5,654 research outputs found
Expanding Documentation, or making the most of the cracks in the wall
Performance in the digital age has undergone a radical shift in which a once ephemeral art form can now be relived, replayed and repeated. Until now, much scholarship has been devoted to the nature of live performance in the digital age; Documenting Performance is the first book to provide a collection of key writings about the process of documenting performance, focused not on questions of liveness or the artistic qualities of documents, but rather on the professional approaches to recovering, preserving and disseminating knowledge of live performance.
Through its four-part structure, the volume introduces readers to important writings by international practitioners and scholars on:
* the contemporary context for documenting performance
* processes of documenting performance
* documenting bodies in motion
* documenting to create
In each, chapters examine the ways performance is documented and the issues arising out of the process of documenting performance. While theorists have argued that performance becomes something else whenever it is documented, the writings reveal how the documents themselves cannot be regarded simply as incomplete remains from live events. The methods for preserving and managing them over time, ensuring easy access of such materials in systematic archives and collections, requires professional attention in its own right. Through the process of documenting performance, artists acquire a different perspective on their own work, audiences can recall specific images and sounds for works they have witnessed in person, and others who did not see the original work can trace the memories of particular events, or use them to gain an understanding of something that would otherwise remain unknown to them and their peers
Optical conductivity of wet DNA
Motivated by recent experiments we have studied the optical conductivity of
DNA in its natural environment containing water molecules and counter ions. Our
density functional theory calculations (using SIESTA) for four base pair B-DNA
with order 250 surrounding water molecules suggest a thermally activated doping
of the DNA by water states which generically leads to an electronic
contribution to low-frequency absorption. The main contributions to the doping
result from water near DNA ends, breaks, or nicks and are thus potentially
associated with temporal or structural defects in the DNA.Comment: 4 pages, 4 figures included, final version, accepted for publication
in Phys. Rev. Let
Preferred Basis in a Measurement Process
The effect of decoherence is analysed for a free particle, interacting with
an environment via a dissipative coupling. The interaction between the particle
and the environment occurs by a coupling of the position operator of the
particle with the environmental degrees of freedom. By examining the exact
solution of the density matrix equation one finds that the density matrix
becomes completely diagonal in momentum with time while the position space
density matrix remains nonlocal. This establishes the momentum basis as the
emergent 'preferred basis' selected by the environment which is contrary to the
general expectation that position should emerge as the preferred basis since
the coupling with the environment is via the position coordinate.Comment: Standard REVTeX format, 10 pages of output. Accepted for publication
in Phys. Rev
Evolution of SU(4) Transport Regimes in Carbon Nanotube Quantum Dots
We study the evolution of conductance regimes in carbon nanotubes with doubly
degenerate orbitals (``shells'') by controlling the contact transparency within
the same sample. For sufficiently open contacts, Kondo behavior is observed for
1, 2, and 3 electrons in the topmost shell. As the contacts are opened more,
the sample enters the ``mixed valence'' regime, where different charge states
are strongly hybridized by electron tunneling. Here, the conductance as a
function of gate voltage shows pronounced modulations with a period of four
electrons, and all single-electron features are washed away at low temperature.
We successfully describe this behavior by a simple formula with no fitting
parameters. Finally, we find a surprisingly small energy scale that controls
the temperature evolution of conductance and the tunneling density of states in
the mixed valence regime.Comment: 4 pages + supplementary info. The second part of the original
submission is now split off as a separate paper (0709.1288
Velocity quantization approach of the one-dimensional dissipative harmonic oscillator
Given a constant of motion for the one-dimensional harmonic oscillator with
linear dissipation in the velocity, the problem to get the Hamiltonian for this
system is pointed out, and the quantization up to second order in the
perturbation approach is used to determine the modification on the eigenvalues
when dissipation is taken into consideration. This quantization is realized
using the constant of motion instead of the Hamiltonian.Comment: 10 pages, 2 figure
Structural and electronic properties of the metal-metal intramolecular junctions of single-walled carbon nanotubes
Several intramolecular junctions (IMJs) connecting two metallic (11, 8) and
(9, 6) carbon nanotubes along their common axis have been realized by using a
layer-divided technique to the nanotubes and introducing the topological
defects. Atomic structure of each IMJ configuration is optimized with a
combination of density-functional theory (DFT) and the universal force field
(UFF) method, based upon which a four-orbital tight-binding calculation is made
on its electronic properties. Different topological defect structures and their
distributions on the IMJ interfaces have been found, showing decisive effects
on the localized density of states, while the sigma-pi coupling effect is
negligible near Fermi energy (EF). Finally, a new IMJ model has been proposed,
which probably reflects a real atomic structure of the M-M IMJ observed in the
experiment [Science 291, 97 (2001)].Comment: 11 pages and 3 figure
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