with L≡-i∂x2, and the equation obtained by letting L≡∂x3. The usual restriction of compact support of the initial data is relaxed by allowing it to have a constant amplitude along with a linear phase variation outside a compact domain. We adapt the pseudo-differential approach developed by Antoine et al. (2006) [5] for the NLS equation to the second type of evolution equation, and further, extend the scheme to the aforementioned class of initial data for both of the equations. In addition, we discuss efficient numerical implementation of our scheme and produce the results of several numerical experiments demonstrating its effectiveness.

Mobile glasses-free 3D using compact waveguide hologram

Science.gov (United States)

Pyun, K.; Choi, C.; Morozov, A.; Putilin, A.; Bovsunovskiy, I.; Kim, S.; Ahn, J.; Lee, H.-S.; Lee, S.

2013-02-01

The exploding mobile communication devices make 3D data available anywhere anytime. However, to record and reconstruct 3D, the huge number of optical components is often required, which makes overall device size bulky and image quality degraded due to the error-prone tuning. In addition, if additional glass is required, then user experience of 3D is exhausting and unpleasant. Holography is the ultimate 3D that users experience natural 3D in every direction. For mobile glasses-free 3D experience, it is critical to make holography device that can be as compact and integrated as possible. For reliable and economical mass production, integrated optics is needed as integrated circuits in semiconductor industry. Thus, we propose mobile glasses-free 3D using compact waveguide hologram in terms of overall device sizes, quantity of elements and combined functionality of each element. The main advantages of proposed solution are as follows: First, this solution utilizes various integral optical elements, where each of them is a united not adjustable optical element, replacing separate and adjustable optical elements with various forms and configurations. Second, geometrical form of integral elements provides small sizes of whole device. Third, geometrical form of integral elements allows creating flat device. And finally, absence of adjustable elements provide rigidly of whole device. The usage of integrated optical means based on waveguide holographic elements allows creating a new type of compact and high functional devices for mobile glasses-free 3D applications such as mobile medical 3D data visualization.

Mobile glasses-free 3D using compact waveguide hologram

International Nuclear Information System (INIS)

Pyun, K; Choi, C; Kim, S; Ahn, J; Lee, H-S; Lee, S; Morozov, A; Bovsunovskiy, I; Putilin, A

2013-01-01

The exploding mobile communication devices make 3D data available anywhere anytime. However, to record and reconstruct 3D, the huge number of optical components is often required, which makes overall device size bulky and image quality degraded due to the error-prone tuning. In addition, if additional glass is required, then user experience of 3D is exhausting and unpleasant. Holography is the ultimate 3D that users experience natural 3D in every direction. For mobile glasses-free 3D experience, it is critical to make holography device that can be as compact and integrated as possible. For reliable and economical mass production, integrated optics is needed as integrated circuits in semiconductor industry. Thus, we propose mobile glasses-free 3D using compact waveguide hologram in terms of overall device sizes, quantity of elements and combined functionality of each element. The main advantages of proposed solution are as follows: First, this solution utilizes various integral optical elements, where each of them is a united not adjustable optical element, replacing separate and adjustable optical elements with various forms and configurations. Second, geometrical form of integral elements provides small sizes of whole device. Third, geometrical form of integral elements allows creating flat device. And finally, absence of adjustable elements provide rigidly of whole device. The usage of integrated optical means based on waveguide holographic elements allows creating a new type of compact and high functional devices for mobile glasses-free 3D applications such as mobile medical 3D data visualization.

On the construction of QED using ERG

International Nuclear Information System (INIS)

Sonoda, H

2007-01-01

It has been known for some time that a smooth momentum cutoff is compatible with local gauge symmetries. In this paper, we show concretely how to construct QED using the exact renormalization group (ERG). First, we give a new derivation of the Ward identity for the Wilson action using the technique of composite operators. Second, parametrizing the theory by its asymptotic behaviour for a large cutoff, we show how to fine tune the parameters to satisfy the identity. Third, we recast the identity as an invariance of the Wilson action under a nonlinear BRST transformation

A Many-Atom Cavity QED System with Homogeneous Atom-Cavity Coupling

OpenAIRE

Lee, Jongmin; Vrijsen, Geert; Teper, Igor; Hosten, Onur; Kasevich, Mark A.

2013-01-01

We demonstrate a many-atom-cavity system with a high-finesse dual-wavelength standing wave cavity in which all participating rubidium atoms are nearly identically coupled to a 780-nm cavity mode. This homogeneous coupling is enforced by a one-dimensional optical lattice formed by the field of a 1560-nm cavity mode.

Entanglement concentration and purification of two-mode squeezed microwave photons in circuit QED

Science.gov (United States)

Zhang, Hao; Alsaedi, Ahmed; Hayat, Tasawar; Deng, Fu-Guo

2018-04-01

We present a theoretical proposal for a physical implementation of entanglement concentration and purification protocols for two-mode squeezed microwave photons in circuit quantum electrodynamics (QED). First, we give the description of the cross-Kerr effect induced between two resonators in circuit QED. Then we use the cross-Kerr media to design the effective quantum nondemolition (QND) measurement on microwave-photon number. By using the QND measurement, the parties in quantum communication can accomplish the entanglement concentration and purification of nonlocal two-mode squeezed microwave photons. We discuss the feasibility of our schemes by giving the detailed parameters which can be realized with current experimental technology. Our work can improve some practical applications in continuous-variable microwave-based quantum information processing.

QED the strange theory of light and matter

CERN Document Server

Feynman, Richard Phillips

2006-01-01

Celebrated for his brilliantly quirky insights into the physical world, Nobel laureate Richard Feynman also possessed an extraordinary talent for explaining difficult concepts to the general public. Here Feynman provides a classic and definitive introduction to QED (namely quantum electrodynamics), that part of quantum field theory describing the interactions of light with charged particles. Using everyday language, spatial concepts, visualizations, and his renowned ""Feynman diagrams"" instead of advanced mathematics, Feynman clearly and humorously communicates both the substance and spiri

Compact HTS bandpass filter employing CPW quarter-wavelength resonators with strongly-coupled open stubs

Energy Technology Data Exchange (ETDEWEB)

Satoh, K; Koizumi, D; Narahashi, S [Research Laboratories, NTT DoCoMo, Inc., 3-5 Hikari-no-oka, Yokosuka, Kanagwa, 239-8536 (Japan)], E-mail: satokei@nttdocomo.co.jp

2008-02-01

This paper presents a novel compact high temperature superconducting (HTS) bandpass filter (BPF) that employs a newly developed miniaturized coplanar-waveguide (CPW) quarter-wavelength resonators with strongly-coupled open stubs. The proposed resonator has a structure in which the open stubs are aligned close to the center conductor of the resonator. This is because strongly-coupled resonators have widely-split resonant frequencies, and the lowest resonant frequency is employed as the fundamental resonant frequency of the resonator in order to achieve miniaturization. The proposed resonator is 1.7 mm or less in length for use in the 5-GHz band, whereas the conventional straight resonator is approximately 6.4 mm long. A four-pole Chebyshev HTS BPF is designed and fabricated using the proposed CPW resonators. The entire length of the proposed four-pole filter is 15 mm. The frequency response of the fabricated filter agrees well with the electromagnetic simulation results. The proposed filter achieves a size reduction of at least 50% compared to previously reported filters without any degradation in the frequency characteristics.

Means, methods and performances of the AREVA's HTR compact controls

International Nuclear Information System (INIS)

Banchet, J.; Guillermier, P.; Tisseur, D.; Vitali, M. P.

2008-01-01

In the AREVA's HTR development program, the reactor plant is composed of a prismatic core containing graphite cylindrical fuel elements, called compacts, where TRISO particles are dispersed. Starting from its past compacting process, the latter being revamped through the use of state of the art equipments, CERCA, 100% AREVA NP's subsidiary, was able to recover the quality of past compacts production. The recovered compacting process is composed of the following manufacturing steps: graphite matrix granulation, mix between the obtained granulates and particles, compacting and calcining at low pressure and temperature. To adapt this past process to new manufacturing equipments, non destructive examination tests were carried out to assess the compact quality, the latter being assessed via in house developed equipments and methods at each step of the design of experiments. As for the manufacturing process, past quality control methods were revamped to measure compact dimensional features (diameter, perpendicularity and cone effect), visual aspect, SiC layer failure fraction (via anodic disintegration and burn leach test) and homogeneity via 2D radiography coupled to ceramography. Although meeting quality requirements, 2D radiography method could not provide a quantified specification for compact homogeneity characterization. This limitation yielded the replacement of this past technique by a method based on X-Ray tomography. Development was conducted on this new technique to enable the definition of a criterion to quantify compact homogeneity, as well as to provide information about the distances in between particles. This study also included a comparison between simulated and real compacts to evaluate the accuracy of the technique as well as the influence of particle packing fraction on compact homogeneity. The developed quality control methods and equipments guided the choices of manufacturing parameters adjustments at the development stage and are now applied for

Modelling of the Optical Detector System in a Compact Disc Player

DEFF Research Database (Denmark)

Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

2003-01-01

The cross-couplings between focus and radial tracking servos in compact disc players are important, but the optical cross couplings are not well described in the literature. In this paper an optical model of a compact disc player based on the three beam single foucault detector principle is found...

Application of a Light-Front Coupled Cluster Method

International Nuclear Information System (INIS)

Chabysheva, S.S.; Hiller, J.R.

2012-01-01

As a test of the new light-front coupled-cluster method in a gauge theory, we apply it to the nonperturbative construction of the dressed-electron state in QED, for an arbitrary covariant gauge, and compute the electron's anomalous magnetic moment. The construction illustrates the spectator and Fock-sector independence of vertex and self-energy contributions and indicates resolution of the difficulties with uncanceled divergences that plague methods based on Fock-space truncation. (author)

Contributions of non-intrusive coupling in nonlinear structural mechanics

International Nuclear Information System (INIS)

Duval, Mickael

2016-01-01

This PhD thesis, part of the ANR ICARE project, aims at developing methods for complex analysis of large scale structures. The scientific challenge is to investigate very localised areas, but potentially critical as of mechanical systems resilience. Classically, representation models, discretizations, mechanical behaviour models and numerical tools are used at both global and local scales for simulation needs of graduated complexity. Global problem is handled by a generic code with topology (plate formulation, geometric approximation...) and behaviour (homogenization) simplifications while local analysis needs implementation of specialized tools (routines, dedicated codes) for an accurate representation of the geometry and behaviour. The main goal of this thesis is to develop an efficient non-intrusive coupling tool for multi-scale and multi-model structural analysis. Constraints of non-intrusiveness result in the non-modification of the stiffness operator, connectivity and the global model solver, allowing to work in a closed source software environment. First, we provide a detailed study of global/local non-intrusive coupling algorithm. Making use of several relevant examples (cracking, elastic-plastic behaviour, contact...), we show the efficiency and the flexibility of such coupling method. A comparative analysis of several optimisation tools is also carried on, and the interacting multiple patches situation is handled. Then, non-intrusive coupling is extended to globally non-linear cases, and a domain decomposition method with non-linear re-localization is proposed. Such methods allowed us to run a parallel computation using only sequential software, on a high performance computing cluster. Finally, we apply the coupling algorithm to mesh refinement with patches of finite elements. We develop an explicit residual based error estimator suitable for multi-scale solutions arising from the non-intrusive coupling, and apply it inside an error driven local mesh

High figure of merit ultra-compact 3-channel parallel-connected photonic crystal mini-hexagonal-H1 defect microcavity sensor array

Science.gov (United States)

Wang, Chunhong; Sun, Fujun; Fu, Zhongyuan; Ding, Zhaoxiang; Wang, Chao; Zhou, Jian; Wang, Jiawen; Tian, Huiping

2017-08-01

In this paper, a photonic crystal (PhC) butt-coupled mini-hexagonal-H1 defect (MHHD) microcavity sensor is proposed. The MHHD microcavity is designed by introducing six mini-holes into the initial H1 defect region. Further, based on a well-designed 1 ×3 PhC Beam Splitter and three optimal MHHD microcavity sensors with different lattice constants (a), a 3-channel parallel-connected PhC sensor array on monolithic silicon on insulator (SOI) is proposed. Finite-difference time-domain (FDTD) simulations method is performed to demonstrate the high performance of our structures. As statistics show, the quality factor (Q) of our optimal MHHD microcavity attains higher than 7×104, while the sensitivity (S) reaches up to 233 nm/RIU(RIU = refractive index unit). Thus, the figure of merit (FOM) >104 of the sensor is obtained, which is enhanced by two orders of magnitude compared to the previous butt-coupled sensors [1-4]. As for the 3-channel parallel-connected PhC MHHD microcavity sensor array, the FOMs of three independent MHHD microcavity sensors are 8071, 8250 and 8250, respectively. In addition, the total footprint of the proposed 3-channel parallel-connected PhC sensor array is ultra-compactness of 12.5 μm ×31 μm (width × length). Therefore, the proposed high FOM sensor array is an ideal platform for realizing ultra-compact highly parallel refractive index (RI) sensing.

QED corrections in deep-inelastic scattering from tensor polarized deuteron target

CERN Document Server

Gakh, G I

2001-01-01

The QED correction in the deep inelastic scattering from the polarized tensor of the deuteron target is considered. The calculations are based on the covariant parametrization of the deuteron quadrupole polarization tensor. The Drell-Yan representations in the electrodynamics are used for describing the radiation real and virtual particles

Inflation in non-minimal matter-curvature coupling theories

Energy Technology Data Exchange (ETDEWEB)

Gomes, C.; Bertolami, O. [Departamento de Física e Astronomia and Centro de Física do Porto, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto (Portugal); Rosa, J.G., E-mail: claudio.gomes@fc.up.pt, E-mail: joao.rosa@ua.pt, E-mail: orfeu.bertolami@fc.up.pt [Departamento de Física da Universidade de Aveiro and CIDMA, Campus de Santiago, 3810-183 Aveiro (Portugal)

2017-06-01

We study inflationary scenarios driven by a scalar field in the presence of a non-minimal coupling between matter and curvature. We show that the Friedmann equation can be significantly modified when the energy density during inflation exceeds a critical value determined by the non-minimal coupling, which in turn may considerably modify the spectrum of primordial perturbations and the inflationary dynamics. In particular, we show that these models are characterised by a consistency relation between the tensor-to-scalar ratio and the tensor spectral index that can differ significantly from the predictions of general relativity. We also give examples of observational predictions for some of the most commonly considered potentials and use the results of the Planck collaboration to set limits on the scale of the non-minimal coupling.

High-precision QED calculations of the hyperfine structure in hydrogen and transition rates in multicharged ions

Energy Technology Data Exchange (ETDEWEB)

Volotka, A.V.

2006-07-01

accounted for preserving gauge invariance. One-loop QED corrections to the magnetic-dipole transition amplitude between the fine-structure levels 2p{sub 3/2} and 2p{sub 1/2} are calculated to all orders in {alpha}Z. Taking into account consistently relativistic, interelectronic-interaction, and QED corrections to the magnetic-dipole transition amplitude allows for predictions of the lifetimes of the states (1s{sup 2}2s{sup 2}2p) {sup 2}P{sub 3/2} in B-like ions and (1s{sup 2}2s2p) {sup 3}P{sub 2} in Be-like ions with utmost precision. The results of corresponding calculations are compared with experimental data obtained in recent measurements at the Heidelberg EBIT. Finally, for He-like ions with nonzero-spin nuclei the effect of hyperfine quenching on the lifetimes of the 2{sup 3}P{sub 0,2} states is investigated and again compared available experimental data. (orig.)

High-precision QED calculations of the hyperfine structure in hydrogen and transition rates in multicharged ions

International Nuclear Information System (INIS)

Volotka, A.V.

2006-01-01

accounted for preserving gauge invariance. One-loop QED corrections to the magnetic-dipole transition amplitude between the fine-structure levels 2p 3/2 and 2p 1/2 are calculated to all orders in αZ. Taking into account consistently relativistic, interelectronic-interaction, and QED corrections to the magnetic-dipole transition amplitude allows for predictions of the lifetimes of the states (1s 2 2s 2 2p) 2 P 3/2 in B-like ions and (1s 2 2s2p) 3 P 2 in Be-like ions with utmost precision. The results of corresponding calculations are compared with experimental data obtained in recent measurements at the Heidelberg EBIT. Finally, for He-like ions with nonzero-spin nuclei the effect of hyperfine quenching on the lifetimes of the 2 3 P 0,2 states is investigated and again compared available experimental data. (orig.)

