References of "Schlagheck, Peter"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailTransport of Bose-Einstein Condensates through Aharonov-Bohm rings
Chrétien, Renaud ULg; Dujardin, Julien ULg; Petitjean, Cyril ULg et al

Poster (2015, May 13)

We study the one-dimensional (1D) transport properties of an ultracold gas of Bose-Einstein condensed atoms through Aharonov-Bohm (AB) rings. Our system consists of a Bose-Einstein condensate (BEC) that ... [more ▼]

We study the one-dimensional (1D) transport properties of an ultracold gas of Bose-Einstein condensed atoms through Aharonov-Bohm (AB) rings. Our system consists of a Bose-Einstein condensate (BEC) that is outcoupled from a magnetic trap into a 1D waveguide which is made of two semi-infinite leads that join a ring geometry exposed to a magnetic flux φ. We specifically investigate the effects of a small atom-atom contact interaction strength on the AB oscillations. The main numerical tools that we use for this purpose are a mean-field Gross-Pitaevskii (GP) description and the truncated Wigner (tW) method. The latter allows for the description of incoherent transport and corresponds to a classical sampling of the evolution of the quantum bosonic many-body state through effective GP trajectories. We find that resonant transmission peaks move with an increasing interaction strength and can be suppressed for sufficiently strong interaction. We also observe that the coherent transmission blockade due to destructive interference at the AB flux φ = π is very robust with respect to the interaction strength. [less ▲]

Detailed reference viewed: 148 (26 ULg)
Full Text
Peer Reviewed
See detailElastic and inelastic transmission in guided atom lasers: A truncated Wigner approach
Dujardin, Julien ULg; Argüelles, Arturo; Schlagheck, Peter ULg

in Physical Review A (2015), 91

We study the transport properties of a Bose-Einstein condensate formed by an ultracold gas of bosonic atoms that is coupled from a magnetic trap into a one-dimensional waveguide. Our theoretical approach ... [more ▼]

We study the transport properties of a Bose-Einstein condensate formed by an ultracold gas of bosonic atoms that is coupled from a magnetic trap into a one-dimensional waveguide. Our theoretical approach to tackling this problem is based on the truncated Wigner method for which we assume the system to consist of two semi-infinite noninteracting leads and a finite interacting scattering region with two constrictions modeling an atomic quantum dot. The transmission is computed in the steady-state regime and we find a good agreement between truncated Wigner and matrix-product state calculations. We also identify clear signatures of inelastic resonant scattering by analyzing the distribution of energy in the transmitted atomic-matter wave beam. [less ▲]

Detailed reference viewed: 70 (4 ULg)
Full Text
Peer Reviewed
See detailA study of one-dimensional transport of Bose-Einstein condensates using exterior complex scaling
Dujardin, Julien ULg; Saenz, Alejandro; Schlagheck, Peter ULg

in Applied Physics B : Lasers & Optics (2014), 117(3), 765

We numerically investigate the one-dimensional transport of Bose-Einstein condensates in the context of guided atom lasers using a mean-field description of the condensate in terms of a spatially ... [more ▼]

We numerically investigate the one-dimensional transport of Bose-Einstein condensates in the context of guided atom lasers using a mean-field description of the condensate in terms of a spatially discretized Gross-Pitaevskii equation. We specifically consider a waveguide configuration in which spatial inhomogeneities and nonvanishing atom-atom interactions are restricted to a spatially localized scattering region of finite extent. We show how the method of smooth exterior complex scaling can be implemented for this particular onfiguration in order to efficiently absorb the outgoing flux within the waveguide. A numerical comparison with the introduction of a complex absorbing potential as well as with the analytically exact elimination of the dynamics of the free non-interacting motion outside the scattering region, giving rise to transparent boundary conditions, clearly confirms the accuracy and efficiency of the smooth exterior complex scaling method. [less ▲]

