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See detailQuantum imaging with uncorrelated single photon sources
Bastin, Thierry ULg; Thiel, C.; Solano, E. et al

Conference (2008)

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See detailQuantum mechanical statistical theories for chemical reactivity. Overlapping resonances
Desouter, Michèle ULg; Chapuisat, Xavier

in Physical Chemistry Chemical Physics [=PCCP] (1999), 1

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See detailQuantum reversibility and echoes in interacting systems
Petitjean, Cyril ULg; Jacquod, Ph

in PHYSICAL REVIEW LETTERS (2006), 97(12), 124103-4

In echo experiments, imperfect time-reversal operations are performed on a subset of the total number of degrees of freedom. To capture the physics of these experiments, we introduce a partial fidelity M ... [more ▼]

In echo experiments, imperfect time-reversal operations are performed on a subset of the total number of degrees of freedom. To capture the physics of these experiments, we introduce a partial fidelity M(B)(t), the Boltzmann echo, where only part of the system's degrees of freedom can be time reversed. We present a semiclassical calculation of M(B)(t). We show that, as the time-reversal operation is performed more and more accurately, the decay rate of M(B)(t) saturates at a value given by the decoherence rate of the controlled degrees of freedom due to their coupling to uncontrolled ones. We connect these results with NMR spin echo experiments. [less ▲]

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See detailQuantum Spin Transport in Carbon Chains
Zanolli, Zeila ULg; Onida, Giovanni; Charlier, Jean-Christophe

in ACS Nano (2010), 4(9), 5174-5180

First-principles and non-equilibrium Green’s function approaches are used to predict spin-polarized electronic transport in monatomic carbon chains covalently connected to graphene nanoribbons, as ... [more ▼]

First-principles and non-equilibrium Green’s function approaches are used to predict spin-polarized electronic transport in monatomic carbon chains covalently connected to graphene nanoribbons, as recently synthetized experimentally (Jin, C.; et al. Phys. Rev. Lett. 2009, 102, 205501−205504). Quantum electron conductances exhibit narrow resonant states resulting from the simultaneous presence of open conductance channels in the contact region and on the chain atoms. Odd-numbered chains, which acquire metallic or semiconducting character depending on the nature of the edge at the graphene contact, always display a net spin polarization. The combination of electrical and magnetic properties of chains and contacts results in nanodevices with intriguing spintronic properties such as the coexistence of magnetic and semiconducting behaviors. [less ▲]

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See detailQuantum State Construction of Matter Qubits via Projective Measurements
von Zanthier, J.; Maser, A.; Schilling, U. et al

Conference (2009)

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See detailQuantum theory of the cold-atom micromaser including gravity
Bastin, Thierry ULg; Martin, John ULg

in Physical Review. A (2005), 72

The quantum theory of the cold-atom micromaser including the effects of gravity is considered. We show that gravity does not break the special properties of the induced emission probability for the ... [more ▼]

The quantum theory of the cold-atom micromaser including the effects of gravity is considered. We show that gravity does not break the special properties of the induced emission probability for the micromaser in the cold atom regime and rather new effects are predicted. In particular, we show that the cavity acts in the gravity field as an additional repulsive and attractive potential, resulting in quasibound states of the atomic motion. This feature gives rise to fine resonances in the induced emission probability that are not restricted to any particular cavity mode function, in contrast to the usual cold-atom micromaser. It is also shown that the atom is able to emit a photon inside the cavity, though classically it does not reach the interaction region. Predictions about the photon number statistics when the cavity is pumped by a flux of excited atoms are finally given. Unusual highly nonclassical "dragon" distributions are still predicted in the vertical geometry. (c) 2005 American Institute of Physics. [less ▲]

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See detailQuantum-confinement effects in InAs-InP core-shell nanowires
Zanolli, Zeila ULg; Pistol, Mats-Eric; Froberg, Linus E et al

in Journal of Physics : Condensed Matter (2007), 19(29),

We report the detection of quantum confinement in single InAs–InP core–shell nanowires. The wires, having an InAs core with ~25 nm diameter, are characterized by emission spectra in which two peaks are ... [more ▼]

We report the detection of quantum confinement in single InAs–InP core–shell nanowires. The wires, having an InAs core with ~25 nm diameter, are characterized by emission spectra in which two peaks are identified under high excitation intensity conditions. The peaks are caused by emission from the ground and excited quantized levels, due to quantum confinement in the plane perpendicular to the nanowire axis. We have identified different energy contributions in the emission spectra, related to the wurtzite structure of the wires, the strain between the wurtzite core and the shell, and the confinement energy of the InAs core. Calculations based on six-band strain-dependent theory allow the theoretical estimation of the confined energy states in such materials, and we found these results to be in good agreement with those from the photoluminescence studies. [less ▲]