Chiral anomalies in QED and QCD at finite temperature

International Nuclear Information System (INIS)

Alvarez-Estrada, R.F.

1991-01-01

Chiral anomalies (a) for QED and QCD at finite temperature are analyzed in imaginary- and real-time formalisms. Both triangle diagrams and functional methods are used. It is found that the expressions for a in terms of finite-temperature fields are formally similar to that for the zero-temperature anomaly as a function of zero-temperature fields, thereby generalizing previous work by other authors. (author). 20 refs.; 1 fig

Transverse Momentum Distributions of Electron in Simulated QED Model

Science.gov (United States)

Kaur, Navdeep; Dahiya, Harleen

2018-05-01

In the present work, we have studied the transverse momentum distributions (TMDs) for the electron in simulated QED model. We have used the overlap representation of light-front wave functions where the spin-1/2 relativistic composite system consists of spin-1/2 fermion and spin-1 vector boson. The results have been obtained for T-even TMDs in transverse momentum plane for fixed value of longitudinal momentum fraction x.

Development of a compact, fiber-coupled, six degree-of-freedom measurement system for precision linear stage metrology

International Nuclear Information System (INIS)

Yu, Xiangzhi; Gillmer, Steven R.; Woody, Shane C.; Ellis, Jonathan D.

2016-01-01

A compact, fiber-coupled, six degree-of-freedom measurement system which enables fast, accurate calibration, and error mapping of precision linear stages is presented. The novel design has the advantages of simplicity, compactness, and relatively low cost. This proposed sensor can simultaneously measure displacement, two straightness errors, and changes in pitch, yaw, and roll using a single optical beam traveling between the measurement system and a small target. The optical configuration of the system and the working principle for all degrees-of-freedom are presented along with the influence and compensation of crosstalk motions in roll and straightness measurements. Several comparison experiments are conducted to investigate the feasibility and performance of the proposed system in each degree-of-freedom independently. Comparison experiments to a commercial interferometer demonstrate error standard deviations of 0.33 μm in straightness, 0.14 μrad in pitch, 0.44 μradin yaw, and 45.8 μrad in roll.

Development of a compact, fiber-coupled, six degree-of-freedom measurement system for precision linear stage metrology

Energy Technology Data Exchange (ETDEWEB)

Yu, Xiangzhi, E-mail: xiangzhi.yu@rochester.edu; Gillmer, Steven R. [Department of Mechanical Engineering, University of Rochester, Rochester, New York 14627 (United States); Woody, Shane C. [InSituTec Incorporated, 7140 Weddington Road, Concord, North Carolina 28027 (United States); Ellis, Jonathan D. [Department of Mechanical Engineering, University of Rochester, Rochester, New York 14627 (United States); The Institute of Optics, University of Rochester, Rochester, New York 14627 (United States)

2016-06-15

A compact, fiber-coupled, six degree-of-freedom measurement system which enables fast, accurate calibration, and error mapping of precision linear stages is presented. The novel design has the advantages of simplicity, compactness, and relatively low cost. This proposed sensor can simultaneously measure displacement, two straightness errors, and changes in pitch, yaw, and roll using a single optical beam traveling between the measurement system and a small target. The optical configuration of the system and the working principle for all degrees-of-freedom are presented along with the influence and compensation of crosstalk motions in roll and straightness measurements. Several comparison experiments are conducted to investigate the feasibility and performance of the proposed system in each degree-of-freedom independently. Comparison experiments to a commercial interferometer demonstrate error standard deviations of 0.33 μm in straightness, 0.14 μrad in pitch, 0.44 μradin yaw, and 45.8 μrad in roll.

The refractive index of curved spacetime II: QED, Penrose limits and black holes

International Nuclear Information System (INIS)

Hollowood, Timothy J.; Shore, Graham M.; Stanley, Ross J.

2009-01-01

This work considers the way that quantum loop effects modify the propagation of light in curved space. The calculation of the refractive index for scalar QED is reviewed and then extended for the first time to QED with spinor particles in the loop. It is shown how, in both cases, the low frequency phase velocity can be greater than c, as found originally by Drummond and Hathrell, but causality is respected in the sense that retarded Green functions vanish outside the lightcone. A 'phenomenology' of the refractive index is then presented for black holes, FRW universes and gravitational waves. In some cases, some of the polarization states propagate with a refractive index having a negative imaginary part indicating a potential breakdown of the optical theorem in curved space and possible instabilities.

Strong/weak coupling duality relations for non-supersymmetric string theories

International Nuclear Information System (INIS)

Blum, J.D.; Dienes, K.R.

1998-01-01

Both the supersymmetric SO(32) and E 8 x E 8 heterotic strings in ten dimensions have known strong-coupling duals. However, it has not been known whether there also exist strong-coupling duals for the non-supersymmetric heterotic strings in ten dimensions. In this paper, we construct explicit open-string duals for the circle compactifications of several of these non-supersymmetric theories, among them the tachyon-free SO(16) x SO(16) string. Our method involves the construction of heterotic and open-string interpolating models that continuously connect non-supersymmetric strings to supersymmetric strings. We find that our non-supersymmetric dual theories have exactly the same massless spectra as their heterotic counterparts within a certain range of our interpolations. We also develop a novel method for analyzing the solitons of non-supersymmetric open-string theories, and find that the solitons of our dual theories also agree with their heterotic counterparts. These are therefore the first known examples of strong/weak coupling duality relations between non-supersymmetric, tachyon-free string theories. Finally, the existence of these strong-coupling duals allows us to examine the non-perturbative stability of these strings, and we propose a phase diagram for the behavior of these strings as a function of coupling and radius. (orig.)

Correlating non-linear properties with spectral states of RXTE data: possible observational evidences for four different accretion modes around compact objects

Science.gov (United States)

Adegoke, Oluwashina; Dhang, Prasun; Mukhopadhyay, Banibrata; Ramadevi, M. C.; Bhattacharya, Debbijoy

2018-05-01

By analysing the time series of RXTE/PCA data, the non-linear variabilities of compact sources have been repeatedly established. Depending on the variation in temporal classes, compact sources exhibit different non-linear features. Sometimes they show low correlation/fractal dimension, but in other classes or intervals of time they exhibit stochastic nature. This could be because the accretion flow around a compact object is a non-linear general relativistic system involving magnetohydrodynamics. However, the more conventional way of addressing a compact source is the analysis of its spectral state. Therefore, the question arises: What is the connection of non-linearity to the underlying spectral properties of the flow when the non-linear properties are related to the associated transport mechanisms describing the geometry of the flow? This work is aimed at addressing this question. Based on the connection between observed spectral and non-linear (time series) properties of two X-ray binaries: GRS 1915+105 and Sco X-1, we attempt to diagnose the underlying accretion modes of the sources in terms of known accretion classes, namely, Keplerian disc, slim disc, advection dominated accretion flow and general advective accretion flow. We explore the possible transition of the sources from one accretion mode to others with time. We further argue that the accretion rate must play an important role in transition between these modes.

Inflation with non-minimal coupling. Metric vs. Palatini formulations

International Nuclear Information System (INIS)

Bauer, F.; Demir, D.A.; Izmir Institute of Technology

2008-03-01

We analyze non-minimally coupled scalar field theories in metric (second-order) and Palatini (first-order) formalisms in a comparative fashion. After contrasting them in a general setup, we specialize to inflation and find that the two formalisms differ in their predictions for various cosmological parameters. The main reason is that dependencies on the non-minimal coupling parameter are different in the two formalisms. For successful inflation, the Palatini approach prefers a much larger value for the non-minimal coupling parameter than the Metric approach. Unlike the Metric formalism, in Palatini, the inflaton stays well below the Planck scale whereby providing a natural inflationary epoch. (orig.)

Non-CMC Solutions of the Einstein Constraint Equations on Compact Manifolds with Apparent Horizon Boundaries

Science.gov (United States)

Holst, Michael; Meier, Caleb; Tsogtgerel, G.

2018-01-01

In this article we continue our effort to do a systematic development of the solution theory for conformal formulations of the Einstein constraint equations on compact manifolds with boundary. By building in a natural way on our recent work in Holst and Tsogtgerel (Class Quantum Gravity 30:205011, 2013), and Holst et al. (Phys Rev Lett 100(16):161101, 2008, Commun Math Phys 288(2):547-613, 2009), and also on the work of Maxwell (J Hyperbolic Differ Eqs 2(2):521-546, 2005a, Commun Math Phys 253(3):561-583, 2005b, Math Res Lett 16(4):627-645, 2009) and Dain (Class Quantum Gravity 21(2):555-573, 2004), under reasonable assumptions on the data we prove existence of both near- and far-from-constant mean curvature (CMC) solutions for a class of Robin boundary conditions commonly used in the literature for modeling black holes, with a third existence result for CMC appearing as a special case. Dain and Maxwell addressed initial data engineering for space-times that evolve to contain black holes, determining solutions to the conformal formulation on an asymptotically Euclidean manifold in the CMC setting, with interior boundary conditions representing excised interior black hole regions. Holst and Tsogtgerel compiled the interior boundary results covered by Dain and Maxwell, and then developed general interior conditions to model the apparent horizon boundary conditions of Dainand Maxwell for compact manifolds with boundary, and subsequently proved existence of solutions to the Lichnerowicz equation on compact manifolds with such boundary conditions. This paper picks up where Holst and Tsogtgerel left off, addressing the general non-CMC case for compact manifolds with boundary. As in our previous articles, our focus here is again on low regularity data and on the interaction between different types of boundary conditions. While our work here serves primarily to extend the solution theory for the compact with boundary case, we also develop several technical tools that have

QED radiative corrections to impact factors

International Nuclear Information System (INIS)

Kuraev, E.A.; Lipatov, L.N.; Shishkina, T.V.

2001-01-01

We consider radiative corrections to the electron and photon impact factors. The generalized eikonal representation for the e + e - scattering amplitude at high energies and fixed momentum transfers is violated by nonplanar diagrams. An additional contribution to the two-loop approximation appears from the Bethe-Heitler mechanism of fermion pair production with the identity of the fermions in the final state taken into account. The violation of the generalized eikonal representation is also related to the charge parity conservation in QED. A one-loop correction to the photon impact factor for small virtualities of the exchanged photon is obtained using the known results for the cross section of the e + e - production during photon-nuclei interactions

Leading order finite size effects with spins for inspiralling compact binaries

Energy Technology Data Exchange (ETDEWEB)

Levi, Michele [Université Pierre et Marie Curie-Paris VI, CNRS-UMR 7095, Institut d’Astrophysique de Paris, 98 bis Boulevard Arago, 75014 Paris (France); Sorbonne Universités, Institut Lagrange de Paris, 98 bis Boulevard Arago, 75014 Paris (France); Steinhoff, Jan [Max-Planck-Institute for Gravitational Physics - Albert-Einstein-Institute,Am Mühlenberg 1, 14476 Potsdam-Golm (Germany); Centro Multidisciplinar de Astrofisica, Instituto Superior Tecnico, Universidade de Lisboa,Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal)

2015-06-10

The leading order finite size effects due to spin, namely that of the cubic and quartic in spin interactions, are derived for the first time for generic compact binaries via the effective field theory for gravitating spinning objects. These corrections enter at the third and a half and fourth post-Newtonian orders, respectively, for rapidly rotating compact objects. Hence, we complete the leading order finite size effects with spin up to the fourth post-Newtonian accuracy. We arrive at this by augmenting the point particle effective action with new higher dimensional nonminimal coupling worldline operators, involving higher-order derivatives of the gravitational field, and introducing new Wilson coefficients, corresponding to constants, which describe the octupole and hexadecapole deformations of the object due to spin. These Wilson coefficients are fixed to unity in the black hole case. The nonminimal coupling worldline operators enter the action with the electric and magnetic components of the Weyl tensor of even and odd parity, coupled to even and odd worldline spin tensors, respectively. Moreover, the non relativistic gravitational field decomposition, which we employ, demonstrates a coupling hierarchy of the gravito-magnetic vector and the Newtonian scalar, to the odd and even in spin operators, respectively, which extends that of minimal coupling. This observation is useful for the construction of the Feynman diagrams, and provides an instructive analogy between the leading order spin-orbit and cubic in spin interactions, and between the leading order quadratic and quartic in spin interactions.

Perturbative Critical Behavior from Spacetime Dependent Couplings

International Nuclear Information System (INIS)

Torroba, Gonzalo

2012-01-01

We find novel perturbative fixed points by introducing mildly spacetime-dependent couplings into otherwise marginal terms. In four-dimensional QFT, these are physical analogues of the small-ε Wilson-Fisher fixed point. Rather than considering 4-ε dimensions, we stay in four dimensions but introduce couplings whose leading spacetime dependence is of the form λx κ μ κ , with a small parameter κ playing a role analogous to ε. We show, in φ 4 theory and in QED and QCD with massless flavors, that this leads to a critical theory under perturbative control over an exponentially wide window of spacetime positions x. The exact fixed point coupling λ * (x) in our theory is identical to the running coupling of the translationally invariant theory, with the scale replaced by 1/x. Similar statements hold for three-dimensional φ 6 theories and two-dimensional sigma models with curved target spaces. We also describe strongly coupled examples using conformal perturbation theory.

Geometrical Aspects During Formation of Compact Aggregates of Red Blood Cells

Directory of Open Access Journals (Sweden)

Cardoso A.V.

2002-01-01

Full Text Available In the past forty years considerable progress has been achieved on the knowledge of human blood as a non-Newtonian shear-thinning suspension, whose initial state, that is at rest (stasis or at very low shear rates, has a gel-like internal structure which is destroyed as shear stress increases. The main goal of this communication is to describe the role of geometrical aspects during RBC (red blood cell aggregate formation, growth and compaction on naturally aggregate (porcine blood and non-aggregate (bovine blood samples. We consider how these aspects coupled with tension equilibrium are decisive to transform red cell linear roleaux to three-dimensional aggregates or clusters. Geometrical aspects are also crucial on the compaction of red blood cell aggregates. These densely packed aggregates could precipitate out of blood- either as dangerous deposits on arterial walls, or as clots which travel in suspension until they block some crucial capillary.

Generalized bi-quasi-variational inequalities for quasi-semi-monotone and bi-quasi-semi-monotone operators with applications in non-compact settings and minimization problems

Directory of Open Access Journals (Sweden)

Chowdhury Molhammad SR

2000-01-01

Full Text Available Results are obtained on existence theorems of generalized bi-quasi-variational inequalities for quasi-semi-monotone and bi-quasi-semi-monotone operators in both compact and non-compact settings. We shall use the concept of escaping sequences introduced by Border (Fixed Point Theorem with Applications to Economics and Game Theory, Cambridge University Press, Cambridge, 1985 to obtain results in non-compact settings. Existence theorems on non-compact generalized bi-complementarity problems for quasi-semi-monotone and bi-quasi-semi-monotone operators are also obtained. Moreover, as applications of some results of this paper on generalized bi-quasi-variational inequalities, we shall obtain existence of solutions for some kind of minimization problems with quasi- semi-monotone and bi-quasi-semi-monotone operators.

Laser emission in Nd3+ doped barium–titanium–silicate microspheres under continuous and chopped wave pumping in a non-coupled pumping scheme

International Nuclear Information System (INIS)

Martín, L L; Pérez-Rodríguez, C; Martín, I R; Navarro-Urrios, D; Ferrarese-Lupi, F; Garrido, B; Montserrat, J; Dominguez, C; Capuj, N

2013-01-01

Laser action using non-coupled excitation and detection of microspheres made of Nd 3+ doped barium–titanium–silicate glass has been demonstrated and measured. The microspheres have also been successfully deposited over Si 3 N 4 strip waveguides with a SiO 2 separation layer, thus enabling the laser emission extraction onto a CMOS compatible photonic circuit. The dynamics of the lasing wavelength and intensity has been studied as a function of the pump power and interpreted in terms of thermal effects generated through non-radiative recombination of the excited ions. (paper)

QED in d=3 from the epsilon-expansion.

CERN Multimedia

CERN. Geneva

2015-01-01

In my talk, based on the recent work 1508.06278, I will consider the Renormalization Group flow of Quantum Electrodynamics in d=3 coupled to N_f flavors of fermions. For N_f smaller than a critical value N_f^c, chiral symmetry breaking is believed to take place. For N_f > N_f^c, the theory flows to an interacting fixed point that can be studied in the epsilon-expansion, using the fixed point in d=4-2\\epsilon. I will discuss the computation of the anomalous dimensions of fermion bilinears and quadrilinear operators, as well as some more conceptual aspects concerning the enhancement of global symmetries in d=3. For small N_f, a quadrilinear operator can become relevant in the IR and destabilize the fixed point. Therefore, the epsilon-expansion can be used to estimate N_f^c.