Detailed reference viewed: 91 (32 ULg)
See detailOn the analogy of quantum wave-particle duality with bouncing droplets
Richardson, Chris D.; Schlagheck, Peter ULg; Martin, John ULg et al

E-print/Working paper (2014)

We explore the hydrodynamic analogues of quantum wave-particle duality in the context of a bouncing droplet system which we model in such a way as to promote comparisons to the de Broglie-Bohm ... [more ▼]

We explore the hydrodynamic analogues of quantum wave-particle duality in the context of a bouncing droplet system which we model in such a way as to promote comparisons to the de Broglie-Bohm interpretation of quantum mechanics. Through numerical means we obtain single-slit diffraction and double-slit interference patterns that strongly resemble those reported in experiment and that reflect a striking resemblance to quantum diffraction and interference on a phenomenological level. We, however, identify evident differences from quantum mechanics which arise from the governing equations at the fundamental level. [less ▲]

Detailed reference viewed: 6 (0 ULg)
See detailCoherent backscattering in the Fock space of a disordered Bose-Hubbard system
Schlagheck, Peter ULg

Conference (2014, June)

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 [1]. 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 [1]. 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 which 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. We furthermore propose a specific experimental setup in order to detect this many-body coherent backscattering phenomenon with ultracold bosonic atoms. [less ▲]

Detailed reference viewed: 17 (2 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 62 (5 ULg)
Full Text
Peer Reviewed
See detailNonlinear Schrödinger wave equation with linear quantum behavior
Richardson, Christopher ULg; Schlagheck, Peter ULg; Martin, John ULg et al

in Physical Review A (2014), 89

We show that a nonlinear Schroedinger wave equation can reproduce all the features of linear quantum mechanics. This nonlinear wave equation is obtained by exploring, in a uniform language, the transition ... [more ▼]

We show that a nonlinear Schroedinger wave equation can reproduce all the features of linear quantum mechanics. This nonlinear wave equation is obtained by exploring, in a uniform language, the transition from fully classical theory governed by a nonlinear classical wave equation to quantum theory. The classical wave equation includes a nonlinear classicality enforcing potential which when eliminated transforms the wave equation into the linear Schro ̈dinger equation. We show that it is not necessary to completely cancel this nonlinearity to recover the linear behavior of quantum mechanics. Scaling the classicality enforcing potential is sufficient to have quantumlike features appear and is equivalent to scaling Planck’s constant. [less ▲]

Detailed reference viewed: 32 (7 ULg)
Full Text
Peer Reviewed
See detailSemiclassical description of resonance-assisted tunneling in one-dimensional integrable models
Le Deunff, Jérémy; Mouchet, Amaury; Schlagheck, Peter ULg

in Physical Review. E : Statistical, Nonlinear, and Soft Matter Physics (2013), 88

Resonance-assisted tunneling is investigated within the framework of one-dimensional integrable systems. We present a systematic recipe, based on Hamiltonian normal forms, to construct one-dimensional ... [more ▼]

Resonance-assisted tunneling is investigated within the framework of one-dimensional integrable systems. We present a systematic recipe, based on Hamiltonian normal forms, to construct one-dimensional integrable models that exhibit resonance island chain structures with accurately controlled sizes and positions of the islands. Using complex classical trajectories that evolve along suitably defined paths in the complex time domain, we construct a semiclassical theory of the resonance-assisted tunneling process. This semiclassical approach yields a compact analytical expression for tunnelling-induced level splittings which is found to be in very good agreement with the exact splittings obtained through numerical diagonalization. [less ▲]

Detailed reference viewed: 33 (0 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 43 (8 ULg)
Full Text
Peer Reviewed
See detailDelocalization of ultracold atoms in a disordered potential due to light scattering
Nowak, Boris; Kinnunen, Jami J.; Holland, Murray J. et al

in Physical Review. A (2012), 86

We numerically study the expansion dynamics of ultracold atoms in a one-dimensional disordered potential in the presence of a weak position measurement of the atoms. We specifically consider this position ... [more ▼]

