Ref HAL: hal-01448442_v1
DOI: 10.1103/PhysRevA.95.012138
WoS: 000396130200004
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4 Citations
Résumé:

We investigate the transport of energy in a linear chain of two-level quantum emitters (atoms) weakly coupled to a blackbody radiation bath. We show that simply by displacing one or more atoms from their regular-chain positions, the efficiency of the energy transport can be considerably amplified of at least one order of magnitude. In addition, in configurations providing an efficiency greater than 100%, the distance between the last two atoms of the chain can be up to 20 times larger than the one in the regular chain, thus achieving a much longer-range energy transport. By performing both a stationary and time-dependent analysis, we ascribe this effect to an elementary block of three atoms, playing the role of excitation injector from the blackbody bath to the extraction site. By considering chains with up to seven atoms, we also show that the amplification is robust and can be further enhanced up to 1400%.

Commentaires: Article 012138

Résumé:

In these lectures we present some results concerning the theoretical study of light waves [1-3] and of atomic matter waves [4-6] propagating in artificial atomic crystals realized by atoms trapped at the notes of an optical lattice and forming 2D or 3D (Bravais or non-Bravais) crystals. The case of not perfectly filled lattices will be also considered to study of the absence of transport due to the occurrence of the Anderson localization in disordered systems. ---------- [1] Fano-Hopfield model and photonic band gaps for an arbitrary atomic lattice Mauro Antezza, Yvan Castin Phys. Rev. A 80, 013816 (2009) [2] Spectrum of light in a quantum fluctuating periodic structure Mauro Antezza, Yvan Castin Phys. Rev. Lett. 103, 123903 (2009) [3] Photonic band gap in an imperfect atomic diamond lattice: penetration depth and effects of finite size and vacancies Mauro Antezza, Yvan Castin Phys. Rev. A 88, 033844 (2013) [4] Quantitative study of two- and three-dimensional strong localization of matter waves by atomic scatterers Mauro Antezza, Yvan Castin, David A. W. Hutchinson Phys. Rev. A 82, 043602 (2010) [5] Matter waves in atomic artificial graphene Nicola Bartolo, and Mauro Antezza Europhys. Lett. 107, 30006 (2014) [6] Matter waves in two-dimensional arbitrary atomic crystals Nicola Bartolo, and Mauro Antezza Phys. Rev. A 90, 033617 (2014)

Commentaires: Cours à l'École de Physique d’été de Mittelwir : Ultracold few and many-body systems: quantum mechanics made crystals clear

Ref HAL: hal-01422091_v1
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We derive the explicit expression for the Casimir energy between a sphere and a 1D grating under thermal equilibrium, in terms of the sphere and grating reflection matrices, and valid for arbitrary materials, sphere radius, and grating geometric parameters.

Ref HAL: hal-01421877_v1
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Planar structures cannot emit more heat by radiation than predicted by Stefan- Boltzmann’s law. However, when two reservoirs are connected by an intermediate slab which is placed in their near-field one can in principle observe a super-Planckian heat flux at separation distances larger than the thermal wavelength, if the evanescent contributions can be perfectly guided through the intermediate slab. In this case study we discuss in particular how the thermal near-field of the surface modes of two SiC reservoirs can be guided through an ideal dielectric, a perfect lens and a hyperbolic waveguide. A detailed study of the parameters needed in order to have a long-range guiding of thermal radiation shows which properties are ideally needed in order to observe a super-Planckian heat flux. In particular hyperbolic materials which are known for their large penetration depth of radiative heat fluxes are promising materials. This result opens the way to long distance transport of near-field thermal energy.

Ref HAL: hal-01421873_v1
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Résumé:

We show that the electromagnetic forces generated by the excitations of a mode in graphene-based optomechanical systems are highly tunable by varying the graphene chemical potential, and orders of magnitude stronger than usual non-graphene-based devices, in both attractive and repulsive regimes. We analyze coupled waveguides made of two parallel graphene sheets, either suspended or supported by dielectric slabs, and study the interplay between the light-induced force and the Casimir-Lifshitz interaction. These findings pave the way to advanced possibilities of control and fast modulation for optomechanical devices and sensors at the nano- and microscales.