One-step generation of continuous-variable quadripartite cluster states in a circuit QED system

Science.gov (United States)

Yang, Zhi-peng; Li, Zhen; Ma, Sheng-li; Li, Fu-li

2017-07-01

We propose a dissipative scheme for one-step generation of continuous-variable quadripartite cluster states in a circuit QED setup consisting of four superconducting coplanar waveguide resonators and a gap-tunable superconducting flux qubit. With external driving fields to adjust the desired qubit-resonator and resonator-resonator interactions, we show that continuous-variable quadripartite cluster states of the four resonators can be generated with the assistance of energy relaxation of the qubit. By comparison with the previous proposals, the distinct advantage of our scheme is that only one step of quantum operation is needed to realize the quantum state engineering. This makes our scheme simpler and more feasible in experiment. Our result may have useful application for implementing quantum computation in solid-state circuit QED systems.

On the nucleon-nucleon potential obtained from non-linear coupling

International Nuclear Information System (INIS)

El Ghabaty, S.S.

1975-07-01

The static limit of a pseudoscalar symmetric meson theory of nuclear forces is examined. The Born-Oppenheimer potential is determined for the case of two very heavy nucleons exchanging pseudoscalar isovector pions with non-linear coupling. It is found that the non-linear terms induced by the γ 5 coupling are cancelled by the additional pion-nucleon coupling of the non-linear sigma model. The nucleon-nucleon potential thus obtained is the same as the Yukava potential except for strength at different separations between the two nucleons

Electron Microscopic Examination of Irradiated TRISO Coated Particles of Compact 6-3-2 of AGR-1 Experiment

Energy Technology Data Exchange (ETDEWEB)

Van Rooyen, Isabella Johanna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Demkowicz, Paul Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States); Riesterer, Jessica Lori [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, Brandon Douglas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Janney, Dawn Elizabeth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ploger, Scott Arden [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2012-12-01

The electron microscopic examination of selected irradiated TRISO coated particles of the AGR-1 experiment of fuel compact 6-3-2 are presented in this report. Compact 6-3-2 refers to the compact in Capsule 6 at level 3 of Stack 2. The fuel used in capsule 6 compacts, are called the “baseline” fuel as it is fabricated with refined coating process conditions used to fabricate historic German fuel, because of its excellent irradiation performance with UO2 kernels. The AGR-1 fuel is however made of low-enriched uranium oxycarbide (UCO). Kernel diameters are approximately 350 µm with a U-235 enrichment of approximately 19.7%. Compact 6-3-2 has been irradiated to 11.3% FIMA compact average burn-up with a time average, volume average temperature of 1070.2°C and with a compact average fast fluence of 2.38E21 n/cm

Electron Microscopic Examination of Irradiated TRISO Coated Particles of Compact 6-3-2 of AGR-1 Experiment

Energy Technology Data Exchange (ETDEWEB)

Van Rooyen, Isabella Johanna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Demkowicz, Paul Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States); Riesterer, Jessica Lori [Idaho National Lab. (INL), Idaho Falls, ID (United States); Miller, Brandon Douglas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Janney, Dawn Elizabeth [Idaho National Lab. (INL), Idaho Falls, ID (United States); Harp, Jason Michael [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ploger, Scott Arden [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2012-12-01

The electron microscopic examination of selected irradiated TRISO coated particles of the AGR-1 experiment of fuel compact 6-3-2 are presented in this report. Compact 6-3-2 refers to the compact in Capsule 6 at level 3 of Stack 2. The fuel used in capsule 6 compacts, are called the “baseline” fuel as it is fabricated with refined coating process conditions used to fabricate historic German fuel, because of its excellent irradiation performance with UO₂ kernels. The AGR-1 fuel is however made of low-enriched uranium oxycarbide (UCO). Kernel diameters are approximately 350 µm with a U-235 enrichment of approximately 19.7%. Compact 6-3-2 has been irradiated to 11.3% FIMA compact average burn-up with a time average, volume average temperature of 1070.2°C and with a compact average fast fluence of 2.38E21 n/cm

Evaluation of Air Coupled Ultrasound for Composite Aerospace Structure

Science.gov (United States)

Tat, H.; Georgeson, G.; Bossi, R.

2009-03-01

Non-contact air coupled ultrasound suffers from the high acoustic impedance mismatch characteristics of air to solid interfaces. Advances in transducer technology, particularly MEMS, have improved the acoustic impedance match at the transmission stage and the signal to noise at the reception stage. Comparisons of through transmission (TTU) scanning of laminate and honeycomb test samples using conventional piezoelectric air coupled transducers, new MEMS air coupled transducers, and standard water coupled inspections have been performed to assess the capability. An additional issue for air coupled UT inspection is the need for a lean implementation for both manufacturing and in-service operations. Concepts and applications utilizing magnetic coupling of transducers have been developed that allows air coupled inspection operations in compact low cost configurations.

Development of compact Compton camera for 3D image reconstruction of radioactive contamination

Science.gov (United States)

Sato, Y.; Terasaka, Y.; Ozawa, S.; Nakamura Miyamura, H.; Kaburagi, M.; Tanifuji, Y.; Kawabata, K.; Torii, T.

2017-11-01

The Fukushima Daiichi Nuclear Power Station (FDNPS), operated by Tokyo Electric Power Company Holdings, Inc., went into meltdown after the large tsunami caused by the Great East Japan Earthquake of March 11, 2011. Very large amounts of radionuclides were released from the damaged plant. Radiation distribution measurements inside FDNPS buildings are indispensable to execute decommissioning tasks in the reactor buildings. We have developed a compact Compton camera to measure the distribution of radioactive contamination inside the FDNPS buildings three-dimensionally (3D). The total weight of the Compton camera is lower than 1.0 kg. The gamma-ray sensor of the Compton camera employs Ce-doped GAGG (Gd3Al2Ga3O12) scintillators coupled with a multi-pixel photon counter. Angular correction of the detection efficiency of the Compton camera was conducted. Moreover, we developed a 3D back-projection method using the multi-angle data measured with the Compton camera. We successfully observed 3D radiation images resulting from the two 137Cs radioactive sources, and the image of the 9.2 MBq source appeared stronger than that of the 2.7 MBq source.

Effects of the fermionic vacuum polarization in QED

Energy Technology Data Exchange (ETDEWEB)

Medeiros, M.F.X.P.; Barone, F.A. [IFQ-Universidade Federal de Itajuba, Itajuba, MG (Brazil); Barone, F.E.

2018-01-15

Some effects of vacuum polarization in QED due to the presence of field sources are investigated. We focus on effects with no counter-part in Maxwell electrodynamics. The Uehling interaction energy between two stationary point-like charges is calculated exactly in terms of Meijer-G functions. Effects induced on a hydrogen atom by the vacuum polarization in the vicinity of a Dirac string are considered. We also calculate the interaction between two parallel Dirac strings and corrections to the energy levels of a quantum particle constrained to move on a ring circumventing a solenoid. (orig.)

Dynamical breakdown of chiral symmetry in vectorial theories: QED and QCD

International Nuclear Information System (INIS)

Garcia, J.C.M.

1987-01-01

Using a variational approach for the Effective Potential for composite operators we dicuss the dynamical breakdown of chiral symmetry in two vectorial theories: Quantum Electrodynamics (QED) and Quantum Chromodynamics (QCD). We study the energetic aspects of the problem calculating the Effective Potential with the asymptotic nonperturbative solutions of the Schwinger-Dyson equation for the fermion selfenergy. (author) [pt

QED polarization asymmetries for e+e- scattering due to helicity flips

International Nuclear Information System (INIS)

Anders, T.B.; Sell, E.W.

1992-01-01

The polarization asymmetries for the e + e - scattering with polarized incoming of outgoing beams, which are proportional to the amplitudes φ 5 describing one helicity flip and φ 2 describing two helicity flips, have been calculated including their pure QED radiative corrections. These asymmetries are partly large and can be observed well at low energies. (orig.)

Non-contact optoacoustic imaging with focused air-coupled transducers

Energy Technology Data Exchange (ETDEWEB)

Deán-Ben, X. Luís [Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg (Germany); Pang, Genny A.; Razansky, Daniel, E-mail: dr@tum.de [Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg (Germany); School of Medicine, Technische Universität München (TUM), Munich (Germany); Montero de Espinosa, Francisco [CSIC, Institute of Physics and Communication Technologies, Madrid (Spain)

2015-08-03

Non-contact optoacoustic imaging employing raster-scanning of a spherically focused air-coupled ultrasound transducer is showcased herein. Optoacoustic excitation with laser fluence within the maximal permissible human exposure limits in the visible and near-infrared spectra is applied to objects with characteristic dimensions smaller than 1 mm and absorption properties representative of the whole blood at near-infrared wavelengths, and these signals are shown to be detectable without contact to the sample using an air-coupled transducer with reasonable signal averaging. Optoacoustic images of vessel-mimicking tubes embedded in an agar phantom captured with this non-contact sensing technique are also showcased. These initial results indicate that an air-coupled ultrasound detection approach can be suitable for non-contact biomedical imaging with optoacoustics.

QED's School Market Trends: Teacher Buying Behavior & Attitudes, 2001-2002. Research Report.

Science.gov (United States)

Quality Education Data, Inc., Denver, CO.

This study examined teachers' classroom material buying behaviors and trends. Data came from Quality Education Data's National Education Database, which includes U.S. K-12 public, private, and Catholic schools and districts. Researchers surveyed K-8 teachers randomly selected from QED's National Education Database. Results show that teachers spend…

Preparation of genuine Yeo-Chua entangled state and teleportation of two-atom state via cavity QED

Institute of Scientific and Technical Information of China (English)

无

2010-01-01

We first propose a scheme for preparing the genuine Yeo-Chua 4-qubit entangled state via cavity QED. Using the genuine Yeo-Chua atomic state, we further propose a cavity QED scheme for teleporting an arbitrary two-atom state. In two schemes the large-detuning is chosen and the necessary time is designed to be much shorter than Rydberg-atom’s lifespan. Both schemes share the distinct advantage that cavity decay and atom decay can be neglected. As for the interaction manipulation, our preparation scheme is more feasible than a recent similar one. Compared with the Yeo and Chua’s scheme, our teleportation scheme has significantly reduced the measuring difficulty.

Gravity- and non-gravity-mediated couplings in multiple-field inflation

International Nuclear Information System (INIS)

Bernardeau, Francis

2010-01-01

Mechanisms for the generation of primordial non-Gaussian metric fluctuations in the context of multiple-field inflation are reviewed. As long as kinetic terms remain canonical, it appears that nonlinear couplings inducing non-Gaussianities can be split into two types. The extension of the one-field results to multiple degrees of freedom leads to gravity-mediated couplings that are ubiquitous but generally modest. Multiple-field inflation offers however the possibility of generating non-gravity-mediated coupling in isocurvature directions that can eventually induce large non-Gaussianities in the metric fluctuations. The robustness of the predictions of such models is eventually examined in view of a case study derived from a high-energy physics construction.

Quantum chaos and chiral symmetry at the QCD and QED phase transition

International Nuclear Information System (INIS)

Bittner, Elmar; Markum, Harald; Pullirsch, Rainer

2001-01-01

We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3) gauge theory and in full QCD as well as in quenched U(1) theory. As a measure of the fluctuation properties of the eigenvalues, we consider the nearest-neighbor spacing distribution. We find that in all regions of their phase diagrams, compact lattice gauge theories have bulk spectral correlations given by random matrix theory, which is an indication for quantum chaos. In the confinement phase, the low-lying Dirac spectrum of these quantum field theories is well described by random matrix theory, exhibiting universal behavior. Related results for gauge theories with minimal coupling are now discussed also in the chirally symmetric phase

Topological strings on compact Calabi-Yau's

Energy Technology Data Exchange (ETDEWEB)

Hollands, Lotte, E-mail: lhollands@science.uva.nl

2007-09-15

Some steps towards solving topological string amplitudes on Calabi-Yau spaces have been taken lately: all-genus amplitudes have been computed for non-compact toric Calabi-Yau threefolds, local Riemann surfaces and K3-fibrations, while progression has been made for the Fermat quintic threefold. However, the building blocks of all-genus topological string amplitudes for general compact Calabi-Yau's remain unknown. We study some aspects of the underlying geometry and discuss difficulties.

Two-loop operator matrix elements for massive fermionic local twist-2 operators in QED

International Nuclear Information System (INIS)

Bluemlein, J.; Freitas, A. de; Universidad Simon Bolivar, Caracas; Neerven, W.L. van

2011-11-01

We describe the calculation of the two--loop massive operator matrix elements with massive external fermions in QED. We investigate the factorization of the O(α 2 ) initial state corrections to e + e - annihilation into a virtual boson for large cms energies s >>m 2 e into massive operator matrix elements and the massless Wilson coefficients of the Drell-Yan process adapting the color coefficients to the case of QED, as proposed by F. A. Berends et. al. (Nucl. Phys. B 297 (1988)429). Our calculations show explicitly that the representation proposed there works at one-loop order and up to terms linear in ln (s/m 2 e ) at two-loop order. However, the two-loop constant part contains a few structural terms, which have not been obtained in previous direct calculations. (orig.)

A coupled THMC model of a heating and hydration laboratory experiment in unsaturated compacted FEBEX bentonite

Energy Technology Data Exchange (ETDEWEB)

Zheng, L.; Samper, J.; Montenegro, L.; Fernandez, A.M.

2010-05-01

Unsaturated compacted bentonite is foreseen by several countries as a backfill and sealing material in high-level radioactive waste repositories. The strong interplays between thermal (T), hydrodynamic (H), mechanical (M) and chemical (C) processes during the hydration stage of a repository call for fully coupled THMC models. Validation of such THMC models is prevented by the lack of comprehensive THMC experiments and the difficulties of experimental methods to measure accurately the chemical composition of bentonite porewater. We present here a non-isothermal multiphase flow and multicomponent reactive solute transport model for a deformable medium of a heating and hydration experiment performed on a sample of compacted FEBEX bentonite. Besides standard solute transport and geochemical processes, the model accounts for solute cross diffusion and thermal and chemical osmosis. Bentonite swelling is solved with a state-surface approach. The THM model is calibrated with transient temperature, water content and porosity data measured at the end of the experiment. The reactive transport model is calibrated with porewater chemical data derived from aqueous extract data. Model results confirm that thermal osmosis is relevant for the hydration of FEBEX bentonite while chemical osmosis can be safely neglected. Dilution and evaporation are the main processes controlling the concentration of conservative species. Dissolved cations are mostly affected by calcite dissolution-precipitation and cation exchange reactions. Dissolved sulphate is controlled by gypsum/anhydrite dissolution-precipitation. pH is mostly buffered by protonation/deprotonation via surface complexation. Computed concentrations agree well with inferred aqueous extract data at all sections except near the hydration boundary where cation data are affected by a sampling artifact. The fit of Cl{sup -} data is excellent except for the data near the heater. The largest deviations of the model from inferred aqueous

Vacuum fluctuations and topological Casimir effect in Friedmann-Robertson-Walker cosmologies with compact dimensions

International Nuclear Information System (INIS)

Saharian, A.A.; Mkhitaryan, A.L.

2010-01-01

We investigate the Wightman function, the vacuum expectation values of the field squared and the energy-momentum tensor for a massless scalar field with general curvature coupling parameter in spatially flat Friedmann-Robertson-Walker universes with an arbitrary number of toroidally compactified dimensions. The topological parts in the expectation values are explicitly extracted and in this way the renormalization is reduced to that for the model with trivial topology. In the limit when the comoving lengths of the compact dimensions are very short compared to the Hubble length, the topological parts coincide with those for a conformal coupling and they are related to the corresponding quantities in the flat spacetime by standard conformal transformation. This limit corresponds to the adiabatic approximation. In the opposite limit of large comoving lengths of the compact dimensions, in dependence of the curvature coupling parameter, two regimes are realized with monotonic or oscillatory behavior of the vacuum expectation values. In the monotonic regime and for non-conformally and non-minimally coupled fields the vacuum stresses are isotropic and the equation of state for the topological parts in the energy density and pressures is of barotropic type. For conformal and minimal couplings the leading terms in the corresponding asymptotic expansions vanish and the vacuum stresses, in general, are anisotropic, though the equation of state remains of barotropic type. In the oscillatory regime, the amplitude of the oscillations for the topological part in the expectation value of the field squared can be either decreasing or increasing with time, whereas for the energy-momentum tensor the oscillations are damping. The limits of validity of the adiabatic approximation are discussed. (orig.)