We numerically study the expansion dynamics of ultracold atoms in a one-dimensional disordered potential in the presence of a weak position measurement of the atoms. We specifically consider this position measurement to be realized by a combination of an external laser and a periodic array of optical microcavities along a waveguide. The position information is acquired through the scattering of a near-resonant laser photon into a specific eigenmode of one of the cavities. The time evolution of the atomic density in the presence of this light-scattering mechanism is described within a Lindblad master equation approach, which is numerically implemented using the Monte Carlo wave function technique. We find that an arbitrarily weak rate of photon emission leads to a breakdown of Anderson localization of the atoms. [less ▲]

Detailed reference viewed: 53 (3 ULg)
See detailWeak localization with interacting Bose-Einstein condensates
Schlagheck, Peter ULg

Conference (2012, August)

Detailed reference viewed: 13 (2 ULg)
Full Text
See detailWeak localization with interacting Bose-Einstein condensates
Hartmann, Timo; Hartung, Michael; Michl, Josef et al

Poster (2012, June)

We study the quasi-stationary propagation of Bose-Einstein condensates through two-dimensional mesoscopic scattering geometries that correspond to disorder potentials [1] or to ballistic billiard con ... [more ▼]

We study the quasi-stationary propagation of Bose-Einstein condensates through two-dimensional mesoscopic scattering geometries that correspond to disorder potentials [1] or to ballistic billiard con nements with chaotic classical dynamics [2]. Our theoretical approach is based on the two-dimensional Gross-Pitaevskii equation, which is numerically integrated in order to determine reflection and transmission probabilities associated with self-consistent stationary scattering states, and which represents the starting point for an analytical description of the scattering process in terms of a nonlinear diagrammatic theory. Both numerically and analytically, we nd that the presence of the atom-atom interaction within the condensate gives rise to signatures of weak antilocalization, i.e. to an inversion of the coherent backscattering peak in disordered systems [1] and to a reduction, instead of an enhancement, of the retro-reflection probability in chaotic billiard geometries [2]. Short-path contributions associated, in particular, with self-retraced trajectories are conjectured to be at the origin of this antilocalization phenomenon. References: [1] M. Hartung, T. Wellens, C. A. M uller, K. Richter, and P. Schlagheck, PRL 101, 020603 (2008). [2] T. Hartmann, J. Michl, C. Petitjean, T. Wellens, J.-D. Urbina, K. Richter, and P. Schlagheck, Ann. Phys., in press, (arXiv:1112.5603). [less ▲]

Detailed reference viewed: 24 (1 ULg)
Full Text
See detail1D many-body quantum transport of Bose-Einstein condensates : a truncated Wigner approach
Dujardin, Julien ULg; Argüelles Parra, Arturo ULg; Schlagheck, Peter ULg

Poster (2012, March 29)

We calculate the transport properties of an ultracold gas of Bose- Einstein condensed atoms that is coupled from a magnetic trap into a one-dimensional waveguide. A central aim of such guided atom lasers ... [more ▼]

We calculate the transport properties of an ultracold gas of Bose- Einstein condensed atoms that is coupled from a magnetic trap into a one-dimensional waveguide. A central aim of such guided atom lasers is to study the role of atom-atom interaction in many-body transport processes across finite scattering regions within the waveguide resembling tunnel junctions and quantum dots. Our numerical approach to solve this many-body scattering problem is based on a home-made theory where the boundaries of the system are simulating an open system enabling us to calulate observable in the steady-state regime such as density, current, transmission. The results are compared to the mean-field regime. [less ▲]

Detailed reference viewed: 107 (8 ULg)
See detailMesoscopic transport with ultracold atoms
Schlagheck, Peter ULg

Conference (2012, March)

