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Single-photon sources with near-unity efficiency and indistinguishability play a major role in the development of quantum technologies. However, on-demand excitation of the emitter imposes substantial limitations to the source performance.…

Quantum Physics · Physics 2023-05-30 Luca Vannucci , Niels Gregersen

We present a novel approach for solving the shallow water equations using a discontinuous Galerkin spectral element method. The method we propose has three main features. First, it enjoys a discrete well-balanced property, in a spirit…

Numerical Analysis · Mathematics 2023-09-15 Yogiraj Mantri , Philipp Öffner , Mario Ricchiuto

Resonant optical pumping in dense atomic media is discussed, where the absorption length is less than the smallest characteristic dimension of the sample. It is shown that reabsorption and multiple scattering of spontaneous photons…

Quantum Physics · Physics 2009-10-31 Michael Fleischhauer

We consider energy norm a posteriori error analysis of conforming finite element approximations of singularly perturbed reaction-diffusion problems on simplicial meshes in arbitrary space dimension. Using an equilibrated flux…

Numerical Analysis · Mathematics 2020-11-25 Iain Smears , Martin Vohralík

We characterize the optical response of a three-level atom subjected to an incoherent pump and continuously illuminated with a weak, quasi-resonant probe field. To this end, we apply a wavefunction approach based on QED Hamiltonian…

Quantum Physics · Physics 2021-10-27 Manuel Donaire

We have developed an improved scheme for loading atoms into a magneto-optical trap (MOT) from a directed alkali metal dispenser in < 10^-10 torr ultra-high vacuum conditions. A current-driven dispenser was surrounded with a cold absorbing…

Atom interferometers allow determining inertial effects to high accuracy. Quantum-projection noise as well as systematic effects impose demands on large atomic flux as well as ultra-low expansion rates. Here we report on a high-flux source…

Recent approaches in source separation leverage semantic information about their input mixtures and constituent sources that when used in conditional separation models can achieve impressive performance. Most approaches along these lines…

Sound · Computer Science 2023-09-27 Dimitrios Bralios , Efthymios Tzinis , Paris Smaragdis

This paper is concerned with reconstructing an acoustic obstacle and its excitation sources from the phaseless near-field measurements. By supplementing some artificial sources to the inverse scattering system, this co-inversion problem can…

Numerical Analysis · Mathematics 2022-12-20 Deyue Zhang , Yue Wu , Yukun Guo

A novel laser molecular beam epitaxy (LMBE) system for the fabrication of atomically controlled oxides superlattices and an x-ray diffractometer that measures spatially-resolved x-ray diffraction spectra have been developed based on the…

Materials Science · Physics 2009-11-11 M. Ohtani , M. Lippmaa , T. Ohnishi , M. Kawasaki

We investigate the identification of the time-dependent source term in the diffusion equation using boundary measurements. This facilitates tracing back the origins of environmental pollutants. Employing the concept of dynamic complex…

Numerical Analysis · Mathematics 2023-11-21 Lingyun Qiu , Zhongjing Wang , Hui Yu , Shenwen Yu

We describe a pulsed rotating supersonic beam source, evolved from an ancestral device [M. Gupta and D. Herschbach, J. Phys. Chem. A 105, 1626 (2001)]. The beam emerges from a nozzle near the tip of a hollow rotor which can be spun at…

A high pumping speed is required in neutral beam injectors to minimise re-ionisation of the neutral beams. The neutral beam injectors on MAST use titanium sublimation pumps. These pumps do not have a constant pumping speed; their pumping…

Accelerator Physics · Physics 2015-10-29 R McAdams

We discuss a new compact gamma-ray source aiming at high spectral density, up to two orders of magnitude higher than currently available bremsstrahlung sources, and conceptually similar to Compton Sources based on conventional linear…

Plasma Physics · Physics 2015-06-12 L. A. Gizzi , M. P. Anania , G. Gatti , D. Giulietti , G. Grittani , M. Kando , M. Krus , L. Labate , T. Levato , Y. Oishi , F. Rossi

We consider an inverse problem for the linear one-dimensional wave equation with variable coefficients consisting in determining an unknown source term from a boundary observation. A method to obtain approximations of this inverse problem…

Numerical Analysis · Mathematics 2025-01-22 Carlos Castro , Sorin Micu

Flow in fractured porous media represents a challenge for discretization methods due to the disparate scales and complex geometry. Herein we propose a new discretization, based on the mixed finite element method and mortar methods. Our…

Numerical Analysis · Mathematics 2017-07-18 Wietse M. Boon , Jan M. Nordbotten , Ivan Yotov

When two binary solutions are separated by a permeable barrier, the individual species typically diffuse and mix, dissipating their chemical potential gradients. However, we use model lattice simulations to show that single-file…

Statistical Mechanics · Physics 2009-10-31 Tom Chou , Detlef Lohse

We propose the new method of essential decrease of transit-time broadening of Doppler-free absorption resonances on transitions between long-lived quantum levels of atoms (or molecules) of a rarefied gas medium. This method is based on…

Atomic Physics · Physics 2018-02-06 Azad Ch. Izmailov

We propose a mixed finite element method for Stokes flow with one degree of freedom per element and facet of simplicial grids. The method is derived by considering the vorticity-velocity-pressure formulation and eliminating the vorticity…

Numerical Analysis · Mathematics 2022-08-30 Wietse M. Boon , Alessio Fumagalli

A topological pump enables robust transport of quantized particles when the system parameters are varied in a cyclic process. In previous studies, topological pump was achieved inhomogeneous systems guaranteed by a topological invariant of…

Mesoscale and Nanoscale Physics · Physics 2021-04-08 Bi-Ye Xie , Oubo You , Shuang Zhang