New Evidence for a Black Hole in the Compact Binary Cygnus X-3

Science.gov (United States)

Shrader, Chris R.; Titarchuk, Lev; Shaposhnikov, Nikolai

2010-01-01

The bright and highly variable X-ray and radio source known as Cygnus X-3 was among the first X-ray sources discovered, yet it remains in many ways an enigma. Its known to consist of a massive. Wolf-Rayet primary in an extremely tight orbit with a compact object. Yet one of the most basic of pa.ranietern the mass of the compact object - is not known. Nor is it even clear whether its is a neutron star or a black hole. In this Paper we present our analysis of the broad-band high-energy continua covering a substantial range in luminosity and spectral morphology. We apply these results to a recently identified scaling relationship which has been demonstrated to provide reliable estimates of the compact object mass in a number of accretion powered binaries. This analysis leads us to conclude that the compact object in Cygnus X-3 has a mass greater than 4.2 solar mass thus clearly indicative of a black hole and as such resolving a longstanding issue. The full range of uncertainty in our analysis and from using a. range of recently published distance estimates constrains the compact object mass to lie between 4.2 solar mass and 14.4 solar mass. Our favored estimate, based on a 9.0 kpc distance estimate is approx. l0 solar mass, with the. error margin of 3.2 solar masses. This result may thus pose challenges to shared-envelope evolutionary models of compact binaries. as well as establishing Cygnus X-3 as the first confirmed accretion-powered galactic gamma: ray source.

Measurement of the Proton Structure Function $F_{2}$ at low $Q^{2}$ in QED Compton Scattering at HERA

CERN Document Server

Aktas, A.; Anthonis, T.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brisson, V.; Broker, H.-B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; Collard, C.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garutti, E.; Garvey, J.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Grassler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Heuer, R.-D.; Hildebrandt, M.; Hiller, K.H.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Koblitz, B.; Korbel, V.; Kostka, P.; Koutouev, R.; Kropivnitskaya, A.; Kroseberg, J.; Kuckens, J.; Kuhr, T.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michine, S.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morozov, I.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Ossoskov, G.; Ozerov, D.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Poschl, R.; Portheault, B.; Povh, B.; Raicevic, N.; Ratiani, Z.; Reimer, P.; Reisert, B.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.-P.; Schleper, P.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Winter, G.-G.; Wissing, Ch.; Woehrling, E.-E.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

2004-01-01

The proton structure function F_2(x,Q^2) is measured in inelastic QED Compton scattering using data collected with the H1 detector at HERA. QED Compton events are used to access the kinematic range of very low virtualities of the exchanged photon, Q^2, down to 0.5 GeV^2, and Bjorken x up to \\sim 0.06, a region which has not been covered previously by inclusive measurements at HERA. The results are in agreement with the measurements from fixed target lepton-nucleon scattering experiments.

Constraining non-minimally coupled tachyon fields by the Noether symmetry

International Nuclear Information System (INIS)

De Souza, Rudinei C; Kremer, Gilberto M

2009-01-01

A model for a homogeneous and isotropic Universe whose gravitational sources are a pressureless matter field and a tachyon field non-minimally coupled to the gravitational field is analyzed. The Noether symmetry is used to find expressions for the potential density and for the coupling function, and it is shown that both must be exponential functions of the tachyon field. Two cosmological solutions are investigated: (i) for the early Universe whose only source of gravitational field is a non-minimally coupled tachyon field which behaves as an inflaton and leads to an exponential accelerated expansion and (ii) for the late Universe whose gravitational sources are a pressureless matter field and a non-minimally coupled tachyon field which plays the role of dark energy and is responsible for the decelerated-accelerated transition period.

On the non-minimal gravitational coupling to matter

International Nuclear Information System (INIS)

Bertolami, O; Paramos, J

2008-01-01

The connection between f(R) theories of gravity and scalar-tensor models with a 'physical' metric coupled to the scalar field is well known. In this work, we pursue the equivalence between a suitable scalar theory and a model that generalizes the f(R) scenario, encompassing both a non-minimal scalar curvature term and a non-minimum coupling of the scalar curvature and matter. This equivalence allows for the calculation of the PPN parameters β and γ and, eventually, a solution to the debate concerning the weak-field limit of f(R) theories

Overview on the anomaly and Schwinger term in two dimensional QED

International Nuclear Information System (INIS)

Adam, C.; Bertlmann, R.A.; Hofer, P.

1993-01-01

The axial anomaly of two-dimensional QED is computed in different ways (perturbative, via dispersion integrals, path integral and index theorem) and their relation is discussed as well as the relation between anomaly, Schwinger term and the Dirac vacuum. Some features of the special case of massless fermions (Schwinger model) and some methods of exactly solving it are demonstrated. (authors)

Temperature evolution during compaction of pharmaceutical powders.

Science.gov (United States)

Zavaliangos, Antonios; Galen, Steve; Cunningham, John; Winstead, Denita

2008-08-01

A numerical approach to the prediction of temperature evolution in tablet compaction is presented here. It is based on a coupled thermomechanical finite element analysis and a calibrated Drucker-Prager Cap model. This approach is capable of predicting transient temperatures during compaction, which cannot be assessed by experimental techniques due to inherent test limitations. Model predictions are validated with infrared (IR) temperature measurements of the top tablet surface after ejection and match well with experiments. The dependence of temperature fields on speed and degree of compaction are naturally captured. The estimated transient temperatures are maximum at the end of compaction at the center of the tablet and close to the die wall next to the powder/die interface.

Non-Weyl asymptotics for quantum graphs with general coupling conditions

International Nuclear Information System (INIS)

Davies, E Brian; Exner, Pavel; Lipovsky, JirI

2010-01-01

Inspired by a recent result of Davies and Pushnitski, we study resonance asymptotics of quantum graphs with general coupling conditions at the vertices. We derive a criterion for the asymptotics to be of a non-Weyl character. We show that for balanced vertices with permutation-invariant couplings the asymptotics is non-Weyl only in the case of Kirchhoff or anti-Kirchhoff conditions. While for graphs without permutation symmetry numerous examples of non-Weyl behaviour can be constructed. Furthermore, we present an insight into what makes the Kirchhoff/anti-Kirchhoff coupling particular from the resonance point of view. Finally, we demonstrate a generalization to quantum graphs with unequal edge weights.

Topological Symmetry, Spin Liquids and CFT Duals of Polyakov Model with Massless Fermions

Energy Technology Data Exchange (ETDEWEB)

Unsal, Mithat

2008-04-30

We prove the absence of a mass gap and confinement in the Polyakov model with massless complex fermions in any representation of the gauge group. A U(1){sub *} topological shift symmetry protects the masslessness of one dual photon. This symmetry emerges in the IR as a consequence of the Callias index theorem and abelian duality. For matter in the fundamental representation, the infrared limits of this class of theories interpolate between weakly and strongly coupled conformal field theory (CFT) depending on the number of flavors, and provide an infinite class of CFTs in d = 3 dimensions. The long distance physics of the model is same as certain stable spin liquids. Altering the topology of the adjoint Higgs field by turning it into a compact scalar does not change the long distance dynamics in perturbation theory, however, non-perturbative effects lead to a mass gap for the gauge fluctuations. This provides conceptual clarity to many subtle issues about compact QED{sub 3} discussed in the context of quantum magnets, spin liquids and phase fluctuation models in cuprate superconductors. These constructions also provide new insights into zero temperature gauge theory dynamics on R{sup 2,1} and R{sup 2,1} x S{sup 1}. The confined versus deconfined long distance dynamics is characterized by a discrete versus continuous topological symmetry.

Numerical and Experimental Study of an Ambient Air Vaporizer Coupled with a Compact Heat Exchanger

Science.gov (United States)

Kimura, Randon

The University of Washington was tasked with designing a "21st century engine" that will make use of the thermal energy available in cryogenic gasses due to their coldness. There are currently large quantities of cryogenic gases stored throughout the U.S. at industrial facilities whereupon the regasification process, the potential for the fluid to do work is wasted. The engine proposed by the University of Washington will try to capture some of that wasted energy. One technical challenge that must be overcome during the regasification process is providing frost free operation. This thesis presents the numerical analysis and experimental testing of a passive heat exchange system that uses ambient vaporizers coupled with compact heat exchangers to provide frost free operation while minimizing pressure drop.

On non-linear dynamics of a coupled electro-mechanical system

DEFF Research Database (Denmark)

Darula, Radoslav; Sorokin, Sergey

2012-01-01

Electro-mechanical devices are an example of coupled multi-disciplinary weakly non-linear systems. Dynamics of such systems is described in this paper by means of two mutually coupled differential equations. The first one, describing an electrical system, is of the first order and the second one...... excitation. The results are verified using a numerical model created in MATLAB Simulink environment. Effect of non-linear terms on dynamical response of the coupled system is investigated; the backbone and envelope curves are analyzed. The two phenomena, which exist in the electro-mechanical system: (a......, for mechanical system, is of the second order. The governing equations are coupled via linear and weakly non-linear terms. A classical perturbation method, a method of multiple scales, is used to find a steadystate response of the electro-mechanical system exposed to a harmonic close-resonance mechanical...

On a manifestation of the anomalies in the massless QED

International Nuclear Information System (INIS)

Gorskij, A.S.

1989-01-01

The questions concerned with the axial and conformal anomalies in the massless QED are discussed. It is shown that the interaction of the longitudinal real photons is proportional to the β function of the theory and the corresponding matrix element L |Θ αβ |γ L > where Θ αβ is energy-momentum tensor has a common features with the nonvanishing matrix element α |γ> in the massless limit. 7 refs.; 2 figs

Energy-momentum tensor in theories with scalar fields and two coupling constants. I. Non-Abelian case

International Nuclear Information System (INIS)

Joglekar, S.D.; Misra, A.

1989-01-01

In this paper, we generalize our earlier discussion of renormalization of the energy-momentum tensor in scalar QED to that in non-Abelian gauge theories involving scalar fields. We show the need for adding an improvement term to the conventional energy-momentum tensor. We consider two possible forms for the improvement term: (i) one in which the improvement coefficient is a finite function of bare parameters of the theory (so that the energy-momentum tensor can be derived from an action that is a finite function of bare quantities); (ii) one in which the improvement coefficient is a finite quantity, i.e., a finite function of renormalized parameters. We establish a negative result; viz., neither form leads to a finite energy-momentum tensor to O(e 2 λ/sup n/)

Dynamic compaction of Al2O3-ZrO2 compositions

International Nuclear Information System (INIS)

Tunaboylu, B.; McKittrick, J.; Nutt, S.R.

1994-01-01

Shock compaction of Al 2 O 3 -ZrO 2 binary and ternary powder compositions resulted in dense, one-piece samples without visible cracks for pressures ≤12.6 GPa. Dynamic pressures were achieved by using a 6.5-m-long two-state gas gun. It is believed that plastic deformation by dislocation slip of α-Al 2 O 3 partially accommodates the tensile stresses created during the release of shock pressures. A fine and narrow particle size distribution is necessary to achieve high bulk densities, but the bulk structural integrity was not strongly related to the distribution. A high-pressure phase of ZrO 2 , which was formed from the monoclinic polymorph, was found at and above shock pressure of 6.3 GPa. No evidence of the orthorhombic cotunnite structure was observed. Compaction of glassy and submicrocrystalline rapidly solidified starting materials showed good structural integrity, although the bulk density was relatively low. It is not clear what the densification/bonding mechanism is in these materials, although it appears not to be plastic deformation. Microstructural analysis showed that fine and uniform microstructures are retained after compaction at appropriate dynamic pressures for all compositions, with some interparticle cohesion present

Compact stars in alternative theories of gravity: Einstein-Dilaton-Gauss-Bonnet gravity

International Nuclear Information System (INIS)

Pani, Paolo; Berti, Emanuele; Cardoso, Vitor; Read, Jocelyn

2011-01-01

We develop a theoretical framework to study slowly rotating compact stars in a rather general class of alternative theories of gravity, with the ultimate goal of investigating constraints on alternative theories from electromagnetic and gravitational-wave observations of compact stars. Our Lagrangian includes as special cases scalar-tensor theories (and indirectly f(R) theories) as well as models with a scalar field coupled to quadratic curvature invariants. As a first application of the formalism, we discuss (for the first time in the literature) compact stars in Einstein-Dilaton-Gauss-Bonnet gravity. We show that compact objects with central densities typical of neutron stars cannot exist for certain values of the coupling constants of the theory. In fact, the existence and stability of compact stars sets more stringent constraints on the theory than the existence of black hole solutions. This work is a first step in a program to systematically rule out (possibly using Bayesian model selection) theories that are incompatible with astrophysical observations of compact stars.

Fried-Yennie gauge in dimensionally regularized QED

International Nuclear Information System (INIS)

Adkins, G.S.

1993-01-01

The Fried-Yennie gauge in QED is a covariant gauge with agreeable infrared properties. That is, the mass-shell renormalization scheme can be implemented without introducing artificial infrared divergences, and terms having spuriously low orders in α disappear in certain bound-state calculations. The photon propagator in the Fried-Yennie gauge has the form D β μν (k)=(-1/k 2 )[g μν +βk μ kν/k 2 ], where β is the gauge parameter. In this work, I show that the Fried-Yennie gauge parameter is β=2/(1-2ε) when dimensional regularization (with n=4-2ε dimensions of spacetime) is used to regulate the theory

Does soil compaction increase floods? A review

Science.gov (United States)

Alaoui, Abdallah; Rogger, Magdalena; Peth, Stephan; Blöschl, Günter

2018-02-01

Europe has experienced a series of major floods in the past years which suggests that flood magnitudes may have increased. Land degradation due to soil compaction from crop farming or grazing intensification is one of the potential drivers of this increase. A literature review suggests that most of the experimental evidence was generated at plot and hillslope scales. At larger scales, most studies are based on models. There are three ways in which soil compaction affects floods at the catchment scale: (i) through an increase in the area affected by soil compaction; (ii) by exacerbating the effects of changes in rainfall, especially for highly degraded soils; and (iii) when soil compaction coincides with soils characterized by a fine texture and a low infiltration capacity. We suggest that future research should focus on better synthesising past research on soil compaction and runoff, tailored field experiments to obtain a mechanistic understanding of the coupled mechanical and hydraulic processes, new mapping methods of soil compaction that combine mechanical and remote sensing approaches, and an effort to bridge all disciplines relevant to soil compaction effects on floods.

Diffusion through statically compacted clay

International Nuclear Information System (INIS)

Ho, C.L.; Shebl, M.A.A.

1994-01-01

This paper presents experimental work on the effect of compaction on contaminant flow through clay liners. The experimental program included evaluation of soil properties, compaction, permeability and solute diffusion. A permeameter was built of non reactive materials to test samples compacted at different water contents and compactive efforts. The flow of a permeating solute, LiCl, was monitored. Effluent samples were collected for solute concentration measurements. The concentrations were measured by performing atomic adsorption tests. The analyzed results showed different diffusion characteristics when compaction conditions changed. At each compactive effort, permeability decreased as molding water content increased. Consequently, transit time (measured at relative concentration 50%) increased and diffusivity decreased. As compactive effort increased for soils compacted dry of optimum, permeability and diffusion decreased. On the other hand, as compactive effort increased for soils compacted wet of optimum, permeability and diffusivity increased. Tortuosity factor was indirectly measured from the diffusion and retardation rate. Tortuosity factor also decreased as placement water content was increased from dry of optimum to wet of optimum. Then decreases were more pronounced for low compactive effort tests. 27 refs., 7 figs., 5 tabs

Extra force and extra mass from non-compact Kaluza-Klein theory in a cosmological model

International Nuclear Information System (INIS)

MadrizAguilar, J.E.; Bellini, M.

2005-01-01

Using the Hamilton-Jacobi formalism, we study extra force and extra mass in a recently introduced non-compact Kaluza-Klein cosmological model. We examine the inertial 4D mass m 0 of the inflaton field on a 4D FRW bulk in two examples. We find that m 0 has a geometrical origin and antigravitational effects on a non-inertial 4D bulk should be a consequence of the motion of the fifth coordinate with respect to the 4D bulk. (orig.)

Thermal evolution of compact stars

International Nuclear Information System (INIS)

Schaab, C.; Glendenning, N.K.

