793 research outputs found
Singular maps on exotic 4-manifold pairs
We show examples of pairs of smooth, compact, homeomorphic 4-manifolds, whose
diffeomorphism types are distinguished by the topology of the singular sets of
smooth stable maps defined on them. In this distinction we rely on results from
Seiberg-Witten theory.Comment: 17 pages, 6 figures, minor modifications following referee's comment
The Qupit Stabiliser ZX-travaganza: Simplified Axioms, Normal Forms and Graph-Theoretic Simplification
We present a smorgasbord of results on the stabiliser ZX-calculus for odd
prime-dimensional qudits (i.e. qupits). We derive a simplified rule set that
closely resembles the original rules of qubit ZX-calculus. Using these rules,
we demonstrate analogues of the spider-removing local complementation and
pivoting rules. This allows for efficient reduction of diagrams to the affine
with phases normal form. We also demonstrate a reduction to a unique form,
providing an alternative and simpler proof of completeness. Furthermore, we
introduce a different reduction to the graph state with local Cliffords normal
form, which leads to a novel layered decomposition for qupit Clifford
unitaries. Additionally, we propose a new approach to handle scalars formally,
closely reflecting their practical usage. Finally, we have implemented many of
these findings in DiZX, a new open-source Python library for qudit
ZX-diagrammatic reasoning.Comment: 44 pages, lots of figures, accepted to QPL 202
Basidiocarp and mycelium morphology of Ganoderma lucium Karst. Strains isolated in Hungary
Morphological, anatomical and cultural characteristics of 14 Ganoderma lucidum(Fr.) Karst strains isolated in Hungary have been investigated. Macroscopically the basidiocarps of the Hungarian strains are absolutely identical with those of described previously about the Ganoderma lucidumspecies-complex. Microscopic features of the fruitbodies and basidiospores showed some differences from the typical G. lucidumspecies. Pilocystidia, forming a homogenous layer on the surface of the pileus, have smooth heads without protrusions and stalks not ramifying. Cell wall pillar density and width of the basidiospores also differ from that of regarded to be characteristic toG. lucidum. Although according to several authors chlamydospore formation is a characteristic feature of G. lucidumit has not been observed in mycelial cultures of the Hungarian strains. Antagonistic reactions between the Hungarian and Far Eastern G. lucidumisolates were mostly similar to the interspecific reactions between the two speciesG. lucidumand G. applanatumand corresponded only in a few cases to the interactions within one species. Our results suggest that the Hungarian strains significantly differ from the Far Eastern strains. To determine the taxonomic degree of this divergence genetical examinations should be carried out
Ancillary science with Ariel: Feasibility and scientific potential of young stellar object observations
To investigate the feasibility of ancillary target observations with ESA's
Ariel mission, we compiled a list of potentially interesting young stars:
FUors, systems harbouring extreme debris discs and a larger sample of young
stellar objects showing strong near/mid-infrared excess. These objects can be
observed as additional targets in the waiting times between the scheduled
exoplanet transit and occultation observations. After analyzing the schedule
for Ariel an algorithm was constructed to find the optimal target to be
observed in each gap. The selection was mainly based on the slew and
stabilization time needed to observe the selected YSO, but it also incorporated
the scientific importance of the targets and whether they have already been
sufficiently measured. After acquiring an adequately large sample of simulation
data, it was concluded that approximately 99.2% of the available -- at least
one hour long -- gaps could be used effectively. With an average slewing and
stabilization time of about 16.7 minutes between scheduled exoplanet transits
and ancillary targets, this corresponds to an additional hours of
active data gathering. When this additional time is used to observe our
selected 200 ancillary targets, a typical signal-to-noise ratio of 10
can be achieved along the whole spectral window covered by Ariel.Comment: Accepted for publication in Experimental Astronom
Pairing Fluctuation Theory of Superconducting Properties in Underdoped to Overdoped Cuprates
We propose a theoretical description of the superconducting state of under-
to overdoped cuprates, based on the short coherence length of these materials
and the associated strong pairing fluctuations. The calculated and the
zero temperature excitation gap , as a function of hole
concentration , are in semi-quantitative agreement with experiment. Although
the ratio has a strong dependence, different from the
universal BCS value, and deviates significantly from the BCS
prediction, we obtain, quite remarkably, quasi-universal behavior, for the
normalized superfluid density and the Josephson critical
current , as a function of . While experiments on
are consistent with these results, future measurements on
are needed to test this prediction.Comment: 4 pages, 3 figures, REVTeX, submitted to Phys. Rev. Let
VHMPID: a new detector for the ALICE experiment at LHC
This article presents the basic idea of VHMPID, an upgrade detector for the
ALICE experiment at LHC, CERN. The main goal of this detector is to extend the
particle identification capabilities of ALICE to give more insight into the
evolution of the hot and dense matter created in Pb-Pb collisions. Starting
from the physics motivations and working principles the challenges and current
status of development is detailed.Comment: 4 pages, 6 figures. To be published in EPJ Web of Conference
Theory of Scanning Tunneling Spectroscopy of Magnetic-Field-Induced Discrete Nodal States in a D-Wave Superconductor
In the presence of an external magnetic field, the low lying elementary
excitations of a d-wave superconductor have quantized energy and their momenta
are locked near the node direction. It is argued that these discrete states can
most likely be detected by a local probe, such as a scanning tunneling
microscope. The low temperature local tunneling conductance on the Wigner-Seitz
cell boundaries of the vortex lattice is predicted to show peaks spaced as . The peak is anomalous, and it is present only
if the superconducting order parameter changes sign at certain points on the
Fermi surface. Away from the cell boundary, where the superfluid velocity is
nonzero, each peak splits, in general, into four peaks, corresponding to the
number of nodes in the order parameter.Comment: RevTeX 3.0, 4 pages, 3 figures (included
Incoherent Pair Tunneling as a Probe of the Cuprate Pseudogap
We argue that incoherent pair tunneling in a cuprate superconductor junction
with an optimally doped superconducting and an underdoped normal lead can be
used to detect the presence of pairing correlations in the pseudogap phase of
the underdoped lead. We estimate that the junction characteristics most
suitable for studying the pair tunneling current are close to recently
manufactured cuprate tunneling devices.Comment: ReVTeX 3.1; 4 pages, 2 EPS figures (included
Dispersion of the neutron resonance in cuprate superconductors
We argue that recently measured downward dispersion of the neutron resonance
peak in cuprate superconductors is naturally explained if the resonance is
viewed as a spin-1 collective mode in a d-wave superconductor. The reduction of
the resonant frequency away from the antiferromagnetic wave vector is a direct
consequence of the momentum dependence of the d-wave superconducting gap. When
the magnetic correlation length becomes large, the dispersion should become
magnon-like, i.e., curve upwards from (pi,pi).Comment: 4 pages, 3 inline PostScript figures. Added reference
Superconducting transitions from the pseudogap state: d-wave symmetry, lattice, and low-dimensional effects
We investigate the behavior of the superconducting transition temperature
within a previously developed BCS-Bose Einstein crossover picture. This
picture, based on a decoupling scheme of Kadanoff and Martin, further extended
by Patton, can be used to derive a simple form for the superconducting
transition temperature in the presence of a pseudogap. We extend previous work
which addressed the case of s-wave pairing in jellium, to explore the solutions
for T_c as a function of variable coupling in more physically relevant
situations. We thereby ascertain the effects of reduced dimensionality,
periodic lattices and a d-wave pairing interaction. Implications for the
cuprate superconductors are discussed.Comment: REVTeX, 11 pages, 6 EPS figures included, Replace with published
versio
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