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Neutrino Spectra And Uncertainties For MINOS
The MINOS experiment [1] at Fermilab has released an updated. result on muon disappearance [2]. The experiment utilizes the intense source of muon neutrinos provided by the NuMI beam line. This note summarizes the systematic uncertainties in the experiment's knowledge of the flux and energy spectrum of the neutrinos from NuMI.Physic
The NuMI Beam At FNAL And Its Use For Neutrino Cross Section Measurements
The Neutrinos at the Main Injector (NuMI) facility at Fermilab began operations in late 2004. NuMI will deliver an intense v, beam of variable energy (2-20 GeV). Several aspects of the design and results from runs of the MINOS experiment are reviewed. I also discuss technique to measure directly the neutrino flux using a muon flux system at the end of the NuMI line.Physic
Exact results in a slave boson saddle point approach for a strongly correlated electron model
We revisit the Kotliar-Ruckenstein (KR) slave boson saddle point evaluation
for a two-site correlated electron model. As the model can be solved
analytically, it is possible to compare the KR saddle point results to the
exact many particle levels. The considered two site cluster mimics an
infinite- single-impurity Anderson model with a nearest neighbor Coulomb
interaction: one site is strongly correlated with an infinite local Coulomb
repulsion which hybridizes with the second site, on which the local Coulomb
repulsion vanishes. Making use of the flexibility of the representation we
introduce appropriate weight factors in the KR saddle point scheme. Ground
state and all excitation levels agree with the exact diagonalization results.
Thermodynamics and correlation functions may be recovered in a suitably
renormalized saddle point evaluation.Comment: 4 page
Generating weights for the Weil representation attached to an even order cyclic quadratic module
We develop geometric methods to study the generating weights of free modules
of vector valued modular forms of half-integral weight, taking values in a
complex representation of the metaplectic group. We then compute the generating
weights for modular forms taking values in the Weil representation attached to
cyclic quadratic modules of order 2p^r, where p is a prime greater than three.
We also show that the generating weights approach a simple limiting
distribution as p grows, or as r grows and p remains fixed
Semiclassical transport in nearly symmetric quantum dots. I. Symmetry breaking in the dot
We apply the semiclassical theory of transport to quantum dots with exact and approximate spatial symmetries; left-right mirror symmetry, up-down mirror symmetry, inversion symmetry, or fourfold symmetry. In this work—the first of a pair of articles—we consider (a) perfectly symmetric dots and (b) nearly symmetric dots in which the symmetry is broken by the dot's internal dynamics. The second article addresses symmetry-breaking by displacement of the leads. Using semiclassics, we identify the origin of the symmetry-induced interference effects that contribute to weak localization corrections and universal conductance fluctuations. For perfect spatial symmetry, we recover results previously found using the random-matrix theory conjecture. We then go on to show how the results are affected by asymmetries in the dot, magnetic fields, and decoherence. In particular, the symmetry-asymmetry crossover is found to be described by a universal dependence on an asymmetry parameter gamma_asym. However, the form of this parameter is very different depending on how the dot is deformed away from spatial symmetry. Symmetry-induced interference effects are completely destroyed when the dot's boundary is globally deformed by less than an electron wavelength. In contrast, these effects are only reduced by a finite amount when a part of the dot's boundary smaller than a lead-width is deformed an arbitrarily large distance
How Large is the Intrinsic Flux Noise of a Magnetic Flux Quantum, of Half a Flux Quantum and of a Vortex-Free Superconductor?
This article addresses the question whether the magnetic flux of stationary
vortices or of half flux quanta generated by frustrated superconducting rings
is noisy. It is found that the flux noise generated intrinsically by a
superconductor is, in good approximation, not enhanced by stationary vortices.
Half flux quanta generated by -rings are characterized by considerably
larger noise.Comment: 11 pages, 3 figures. in: A. Bussmann-Holder, H. Keller (Eds.) High Tc
Superconductors and Related Transition Metal Oxides, Springer, 237-242; also
to be published in: Journal of Superconductivity (2007
Semiclassical transport in nearly symmetric quantum dots II: symmetry-breaking due to asymmetric leads
In this work - the second of a pair of articles - we consider transport
through spatially symmetric quantum dots with leads whose widths or positions
do not obey the spatial symmetry. We use the semiclassical theory of transport
to find the symmetry-induced contributions to weak localization corrections and
universal conductance fluctuations for dots with left-right, up-down, inversion
and four-fold symmetries. We show that all these contributions are suppressed
by asymmetric leads, however they remain finite whenever leads intersect with
their images under the symmetry operation. For an up-down symmetric dot, this
means that the contributions can be finite even if one of the leads is
completely asymmetric. We find that the suppression of the contributions to
universal conductance fluctuations is the square of the suppression of
contributions to weak localization. Finally, we develop a random-matrix theory
model which enables us to numerically confirm these results.Comment: (18pages - 9figures) This is the second of a pair of articles (v3
typos corrected - including in equations
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