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.

/pdf/many-body-physics-with-ultracold-gases-552s10zfdn.pdf

Many-Body Physics with Ultracold Gases

The semiconductor industry has seen a remarkable miniaturization trend, driven by many scientific and technological innovations. But if this trend is to continue, and provide ever faster and cheaper computers, the size of microelectronic circuit components will soon need to reach the scale of atoms or molecules—a goal that will require conceptually new device structures. The idea that a few molecules, or even a single molecule, could be embedded between electrodes and perform the basic functions of digital electronics—rectification, amplification and storage—was first put forward in the mid-1970s. The concept is now realized for individual components, but the economic fabrication of complete circuits at the molecular level remains challenging because of the difficulty of connecting molecules to one another. A possible solution to this problem is ‘mono-molecular’ electronics, in which a single molecule will integrate the elementary functions and interconnections required for computation.

Electronics using hybrid-molecular and mono-molecular devices

http://ltl.tkk.fi/ice/Kevo/noisereview.pdf

Shot noise in mesoscopic conductors

Gold nanorods: Synthesis, characterization and applications

This Account reports the synthesis and characterization of dendrimer-encapsulated metal nanoparticles and their applications to catalysis. These materials are prepared by sequestering metal ions within dendrimers followed by chemical reduction to yield the corresponding zerovalent metal nanoparticle. The size of such particles depends on the number of metal ions initially loaded into the dendrimer. Intradendrimer hydrogenation and carbon−carbon coupling reactions in water, organic solvents, biphasic fluorous/organic solvents, and supercritical CO2 are also described.

http://rcrooks.cm.utexas.edu/research/resources/Publications/rmc113.pdf

Dendrimer-Encapsulated Metal Nanoparticles: Synthesis, Characterization, and Applications to Catalysis

The potentiostatic electrochemical template synthesis of nanowires (Ni, Co, Cu, Au, and polyporrole) in polycarbonate track-etched membranes with nominal pore diameters dN between 10 and 200 nm is ...

Template synthesis of nanowires in porous polycarbonate membranes: electrochemistry and morphology

A Hanbury Brown and Twiss experiment for a beam of electrons has been realized in a two-dimensional electron gas in the quantum Hall regime. A metallic split gate serves as a tunable beam splitter to partition the incident beam into transmitted and reflected partial beams. In the nonequilibrium case the fluctuations in the partial beams are shown to be fully anticorrelated, demonstrating that fermions exclude each other. In equilibrium, the cross-correlation of current fluctuations at two different contacts is also found to be negative and nonzero, provided that a direct transmission exists between the contacts.

/pdf/the-fermionic-hanbury-brown-and-twiss-experiment-l3hstq2v29.pdf

The Fermionic Hanbury Brown and Twiss Experiment

Contact resistances of multiwalled nanotubes deposited on gold contact fingers are very large. We show that the contact resistances decrease by orders of magnitudes when the contact areas are selectively exposed to the electron beam in a scanning electron microscope. The focused electron beam enables the selection of one particular nanotube for electrical measurement in a four-terminal configuration, even if a loose network of nanotubes is deposited on the gold electrodes. For all measured nanotubes, resistance values lie in a narrow range of 0.35–2.6 kΩ at room temperature.

Contacting carbon nanotubes selectively with low-ohmic contacts for four-probe electric measurements

We report low-temperature shot-noise measurements of short diffusive Au wires attached to electron reservoirs of varying sizes. The measured noise suppression factor compared to the classical noise value $2e|I|$ strongly depends on the electric heat conductance of the reservoirs. For small reservoirs injection of hot electrons increases the measured noise, and hence the suppression factor. The universal $1/3$ suppression factor can only asymptotically be reached for macroscopically large and thick electron reservoirs. A heating model based on the Wiedemann-Franz law is used to explain this effect.

https://arxiv.org/pdf/cond-mat/9808042.pdf

1/3-shot-noise suppression in diffusive nanowires

We realized an equivalent Hanbury Brown and Twiss experiment for a beam of electrons in a two-dimensional electron gas in the quantum Hall regime. A metallic split gate serves as a tunable beam splitter which is used to partition the incident beam into transmitted and reflected partial beams. The current fluctuations in the reflected and transmitted beam are fully anticorrelated demonstrating that fermions tend to exclude each other (anti-bunching). If the occupation probability of the incident beam is lowered by an additional gate, the anticorrelation is reduced and disappears in the classical limit of a highly diluted beam.

M. Henny

Papers

Template synthesis of nanowires in porous polycarbonate membranes: electrochemistry and morphology

The Fermionic Hanbury Brown and Twiss Experiment

Contacting carbon nanotubes selectively with low-ohmic contacts for four-probe electric measurements

1/3-shot-noise suppression in diffusive nanowires

The Hanbury Brown and Twiss experiment with fermions