Adiabatic techniques are known to allow for engineering quantum states with high fidelity. This requirement is currently of large interest, as applications in quantum information require the preparation and manipulation of quantum states with minimal errors. Here we review recent progress on developing techniques for the preparation of spatial states through adiabatic passage, particularly focusing on three state systems. These techniques can be applied to matter waves in external potentials, such as cold atoms or electrons, and to classical waves in waveguides, such as light or sound

%B Reports on Progress in Physics %V 79 %U http://stacks.iop.org/0034-4885/79/i=7/a=074401 %& 074401 %0 Journal Article %J New Journal of Physics %D 2016 %T Transport of ultracold atoms between concentric traps via spatial adiabatic passage %A J. Polo %A A. Benseny %A T. Busch %A V. Ahufinger %A J. Mompart %XSpatial adiabatic passage processes for ultracold atoms trapped in tunnel-coupled cylindrically symmetric concentric potentials are investigated. Specifically, we discuss the matter-wave analog of the rapid adiabatic passage (RAP) technique for a high fidelity and robust loading of a single atom into a harmonic ring potential from a harmonic trap, and for its transport between two concentric rings. We also consider a system of three concentric rings and investigate the transport of a single atom between the innermost and the outermost rings making use of the matter-wave analog of the stimulated Raman adiabatic passage (STIRAP) technique. We describe the RAP-like and STIRAP-like dynamics by means of a two- and a three-state model, respectively, obtaining good agreement with the numerical simulations of the corresponding two-dimensional Schrödinger equation.

%B New Journal of Physics %V 18 %P 015010 %U http://stacks.iop.org/1367-2630/18/i=1/a=015010 %0 Journal Article %J European Physical Journal D %D 2014 %T Applied Bohmian mechanics %A A. Benseny %A G. Albareda %A A. S. Sanz %A J. Mompart %A X. Oriols %X Bohmian mechanics provides an explanation of quantum phenomena in terms of point-like particles guided by wave functions. This review focuses on the use of nonrelativistic Bohmian mechanics to address practical problems, rather than on its interpretation. Although the Bohmian and standard quantum theories have different formalisms, both give exactly the same predictions for all phenomena. Fifteen years ago, the quantum chemistry community began to study the practical usefulness of Bohmian mechanics. Since then, the scientific community has mainly applied it to study the (unitary) evolution of single-particle wave functions, either by developing efficient quantum trajectory algorithms or by providing a trajectorybased explanation of complicated quantum phenomena. Here we present a large list of examples showing how the Bohmian formalism provides a useful solution in different forefront research fields for this kind of problems (where the Bohmian and the quantum hydrodynamic formalisms coincide). In addition, this work also emphasizes that the Bohmian formalism can be a useful tool in other types of (nonunitary and nonlinear) quantum problems where the influence of the environment or the nonsimulated degrees of freedom are relevant. This review contains also examples on the use of the Bohmian formalism for the many-body problem, decoherence and measurement processes. The ability of the Bohmian formalism to analyze this last type of problems for (open) quantum systems remains mainly unexplored by the scientific community. The authors of this review are convinced that the final status of the Bohmian theory among the scientific community will be greatly influenced by its potential success in those types of problems that present nonunitary and/or nonlinear quantum evolutions. A brief introduction of the Bohmian formalism and some of its extensions are presented in the last part of this review. %B European Physical Journal D %V 68 %P 1-42 %8 10/2014 %U http://link.springer.com/article/10.1140%2Fepjd%2Fe2014-50222-4 %9 Topical Review %& 286 %R 10.1140/epjd/e2014-50222-4 %0 Journal Article %J Quantum Information Processing %D 2013 %T Speeding up the spatial adiabatic passage of matter waves in optical microtraps by optimal control %A A. Negretti %A A. Benseny %A J. Mompart %A T. Calarco %K Atomic molecular and optical physics %K Control of matter waves %K Numerical optimization methods %K Quantum optimal control %B Quantum Information Processing %V 12 %P 1439-1467 %8 03/2013 %U