1996-01-01

A collection of modern, field-theoretical equations of state is applied to the investigation of cooling properties of compact stars. These comprise neutron stars as well as hypothetical strange-matter stars, made up of absolutely stable 3-flavor strange-quark matter. Various uncertainties in the behavior of matter at supernuclear densities, e.g., hyperonic degrees of freedom, behavior of coupling strengths in matter, pion and meson condensation, superfluidity, transition to quark matter, absolute stability of strange-quark matter, and last but not least the many-body technique itself are tested against the body of observed cooling data. (orig.)

Proof of the relativistic covariance of the fermion Green function in QED

International Nuclear Information System (INIS)

Nguyen Suan Han.

1995-02-01

This paper is devoted to the calculation of the fermion Green function in QED in the framework of the Minimal Quantization Method, based on an explicit solution of the constraint equations and the gauge-invariance principle. The relativistic invariant expression for the fermion Green function which has the right analytical properties is obtained. (author). 24 refs

Ultra-compact coherent receiver with serial interface for pluggable transceiver.

Science.gov (United States)

Itoh, Toshihiro; Nakajima, Fumito; Ohno, Tetsuichiro; Yamanaka, Shogo; Soma, Shunichi; Saida, Takashi; Nosaka, Hideyuki; Murata, Koichi

2014-09-22

An ultra-compact integrated coherent receiver with a volume of 1.3 cc using a quad-channel transimpedance amplifier (TIA)-IC chip with a serial peripheral interface (SPI) is demonstrated for the first time. The TIA with the SPI and photodiode (PD) bias circuits, a miniature dual polarization optical hybrid, an octal-PD and small optical coupling system enabled the realization of the compact receiver. Measured transmission performance with 32 Gbaud dual-polarization quadrature phase shift keying signal is equivalent to that of the conventional multi-source agreement-based integrated coherent receiver with dual channel TIA-ICs. By comparing the bit-error rate (BER) performance with that under continuous SPI access, we also confirmed that there is no BER degradation caused by SPI interface access. Such an ultra-compact receiver is promising for realizing a new generation of pluggable transceivers.

Cancellation of soft and collinear divergences in noncommutative QED

International Nuclear Information System (INIS)

Mirza, B.; Zarei, M.

2006-01-01

In this paper, we investigate the behavior of noncommutative IR divergences and will also discuss their cancellation in the physical cross sections. The commutative IR (soft) divergences existing in the nonplanar diagrams will be examined in order to prove an all-order cancellation of these divergences using the Weinberg's method. In noncommutative QED, collinear divergences due to triple photon splitting vertex, were encountered, which are shown to be canceled out by the noncommutative version of KLN theorem. This guarantees that there is no mixing between the Collinear, soft divergences and noncommutative IR divergences

Coding chaotic billiards: I-Non-Compact billiards on a negative curvature manifold

International Nuclear Information System (INIS)

Giannoni, M.J.; Ullmo, D.

1989-03-01

This paper presents a method for coding billiards. The main device is to use a proper surface of section, the bounce mapping, and foliate the reduced phase space into regions associated with a given code. The alphabet is merely the ensemble of the labels of the sides of the billiard. The procedure is applied here to non-compact polygonal billiard defined on a manifold of constant negative curvature, with all vertices at infinity. A simple grammar rule is necessary and sufficient to insure existence and uniqueness of the coding

Investigating non-Markovian dynamics of quantum open systems

Science.gov (United States)

Chen, Yusui

Quantum open system coupled to a non-Markovian environment has recently attracted widespread interest for its important applications in quantum information processing and quantum dissipative systems. New phenomena induced by the non-Markovian environment have been discovered in variety of research areas ranging from quantum optics, quantum decoherence to condensed matter physics. However, the study of the non-Markovian quantum open system is known a difficult problem due to its technical complexity in deriving the fundamental equation of motion and elusive conceptual issues involving non-equilibrium dynamics for a strong coupled environment. The main purpose of this thesis is to introduce several new techniques of solving the quantum open systems including a systematic approach to dealing with non-Markovian master equations from a generic quantum-state diffusion (QSD) equation. In the first part of this thesis, we briefly introduce the non-Markovian quantum-state diffusion approach, and illustrate some pronounced non-Markovian quantum effects through numerical investigation on a cavity-QED model. Then we extend the non-Markovian QSD theory to an interesting model where the environment has a hierarchical structure, and find out the exact non-Markovian QSD equation of this model system. We observe the generation of quantum entanglement due to the interplay between the non-Markovian environment and the cavity. In the second part, we show an innovative method to obtain the exact non-Markovian master equations for a set of generic quantum open systems based on the corresponding non-Markovian QSD equations. Multiple-qubit systems and multilevel systems are discussed in details as two typical examples. Particularly, we derive the exact master equation for a model consisting of a three-level atom coupled to an optical cavity and controlled by an external laser field. Additionally, we discuss in more general context the mathematical similarity between the multiple

The effect of native Al2O3 skin disruption on properties of fine Al powder compacts

International Nuclear Information System (INIS)

Balog, Martin; Poletti, Cecilia; Simancik, Frantisek; Walcher, Martin; Rajner, Walter

2011-01-01

Research highlights: → The effect of various powder metallurgy compaction routes on the microstructures and properties of ultra-fine atomized Al powder compacts. → Applied compaction route affects the deformation and fracture of native Al 2 O 3 layer present on the surface of as-atomized powder. → Distribution, morphology and interconnectivity of in situ introduced Al 2 O 3 dispersoids distinctly determine the compacts properties. - Abstract: In the presented study we characterize how various powder metallurgical routes (extrusion, forging, and HIP/sintering) affect the fracture of native Al 2 O 3 layer present on the surface of ultra-fine atomized Al powders. It is shown that the different distribution, morphology and interconnectivity of in situ introduced Al 2 O 3 dispersoids strongly affect the thermal stability and mechanical and thermal properties of subsequent powder compacts.

Slot-coupled CW standing wave accelerating cavity

Energy Technology Data Exchange (ETDEWEB)

Wang, Shaoheng; Rimmer, Robert; Wang, Haipeng

2017-05-16

A slot-coupled CW standing wave multi-cell accelerating cavity. To achieve high efficiency graded beta acceleration, each cell in the multi-cell cavity may include different cell lengths. Alternatively, to achieve high efficiency with acceleration for particles with beta equal to 1, each cell in the multi-cell cavity may include the same cell design. Coupling between the cells is achieved with a plurality of axially aligned kidney-shaped slots on the wall between cells. The slot-coupling method makes the design very compact. The shape of the cell, including the slots and the cone, are optimized to maximize the power efficiency and minimize the peak power density on the surface. The slots are non-resonant, thereby enabling shorter slots and less power loss.

Linear supermultiplets and non-holomorphic gauge coupling functions

International Nuclear Information System (INIS)

Binetruy, P.; Grimm, R.; Girardi, G.

1991-04-01

The general couplings of linear multiplets, including Chern-Simons forms, to chiral matter as well as to the standard supergravity-matter system are constructed. Insisting on a canonically normalised Einstein term in particular the appearance of non-holomorphic gauge couplings are discussed and duality transformations in full generality are performed. The implications of these structures for the effective description of sigma model anomalies are presented with and without coupling to supergravity, following recent proposals of Derendinger, Ferrara, Kounnas and Zwirner and of Cardoso and Ovrut. (author) 14 refs

Regression of non-linear coupling of noise in LIGO detectors

Science.gov (United States)

Da Silva Costa, C. F.; Billman, C.; Effler, A.; Klimenko, S.; Cheng, H.-P.

2018-03-01

In 2015, after their upgrade, the advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors started acquiring data. The effort to improve their sensitivity has never stopped since then. The goal to achieve design sensitivity is challenging. Environmental and instrumental noise couple to the detector output with different, linear and non-linear, coupling mechanisms. The noise regression method we use is based on the Wiener–Kolmogorov filter, which uses witness channels to make noise predictions. We present here how this method helped to determine complex non-linear noise couplings in the output mode cleaner and in the mirror suspension system of the LIGO detector.

Cardiac magnetic resonance imaging for evaluation of non-compaction cardiomyopathy in patients with or without left ventricular systolic dysfunction

International Nuclear Information System (INIS)

Deviggiano, A.; Deschle, H.; Lewkowicz, J.M.; Tajer, C.D.; Carrascosa, P.; Capunay, C.; Vallejos, J.; Stewart Harris, A.

2011-01-01

Background: Non-compaction cardiomyopathy (NCC) is a genetic disorder characterized by deep trabeculations in the ventricular wall, which define recesses communicating with the main ventricular chamber. The prevalence of NCC is greater in symptomatic populations with left ventricular dysfunction; yet, it may also be detected in asymptomatic patients with normal left ventricular function using novel diagnostic tools. However, this condition is under-diagnosed due to a low index of clinical suspicion and to the use of echocardiography classifications based on different diagnostic criteria. The use of cardiac magnetic resonance imaging (CMRI) has established two diagnostic criteria that clearly recognize this disease. Objective: To evaluate the clinical and morphological characteristics of patients with NCC with and without systolic dysfunction undergoing cardiac magnetic resonance imaging (CMRI). Material and Methods: A total of 20 patients with NCC were retrospectively included. The following parameters were determined: left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV); left ventricular end-diastolic diameter (LVEDD); left ventricular end-systolic diameter (LVESD); cardiac mass and left ventricular trabeculations. The distribution of NC myocardium was evaluated according to the model of 17 myocardial segments. Results: Mean myocardial thickness was 13.1 ± 3.3 mm and 3.6 ± 0.6 mm in NC versus normal myocardium, respectively. Patients with left ventricular dysfunction presented increased LVEDD, LVEDV, total cardiac mass, and LV non-compaction and trabeculations. We found a positive correlation and a linear relationship between LVEDD and TLVM (g/m 2 ): r=0.76; r 2 =0.59; p [es

Quantum networks in divergence-free circuit QED

Science.gov (United States)

Parra-Rodriguez, A.; Rico, E.; Solano, E.; Egusquiza, I. L.

2018-04-01

Superconducting circuits are one of the leading quantum platforms for quantum technologies. With growing system complexity, it is of crucial importance to develop scalable circuit models that contain the minimum information required to predict the behaviour of the physical system. Based on microwave engineering methods, divergent and non-divergent Hamiltonian models in circuit quantum electrodynamics have been proposed to explain the dynamics of superconducting quantum networks coupled to infinite-dimensional systems, such as transmission lines and general impedance environments. Here, we study systematically common linear coupling configurations between networks and infinite-dimensional systems. The main result is that the simple Lagrangian models for these configurations present an intrinsic natural length that provides a natural ultraviolet cutoff. This length is due to the unavoidable dressing of the environment modes by the network. In this manner, the coupling parameters between their components correctly manifest their natural decoupling at high frequencies. Furthermore, we show the requirements to correctly separate infinite-dimensional coupled systems in local bases. We also compare our analytical results with other analytical and approximate methods available in the literature. Finally, we propose several applications of these general methods to analogue quantum simulation of multi-spin-boson models in non-perturbative coupling regimes.

A Compact Multiband BPF Using Step-impedance Resonators with Interdigital Capacitors

Directory of Open Access Journals (Sweden)

S. Meesomklin

2016-06-01

Full Text Available A compact multiband band-pass filter design for applications of GSM, Wi-MAX and WLAN systems is presented. The design is based on the resonant characteristics of step-impedance and interdigital capacitor resonators with overlap cross coupling structure. The fabricated filter has been operated at the fundamental, first and second harmonic resonant frequencies of 1.8 GHz, 3.7 GHz, and 5.2 GHz, respectively. The experimental results of the fabricated filter agree very well with the simulation expectations using IE3D package. The proposed filter has good performances, while the resonator size can be reduced from λ/2 to λ/8, resulting in the most compact multiband band-pass filter compared with the others using transmission line resonators .

Compactibility of Al/Al2O3 Isotropic Composite with Variation of Holding Time Sintering.

Directory of Open Access Journals (Sweden)

Eddy S Siradj

2008-11-01

Full Text Available The requirement of component with structural ability, light weight and also strength is increasing base on Metal Matrix Composites (MMCs by aluminum as matrix (AMCs. A structural ability is connected to composites compactibility which is depend on quality of interfacial bounding. Powder metallurgy is one of method to produce composite with powder mixing, compacting and sintering. Volume fractions reinforced and sintering time can influence composites compactibility. Volume fractions reinforced variable can produce different reinforcement effect. Beside that, on sintering enables the formation of new phase during sintering time. In this research, Al/Al2O3 isotropic composites are made with aluminum as matrix and alumina (Al2O3 as reinforced. Volume fraction reinforced used 10%. 20%. 30% and 40%. Sintering temperature and compaction pressure are each 600oC and 15 kN. The tests that applied are compression and metallographic test. The result that obtained is optimum compactibility of Al/Al2O3 composite reached at holding time 2 hour. During sintering, new phase can occur that is aluminum oxides (alumina, with unstable properties. The best volume fraction reinforced and holding time sintering are 40% and 2 hours.

Tunable blue–violet Cr3+:LiCAF + BiBO compact laser

International Nuclear Information System (INIS)

Maestre, H; Torregrosa, A J; Capmany, J

2015-01-01

We present a compact continuous wave (CW) external-cavity tunable Cr 3+ :LiCaAlF 6 (Cr:LiCAF) laser which is intracavity frequency doubled using a BiB 3 O 6 (BiBO) nonlinear crystal to obtain tunable blue–violet radiation. The generated second harmonic (SH) can be tuned by means of either angular or temperature variation of the nonlinear crystal. We have obtained SH radiation between 390–415 nm and a maximum output power of 34 mW at 400 nm. Future improvements on the SH tuning range and output power are addressed in the text. Our results may be applied in the design of compact tunable composite external-cavity solid-state lasers. (paper)

Development of a compaction system for solid waste

International Nuclear Information System (INIS)

Nair, J.S.; Roy, P.R.

1990-01-01

The Bhabha Atomic Research Centre has set up a Beryllium Pilot Plant at Vashi, New Bombay, which is in operation for nearly a decade now. In view of the high toxicity of beryllium and its compounds, the plant has a specially designed ventilation system with a bank of pre and absolute HEPA filters to prevent the escape of any toxic material into the outside atmosphere. The filters are periodically replaced to maintain efficiency. The used filters are sealed in cardboard cartons and stored in RCC containers. In order to minimise the expenditure on waste disposal, a solid waste compaction system with suitable toolings has been designed and fabricated in the plant. The compaction trials carried out using this system on non-toxic HEPA filters have shown that a reduction by a factor of 3 could be achieved in the overall volume of the filter. It is interesting to note that the actual volume reduction is limited by spring-back effects of the filter media. The paper gives details of the compaction system and presents some of the important results obtained in the trials using non-toxic filters. Efforts are presently being made to incorporate pneumatically operated robot in the place of the existing electromechanical devices for compaction. (author). 2 refs., 6 tabs

Present status and prospect of the experimental study of QED in high Z ions

International Nuclear Information System (INIS)

Briand, J.P.

1993-01-01

I summarize in this paper the present status of our experimental knowledge on the Lamb shift of high Z hydrogenlike ions. Some tentative prospect on the future improvements with the new large accelerators and ion sources are discussed and compared with the present accuracy of QED corrections. (orig.)

Compact 84 GHz passive mode-locked fiber laser using dual-fiber coupled fused-quartz microresonator

Science.gov (United States)

Liu, Tze-An; Hsu, Yung; Chow, Chi-Wai; Chuang, Yi-Chen; Ting, Wei-Jo; Wang, Bo-Chun; Peng, Jin-Long; Chen, Guan-Hong; Chang, Yuan-Chia

2017-10-01

We propose and demonstrate a compact and portable-size 84-GHz passive mode-locked fiber laser, in which a dual-fiber coupled fused-quartz microresonator is employed as the intracavity optical comb filter as well as the optical nonlinear material for optical frequency comb generation. About eight coherent optical tones can be generated in the proposed fiber laser. The 20-dB bandwidth is larger than 588 GHz. The full-width half-maximum pulse-width of the proposed laser is 2.5 ps. We also demonstrate the feasibility of using the proposed passive mode-locked fiber laser to carry a 5-Gbit/s on-off-keying signal and transmit over 20-km standard single mode fiber. A 7% forward error correction requirement can be achieved, showing the proposed fiber laser can be a potential candidate for fiber-wireless applications.

Multiphoton production and tests of QED at LEP-II

International Nuclear Information System (INIS)

Winter, M.

