6,190,353 research outputs found
'The live dynamic whole of feeling and behavior': capital punishment and the politics of emotion, 1945–1957
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Class Observation
As the Fortenbaugh Intern in Research and Instruction, a few weeks ago I had the opportunity to observe a couple of class research sessions which were led by some of the Research and Instruction librarians. Coming from a student perspective, I had always found these sessions informative. Each session has allowed me to become more comfortable with my major’s research guide and permits me to learn more about the various databases (shout out to JSTOR) that are available to use. In short, I have always enjoyed these sessions that are led by Research and Instruction librarians, because I am able to review what skills I have learned previously, and allow those skills to become the foundation that allows me to learn and advance my research skills. [excerpt
Synthesis observation equivalence and weak synthesis observation equivalence
This working paper proposes an algorithm to simplify automata in such a way that compositional synthesis results are preserved in every possible context. It relaxes some requirements of synthesis observation equivalence from previous work, so that better abstractions can be obtained. The paper describes the algorithm, adapted from known bisimulation equivalence algorithms, for the improved abstraction method. The algorithm has been implemented in the DES software tool Supremica and has been used to compute modular supervisors for several large benchmark examples. It successfully computes modular supervisors for systems with more than 10¹² reachable states
Does Observation Create Reality?
It has been suggested that the locality of information transfer in quantum
entanglement indicates that reality is subjective, meaning that there is an
innate inseparability between the physical system and the conscious mind of the
observer. This paper attempts to outline the relation between macroscopic and
microscopic worlds in the measurement process in regards to whether observation
creates reality. Indeed, the Maxwell's demon thought experiment suggests a
correlation between a microscopic (quantum) system and a macroscopic
(classical) apparatus, which leads to an energy transfer from the quantum
vacuum to the physical world, similar to particle creation from a vacuum. This
explanation shows that observation in quantum theory conserves, rather than
creates, energy.Comment: 5 pages, 6 figure
Observation of B0->pi0pi0
We report the first observation of the decay B0->pi0pi0, using a 253/fb data
sample collected at the Upsilon(4S) resonance with the Belle detector at the
KEKB e+e- collider. The measured branching fraction is BF(B0->pi0pi0) = {2.32
+0.4-0.5(stat) +0.2-0.3(syst)} x 10^-6, with a significance of 5.8 standard
deviations including systematic uncertainties. We also make the first
measurement of the direct CP violating asymmetry in this mode.Comment: 6 pages, 2 figures, submitted to ICHEP04, Beijing and Physical Review
Letters. v2: a possible pile-up background is checked and a systematic error
for it is include
Observation of Bose-Einstein Condensation in a Strong Synthetic Magnetic Field
Extensions of Berry's phase and the quantum Hall effect have led to the
discovery of new states of matter with topological properties. Traditionally,
this has been achieved using gauge fields created by magnetic fields or spin
orbit interactions which couple only to charged particles. For neutral
ultracold atoms, synthetic magnetic fields have been created which are strong
enough to realize the Harper-Hofstadter model. Despite many proposals and major
experimental efforts, so far it has not been possible to prepare the ground
state of this system. Here we report the observation of Bose-Einstein
condensation for the Harper-Hofstadter Hamiltonian with one-half flux quantum
per lattice unit cell. The diffraction pattern of the superfluid state directly
shows the momentum distribution on the wavefuction, which is gauge-dependent.
It reveals both the reduced symmetry of the vector potential and the twofold
degeneracy of the ground state. We explore an adiabatic many-body state
preparation protocol via the Mott insulating phase and observe the superfluid
ground state in a three-dimensional lattice with strong interactions.Comment: 6 pages, 5 figures. Supplement: 6 pages, 4 figure
Observation and Quantum Objectivity
The paradox of Wigner's friend challenges the objectivity of description in
quantum theory. A pragmatist interpretation can meet this challenge by
judicious appeal to decoherence. On this interpretation, quantum theory
provides situated agents with resources for predicting and explaining what
happens in the physical world---not conscious observations of it. Even in
Wigner's friend scenarios, differently situated agents agree on the objective
content of statements about the values of physical magnitudes. In more
realistic circumstances quantum Darwinism also permits differently situated
agents equal observational access to evaluate their truth. In this view,
quantum theory has nothing to say about consciousness or conscious experiences
of observers. But it does prompt us to reexamine the significance even of
everyday claims about the physical world
Observation of accelerating parabolic beams
We report the first observation of accelerating parabolic beams. These accelerating parabolic beams are similar to the Airy beams because they exhibit the unusual ability to remain diffraction-free while having a quadratic transverse shift during propagation. The amplitude and phase masks required to generate these beams are encoded onto a single liquid crystal display. Experimental results agree well with theory
Experimental observation of Weyl points
In 1929, Hermann Weyl derived the massless solutions from the Dirac equation
- the relativistic wave equation for electrons. Neutrinos were thought, for
decades, to be Weyl fermions until the discovery of the neutrino mass.
Moreover, it has been suggested that low energy excitations in condensed matter
can be the solutions to the Weyl Hamiltonian. Recently, photons have also been
proposed to emerge as Weyl particles inside photonic crystals. In all cases,
two linear dispersion bands in the three-dimensional (3D) momentum space
intersect at a single degenerate point - the Weyl point. Remarkably, these Weyl
points are monopoles of Berry flux with topological charges defined by the
Chern numbers. These topological invariants enable materials containing Weyl
points to exhibit a wide variety of novel phenomena including surface Fermi
arcs, chiral anomaly, negative magnetoresistance, nonlocal transport, quantum
anomalous Hall effect, unconventional superconductivity[15] and others [16,
17]. Nevertheless, Weyl points are yet to be experimentally observed in nature.
In this work, we report on precisely such an observation in an
inversion-breaking 3D double-gyroid photonic crystal without breaking
time-reversal symmetry.Comment: 4 pages, 3 figure
Observation of pseudogap in MgB2
Pseudogap phase in superconductors continues to be an outstanding puzzle that
differentiates unconventional superconductors from the conventional ones
(BCS-superconductors). Employing high resolution photoemission spectroscopy on
a highly dense conventional superconductor, MgB2, we discover an interesting
scenario. While the spectral evolution close to the Fermi energy is
commensurate to BCS descriptions as expected, the spectra in the wider energy
range reveal emergence of a pseudogap much above the superconducting transition
temperature indicating apparent departure from the BCS scenario. The energy
scale of the pseudogap is comparable to the energy of E2g phonon mode
responsible for superconductivity in MgB2 and the pseudogap can be attributed
to the effect of electron-phonon coupling on the electronic structure. These
results reveal a scenario of the emergence of the superconducting gap within an
electron-phonon coupling induced pseudogap.Comment: 4 figure
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