Detailed reference viewed: 9 (3 ULg)
Full Text
Peer Reviewed
See detailIntensity distribution of non-linear scattering states
Hartmann, Timo; Urbina, Juan-Diego; Richter, Klaus et al

in Robnik, M.; Romanovski, V.G. (Eds.) LET'S FACE CHAOS THROUGH NONLINEAR DYNAMICS (2012)

We investigate the interplay between coherent effects characteristic of the propagation of linear waves, the non-linear effects due to interactions, and the quantum manifestations of classical chaos due ... [more ▼]

We investigate the interplay between coherent effects characteristic of the propagation of linear waves, the non-linear effects due to interactions, and the quantum manifestations of classical chaos due to geometrical confinement, as they arise in the context of the transport of Bose-Einstein condensates. We specifically show that, extending standard methods for non-interacting systems, the body of the statistical distribution of intensities for scattering states solving the Gross-Pitaevskii equation is very well described by a local Gaussian ansatz with a position-dependent variance. We propose a semiclassical approach based on interfering classical paths to fix the single parameter describing the universal deviations from a global Gaussian distribution. Being tail effects, rare events like rogue waves characteristic of non-linear field equations do not affect our results. [less ▲]

Detailed reference viewed: 32 (4 ULg)
Full Text
Peer Reviewed
See detailWeak localization with nonlinear bosonic matter waves
Hartmann, Timo; Michl, Josef; Petitjean, Cyril et al

in Annals of Physics (2012), 327

We investigate the coherent propagation of dilute atomic Bose-Einstein condensates through irregularly shaped billiard geometries that are attached to uniform incoming and outgoing waveguides. Using the ... [more ▼]

We investigate the coherent propagation of dilute atomic Bose-Einstein condensates through irregularly shaped billiard geometries that are attached to uniform incoming and outgoing waveguides. Using the mean-field description based on the nonlinear Gross–Pitaevskii equation, we develop a diagrammatic theory for the self-consistent stationary scattering state of the interacting condensate, which is combined with the semiclassical representation of the single-particle Green function in terms of chaotic classical trajectories within the billiard. This analytical approach predicts a universal dephasing of weak localization in the presence of a small interaction strength between the atoms, which is found to be in good agreement with the numerically computed reflection and transmission probabilities of the propagating condensate. The numerical simulation of this quasi-stationary scattering process indicates that this interaction-induced dephasing mechanism may give rise to a signature of weak antilocalization, which we attribute to the influence of non-universal short-path contributions. [less ▲]

Detailed reference viewed: 38 (3 ULg)
See detailResonance-assisted tunneling in mixed regular-chaotic systems
Schlagheck, Peter ULg

Conference (2011, June)

Detailed reference viewed: 12 (0 ULg)
Full Text
See detailResonance-assisted tunneling in mixed regular-chaotic systems
Schlagheck, Peter ULg; Mouchet, Amaury; Ullmo, Denis

in Keshavamurthy, Srihari; Schlagheck, Peter (Eds.) Dynamical Tunneling - Theory and Experiment (2011)

Detailed reference viewed: 34 (4 ULg)
Full Text
Peer Reviewed
See detailEffective spin model for interband transport in a Wannier-Stark lattice system
Plötz, Patrick; Schlagheck, Peter ULg; Wimberger, Sandro

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2011), 63

We show that the interband dynamics in a tilted two-band Bose-Hubbard model can be reduced to an analytically accessible spin model in the case of resonant interband oscillations. This allows us to ... [more ▼]

We show that the interband dynamics in a tilted two-band Bose-Hubbard model can be reduced to an analytically accessible spin model in the case of resonant interband oscillations. This allows us to predict the revival time of these oscillations which decay and revive due to inter-particle interactions. The presented mapping onto the spin model and the so achieved reduction of complexity has interesting perspectives for future studies of many-body systems. [less ▲]

Detailed reference viewed: 25 (2 ULg)