2001-01-01

Data collected by the 4 LEP collaboration from 1995 to 2000 at collision energies ranging from 130 to 208 GeV were used to measure the cross-section of the process e + e - →γγ(γ). QED predictions for this reaction were tested with a few per-cent accuracy and manifestations of physics beyond the Standard Model (SM) were investigated. Preliminary lower bounds on the cut-off parameter Λ ± , the mass of an excited electron, the string mass scale underlying low-scale Quantum Gravity and on energy scales expression various contact interactions were derived. (author)

Holomorphic couplings in non-perturbative string compactifications

International Nuclear Information System (INIS)

Klevers, Denis Marco

2011-06-01

In this thesis we present an analysis of several aspects of four-dimensional, non-perturbative N = 1 compactifications of string theory. Our focus is on the study of brane dynamics and their effective physics as encoded in the holomorphic couplings of the low-energy N=1 effective action, most prominently the superpotential W. The thesis is divided into three parts. In part one we derive the effective action of a spacetime-filling D5-brane in generic Type IIB Calabi-Yau orientifold compactifications. In the second part we invoke tools from string dualities, namely from F-theory, heterotic/F-theory duality and mirror symmetry, for a more elaborate study of the dynamics of (p, q) 7-branes and heterotic five-branes. In this context we demonstrate exact computations of the complete perturbative effective superpotential, both due to branes and background fluxes. Finally, in the third part we present a novel geometric description of five-branes in Type IIB and heterotic M-theory Calabi-Yau compactifications via a non-Calabi-Yau threefold Z 3 , that is canonically constructed from the original five-brane and Calabi-Yau threefold Z 3 via a blow-up. We exploit the use of the blow-up threefold Z 3 as a tool to derive open-closed Picard-Fuchs differential equations, that govern the complete effective brane and flux superpotential. In addition, we present first evidence to interpret Z 3 as a flux compactification dual to the original five-brane by defining an SU(3)-structure on Z 3 , that is generated dynamically by the five-brane backreaction. (orig.)

Multiloop stringlike formulas for QED

International Nuclear Information System (INIS)

Lam, C.S.

1993-01-01

Multiloop gauge-theory amplitudes written in the Feynman-parameter representation are poised to take advantage of two important developments of the past decade: the spinor-helicity technique and the superstring reorganization. The former has been considered in a previous paper; the latter will be elaborated in this paper. We show here how to write multiloop stringlike formulas in the Feynman-parameter representation for any diagram in QED, including those involving other nonelectromagnetic interactions, provided the internal photon lines are not adjacent to any external photon line. The general connection between the Feynman-parameter approach and the superstring and/or first-quantized approach is discussed. In the special case of a one-loop multiphoton amplitude, these formulas reduce to the ones obtained by the superstring and the first-quantized methods. The stringlike formulas exhibit a simple gauge structure which makes the Ward-Takahashi identity apparent, and enables the integration-by-parts technique of Bern and Kosower to be applied, so that gauge-invariant parts can be extracted diagram by diagram with the seagull vertex neglected

Matrix models as non-commutative field theories on R3

International Nuclear Information System (INIS)

Livine, Etera R

2009-01-01

In the context of spin foam models for quantum gravity, group field theories are a useful tool allowing on the one hand a non-perturbative formulation of the partition function and on the other hand admitting an interpretation as generalized matrix models. Focusing on 2d group field theories, we review their explicit relation to matrix models and show their link to a class of non-commutative field theories invariant under a quantum-deformed 3d Poincare symmetry. This provides a simple relation between matrix models and non-commutative geometry. Moreover, we review the derivation of effective 2d group field theories with non-trivial propagators from Boulatov's group field theory for 3d quantum gravity. Besides the fact that this gives a simple and direct derivation of non-commutative field theories for the matter dynamics coupled to (3d) quantum gravity, these effective field theories can be expressed as multi-matrix models with a non-trivial coupling between matrices of different sizes. It should be interesting to analyze this new class of theories, both from the point of view of matrix models as integrable systems and for the study of non-commutative field theories.

Chimera states and the interplay between initial conditions and non-local coupling

Science.gov (United States)

Kalle, Peter; Sawicki, Jakub; Zakharova, Anna; Schöll, Eckehard

2017-03-01

Chimera states are complex spatio-temporal patterns that consist of coexisting domains of coherent and incoherent dynamics. We study chimera states in a network of non-locally coupled Stuart-Landau oscillators. We investigate the impact of initial conditions in combination with non-local coupling. Based on an analytical argument, we show how the coupling phase and the coupling strength are linked to the occurrence of chimera states, flipped profiles of the mean phase velocity, and the transition from a phase- to an amplitude-mediated chimera state.

Recent achievements in the Hamiltonian treatment of the dynamics and motion of compact binaries in general relativity

International Nuclear Information System (INIS)

Schäfer, Gerhard

2014-01-01

The current knowledge in the post-Newtonian (PN) dynamics and motion of non-spinning and spinning compact binaries will be presented based on the Arnowitt-Deser-Misner Hamiltonian approach to general relativity. The presentation will cover the binary dynamics with non-spinning components up to the 4PN order and for spinning binaries up to the next-to-next-to-leading order in the spin-orbit and spin-spin couplings. Radiation reaction will be treated for both non-spinning and spinning binaries. Explicit analytic expressions for the motion will be given, innermost stable circular orbits will be discussed

Calculation of non-adiabatic coupling vectors in a local-orbital basis set

Czech Academy of Sciences Publication Activity Database

Abad, E.; Lewis, J.P.; Zobač, Vladimír; Hapala, Prokop; Jelínek, Pavel; Ortega, J.

2013-01-01

Roč. 138, č. 15 (2013), "154106-1"-"154106-8" ISSN 0021-9606 R&D Projects: GA ČR GAP204/10/0952; GA MŠk ME09048 Institutional support: RVO:68378271 Keywords : non adiabatic couplings * molecular dynamics * DFT Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.122, year: 2013

Non-perturbative plaquette in 3d pure SU(3)

CERN Document Server

Hietanen, A; Laine, Mikko; Rummukainen, K; Schröder, Y

2005-01-01

We present a determination of the elementary plaquette and, after the subsequent ultraviolet subtractions, of the finite part of the gluon condensate, in lattice regularization in three-dimensional pure SU(3) gauge theory. Through a change of regularization scheme to MSbar and a matching back to full four-dimensional QCD, this result determines the first non-perturbative contribution in the weak-coupling expansion of hot QCD pressure.

Where are compact groups in the local Universe?

Science.gov (United States)

Díaz-Giménez, Eugenia; Zandivarez, Ariel

2015-06-01

Aims: The purpose of this work is to perform a statistical analysis of the location of compact groups in the Universe from observational and semi-analytical points of view. Methods: We used the velocity-filtered compact group sample extracted from the Two Micron All Sky Survey for our analysis. We also used a new sample of galaxy groups identified in the 2M++ galaxy redshift catalogue as tracers of the large-scale structure. We defined a procedure to search in redshift space for compact groups that can be considered embedded in other overdense systems and applied this criterion to several possible combinations of different compact and galaxy group subsamples. We also performed similar analyses for simulated compact and galaxy groups identified in a 2M++ mock galaxy catalogue constructed from the Millennium Run Simulation I plus a semi-analytical model of galaxy formation. Results: We observed that only ~27% of the compact groups can be considered to be embedded in larger overdense systems, that is, most of the compact groups are more likely to be isolated systems. The embedded compact groups show statistically smaller sizes and brighter surface brightnesses than non-embedded systems. No evidence was found that embedded compact groups are more likely to inhabit galaxy groups with a given virial mass or with a particular dynamical state. We found very similar results when the analysis was performed using mock compact and galaxy groups. Based on the semi-analytical studies, we predict that 70% of the embedded compact groups probably are 3D physically dense systems. Finally, real space information allowed us to reveal the bimodal behaviour of the distribution of 3D minimum distances between compact and galaxy groups. Conclusions: The location of compact groups should be carefully taken into account when comparing properties of galaxies in environments that are a priori different. Appendices are available in electronic form at http://www.aanda.orgFull Tables B.1 and B.2

Compaction of Ti–6Al–4V powder using high velocity compaction technique

International Nuclear Information System (INIS)

Khan, Dil Faraz; Yin, Haiqing; Li, He; Qu, Xuanhui; Khan, Matiullah; Ali, Shujaat; Iqbal, M. Zubair

2013-01-01

Highlights: • We compacted Ti–6Al–4V powder by HVC technique. • As impact force rises up, the green density of the compacts increases gradually. • At impact force 1.857 kN relative sintered density of the compacts reaches 99.88%. • Spring back of the green compact’s decreases gradually with increasing impact force. • Mechanical properties of the samples increases with increasing impact force. - Abstract: High velocity compaction technique was applied to the compaction of pre-alloyed, hydride–dehydride Ti–6Al–4V powder. The powder was pressed in single stroke with a compaction speed of 7.10–8.70 ms −1 . When the speed was 8.70 ms −1 , the relative density of the compacts reaches up to 85.89% with a green density of 3.831 g cm −3 . The green samples were sintered at 1300 °C in Ar-gas atmosphere. Scanning electron microscope (SEM) was used to examine the surface of the sintered samples. Density and mechanical properties such as Vickers micro hardness and bending strength of the powder samples were investigated. Experimental results indicated that with the increase in impact force, the density and mechanical properties of the compacts increased. The sintered compacts exhibited a maximum relative density of 99.88% with a sintered density of 4.415 g cm −3 , hardness of 364–483 HV and the bending strength in the range of 103–126.78 MPa. The springback of the compacts decreased with increasing impact force

Strong gravitational lensing by a Konoplya-Zhidenko rotating non-Kerr compact object

Energy Technology Data Exchange (ETDEWEB)

Wang, Shangyun; Chen, Songbai; Jing, Jiliang, E-mail: shangyun_wang@163.com, E-mail: csb3752@hunnu.edu.cn, E-mail: jljing@hunnu.edu.cn [Institute of Physics and Department of Physics, Hunan Normal University, Changsha, Hunan 410081 (China)

2016-11-01

Konoplya and Zhidenko have proposed recently a rotating non-Kerr black hole metric beyond General Relativity and make an estimate for the possible deviations from the Kerr solution with the data of GW 150914. We here study the strong gravitational lensing in such a rotating non-Kerr spacetime with an extra deformation parameter. We find that the condition of existence of horizons is not inconsistent with that of the marginally circular photon orbit. Moreover, the deflection angle of the light ray near the weakly naked singularity covered by the marginally circular orbit diverges logarithmically in the strong-field limit. In the case of the completely naked singularity, the deflection angle near the singularity tends to a certain finite value, whose sign depends on the rotation parameter and the deformation parameter. These properties of strong gravitational lensing are different from those in the Johannsen-Psaltis rotating non-Kerr spacetime and in the Janis-Newman-Winicour spacetime. Modeling the supermassive central object of the Milk Way Galaxy as a Konoplya-Zhidenko rotating non-Kerr compact object, we estimated the numerical values of observables for the strong gravitational lensing including the time delay between two relativistic images.

A Compact Multiple Notched Ultra-Wide Band Antenna with an Analysis of the CSRR-TO-CSRR Coupling for Portable UWB Applications.

Science.gov (United States)

Rahman, MuhibUr; Ko, Dong-Sik; Park, Jung-Dong

2017-09-25

We present a compact ultra-wideband (UWB) antenna integrated with sharp notches with a detailed analysis of the mutual coupling of the multiple notch resonators. By utilizing complementary split ring resonators (CSRR) on the radiating semi-circular patch, we achieve the sharp notch-filtering of various bands within the UWB band without increasing the antenna size. The notched frequency bands include WiMAX, INSAT, and lower and upper WLAN. In order to estimate the frequency shifts of the notch due to the coupling of the nearby CSRRs, an analysis of the coupling among the multiple notch resonators is carried out and we construct the lumped-circuit equivalent model. The time domain analysis of the proposed antenna is performed to show its validity on the UWB application. The measured frequency response of the input port corresponds quite well with the calculations and simulations. The radiation pattern of the implemented quad-notched UWB antenna is nearly omnidirectional in the passband.

CANDELS+3D-HST: Compact SFGs at z ∼ 2-3, the progenitors of the first quiescent galaxies

Energy Technology Data Exchange (ETDEWEB)

Barro, G.; Faber, S. M.; Koo, D. C.; Guo, Y. [UCO/Lick Observatory and Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Pérez-González, P. G. [Universidad Complutense de Madrid, F. CC. Físicas, 28040 Madrid (Spain); Pacifici, C. [Yonsei University Observatory, Yonsei University, Seoul 120-749 (Korea, Republic of); Trump, J. R. [Pennsylvania State University, University Park, PA 16802 (United States); Wuyts, S.; Hsu, L. [Max-Planck-Institut für extraterrestrische Physik, Postfach 1312, Giessenbachstr., D-85741 Garching (Germany); Bell, E. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Dekel, A. [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Porter, L.; Primack, J. [Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064 (United States); Ferguson, H. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Ashby, M. L. N.; Fazio, G. G. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Caputi, K. [Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen (Netherlands); Ceverino, D. [Departamento de Física Teórica, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Croton, D. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn, VIC 3122 (Australia); Giavalisco, M. [Astronomy Department, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); and others

2014-08-10

We analyze the star-forming and structural properties of 45 massive (log(M/M{sub ☉}) >10) compact star-forming galaxies (SFGs) at 2 < z < 3 to explore whether they are progenitors of compact quiescent galaxies at z ∼ 2. The optical/NIR and far-IR Spitzer/Herschel colors indicate that most compact SFGs are heavily obscured. Nearly half (47%) host an X-ray-bright active galactic nucleus (AGN). In contrast, only about 10% of other massive galaxies at that time host AGNs. Compact SFGs have centrally concentrated light profiles and spheroidal morphologies similar to quiescent galaxies and are thus strikingly different from other SFGs, which typically are disk-like and sometimes clumpy or irregular. Most compact SFGs lie either within the star formation rate (SFR)-mass main sequence (65%) or below it (30%), on the expected evolutionary path toward quiescent galaxies. These results show conclusively that galaxies become more compact before they lose their gas and dust, quenching star formation. Using extensive HST photometry from CANDELS and grism spectroscopy from the 3D-HST survey, we model their stellar populations with either exponentially declining (τ) star formation histories (SFHs) or physically motivated SFHs drawn from semianalytic models (SAMs). SAMs predict longer formation timescales and older ages ∼2 Gyr, which are nearly twice as old as the estimates of the τ models. Both models yield good spectral energy distribution fits, indicating that the systematic uncertainty in the age due to degeneracies in the SFH is of that order of magnitude. However, SAM SFHs better match the observed slope and zero point of the SFR-mass main sequence. Contrary to expectations, some low-mass compact SFGs (log(M/M{sub ☉}) =10-10.6) have younger ages but lower specific SFRs than that of more massive galaxies, suggesting that the low-mass galaxies reach the red sequence faster. If the progenitors of compact SFGs are extended SFGs, state-of-the-art SAMs show that mergers

CANDELS+3D-HST: Compact SFGs at z ∼ 2-3, the progenitors of the first quiescent galaxies

International Nuclear Information System (INIS)

Barro, G.; Faber, S. M.; Koo, D. C.; Guo, Y.; Pérez-González, P. G.; Pacifici, C.; Trump, J. R.; Wuyts, S.; Hsu, L.; Bell, E.; Dekel, A.; Porter, L.; Primack, J.; Ferguson, H.; Ashby, M. L. N.; Fazio, G. G.; Caputi, K.; Ceverino, D.; Croton, D.; Giavalisco, M.

2014-01-01

We analyze the star-forming and structural properties of 45 massive (log(M/M ☉ ) >10) compact star-forming galaxies (SFGs) at 2 < z < 3 to explore whether they are progenitors of compact quiescent galaxies at z ∼ 2. The optical/NIR and far-IR Spitzer/Herschel colors indicate that most compact SFGs are heavily obscured. Nearly half (47%) host an X-ray-bright active galactic nucleus (AGN). In contrast, only about 10% of other massive galaxies at that time host AGNs. Compact SFGs have centrally concentrated light profiles and spheroidal morphologies similar to quiescent galaxies and are thus strikingly different from other SFGs, which typically are disk-like and sometimes clumpy or irregular. Most compact SFGs lie either within the star formation rate (SFR)-mass main sequence (65%) or below it (30%), on the expected evolutionary path toward quiescent galaxies. These results show conclusively that galaxies become more compact before they lose their gas and dust, quenching star formation. Using extensive HST photometry from CANDELS and grism spectroscopy from the 3D-HST survey, we model their stellar populations with either exponentially declining (τ) star formation histories (SFHs) or physically motivated SFHs drawn from semianalytic models (SAMs). SAMs predict longer formation timescales and older ages ∼2 Gyr, which are nearly twice as old as the estimates of the τ models. Both models yield good spectral energy distribution fits, indicating that the systematic uncertainty in the age due to degeneracies in the SFH is of that order of magnitude. However, SAM SFHs better match the observed slope and zero point of the SFR-mass main sequence. Contrary to expectations, some low-mass compact SFGs (log(M/M ☉ ) =10-10.6) have younger ages but lower specific SFRs than that of more massive galaxies, suggesting that the low-mass galaxies reach the red sequence faster. If the progenitors of compact SFGs are extended SFGs, state-of-the-art SAMs show that mergers and disk

Probabilistic Teleportation of an Arbitrary Two-Atom State in Cavity QED

Institute of Scientific and Technical Information of China (English)

LIU Jin-Ming

2007-01-01

We propose a scheme for the teleportation of an arbitrary two-atom state by using two pairs of two-atom nonmaximally entangled states as the quantum channel in cavity QED.It is shown that no matter whether the arbitrary two-atom pure state to be teleported is entangled or not,our teleportation scheme can always be probabilistically realized.The success probability of teleportation is determined by the smaller coefficients of the two initially entangled atom pairs.

