14 research outputs found

    Phase Space Tomography of Matter-Wave Diffraction in the Talbot Regime

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    We report on the theoretical investigation of Wigner distribution function (WDF) reconstruction of the motional quantum state of large molecules in de Broglie interference. De Broglie interference of fullerenes and as the like already proves the wavelike behaviour of these heavy particles, while we aim to extract more quantitative information about the superposition quantum state in motion. We simulate the reconstruction of the WDF numerically based on an analytic probability distribution and investigate its properties by variation of parameters, which are relevant for the experiment. Even though the WDF described in the near-field experiment cannot be reconstructed completely, we observe negativity even in the partially reconstructed WDF. We further consider incoherent factors to simulate the experimental situation such as a finite number of slits, collimation, and particle-slit van der Waals interaction. From this we find experimental conditions to reconstruct the WDF from Talbot interference fringes in molecule Talbot-Lau interferometry.Comment: 16 pages, 9 figures, accepted at New Journal of Physic

    Tailoring discrete quantum walk dynamics via extended initial conditions: Towards homogeneous probability distributions

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    We study the evolution of initially extended distributions in the coined quantum walk on the line by analyzing the dispersion relation of the process and its associated wave equations. This allows us, in particular, to devise an initially extended condition leading to a uniform probability distribution whose width increases linearly with time, with increasing homogeneity.Comment: 4 pages, 2 figure

    The particle in the box: Intermode traces in the propagator

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    Characteristic structures such as canals and ridges-intermode traces-emerge in the spacetime representation of the probability distribution of a particle in a one-dimensional box. We show that the corresponding propagator already contains these structures. We relate their visibility to the factorization property of the initial wave packet

    Quantum carpet interferometry for trapped atomic Bose-Einstein condensates

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    We propose an ``interferometric'' scheme for Bose-Einstein condensates using near-field diffraction. The scheme is based on the phenomenon of intermode traces or quantum carpets; we show how it may be used in the detection of weak forces.Comment: 4 figures. Submitted to Phys. Rev.

    Quantum carpets woven by Wigner functions

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    The dynamics of many different quantum systems is characterized by a regular net of minima and maxima of probability stretching out in a spacetime representation. We offer an explanation to this phenomenon in terms of the Wigner function. This approach illustrates very clearly the crucial role played by interference

    Quantum carpets and Wigner functions

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    A particle confined to an infinitely deep potential well is the ideal toy model for studying the origin of the regular patterns appearing for many physical systems in the spacetime representation of the probability density. The Wigner function is a useful tool to bring out the role of interference in the formation of these so-called "quantum carpets"
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