Gas phase photodissociation electronic spectra of protonated azobenzene (ABH(+)) and 4-(dimethylamino)azobenzene (dmaABH(+)) were measured in a cryogenically cooled ion trap at temperatures of a few tens of Kelvin. Experimental results were complemented with electronic structure calculations in the ground state at the MP2/cc-pVDZ level of theory, and in the low lying excited states using the RI...

Highly photoconductive thin films of inorganic-capped PbS nanocrystal quantum dots (QDs) are reported. Stable colloidal dispersions of (NH4)3AsS3-capped PbS QDs were processed by a conventional dip-coating technique into a thin homogeneous film of electronically coupled PbS QDs. Upon drying at 130 °C, (NH4)3AsS3 capping ligands were converted into a thin layer of As2S3, acting as an infrared-tr...

Optical traps or "tweezers" use high-power, near-infrared laser beams to manipulate and apply forces to biological systems, ranging from individual molecules to cells. Although previous studies have established that optical tweezers induce photodamage in live cells, the effects of trap irradiation have yet to be examined in vitro, at the single-molecule level. In this study, we investigate trap...

We study the Gross-Pitaevskii functional for a rotating two-dimensional Bose gas in a trap. We prove that there is a breaking of the rotational symmetry in the ground state; more precisely, for any value of the angular velocity and for large enough values of the interaction strength, the ground state of the functional is not an eigenfunction of the angular momentum. This has interesting consequ...

We study the Gross-Pitaevskii functional for a rotating two-dimensional Bose gas in a trap. We prove that there is a breaking of the rotational symmetry in the ground state; more precisely, for any value of the angular velocity and for large enough values of the interaction strength, the ground state of the functional is not an eigenfunction of the angular momentum. This has interesting consequ...

A sharply focused laser is able to trap small particles at the laser focal point due to the difference in refractive index of the particles and that of the surrounding medium. This technique, called laser trapping, can be used to manipulate animal or bacterial cells without any contact and has been widely applied in biological research. However, it has been difficult to trap biological macromol...

The study of ultracold collisions between groundand excited-state atoms has received a great deal of attention @1#. Trap-loss measurements have revealed hyperfine@2# and fine-structure-changing collisions @3#, the rich detail of ultracold photoassociative spectroscopy has provided important information about long-range atom-atom interaction potentials @4#, and intensity and time-resolved studie...

The Venus flytrap (Dionaea muscipula) possesses an active trapping mechanism to capture insects with one of the most rapid movements in the plant kingdom, as described by Darwin. This article presents a detailed experimental investigation of trap closure by mechanical and electrical stimuli and the mechanism of this process. Trap closure consists of three distinctive phases: a silent phase with...

We consider the precise quantum state of two trapped, coupled Bose Einstein condensates in the two-mode approximation. We seek a representation of the state in terms of a Wigner-like distribution on the two-mode Bloch sphere. The problem is solved using a self-consistent rotation of the unknown state to the south pole of the sphere. The two-mode Hamiltonian is projected onto the harmonic oscill...

We report a two-color magneto-optical trap (MOT) for ytterbium atoms operating at a low magnetic field gradient down to 2 G/cm where a conventional MOT using the singlet transition (6s 1S0 → 6s6p 1P1) is unable to trap atoms. By simultaneously applying laser light on both the broad-linewidth singlet transition and the narrow-linewidth triplet transition (6s 1S0 → 6s6p 3P1), we load and trap 4.0...