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See detailQuarante ans d'exécution de remembrements ruraux en Région wallonne.
Schmitz, Serge ULg; Christians, Charles ULg

in Acta Geographica Lovaniensia (1998), 37

For forty years, a third of the farming area has been regrouped in Wallonia. The paper draws the development of land consolidation and underlines the increase of non agricultural aims, especially ... [more ▼]

For forty years, a third of the farming area has been regrouped in Wallonia. The paper draws the development of land consolidation and underlines the increase of non agricultural aims, especially environment concerns. So land consolidations with stark productivity concerns in the sixties changed to a new way of land consolidation respectful of the inherited balances and concerned with the functional diversification of the rural areas. However the distribution of land consolidation projects still shows stark productivity concerns : land consolidation projects remain first in ploughed land areas with large farming. [less ▲]

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See detailQuarante ans de céréaliculture en Belgique : évolution des superficies, des rendements et du nombre d'exploitations
Burny, Philippe ULg

in CRA-w; FUSAGx (Eds.) 40 ans Livre blanc Céréales-Gembloux : Economie de la production céréalière en Belgique : Evolution en 40 ans de Politique Agricole Commune et perspectives d’avenir (2007)

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See detailQuarante ans de céréaliculture en Belgique : évolution des superficies, des rendements et du nombre d’exploitations
Burny, Philippe ULg

in Faculté universitaire des Sciences agronomiques de Gembloux; Centre wallon de Recherches agronomiques (Eds.) 40 ans Livre blanc Céréales-Gembloux "Economie de la production céréalière en Belgique : évolution en 40 ans de Politique Agricole Commune et perspectives d’avenir" (2007)

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See detailLe quarantième anniversaire de l’Orchestre Philharmonique de Liège
Pirenne, Christophe ULg; Mairlot, Éric

Conference given outside the academic context (2000)

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See detailQuark and gluon condensates and the small x limit of the nucleon structure functions
Cudell, Jean-René ULg; Donnachie, A.; Landshoff, P. V.

in Nuclear Physics B (1989), 322

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See detailQUARK CONDENSATES, POMERON STRUCTURE AND DISTRIBUTION FUNCTIONS
Cudell, Jean-René ULg

in Tran Thanh Van, Jean (Ed.) Moriond 1989: Hadronic interactions (1989)

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See detailQuark model analysis of the Sivers function
Courtoy, Aurore ULg; Fratini, F.; Scopetta, S. et al

in Physical Review. D, Particles, Fields, Gravitation, and Cosmology (2008), 78(3),

We develop a formalism to evaluate the Sivers function. The approach is well suited for calculations which use constituent quark models to describe the structure of the nucleon. A nonrelativistic ... [more ▼]

We develop a formalism to evaluate the Sivers function. The approach is well suited for calculations which use constituent quark models to describe the structure of the nucleon. A nonrelativistic reduction of the scheme is performed and applied to the Isgur-Karl model of hadron structure. The results obtained are consistent with a sizable Sivers effect and the signs for the u and d flavor contributions turn out to be opposite. This pattern is in agreement with the one found analyzing, in the same model, the impact parameter dependent generalized parton distributions. The Burkardt sum rule turns out to be fulfilled to a large extent. We estimate the QCD evolution of our results from the momentum scale of the model to the experimental one and obtain reasonable agreement with the available data. © 2008 The American Physical Society. [less ▲]

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See detailQuark model: recent issues
Stancu, Floarea ULg

Conference (2007)

In the first part I briefly survey recent issues in constituent quark models raised by the observation of unusual hadronic states. In particular I discuss the role of higher Fock components in the wave ... [more ▼]

In the first part I briefly survey recent issues in constituent quark models raised by the observation of unusual hadronic states. In particular I discuss the role of higher Fock components in the wave function of baryons and the possible interpretation of open charm and of new charmonium-type resonances as tetraquarks. In the second part I show support for the quark model dynamics obtained in a model independent way from the 1/Nc expansion approach of QCD which proved to be successful in describing baryon properties. [less ▲]