http://link.springer.com/article/10.1007%2Fs11128-012-0357-z %) http://arxiv.org/abs/1112.3828 %& 1439 %R 10.1007/s11128-012-0357-z %0 Journal Article %J Phys. Rev. A %D 2012 %T Need for relativistic corrections in the analysis of spatial adiabatic passage of matter waves %A A. Benseny %A J. Bagudà %A X. Oriols %A J. Mompart %X We investigate the coherent transport of a single particle and a Bose-Einstein condensate between the two extreme traps of a triple-well potential by means of the spatial adiabatic passage technique. This matter wave transport technique consists of adiabatically following an energy eigenstate of the system that only populates the vibrational ground states of the two extreme wells and presents at all times a node in the central region. Unraveling the (nonlinear) time-dependent Schrödinger equation in terms of Bohmian quantum trajectories, we show that by slowing down the total time duration of the transport process, Bohmian velocities in the central region are orders of magnitude larger than the mean atomic velocities. This leads to a very counterintuitive effect: in the regime of almost perfect adiabaticity, these velocities require relativistic corrections to properly address the transfer process and avoid superluminal propagation. %B Phys. Rev. A %I American Physical Society %V 85 %P 053619 %8 05/2012 %U http://link.aps.org/doi/10.1103/PhysRevA.85.053619 %) http://arxiv.org/abs/1107.4276 %R 10.1103/PhysRevA.85.053619 %0 Journal Article %J Journal of Optics %D 2011 %T Spin and orbital angular momentum propagation in anisotropic media: theory %A A. Picón %A A. Benseny %A J. Mompart %A G F Calvo %X This paper is devoted to a study of the propagation of light beams carrying orbital angular momentum in optically anisotropic media. We first review some properties of homogeneous anisotropic media, and describe how the paraxial formalism is modified in order to proceed with a new approach dealing with the general setting of paraxial propagation along uniaxial inhomogeneous media. This approach is suitable for describing space-variant optical-axis phase plates. %B Journal of Optics %V 13 %P 064019 %U http://stacks.iop.org/2040-8986/13/i=6/a=064019 %0 Journal Article %J Phys. Rev. A %D 2010 %T Atomtronics with holes: Coherent transport of an empty site in a triple-well potential %A A. Benseny %A S. Fernández-Vidal %A J. Bagudà %A R. Corbalán %A A. Picón %A L. Roso %A G. Birkl %A J. Mompart %X We investigate arrays of three traps with two fermionic or bosonic atoms. The tunneling interaction between neighboring sites is used to prepare multisite dark states for the empty site (i.e., the hole) which allows for the coherent manipulation of its external degrees of freedom. By means of an ab initio integration of the Schrödinger equation, we investigate the adiabatic transport of a hole between the two extreme traps of a triple-well potential. Furthermore, a quantum-trajectory approach based on the de Broglie–Bohm formulation of quantum mechanics is used to get physical insight into the transport process. Finally, we discuss the use of the hole for the construction of a coherent single hole diode and a coherent single hole transistor. %B Phys. Rev. A %I American Physical Society %V 82 %P 013604 %8 Jul %U http://link.aps.org/doi/10.1103/PhysRevA.82.013604 %R 10.1103/PhysRevA.82.013604 %0 Journal Article %J New Journal of Physics %D 2010 %T Transferring orbital and spin angular momenta of light to atoms %A A. Picón %A A. Benseny %A J. Mompart %A J R Vázquez de Aldana %A L. Plaja %A G F Calvo %A L. Roso %X Light beams carrying orbital angular momentum (OAM), such as Laguerre–Gaussian (LG) beams, give rise to the violation of the standard dipolar selection rules during interaction with matter, yielding, in general, an exchange of angular momentum larger than ##IMG## [http://ej.iop.org/icons/Entities/planck.gif] {planck} per absorbed photon. By means of ab initio three-dimensional (3D) numerical simulations, we investigate in detail the interaction of a hydrogen atom with intense Gaussian and LG light pulses. We analyze the dependence of the angular momentum exchange with the polarization, the OAM and the carrier-envelope phase of light, as well as with the relative position between the atom and the light vortex. In addition, a quantum-trajectory approach based on the de Broglie–Bohm formulation of quantum mechanics is used to gain physical insight into the absorption of angular momentum by the hydrogen atom. %B New Journal of Physics %V 12 %P 083053 %U http://stacks.iop.org/1367-2630/12/i=8/a=083053