Abdelhamid Maali

Bio: Abdelhamid Maali is an academic researcher from University of Bordeaux. The author has contributed to research in topics: Slip (materials science) & Cantilever. The author has an hindex of 25, co-authored 54 publications receiving 4950 citations. Previous affiliations of Abdelhamid Maali include École Normale Supérieure & Centre national de la recherche scientifique.

Observing the Progressive Decoherence of the 'Meter' in a Quantum Measurement

Abstract: A mesoscopic superposition of quantum states involving radiation fields with classically distinct phases was created and its progressive decoherence observed. The experiment involved Rydberg atoms interacting one at a time with a few photon coherent field trapped in a high $Q$ microwave cavity. The mesoscopic superposition was the equivalent of an `` $\mathrm{atom}+\mathrm{measuring}\mathrm{apparatus}$'' system in which the ``meter'' was pointing simultaneously towards two different directions---a ``Schr\"odinger cat.'' The decoherence phenomenon transforming this superposition into a statistical mixture was observed while it unfolded, providing a direct insight into a process at the heart of quantum measurement.

Photothermal imaging of nanometer-sized metal particles among scatterers.

Abstract: Ambient optical detection of labeled molecules is limited for fluorescent dyes by photobleaching and for semiconducting nanoparticles by “blinking” effects. Because nanometer-sized metal particles do not optically bleach, they may be useful optical labels if suitable detection signals can be found. We demonstrate far-field optical detection of gold colloids down to diameters of 2.5 nanometers with a photothermal method that combines high-frequency modulation and polarization interference contrast. The photothermal image is immune to the effects of scattering background, which limits particle imaging through Rayleigh scattering to diameters larger than 40 nanometers.

Quantum Rabi oscillation: A direct test of field quantization in a cavity.

Abstract: We have observed the Rabi oscillation of circular Rydberg atoms in the vacuum and in small coherent fields stored in a high Q cavity. The signal exhibits discrete Fourier components at frequencies proportional to the square root of successive integers. This provides direct evidence of field quantization in the cavity. The weights of the Fourier components yield the photon number distribution in the field. This investigation of the excited levels of the atom-cavity system reveals nonlinear quantum features at extremely low field strengths.

Ten Years of Single-Molecule Spectroscopy

Abstract: Single-molecule spectroscopy (SMS) combines some of the advantages of local probe microscopies with those of optics. Since this field came into being 10 years ago, it has expanded at a breathtaking pace. From the first cryogenic experiments up to the recent studies of basic processes in molecular biology, single-molecule methods have found their way into an ever broadening range of applications. Their common feature is the complete elimination of ensemble averaging. By exposing individual variations as well as dynamical fluctuations, SMS provides new insights into any system with spatial or temporal inhomogeneity. The present article illustrates single molecule spectroscopic experiments at cryogenic temperatures, mainly from the authors' group. The results reviewed here range from molecular photophysics, to the dynamics of the solid matrix around the molecule, and to the interactions between a single molecule and electromagnetic fields, i.e., quantum optics. SMS is now ripe for a variety of applications i...

Hydrodynamics of oscillating atomic force microscopy cantilevers in viscous fluids

Abstract: We present a study of thermal noise of commercially available atomic force microscopy (AFM) cantilevers in air and in water. The purpose of this work is to investigate the oscillation behavior of a clamped AFM microlever in liquids. Up to eight vibration modes are recorded. The experimental results are compared to theoretical predictions from the hydrodynamic functions corresponding to rigid transverse oscillations of an infinitely long rectangular beam. Except for the low-frequency modes, the known hydrodynamic functions cannot describe the amount of dissipated energy due to the liquid motion induced by the cantilever oscillation. The observed variation of the damping coefficient is smaller than the one predicted. The difference at higher modes between the mentioned theoretical description and experimental results is discussed with the help of numerical solutions of the three-dimensional Navier–Stokes equation.

Plasmonics: Fundamentals and Applications

Abstract: Fundamentals of Plasmonics.- Electromagnetics of Metals.- Surface Plasmon Polaritons at Metal / Insulator Interfaces.- Excitation of Surface Plasmon Polaritons at Planar Interfaces.- Imaging Surface Plasmon Polariton Propagation.- Localized Surface Plasmons.- Electromagnetic Surface Modes at Low Frequencies.- Applications.- Plasmon Waveguides.- Transmission of Radiation Through Apertures and Films.- Enhancement of Emissive Processes and Nonlinearities.- Spectroscopy and Sensing.- Metamaterials and Imaging with Surface Plasmon Polaritons.- Concluding Remarks.

Many-Body Physics with Ultracold Gases

Abstract: This paper reviews recent experimental and theoretical progress concerning many-body phenomena in dilute, ultracold gases. It focuses on effects beyond standard weak-coupling descriptions, such as the Mott-Hubbard transition in optical lattices, strongly interacting gases in one and two dimensions, or lowest-Landau-level physics in quasi-two-dimensional gases in fast rotation. Strong correlations in fermionic gases are discussed in optical lattices or near-Feshbach resonances in the BCS-BEC crossover.

Shape‐Controlled Synthesis of Metal Nanocrystals: Simple Chemistry Meets Complex Physics?

Abstract: Nanocrystals are fundamental to modern science and technology. Mastery over the shape of a nanocrystal enables control of its properties and enhancement of its usefulness for a given application. Our aim is to present a comprehensive review of current research activities that center on the shape-controlled synthesis of metal nanocrystals. We begin with a brief introduction to nucleation and growth within the context of metal nanocrystal synthesis, followed by a discussion of the possible shapes that a metal nanocrystal might take under different conditions. We then focus on a variety of experimental parameters that have been explored to manipulate the nucleation and growth of metal nanocrystals in solution-phase syntheses in an effort to generate specific shapes. We then elaborate on these approaches by selecting examples in which there is already reasonable understanding for the observed shape control or at least the protocols have proven to be reproducible and controllable. Finally, we highlight a number of applications that have been enabled and/or enhanced by the shape-controlled synthesis of metal nanocrystals. We conclude this article with personal perspectives on the directions toward which future research in this field might take.

Theory of Bose-Einstein condensation in trapped gases

Abstract: The phenomenon of Bose-Einstein condensation of dilute gases in traps is reviewed from a theoretical perspective. Mean-field theory provides a framework to understand the main features of the condensation and the role of interactions between particles. Various properties of these systems are discussed, including the density profiles and the energy of the ground-state configurations, the collective oscillations and the dynamics of the expansion, the condensate fraction and the thermodynamic functions. The thermodynamic limit exhibits a scaling behavior in the relevant length and energy scales. Despite the dilute nature of the gases, interactions profoundly modify the static as well as the dynamic properties of the system; the predictions of mean-field theory are in excellent agreement with available experimental results. Effects of superfluidity including the existence of quantized vortices and the reduction of the moment of inertia are discussed, as well as the consequences of coherence such as the Josephson effect and interference phenomena. The review also assesses the accuracy and limitations of the mean-field approach.