The Hanbury Brown Twiss effect for atomic matter waves

This paper discusses our recent work on developing the matter wave analogs to the Hanbury Brown Twiss experiment. We discuss experiments using cold atoms, both bosons and fermions, both coherent and incoherent. Simple concepts from classical and quantum optics suffice to understand most of the results, but the ideas can also be traced back to the work of Einstein on the thermodynamics of Bose gases.Comment: also available at http://pos.sissa.it

Chelifer longimanus Kollar, 1848: a nomen nudum corresponding to Neobisium spelaeum (Schiödte, 1847) (Pseudoscorpiones: Chelonethi: Neobisiidae)

The manuscript name Chelifer longimanus Kollar, 1848, most often cited as Obisium longimanum Kollar, was first introduced in a note by Kollar (1848) that has been overlooked in the taxonomic literature on pseudoscorpions. No description or indication has been associated with this name, which is therefore a nomen nudum. It corresponds to the valid pseudoscorpion species Neobisium spelaeum (Schiödte, 1847), having been found at one of the type localities of the latter (Postojna Cave, Slovenia). Two specimens originally identified as O. longimanum (probably by V. Kollar) are present in the collections of the Naturhistorisches Museum Wien

Spectrum-Adapted Tight Graph Wavelet and Vertex-Frequency Frames

We consider the problem of designing spectral graph filters for the construction of dictionaries of atoms that can be used to efficiently represent signals residing on weighted graphs. While the filters used in previous spectral graph wavelet constructions are only adapted to the length of the spectrum, the filters proposed in this paper are adapted to the distribution of graph Laplacian eigenvalues, and therefore lead to atoms with better discriminatory power. Our approach is to first characterize a family of systems of uniformly translated kernels in the graph spectral domain that give rise to tight frames of atoms generated via generalized translation on the graph. We then warp the uniform translates with a function that approximates the cumulative spectral density function of the graph Laplacian eigenvalues. We use this approach to construct computationally efficient, spectrum-adapted, tight vertex-frequency and graph wavelet frames. We give numerous examples of the resulting spectrum-adapted graph filters, and also present an illustrative example of vertex-frequency analysis using the proposed construction

Cavity enhanced light scattering in optical lattices to probe atomic quantum statistics

Different quantum states of atoms in optical lattices can be nondestructively monitored by off-resonant collective light scattering into a cavity. Angle resolved measurements of photon number and variance give information about atom-number fluctuations and pair correlations without single-site access. Observation at angles of diffraction minima provides information on quantum fluctuations insensitive to classical noise. For transverse probing, no photon is scattered into a cavity from a Mott insulator phase, while the photon number is proportional to the atom number for a superfluid.Comment: 4 pages, 3 figures, to published in Phys. Rev. Lett. (March 2007

Quantum state preparation for coupled period tripling oscillators

We investigate the quantum transition to a correlated state of coupled oscillators in the regime where they display period tripling in response to a drive at triple the eigenfrequency. Correlations are formed between the discrete oscillation phases of individual oscillators. The evolution toward the ordered state is accompanied by the transient breaking of the symmetry between seemingly equivalent configurations. We attribute this to the nontrivial geometric phase that characterizes period tripling. We also show that the Wigner distribution of a single damped quantum oscillator can display a minimum at the classically stable zero-amplitude state.Comment: 7 pages, 9 figure