References of "Physical Review Letters"
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See detailTensor Representation of Spin States
Giraud, Olivier; Braun, Daniel; Baguette, Dorian ULg et al

in Physical Review Letters (2015), 114

We propose a generalization of the Bloch sphere representation for arbitrary spin states. It provides a compact and elegant representation of spin density matrices in terms of tensors that share the most ... [more ▼]

We propose a generalization of the Bloch sphere representation for arbitrary spin states. It provides a compact and elegant representation of spin density matrices in terms of tensors that share the most important properties of Bloch vectors. Our representation, based on covariant matrices introduced by Weinberg in the context of quantum field theory, allows for a simple parametrization of coherent spin states, and a straightforward transformation of density matrices under local unitary and partial tracing operations. It enables us to provide a criterion for anticoherence, relevant in a broader context such as quantum polarization of light. [less ▲]

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See detailCoherent Electronic Wave Packet Motion in ${\mathrm{C}}_{60}$ Controlled by the Waveform and Polarization of Few-Cycle Laser Fields
Li, H.; Mignolet, Benoît ULg; Wachter, G. et al

in Physical Review Letters (2015), 114(12), 123004

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See detailTwo Scenarios for Quantum Multifractality Breakdown
Dubertrand, Rémy ULg; Garcia-Mata, Ignacio; Georgeot, Bertrand et al

in Physical Review Letters (2014), 112

We expose two scenarios for the breakdown of quantum multifractality under the effect of perturbations. In the first scenario, multifractality survives below a certain scale of the quantum fluctuations ... [more ▼]

We expose two scenarios for the breakdown of quantum multifractality under the effect of perturbations. In the first scenario, multifractality survives below a certain scale of the quantum fluctuations. In the other one, the fluctuations of the wave functions are changed at every scale and each multifractal dimension smoothly goes to the ergodic value. We use as generic examples a one-dimensional dynamical system and the three-dimensional Anderson model at the metal-insulator transition. Based on our results, we conjecture that the sensitivity of quantum multifractality to perturbation is universal in the sense that it follows one of these two scenarios depending on the perturbation. We also discuss the experimental implications. [less ▲]

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See detailCoherent Backscattering in Fock Space: A Signature of Quantum Many-Body Interference in Interacting Bosonic Systems
Engl, Thomas; Dujardin, Julien ULg; Argüelles, Arturo et al

in Physical Review Letters (2014), 112

We predict a generic signature of quantum interference in many-body bosonic systems resulting in a coherent enhancement of the average return probability in Fock space. This enhancement is robust with ... [more ▼]

We predict a generic signature of quantum interference in many-body bosonic systems resulting in a coherent enhancement of the average return probability in Fock space. This enhancement is robust with respect to variations of external parameters even though it represents a dynamical manifestation of the delicate superposition principle in Fock space. It is a genuine quantum many-body effect that lies beyond the reach of any mean-field approach. Using a semiclassical approach based on interfering paths in Fock space, we calculate the magnitude of the backscattering peak and its dependence on gauge fields that break time-reversal invariance. We confirm our predictions by comparing them to exact quantum evolution probabilities in Bose-Hubbard models, and discuss their relevance in the context of many-body thermalization. [less ▲]

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See detailFirst Principles Explanation of the Positive Seebeck Coefficient of Lithium
Xu, Bin ULg; Verstraete, Matthieu ULg

in Physical Review Letters (2014), 112

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See detailAre Hydrogen-Bonded Charge Transfer Crystals Room Temperature Ferroelectrics?
D'Avino, Gabriele ULg; Verstraete, Matthieu ULg

in Physical Review Letters (2014), 113

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See detailDynamics of a grain-filled ball on a vibrating plate
Pacheco Vazquez, Felipe ULg; Ludewig, François ULg; Dorbolo, Stéphane ULg

in Physical Review Letters (2014), 113

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See detailRole of disorder in the thermodynamics and atomic dynamics of glasses
Chumakov, A. I.; Monaco, G.; Fontana, A. et al

in Physical Review Letters (2014), 112(2),

We measured the density of vibrational states (DOS) and the specific heat of various glassy and crystalline polymorphs of SiO2. The typical (ambient) glass shows a well-known excess of specific heat ... [more ▼]

