Search results for "cold atom"
showing 10 items of 54 documents
2-qubit quantum state transfer in spin chains and cold atoms with weak links
2017
In this paper we discuss the implementation of 2-qubit quantum state transfer (QST) in inhomogeneous spin chains where the sender and the receiver blocks are coupled through the bulk channel via weak links. The fidelity and the typical timescale of the QST are discussed as a function of the parameters of the weak links. Given the possibility of implementing with cold atoms in optical lattices a variety of condensed matter systems, including spin systems, we also discuss the possible implementation of the discussed 2-qubit QST with cold gases with weak links, together with a discussion of the applications and limitations of the presented results.
Quantum engineering of Majorana quasiparticles in one-dimensional optical lattices
2017
We propose a feasible way of engineering Majorana-type quasiparticles in ultracold fermionic gases on a one-dimensional (1D) optical lattice. For this purpose, imbalanced ultracold atoms interacting by the spin-orbit coupling should be hybridized with a three-dimensional Bose-Einstein condensate (BEC) molecular cloud. By constraining the profile of an internal defect potential we show that the Majorana-type excitations can be created or annihilated. This process is modelled within the Bogoliubov-de Gennes approach. This study is relevant also to nanoscopic 1D superconductors where modification of the internal defect potential can be obtained by electrostatic means.
Interacting Rubidium and Caesium Atoms
2007
Binary mixtures of ultracold atoms are of great interest in the research field of quantum optics and are studied by several groups aiming at different applications. This paper works with rubidium and caesium, which are simultaneously stored in a magnetic trap. Species-selective microwave cooling is used on the rubidium groundstate hyperfine transition. Caesium is sympathetically cooled via elastic collisions with rubidium. When cooling down the mixture to temperatures below 1 muK, below 4 muK we observe strong losses of caesium. Analysing the dynamics of sympathetic cooling, lower limit for the modulus of the rubidium-caesium triplet s-wave scattering length is estimated.
From atomic to molecular Bose-Einstein condensates: a physically realizable term-crossing model for cold atom association
2010
Using an exact third-order NL di®erential equation for the molecular state probability, we develop a variational approach which enables us to construct highly accurate analytic approximations describing time dynamics of the coupled atom-molecular system in each of the interaction regimes. We show that the approximation describing time evolution of the molecular state probability both in the weak interaction limit and in the large detuning regime of the strong interaction limit can be written as a sum of two distinct terms; the ¯rst one, being a solution to a limit ¯rst-order NL equation, e®ectively describes the process of the molecule formation while the second one, being a scaled solution…
Cold-atom thermoelectrics
2013
Two coupled reservoirs of cold atoms can be used as a model system to study the thermoelectric effect. [Also see Report by Brantut et al. ]
Optomechanical Rydberg-atom excitation via dynamic Casimir-Polder coupling
2014
We study the optomechanical coupling of a oscillating effective mirror with a Rydberg atomic gas, mediated by the dynamical atom-mirror Casimir-Polder force. This coupling may produce a near-field resonant atomic excitation whose probability scales as $\propto (d^2\;a\;n^4\;t)^2/z_0^8$, where $z_0$ is the average atom-surface distance, $d$ the atomic dipole moment, $a$ the mirror's effective oscillation amplitude, $n$ the initial principal quantum number, and $t$ the time. We propose an experimental configuration to realize this system with a cold atom gas trapped at a distance $\sim 2\cdot10 \, \mu$m from a semiconductor substrate, whose dielectric constant is periodically driven by an ext…
Atomic diffraction from nanostructured optical potentials
2002
We develop a versatile theoretical approach to the study of cold-atom diffractive scattering from light-field gratings by combining calculations of the optical near-field, generated by evanescent waves close to the surface of periodic nanostructured arrays, together with advanced atom wavepacket propagation on this optical potential.
Graded-index optical fiber emulator of an interacting three-atom system: illumination control of particle statistics and classical non-separability
2019
[EN] We show that a system of three trapped ultracold and strongly interacting atoms in one-dimension can be emulated using an optical fiber with a graded-index profile and thin metallic slabs. While the wave-nature of single quantum particles leads to direct and well known analogies with classical optics, for interacting many-particle systems with unrestricted statistics such analoga are not straightforward. Here we study the symmetries present in the fiber eigenstates by using discrete group theory and show that, by spatially modulating the incident field, one can select the atomic statistics, i.e., emulate a system of three bosons, fermions or two bosons or fermions plus an additional di…
Cold-Atom-Induced Control of an Optomechanical Device
2010
We consider a cavity with a vibrating end mirror and coupled to a Bose-Einstein condensate. The cavity field mediates the interplay between mirror and collective oscillations of the atomic density. We study the implications of this dynamics and the possibility of an indirect diagnostic. Our predictions can be observed in a realistic setup that is central to the current quest for mesoscopic quantumness.
Collective-Mode Enhanced Matter-Wave Optics
2021
International audience; In contrast to light, matter-wave optics of quantum gases deals with interactions even in free space and for ensembles comprising millions of atoms. We exploit these interactions in a quantum degenerate gas as an adjustable lens for coherent atom optics. By combining an interaction-driven quadrupole-mode excitation of a Bose-Einstein condensate (BEC) with a magnetic lens, we form a time-domain matter-wave lens system. The focus is tuned by the strength of the lensing potential and the oscillatory phase of the quadrupole mode. By placing the focus at infinity, we lower the total internal kinetic energy of a BEC comprising 101(37) thousand atoms in three dimensions to …