Strong light-matter coupling from atoms to solid-state systems

CERN Document Server

2014-01-01

The physics of strong light-matter coupling has been addressed in different scientific communities over the last three decades. Since the early eighties, atoms coupled to optical and microwave cavities have led to pioneering demonstrations of cavity quantum electrodynamics, Gedanken experiments, and building blocks for quantum information processing, for which the Nobel Prize in Physics was awarded in 2012. In the framework of semiconducting devices, strong coupling has allowed investigations into the physics of Bose gases in solid-state environments, and the latter holds promise for exploiting light-matter interaction at the single-photon level in scalable architectures. More recently, impressive developments in the so-called superconducting circuit QED have opened another fundamental playground to revisit cavity quantum electrodynamics for practical and fundamental purposes. This book aims at developing the necessary interface between these communities, by providing future researchers with a robust conceptu...

Compact 35μm fiber coupled diode laser module based on dense wavelength division multiplexing of NBA mini-bars

Science.gov (United States)

Witte, U.; Traub, M.; Di Meo, A.; Hamann, M.; Rubel, D.; Hengesbach, S.; Hoffmann, D.

2016-03-01

We present a compact, modular and cross talk free approach for dense wavelength division multiplexing of high power diode lasers based on ultra-steep dielectric filters. The mini bars consist of 5 narrow stripe broad area emitters with a beam parameter product in the range of 2 mm mrad and a wavelength spacing of 2.5 nm between 2 adjacent emitters. Experimental results for fiber coupling (35 μm core diameter, NA < 0.2) of internally and externally stabilized diode lasers are presented. Optical losses are analyzed and alternative optical designs to overcome the current limitations of the setup are discussed.

Cohesive granular media modelization with non-convex particles shape: Application to UO2 powder compaction

International Nuclear Information System (INIS)

Saint-Cyr, B.

2011-01-01

We model in this work granular materials composed of non-convex and cohesive aggregates, in view of application to the rheology of UO 2 powders. The effect of non convexity is analyzed in terms of bulk quantities (Coulomb internal friction and cohesion) and micromechanical parameters such as texture anisotropy and force transmission. In particular, we find that the packing fraction evolves in a complex manner with the shape non convexity and the shear strength increases but saturates due to interlocking between the aggregates. We introduce simple models to describe these features in terms of micro-mechanical parameters. Furthermore, a systematic investigation of shearing, uniaxial compaction and simple compression of cohesive packings show that bulk cohesion increases with non-convexity but is strongly influenced by the boundary conditions and shear bands or stress concentration. (author) [fr

A comparative study on the solubility and stability of p-phenylenediamine-based organic redox couples for non-aqueous flow batteries

Science.gov (United States)

Kim, Hyun-seung; Lee, Keon-Joon; Han, Young-Kyu; Ryu, Ji Heon; Oh, Seung M.

2017-04-01

A methyl-substituted p-phenylenediamine (PD), N,N,N‧,N‧-tetramethyl-p-phenylenediamine (TMPD), is examined as a positive redox couple with high energy density for non-aqueous Li-flow batteries. Methyl substitution affects the solubility of the redox couple, as the solubility is increased by a factor of ten, to a maximum solubility of 5.0 M in 1.0 M lithium tetrafluoroborate-propylene carbonate supporting electrolyte due to elimination of the hydrogen bonding between the solute molecules. The methyl substitution also enhances the chemical stability of the cation radical and di-cation being generated from PD, as the redox center is shielded by the methyl groups. Furthermore, this organic redox couple demonstrate two-electron redox reactions at 3.2 and 3.8 V (vs. Li/Li+); therefore, the volumetric capacity is twice higher compared to conventional one-electron involved redox couples. In a non-flowing Li/TMPD coin-cell, this organic redox couple demonstrates very stable cycleability as a positive redox couple for non-aqueous flow batteries.

Supersymmetric QED at finite temperature and the principle of equivalence

International Nuclear Information System (INIS)

Robinett, R.W.

1985-01-01

Unbroken supersymmetric QED is examined at finite temperature and it is shown that the scalar and spinor members of a chiral superfield acquire different temperature-dependent inertial masses. By considering the renormalization of the energy-momentum tensor it is also shown that the T-dependent scalar-spinor gravitational masses are also no longer degenerate and, moreover, are different from their T-dependent inertial mass shifts implying a violation of the equivalence principle. The temperature-dependent corrections to the spinor (g-2) are also calculated and found not to vanish

Particle production after inflation with non-minimal derivative coupling to gravity

International Nuclear Information System (INIS)

Ema, Yohei; Jinno, Ryusuke; Nakayama, Kazunori; Mukaida, Kyohei

2015-01-01

We study cosmological evolution after inflation in models with non-minimal derivative coupling to gravity. The background dynamics is solved and particle production associated with rapidly oscillating Hubble parameter is studied in detail. In addition, production of gravitons through the non-minimal derivative coupling with the inflaton is studied. We also find that the sound speed squared of the scalar perturbation oscillates between positive and negative values when the non-minimal derivative coupling dominates over the minimal kinetic term. This may lead to an instability of this model. We point out that the particle production rates are the same as those in the Einstein gravity with the minimal kinetic term, if we require the sound speed squared is positive definite

Precise single-qubit control of the reflection phase of a photon mediated by a strongly-coupled ancilla–cavity system

Science.gov (United States)

Motzoi, F.; Mølmer, K.

2018-05-01

We propose to use the interaction between a single qubit atom and a surrounding ensemble of three level atoms to control the phase of light reflected by an optical cavity. Our scheme employs an ensemble dark resonance that is perturbed by the qubit atom to yield a single-atom single photon gate. We show here that off-resonant excitation towards Rydberg states with strong dipolar interactions offers experimentally-viable regimes of operations with low errors (in the 10‑3 range) as required for fault-tolerant optical-photon, gate-based quantum computation. We also propose and analyze an implementation within microwave circuit-QED, where a strongly-coupled ancilla superconducting qubit can be used in the place of the atomic ensemble to provide high-fidelity coupling to microwave photons.

Dynamics and non-equilibrium steady state in a system of coupled harmonic oscillators

Energy Technology Data Exchange (ETDEWEB)

Ghesquière, Anne, E-mail: Anne.Ghesquiere@nithep.ac.za; Sinayskiy, Ilya, E-mail: sinayskiy@ukzn.ac.za; Petruccione, Francesco, E-mail: petruccione@ukzn.ac.za

2013-10-15

A system of two coupled oscillators, each of them coupled to an independent reservoir, is analysed. The analytical solution of the non-rotating wave master equation is obtained in the high-temperature and weak coupling limits. No thermal entanglement is found in the high-temperature limit. In the weak coupling limit the system converges to an entangled non-equilibrium steady state. A critical temperature for the appearance of quantum correlations is found.

Time-bin quantum RAM

Science.gov (United States)

Moiseev, E. S.; Moiseev, S. A.

2016-11-01

We have proposed a compact scheme of quantum random access memory (qRAM) based on the impedance matched multi-qubit photon echo quantum memory incorporated with the control four-level atom in two coupled QED cavities. A set of matching conditions for basic physical parameters of the qRAM scheme that provides an efficient quantum control of the fast single photon storage and readout has been found. In particular, it has been discovered that the efficient qRAM operations are determined by the specific properties of the excited photonic molecule coupling the two QED cavities. Herein, the maximal efficiency of the qRAM is realized when the cooperativity parameter of the photonic molecule equals to unity that can be experimentally achievable. We have also elaborated upon the new quantum address scheme where the multi-time-bin photon state is used for the control of the four-level atom during the readout of the photonic qubits from the quantum memory. The scheme reduces the required number of logical elements to one. Experimental implementation by means of current quantum technologies in the optical and microwave domains is also discussed.

High-Q AlAs/GaAs adiabatic micropillar cavities with submicron diameters for cQED experiments

DEFF Research Database (Denmark)

Lermer, M.; Gregersen, Niels; Dunzer, F.

Quantum dot (QD) micropillar cavities represent an interesting class of microresonator systems aiming at the observation and application of cavity quantum electrodynamics (cQED) on a semiconductor platform. They combine valuable properties i.e. a highly directional and approximately Gaussian shaped...

Transformation of bipartite non-maximally entangled states into a ...

Indian Academy of Sciences (India)

We present two schemes for transforming bipartite non-maximally entangled states into a W state in cavity QED system, by using highly detuned interactions and the resonant interactions between ... Proceedings of the International Workshop/Conference on Computational Condensed Matter Physics and Materials Science

Up and Down Quark Masses and Corrections to Dashen's Theorem from Lattice QCD and Quenched QED.

Science.gov (United States)

Fodor, Z; Hoelbling, C; Krieg, S; Lellouch, L; Lippert, Th; Portelli, A; Sastre, A; Szabo, K K; Varnhorst, L

2016-08-19

In a previous Letter [Borsanyi et al., Phys. Rev. Lett. 111, 252001 (2013)] we determined the isospin mass splittings of the baryon octet from a lattice calculation based on N_{f}=2+1 QCD simulations to which QED effects have been added in a partially quenched setup. Using the same data we determine here the corrections to Dashen's theorem and the individual up and down quark masses. Our ensembles include 5 lattice spacings down to 0.054 fm, lattice sizes up to 6 fm, and average up-down quark masses all the way down to their physical value. For the parameter which quantifies violations to Dashen's theorem, we obtain ϵ=0.73(2)(5)(17), where the first error is statistical, the second is systematic, and the third is an estimate of the QED quenching error. For the light quark masses we obtain, m_{u}=2.27(6)(5)(4) and m_{d}=4.67(6)(5)(4)  MeV in the modified minimal subtraction scheme at 2  GeV and the isospin breaking ratios m_{u}/m_{d}=0.485(11)(8)(14), R=38.2(1.1)(0.8)(1.4), and Q=23.4(0.4)(0.3)(0.4). Our results exclude the m_{u}=0 solution to the strong CP problem by more than 24 standard deviations.

Dissolution and compaction instabilities in geomaterials

Science.gov (United States)

Stefanou, I.; Sulem, J.; de Sauvage, J.

2014-12-01

Compaction bands play an important role in reservoir engineering and geological storage. Their presence in geological formations may also provide useful information on various geological processes. Several mechanisms can be involved at different scales and may be responsible for compaction band instabilities [1]. Compaction bands can be seen as a particular instability of the governing mathematical system leading to localization of deformation [2-4]. In a saturated porous rock, the progressive mechanical damage of the solid skeleton during compaction, results in the increase of the interface area of the reactants and consequently in the acceleration of the dissolution rate of the solid phase [2,5]. Thus, the solid skeleton is degraded more rapidly (mass removal because of dissolution), the overall mechanical properties of the system diminish (contraction of the elastic domain - chemical softening), deformations increase and the solid skeleton is further damaged (intergranular fractures, debonding, breakage of the porous network etc.). The stability of this positive feedback process is investigated analytically through linear stability analysis by considering the strong chemo-poro-mechanical coupling due to chemical dissolution. The post bifurcation behavior is then studied analytically and numerically revealing the compaction band thickness and periodicity. The effect of various parameters is studied as for instance the influence of the hydraulic diffusivity on the compaction band thickness. [1] P. Baud, S. Vinciguerra, C. David, A. Cavallo, E. Walker and T. Reuschlé (2009), Pure Appl. Geophys., 166(5-7), 869-898 [2] I. Stefanou and J. Sulem (2014), JGR: Solid Earth, 119(2), 880-899. doi:10.1002/2013JB010342I [3] J.W. Rudnicki and J.R. Rice (1975), Journal of the Mechanics and Physics of Solids 23(6),: 371-394 [4] K.A. Issen and J.W. Rudnicki (2000), JGR, 105(B9), 21529. doi:10.1029/2000JB900185 [5] R. Nova, R. Castellanza and C. Tamagnini (2003), International

Cosmology or Catastrophe? A non-minimally coupled scalar in an inhomogeneous universe

International Nuclear Information System (INIS)

Caputa, Paweł; Haque, Sheikh Shajidul; Olson, Joseph; Underwood, Bret

2013-01-01

A non-minimally coupled scalar field can have, in principle, a negative effective Planck mass squared which depends on the scalar field. Surprisingly, an isotropic and homogeneous cosmological universe with a non-minimally coupled scalar field is perfectly smooth as the rolling scalar field causes the effective Planck mass to change sign and pass through zero. However, we show that any small deviations from homogeneity diverge as the effective Planck mass vanishes, with catastrophic consequences for the cosmology. The physical origin of the divergence is due to the presence of non-zero scalar anisotropic stress from the non-minimally coupled scalar field. Thus, while the homogeneous and isotropic cosmology appears surprisingly sensible when the effective Planck mass vanishes, inhomogeneities tell a different story. (paper)

Holomorphic couplings in non-perturbative string compactifications

Energy Technology Data Exchange (ETDEWEB)

Klevers, Denis Marco

2011-06-15

In this thesis we present an analysis of several aspects of four-dimensional, non-perturbative N = 1 compactifications of string theory. Our focus is on the study of brane dynamics and their effective physics as encoded in the holomorphic couplings of the low-energy N=1 effective action, most prominently the superpotential W. The thesis is divided into three parts. In part one we derive the effective action of a spacetime-filling D5-brane in generic Type IIB Calabi-Yau orientifold compactifications. In the second part we invoke tools from string dualities, namely from F-theory, heterotic/F-theory duality and mirror symmetry, for a more elaborate study of the dynamics of (p, q) 7-branes and heterotic five-branes. In this context we demonstrate exact computations of the complete perturbative effective superpotential, both due to branes and background fluxes. Finally, in the third part we present a novel geometric description of five-branes in Type IIB and heterotic M-theory Calabi-Yau compactifications via a non-Calabi-Yau threefold Z{sub 3}, that is canonically constructed from the original five-brane and Calabi-Yau threefold Z{sub 3} via a blow-up. We exploit the use of the blow-up threefold Z{sub 3} as a tool to derive open-closed Picard-Fuchs differential equations, that govern the complete effective brane and flux superpotential. In addition, we present first evidence to interpret Z{sub 3} as a flux compactification dual to the original five-brane by defining an SU(3)-structure on Z{sub 3}, that is generated dynamically by the five-brane backreaction. (orig.)

Quantum master equation for QED in exact renormalization group

International Nuclear Information System (INIS)

Igarashi, Yuji; Itoh, Katsumi; Sonoda, Hidenori

2007-01-01

Recently, one of us (H. S.) gave an explicit form of the Ward-Takahashi identity for the Wilson action of QED. We first rederive the identity using a functional method. The identity makes it possible to realize the gauge symmetry even in the presence of a momentum cutoff. In the cutoff dependent realization, the nilpotency of the BRS transformation is lost. Using the Batalin-Vilkovisky formalism, we extend the Wilson action by including the antifield contributions. Then, the Ward-Takahashi identity for the Wilson action is lifted to a quantum master equation, and the modified BRS transformation regains nilpotency. We also obtain a flow equation for the extended Wilson action. (author)

The Entropy of Co-Compact Open Covers

Directory of Open Access Journals (Sweden)

Steven Bourquin

2013-06-01

Full Text Available Co-compact entropy is introduced as an invariant of topological conjugation for perfect mappings defined on any Hausdorff space (compactness and metrizability are not necessarily required. This is achieved through the consideration of co-compact covers of the space. The advantages of co-compact entropy include: (1 it does not require the space to be compact and, thus, generalizes Adler, Konheim and McAndrew’s topological entropy of continuous mappings on compact dynamical systems; and (2 it is an invariant of topological conjugation, compared to Bowen’s entropy, which is metric-dependent. Other properties of co-compact entropy are investigated, e.g., the co-compact entropy of a subsystem does not exceed that of the whole system. For the linear system, (R; f, defined by f(x = 2x, the co-compact entropy is zero, while Bowen’s entropy for this system is at least log 2. More generally, it is found that co-compact entropy is a lower bound of Bowen’s entropies, and the proof of this result also generates the Lebesgue Covering Theorem to co-compact open covers of non-compact metric spaces.