We measured the density of vibrational states (DOS) and the specific heat of various glassy and crystalline polymorphs of SiO2. The typical (ambient) glass shows a well-known excess of specific heat relative to the typical crystal (α-quartz). This, however, holds when comparing a lower-density glass to a higher-density crystal. For glassy and crystalline polymorphs with matched densities, the DOS of the glass appears as the smoothed counterpart of the DOS of the corresponding crystal; it reveals the same number of the excess states relative to the Debye model, the same number of all states in the low-energy region, and it provides the same specific heat. This shows that glasses have higher specific heat than crystals not due to disorder, but because the typical glass has lower density than the typical crystal. © 2014 American Physical Society. [less ▲]

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See detailNuclear forward scattering of synchrotron radiation by Ru 99
Bessas, D.; Merkel, D. G.; Chumakov, A. I. et al

in Physical Review Letters (2014), 113(14),

We measured nuclear forward scattering spectra utilizing the Ru99 transition, 89.571(3) keV, with a notably mixed E2/M1 multipolarity. The extension of the standard evaluation routines to include mixed ... [more ▼]

We measured nuclear forward scattering spectra utilizing the Ru99 transition, 89.571(3) keV, with a notably mixed E2/M1 multipolarity. The extension of the standard evaluation routines to include mixed multipolarity allows us to extract electric and magnetic hyperfine interactions from Ru99-containing compounds. This paves the way for several other high-energy Mössbauer transitions, E∼90keV. The high energy of such transitions allows for operando nuclear forward scattering studies in real devices. © 2014 American Physical Society. [less ▲]

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See detailDetecting transition radiation from a magnetic moment
Ivanov, Igor ULg; Karlovets, Dmitry

in Physical Review Letters (2013), 110(26), 2648015

Electromagnetic radiation can be emitted not only by particle charges but also by magnetic moments and higher electric and magnetic multipoles. However, experimental proofs of this fundamental fact are ... [more ▼]

Electromagnetic radiation can be emitted not only by particle charges but also by magnetic moments and higher electric and magnetic multipoles. However, experimental proofs of this fundamental fact are extremely scarce. In particular, the magnetic moment contribution has never been observed in any form of polarization radiation. Here, we propose to detect it using vortex electrons carrying large orbital angular momentum ℓ. The relative contribution of the orbital angular momentum-induced magnetic moment, ℓℏω/Ee, becomes much larger than the spin-induced contribution ℏω/Ee, and it can be observed experimentally. As a particular example, we consider transition radiation from vortex electrons obliquely incident on an interface between a vacuum and a dispersive medium, in which the magnetic moment contribution manifests itself via a left-right angular asymmetry. For electrons with Ee=300  keV and ℓ=100–1000, we predict an asymmetry of the order of 0.1%–1%, which could be measured with existing technology. Thus, vortex electrons emerge as a new tool in the physics of electromagnetic radiation. [less ▲]

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See detailComment on ``Proton Spin Structure from Measurable Parton Distributions''
Leader, Elliot; Lorce, Cédric ULg

in Physical Review Letters (2013), 111

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See detailTotal Current Blockade in an Ultracold Dipolar Quantum Wire
Kristinsdóttir, L.H.; Karlström, O.; Cremon, J.C. et al

in Physical Review Letters (2013), 110

Cold-atom systems offer a great potential for the future design of new mesoscopic quantum systems with properties that are fundamentally different from semiconductor nanostructures. Here, we investigate ... [more ▼]

Cold-atom systems offer a great potential for the future design of new mesoscopic quantum systems with properties that are fundamentally different from semiconductor nanostructures. Here, we investigate the quantum-gas analogue of a quantum wire and find a new scenario for the quantum transport: Attractive interactions may lead to a complete suppression of current in the low-bias range, a total current blockade. We demonstrate this effect for the example of ultracold quantum gases with dipolar interactions. [less ▲]

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See detailRole of Dynamical Instability in the Ab~Initio Phase Diagram of Calcium
Di Gennaro, Marco ULg; Saha, Srijan Kumar; Verstraete, Matthieu ULg

in Physical Review Letters (2013), 111

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See detailAntibubbles dynamics: the drainage of an air film with incompressible interfaces
Scheid, Benoit; Dorbolo, Stéphane ULg; Arriaga, Laura et al

in Physical Review Letters (2012)

