The Super-Strong Coupling Regime of Cavity Quantum Electrodynamics

We describe a qualitatively new regime of cavity quantum electrodynamics, the super strong coupling regime. This regime is characterized by atom-field coupling strengths of the order of the free spectral range of the cavity, resulting in a significant change in the spatial mode functions of the light field. It can be reached in practice for cold atoms trapped in an optical dipole potential inside the resonator. We present a nonperturbative scheme that allows us to calculate the frequencies and linewidths of the modified field modes, thereby providing a good starting point for a quantization of the theory.Comment: Figures rearranged and introduction rewritte

Optically mediated nonlinear quantum optomechanics

We consider theoretically the optomechanical interaction of several mechanical modes with a single quantized cavity field mode for linear and quadratic coupling. We focus specifically on situations where the optical dissipation is the dominant source of damping, in which case the optical field can be adiabatically eliminated, resulting in effective multimode interactions between the mechanical modes. In the case of linear coupling, the coherent contribution to the interaction can be exploited e.g. in quantum state swapping protocols, while the incoherent part leads to significant modifications of cold damping or amplification from the single-mode situation. Quadratic coupling can result in a wealth of possible effective interactions including the analogs of second-harmonic generation and four-wave mixing in nonlinear optics, with specific forms depending sensitively on the sign of the coupling. The cavity-mediated mechanical interaction of two modes is investigated in two limiting cases, the resolved sideband and the Doppler regime. As an illustrative application of the formal analysis we discuss in some detail a two-mode system where a Bose-Einstein condensate is optomechanically linearly coupled to the moving end mirror of a Fabry-P\'erot cavity.Comment: 11 pages, 8 figure

Diffraction of ultra-cold fermions by quantized light fields: Standing versus traveling waves

We study the diffraction of quantum degenerate fermionic atoms off of quantized light fields in an optical cavity. We compare the case of a linear cavity with standing wave modes to that of a ring cavity with two counter-propagating traveling wave modes. It is found that the dynamics of the atoms strongly depends on the quantization procedure for the cavity field. For standing waves, no correlations develop between the cavity field and the atoms. Consequently, standing wave Fock states yield the same results as a classical standing wave field while coherent states give rise to a collapse and revivals in the scattering of the atoms. In contrast, for traveling waves the scattering results in quantum entanglement of the radiation field and the atoms. This leads to a collapse and revival of the scattering probability even for Fock states. The Pauli Exclusion Principle manifests itself as an additional dephasing of the scattering probability

Synchronized and desynchronized phases of coupled non-equilibrium exciton-polariton condensates

We theoretically analyze the synchronized and desynchronized phases of coupled non-equilibrium polariton condensates within mean field theory. An analytical condition for the existence of a synchronized phase is derived for two coupled wells. The case of many wells in a 2D disordered geometry is studied numerically. The relation to recent experiments on polariton condensation in CdTe microcavities is discussed.Comment: 5 pages, 3 figure

Collinear Four-Wave Mixing of Two-Component Matter Waves

We demonstrate atomic four-wave mixing of two-component matter waves in a collinear geometry. Starting from a single-species Bose-Einstein condensate, seed and pump modes are prepared through microwave state transfer and state-selective Kapitza-Dirac diffraction. Four-wave mixing then populates the initially empty output modes. Simulations based on a coupled-mode expansion of the Gross-Pitaevskii equation are in very good agreement with the experimental data. We show that four-wave mixing can play an important role in studies of bosonic mixtures in optical lattices. Moreover our system should be of interest in the context of quantum atom optics.Comment: 4 pages, 4 figures; revised version, essentially as publishe

Observation of atom wave phase shifts induced by van der Waals atom-surface interactions

The development of nanotechnology and atom optics relies on understanding how atoms behave and interact with their environment. Isolated atoms can exhibit wave-like (coherent) behaviour with a corresponding de Broglie wavelength and phase which can be affected by nearby surfaces. Here an atom interferometer is used to measure the phase shift of Na atom waves induced by the walls of a 50 nm wide cavity. To our knowledge this is the first direct measurement of the de Broglie wave phase shift caused by atom-surface interactions. The magnitude of the phase shift is in agreement with that predicted by quantum electrodynamics for a non-retarded van der Waals interaction. This experiment also demonstrates that atom-waves can retain their coherence even when atom-surface distances are as small as 10 nm.Comment: 4 pages, 4 figures, submitted to PR

THE POSSIBILITY OF COPROCESSING MUNICIPAL SOLID WASTE - MSW IN CLINKER KILNS TO CEMENT PRODUCTION

The objective of this paper is to present an analysis of coprocessing in a cement production plant using Municipal Solid Waste - MSW as a secondary fuel and show the main advantages that burn into a incineration plant. The manufacture of Portland cement is a process that requires a large consumption of thermal and electrical energy and front of the immense worldwide energetic demand has increased its value every day. The typical operating cost involving this energy achieves 40% of the final product and due to increasing world consumption justifies the efforts to reduce the costs associated with its production. The use of high efficiency equipment coupled with the replacement of fossil fuels and conventional raw material for alternative products has given good results. The method of disposal of MSW in landfills in large urban centers is being used less and less. The creation of environmental laws increasingly severe shortages of allied areas not disturbed and the high cost of construction and operation of landfills hinders its viability. Moreover, there is a problem related to the emissions  of gaseous and liquid effluents that help raise the cost for its control and treatment. The MSW, when recovered and separated, can become recyclable products and as energy sources. After separation of the usable material (organic matter and recyclable), remaining MSW materials with sufficient calorific value can be used in kilns to produce clinker. Moreover, the ash resulting from combustion may be incorporated in the clinker decreasing the initial amount of raw material. The use of MSW as alternative fuel has shown to be feasible in the clinker kiln, but their use is still limited by their availability, since their segregation is rarely practiced. The substitution of alternative inputs introduce restrictions to the process which must be safely handled in order to ensure the minimum quality and productivity of cement production plants. The use of MSW must have a thorough characterization of your composition, because of directly influences in the final product

Hamiltonian chaos in a coupled BEC -- optomechanical cavity system

We study a hybrid optomechanical system consisting of a Bose-Einstein condensate (BEC) trapped inside a single-mode optical cavity with a moving end-mirror. The intracavity light field has a dual role: it excites a momentum side-mode of the condensate, and acts as a nonlinear spring that couples the vibrating mirror to that collective density excitation. We present the dynamics in a regime where the intracavity optical field, the mirror, and the side-mode excitation all display bistable behavior. In this regime we find that the dynamics of the system exhibits Hamiltonian chaos for appropriate initial conditions.Comment: 5 figure