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See detailThe quark orbital angular momentum from Wigner distributions and light-cone wave functions
Lorce, Cédric ULg; Pasquini, Barbara; Xiong, Xiaonu et al

in Physical Review. D, Particles, Fields, Gravitation, and Cosmology (2012), D85

We investigate the quark orbital angular momentum of the nucleon in the absence of gauge-field degrees of freedom, by using the concept of the Wigner distribution and the light-cone wave functions of the ... [more ▼]

We investigate the quark orbital angular momentum of the nucleon in the absence of gauge-field degrees of freedom, by using the concept of the Wigner distribution and the light-cone wave functions of the Fock-state expansion of the nucleon. The quark orbital angular momentum is obtained from the phase-space average of the orbital angular momentum operator weighted with the Wigner distribution of unpolarized quarks in a longitudinally polarized nucleon. We also derive the light-cone wave-function representation of the orbital angular momentum. In particular, we perform an expansion in the nucleon Fock-state space and decompose the orbital angular momentum into the N-parton state contributions. Explicit expressions are presented in terms of the light-cone wave functions of the three-quark Fock state. Numerical results for the up and down quark orbital angular momenta of the proton are shown in the lightcone constituent quark model and the light-cone chiral quark-soliton model. [less ▲]

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See detailThe quark propagator from the Dyson-Schwinger equations: (I). The chiral solution
Cudell, Jean-René ULg; Gentles, A. J.; Ross, D. A.

in Nuclear Physics B (1995), 440

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See detailQuark transverse charge densities in the Delta(1232) from lattice QCD
Alexandrou, Constantia; Korzec, Tomasz; Giannis, Koutsou et al

in Nuclear Physics A (2009), A825

We extend the formalism relating electromagnetic form factors to transverse quark charge densities in the light-front frame to the case of a spin-3/2 baryon and calculate these transverse densities for ... [more ▼]

We extend the formalism relating electromagnetic form factors to transverse quark charge densities in the light-front frame to the case of a spin-3/2 baryon and calculate these transverse densities for the $\Delta (1232)$ isobar using lattice QCD. The transverse charge densities for a transversely polarized spin-3/2 particle are characterized by monopole, dipole, quadrupole, and octupole patterns representing the structure beyond that of a pure point-like spin-3/2 particle.We present lattice QCD results for the $\Delta$-isobar electromagnetic form factors for pion masses down to approximatively 350 MeV for three cases: quenched QCD, two-degenerate flavors of dynamicalWilson quarks, and three flavors of quarks using a mixed action that combines domain wall valence quarks and dynamical staggered sea quarks. We extract transverse quark charge densities from these lattice results and find that the $Delta$ is prolately deformed, as indicated by the fact that the quadrupole moment $G_{E2}(0)$ is larger than the value −3 characterizing a point particle and the fact that the transverse charge density in a $\Delta^+$ of maximal transverse spin projection is elongated along the axis of the spin. [less ▲]

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See detailQuark Wigner Distributions and Orbital Angular Momentum
Lorce, Cédric ULg; Pasquini, B.

in Physical Review. D, Particles, Fields, Gravitation, and Cosmology (2011), D84

We study the Wigner functions of the nucleon which provide multidimensional images of the quark distributions in phase space. These functions can be obtained through a Fourier transform in the transverse ... [more ▼]

We study the Wigner functions of the nucleon which provide multidimensional images of the quark distributions in phase space. These functions can be obtained through a Fourier transform in the transverse space of the generalized transverse-momentum dependent parton distributions. They depend on both the transverse position and the three-momentum of the quark relative to the nucleon, and therefore combine in a single picture all the information contained in the generalized parton distributions and the transverse-momentum dependent parton distributions. We focus the discussion on the distributions of unpolarized/longitudinally polarized quark in an unpolarized/longitudinally polarized nucleon. In this way, we can study the role of the orbital angular momentum of the quark in shaping the nucleon and its correlations with the quark and nucleon polarizations. The quark orbital angular momentum is also calculated from its phase-space average weighted with the Wigner distribution of unpolarized quarks in a longitudinally polarized nucleon. The corresponding results obtained within different light-cone quark models are compared with alternative definitions of the quark orbital angular momentum, as given in terms of generalized parton distributions and transverse-momentum dependent parton distributions. [less ▲]

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See detailQuartier nègre: nouveau monde et nouveau code
Demoulin, Laurent ULg

in Traces (2012), 20

Le roman Quartier nègre de Simenon est lu ici à la lumière de l'essai de Goffman La Mise en scène de la vie quotidienne.

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