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See detailBreaking Arches with Vibrations: The Role of Defects
Lozano, Celia; Lumay, Geoffroy ULg; Zuriguel, Iker et al

in Physical Review Letters (2012)

We present experimental and numerical results regarding the stability of arches against external vibrations. Two-dimensional strings of mutually stabilizing grains are geometrically analyzed and ... [more ▼]

We present experimental and numerical results regarding the stability of arches against external vibrations. Two-dimensional strings of mutually stabilizing grains are geometrically analyzed and subsequently submitted to a periodic forcing at fixed frequency and increasing amplitude. The main factor that determines the granular arch resistance against vibrations is the maximum angle among those formed between any particle of the arch and its two neighbors: the higher the maximum angle is, the easier it is to break the arch. On the basis of an analysis of the forces, a simple explanation is given for this dependence. From this, interesting information can be extracted about the expected magnitudes of normal forces and friction coefficients of the particles composing the arches. [less ▲]

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See detailComment on "new structural picture of the Ge 2Sb 2Te 5 phase-change alloy"
Raty, Jean-Yves ULg; Bichara, C.; Mazzarello, R. et al

in Physical Review Letters (2012), 108(23),

[No abstract available]

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See detailDensity of states for a specified correlation function and the energy landscape
Gommes, Cédric ULg; Jiao, Yang; Torquato, Salvatore

in Physical Review Letters (2012)

The degeneracy of two-phase disordered microstructures consistent with a specified correlation function is analyzed by mapping it to a ground-state degeneracy. We determine for the first time the ... [more ▼]

The degeneracy of two-phase disordered microstructures consistent with a specified correlation function is analyzed by mapping it to a ground-state degeneracy. We determine for the first time the associated density of states via a Monte Carlo algorithm. Our results are described in terms of the roughness of the energy landscape, defined on a hypercubic configuration space. The use of a Hamming distance in this space enables us to define a roughness metric, which is calculated from the correlation function alone and related quantitatively to the structural degeneracy. This relation is validated for a wide variety of disordered systems. [less ▲]

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See detailAngular-resolved Photoelectron Spectroscopy of Superatom Orbitals of Fullerenes
Johansson, J. Olof; Henderson, Gordon G.; Remacle, Françoise ULg et al

in Physical Review Letters (2012), 108(17), 173401

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See detailLinear magnetoelectric effect by orbital magnetism
Scaramucci, A.; Bousquet, Eric ULg; Fechner, M. et al

in Physical Review Letters (2012), 109(19),

We use symmetry analysis and first-principles calculations to show that the linear magnetoelectric effect can originate from the response of orbital magnetic moments to the polar distortions induced by an ... [more ▼]

We use symmetry analysis and first-principles calculations to show that the linear magnetoelectric effect can originate from the response of orbital magnetic moments to the polar distortions induced by an applied electric field. Using LiFePO 4 as a model compound we show that spin-orbit coupling partially lifts the quenching of the 3d orbitals and causes small orbital magnetic moments (μ (L)≈0.3μ B) parallel to the spins of the Fe2 + ions. An applied electric field E modifies the size of these orbital magnetic moments inducing a net magnetization linear in E. © 2012 American Physical Society. [less ▲]

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See detailHighly Confined Spin-Polarized Two-Dimensional Electron Gas in SrTiO3/SrRuO3 Superlattices
Verissimo-Alves, M.; Garcia-Fernandez, P.; Bilc, Daniel ULg et al

in Physical Review Letters (2012), 108

We report first-principles characterization of the structural and electronic properties of (SrTiO3)5/(SrRuO3)1 superlattices. We show that the system exhibits a spin-polarized two-dimensional electron gas ... [more ▼]

We report first-principles characterization of the structural and electronic properties of (SrTiO3)5/(SrRuO3)1 superlattices. We show that the system exhibits a spin-polarized two-dimensional electron gas, extremely confined to the 4d orbitals of Ru in the SrRuO3 layer. Every interface in the superlattice behaves as a minority-spin half-metal ferromagnet, with a magnetic moment of µ = 2.0µB/SrRuO3 unit. The shape of the electronic density of states, half-metallicity, and magnetism are explained in terms of a simplified tight-binding model, considering only the t2g orbitals plus (i) the bidimensionality of the system and (ii) strong electron correlations. [less ▲]

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