Compact 3D Camera for Shake-the-Box Particle Tracking

Science.gov (United States)

Hesseling, Christina; Michaelis, Dirk; Schneiders, Jan

2017-11-01

Time-resolved 3D-particle tracking usually requires the time-consuming optical setup and calibration of 3 to 4 cameras. Here, a compact four-camera housing has been developed. The performance of the system using Shake-the-Box processing (Schanz et al. 2016) is characterized. It is shown that the stereo-base is large enough for sensible 3D velocity measurements. Results from successful experiments in water flows using LED illumination are presented. For large-scale wind tunnel measurements, an even more compact version of the system is mounted on a robotic arm. Once calibrated for a specific measurement volume, the necessity for recalibration is eliminated even when the system moves around. Co-axial illumination is provided through an optical fiber in the middle of the housing, illuminating the full measurement volume from one viewing direction. Helium-filled soap bubbles are used to ensure sufficient particle image intensity. This way, the measurement probe can be moved around complex 3D-objects. By automatic scanning and stitching of recorded particle tracks, the detailed time-averaged flow field of a full volume of cubic meters in size is recorded and processed. Results from an experiment at TU-Delft of the flow field around a cyclist are shown.

openQ*D simulation code for QCD+QED

Science.gov (United States)

Campos, Isabel; Fritzsch, Patrick; Hansen, Martin; Krstić Marinković, Marina; Patella, Agostino; Ramos, Alberto; Tantalo, Nazario

2018-03-01

The openQ*D code for the simulation of QCD+QED with C* boundary conditions is presented. This code is based on openQCD-1.6, from which it inherits the core features that ensure its efficiency: the locally-deflated SAP-preconditioned GCR solver, the twisted-mass frequency splitting of the fermion action, the multilevel integrator, the 4th order OMF integrator, the SSE/AVX intrinsics, etc. The photon field is treated as fully dynamical and C* boundary conditions can be chosen in the spatial directions. We discuss the main features of openQ*D, and we show basic test results and performance analysis. An alpha version of this code is publicly available and can be downloaded from http://rcstar.web.cern.ch/.

On the uniqueness of the non-minimal matter coupling in massive gravity and bigravity

International Nuclear Information System (INIS)

Huang, Qing-Guo; Ribeiro, Raquel H.; Xing, Yu-Hang; Zhang, Ke-Chao; Zhou, Shuang-Yong

2015-01-01

In de Rham–Gabadadze–Tolley (dRGT) massive gravity and bi-gravity, a non-minimal matter coupling involving both metrics generically reintroduces the Boulware–Deser (BD) ghost. A non-minimal matter coupling via a simple, yet specific composite metric has been proposed, which eliminates the BD ghost below the strong coupling scale. Working explicitly in the metric formulation and for arbitrary spacetime dimensions, we show that this composite metric is the unique consistent non-minimal matter coupling below the strong coupling scale, which emerges out of two diagnostics, namely, the absence of Ostrogradski ghosts in the decoupling limit and the absence of the BD ghost from matter quantum loop corrections

Investigation and development of a non-destructive system to evaluate critical properties of asphalt pavements during the compaction process.

Science.gov (United States)

2013-10-01

The purpose of this report is to present findings from a two-stage investigation to develop a non-destructive system to : evaluate critical properties and characteristics of asphalt pavements during the compaction process. The first stage aligned : c...

3D modelling of the flow of self-compacting concrete with or without steel fibres. Part I: slump flow test

Science.gov (United States)

Deeb, R.; Kulasegaram, S.; Karihaloo, B. L.

2014-12-01

In part I of this two-part paper, a three-dimensional Lagrangian smooth particle hydrodynamics method has been used to model the flow of self-compacting concrete (SCC) with or without short steel fibres in the slump cone test. The constitutive behaviour of this non-Newtonian viscous fluid is described by a Bingham-type model. The 3D simulation of SCC without fibres is focused on the distribution of large aggregates (larger than or equal to 8 mm) during the flow. The simulation of self-compacting high- and ultra-high- performance concrete containing short steel fibres is focused on the distribution of fibres and their orientation during the flow. The simulation results show that the fibres and/or heavier aggregates do not precipitate but remain homogeneously distributed in the mix throughout the flow.

Non-Gaussianity in multi-sound-speed disformally coupled inflation

Energy Technology Data Exchange (ETDEWEB)

De Bruck, Carsten van; Longden, Chris [Consortium for Fundamental Physics, School of Mathematics and Statistics, University of Sheffield, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Koivisto, Tomi, E-mail: C.vandeBruck@sheffield.ac.uk, E-mail: tomi.koivisto@nordita.org, E-mail: cjlongden1@sheffield.ac.uk [Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-10691 Stockholm (Sweden)

2017-02-01

Most, if not all, scalar-tensor theories are equivalent to General Relativity with a disformally coupled matter sector. In extra-dimensional theories such a coupling can be understood as a result of induction of the metric on a brane that matter is confined to. This article presents a first look at the non-Gaussianities in disformally coupled inflation, a simple two-field model that features a novel kinetic interaction. Cases with both canonical and Dirac-Born-Infeld (DBI) kinetic terms are taken into account, the latter motivated by the possible extra-dimensional origin of the disformality. The computations are carried out for the equilateral configuration in the slow-roll regime, wherein it is found that the non-Gaussianity is typically rather small and negative. This is despite the fact that the new kinetic interaction causes the perturbation modes to propagate with different sounds speeds, which may both significantly deviate from unity during inflation.

The perturbative construction of Symanzik's improved action for Φ44 and QED4

International Nuclear Information System (INIS)

Keller, G.

1993-01-01

For the perturbative Euclidean massive Φ 4 4 and QED 4 (with a small photon mass) an explicit construction of Symanzik's improved action is presented. It is established rigorously that all the Green functions exhibit improved convergence as the momentum space UV cutoff is sent to infinity. These results are obtained by an application of the powerful yet technically simple flow equation method. (orig.)

The effect of compaction parameters and dielectric composition on properties of soft magnetic composites

Science.gov (United States)

Xiao, Ling; Sun, Y. H.; Yu, Lie

2011-07-01

This paper investigated the effect of compaction parameters and dielectric composition on mechanical, magnetic and electrical properties of iron-organosilicon epoxy resin soft magnetic composites. In this work, iron powders with high purity were covered by an organic material (organosilicon epoxy resin) and then by coupling agent (KH-550). The coated powders were then cold compacted at 600, 800 and 1000 MPa and cured under vacuum respectively. The results show that the saturation magnetic flux density and electrical resistivity are dependent on compaction pressure and resin content. Increase in the organic phase content leads to decrease of the saturation magnetic flux density, while increase of the electrical resistivity. Furthermore, the samples with 0.9 wt% resins + 0.1 wt% coupling agent at compaction pressure of 800 MPa shows better properties than the others.

The effect of compaction parameters and dielectric composition on properties of soft magnetic composites

International Nuclear Information System (INIS)

Xiao Ling; Yu Lie; Sun, Y H

2011-01-01

This paper investigated the effect of compaction parameters and dielectric composition on mechanical, magnetic and electrical properties of iron-organosilicon epoxy resin soft magnetic composites. In this work, iron powders with high purity were covered by an organic material (organosilicon epoxy resin) and then by coupling agent (KH-550). The coated powders were then cold compacted at 600, 800 and 1000 MPa and cured under vacuum respectively. The results show that the saturation magnetic flux density and electrical resistivity are dependent on compaction pressure and resin content. Increase in the organic phase content leads to decrease of the saturation magnetic flux density, while increase of the electrical resistivity. Furthermore, the samples with 0.9 wt% resins + 0.1 wt% coupling agent at compaction pressure of 800 MPa shows better properties than the others.

Time-independent compaction behavior of quartz sands

NARCIS (Netherlands)

Brzesowsky, R. H.; Spiers, C. J.|info:eu-repo/dai/nl/304829323; Peach, C. J.|info:eu-repo/dai/nl/082101906; Hangx, Suzanne|info:eu-repo/dai/nl/30483579X

Mechanisms such as grain rearrangement, coupled with elastic deformation and grain breakage, are believed to play an important role in the time-independent compaction of sands, controlling porosity and permeability reduction during burial of clastic sediments and during depletion of highly porous

On the uniqueness of the non-minimal matter coupling in massive gravity and bigravity

Directory of Open Access Journals (Sweden)

Qing-Guo Huang

2015-09-01

Full Text Available In de Rham–Gabadadze–Tolley (dRGT massive gravity and bi-gravity, a non-minimal matter coupling involving both metrics generically reintroduces the Boulware–Deser (BD ghost. A non-minimal matter coupling via a simple, yet specific composite metric has been proposed, which eliminates the BD ghost below the strong coupling scale. Working explicitly in the metric formulation and for arbitrary spacetime dimensions, we show that this composite metric is the unique consistent non-minimal matter coupling below the strong coupling scale, which emerges out of two diagnostics, namely, the absence of Ostrogradski ghosts in the decoupling limit and the absence of the BD ghost from matter quantum loop corrections.

Determination of the π3He3H coupling constant

International Nuclear Information System (INIS)

Nichitiu, F.; Sapozhnikov, M.G.

1977-01-01

Despersion relations for the real part of the antisymmetric amplitude of the π +-3 He scattering have been used in order to determine the π 3 He 3 H coupling constant. The coupling constant value determined by this method is larger than the elementary pion-nucleon coupling constant, but is in good agreement with the value obtained by another method. The obtained value is f 2 sub(π 3 He 3 H) = 0.12+-0.01. Shown is the importance of using the Coulomb corrections for dispersion relation calculations because the value of π 3 He 3 H coupling constant obtained with corrected total cross sections is larger by about 0.014 than the one obtained without these corrections. The best energy ranges for future π 3 He experiments are commented

Cavity QED experiments, entanglement and quantum measurement

International Nuclear Information System (INIS)

Brune, M.

2001-01-01

This course is devoted to the physics of entanglement in microwave CQED (cavity quantum electrodynamics) experiments. The heart of this system is a microwave photon trap, made of superconducting mirrors, which stores a few-photon field in a small volume of space for times as long as milliseconds. This field interacts with circular Rydberg atoms injected one by one into the cavity. Section 2 is devoted to the description of the strong coupling regime in Rydberg atom CQED. The tools of the experiment are briefly presented at the beginning of this section as well as the main characteristics of the strong coupling regime. We then show in section 3 how to use the strong interaction with a single photon to perform a non-destructive detection of a single photon with a single atom as a meter. In section 4, we show that the achieved QND (quantum non-demolition) measurement process corresponds to the operation of a quantum phase gate. It allows, in principle, to prepare arbitrary atom + field entangled states. Various methods will be presented for preparing entangled states such as a two atom EPR (Einstein Podolsky Rosen) pair as well as a GHZ triplet. Entanglement involving more and more complex systems will then be investigated in section 5 where the preparation of a ''Schroedinger cat state'' of the cavity field is presented. We especially address in this last section the problem of entanglement between the system and the meter which occurs during any quantum measurement process

Compact models and performance investigations for subthreshold interconnects

CERN Document Server

Dhiman, Rohit

2014-01-01

The book provides a detailed analysis of issues related to sub-threshold interconnect performance from the perspective of analytical approach and design techniques. Particular emphasis is laid on the performance analysis of coupling noise and variability issues in sub-threshold domain to develop efficient compact models. The proposed analytical approach gives physical insight of the parameters affecting the transient behavior of coupled interconnects. Remedial design techniques are also suggested to mitigate the effect of coupling noise. The effects of wire width, spacing between the wires, wi

Shear Viscosity of Hot QED at Finite Chemical Potential from Kubo Formula

International Nuclear Information System (INIS)

Liu Hui; Hou Defu; Li Jiarong

2008-01-01

Within the framework of finite temperature feld theory this paper discusses the shear viscosity of hot QED plasma through Kubo formula at one-loop skeleton diagram level with a finite chemical potential. The effective widths (damping rates) are introduced to regulate the pinch singularities and then gives a reliable estimation of the shear viscous coefficient. The finite chemical potential contributes positively compared to the pure temperature case. The result agrees with that from the kinetics theory qualitatively

Renormalization-scheme-invariant QCD and QED: The method of effective charges

International Nuclear Information System (INIS)

Grunberg, G.

1984-01-01

We review, extend, and give some further applications of a method recently suggested to solve the renormalization-scheme-dependence problem in perturbative field theories. The use of a coupling constant as a universal expansion parameter is abandoned. Instead, to each physical quantity depending on a single scale variable is associated an effective charge, whose corresponding Stueckelberg--Peterman--Gell-Mann--Low function is identified as the proper object on which perturbation theory applies. Integration of the corresponding renormalization-group equations yields renormalization-scheme-invariant results free of any ambiguity related to the definition of the kinematical variable, or that of the scale parameter Λ, even though the theory is not solved to all orders. As a by-product, a renormalization-group improvement of the usual series is achieved. Extension of these methods to operators leads to the introduction of renormalization-group-invariant Green's function and Wilson coefficients, directly related to effective charges. The case of nonzero fermion masses is discussed, both for fixed masses and running masses in mass-independent renormalization schemes. The importance of the scale-invariant mass m is emphasized. Applications are given to deep-inelastic phenomena, where the use of renormalization-group-invariant coefficient functions allows to perform the factorization without having to introduce a factorization scale. The Sudakov form factor of the electron in QED is discussed as an example of an extension of the method to problems involving several momentum scales

Non-Kaehler heterotic string solutions with non-zero fluxes and non-constant dilaton

Energy Technology Data Exchange (ETDEWEB)

Fernández, Marisa [Universidad del País Vasco,Facultad de Ciencia y Tecnología, Departamento de Matemáticas,Apartado 644, 48080 Bilbao (Spain); Ivanov, Stefan [University of Sofia “St. Kl. Ohridski”,Faculty of Mathematics and Informatics,Blvd. James Bourchier 5, 1164 Sofia (Bulgaria); Institute of Mathematics and Informatics, Bulgarian Academy of Sciences (Bulgaria); Ugarte, Luis [Departamento de Matemáticas - I.U.M.A., Universidad de Zaragoza,Campus Plaza San Francisco, 50009 Zaragoza (Spain); Vassilev, Dimiter [Department of Mathematics and Statistics, University of New Mexico,Albuquerque, New Mexico, 87131-0001 (United States)

2014-06-12

Conformally compact and complete smooth solutions to the Strominger system with non vanishing flux, non-trivial instanton and non-constant dilaton using the first Pontrjagin form of the (−)-connection on 6-dimensional non-Kähler nilmanifold are presented. In the conformally compact case the dilaton is determined by the real slices of the elliptic Weierstrass function. The dilaton of non-compact complete solutions is given by the fundamental solution of the Laplacian on R{sup 4}. All solutions satisfy the heterotic equations of motion up to the first order of α{sup ′}.

Extended ΛCDM: generalized non-minimal coupling for dark matter fluids

International Nuclear Information System (INIS)

Bettoni, Dario; Liberati, Stefano; Sindoni, Lorenzo

2011-01-01

In this paper we discuss a class of models that address the issue of explaining the gravitational dynamics at the galactic scale starting from a geometric point of view. Instead of claiming the existence of some hidden coupling between dark matter and baryons, or abandoning the existence of dark matter itself, we consider the possibility that dark matter and gravity have some non trivial interaction able to modify the dynamics at astrophysical scales. This interaction is implemented assuming that dark matter gets non-minimally coupled with gravity at suitably small scales and late times. After showing the predictions of the model in the Newtonian limit we also discuss the possible origin of it non-minimal coupling. This investigation seems to suggest that phenomenological mechanisms envisaged for the dark matter dynamics, such as the Bose-Einstein condensation of dark matter halos, could be connected to this class of models

Hydrodynamically Coupled Brownian Dynamics simulations for flow on non-Newtonian fluids

NARCIS (Netherlands)

Ahuja, Vishal Raju

2018-01-01

This thesis deals with model development for particle-based flow simulations of non-Newtonian fluids such as polymer solutions. A novel computational technique called Hydrodynamically Coupled Brownian Dynamics (HCBD) is presented in this thesis. This technique essentially couples the Brownian motion