73 research outputs found
Lepton-Nucleus Interactions within Microscopic Approaches
This review paper emphasizes the significance of microscopic calculations
with quantified theoretical error estimates in studying lepton-nucleus
interactions and their implications for electron-scattering and accelerator
neutrino-oscillation measurements. We investigate two approaches: Green's
Function Monte Carlo and the extended factorization scheme, utilizing realistic
nuclear target spectral functions. In our study, we include relativistic
effects in Green's Function Monte Carlo and validate the inclusive
electron-scattering cross section on carbon using available data. We compare
the flux folded cross sections for neutrino-Carbon scattering with T2K and
MINERA experiments, noting the substantial impact of relativistic effects
in reducing the theoretical curve strength when compared to MINERA data.
Additionally, we demonstrate that quantum Monte Carlo-based spectral functions
accurately reproduce the quasi-elastic region in electron-scattering data and
T2K flux folded cross sections. By comparing results from Green's Function
Monte Carlo and the spectral function approach, which share a similar initial
target state description, we quantify errors associated with approximations in
the factorization scheme and the relativistic treatment of kinematics in
Green's Function Monte Carlo.Comment: 30 pages, 9 figure
Safety and efficacy of stereotactic body radiation therapy in the treatment of pulmonary metastases from high grade sarcoma.
Introduction. Patients with high-grade sarcoma (HGS) frequently develop metastatic disease thus limiting their long-term survival. Lung metastases (LM) have historically been treated with surgical resection (metastasectomy). A potential alternative for controlling LM could be stereotactic body radiation therapy (SBRT). We evaluated the outcomes from our institutional experience utilizing SBRT. Methods. Sixteen consecutive patients with LM from HGS were treated with SBRT between 2009 and 2011. Routine radiographic and clinical follow-up was performed. Local failure was defined as CT progression on 2 consecutive scans or growth after initial shrinkage. Radiation pneumonitis and radiation esophagitis were scored using Common Toxicity Criteria (CTC) version 3.0. Results. All 16 patients received chemotherapy, and a subset (38%) also underwent prior pulmonary metastasectomy. Median patient age was 56 (12-85), and median follow-up time was 20 months (range 3-43). A total of 25 lesions were treated and evaluable for this analysis. Most common histologies were leiomyosarcoma (28%), synovial sarcoma (20%), and osteosarcoma (16%). Median SBRT prescription dose was 54 Gy (36-54) in 3-4 fractions. At 43 months, local control was 94%. No patient experienced G2-4 radiation pneumonitis, and no patient experienced radiation esophagitis. Conclusions. Our retrospective experience suggests that SBRT for LM from HGS provides excellent local control and minimal toxicity
Form factor and model dependence in neutrino-nucleus cross section predictions
To achieve its design goals, the next generation of neutrino-oscillation
accelerator experiments requires percent-level predictions of neutrino-nucleus
cross sections supplemented by robust estimates of the theoretical
uncertainties involved. The latter arise from both approximations in solving
the nuclear many-body problem and in the determination of the single- and
few-nucleon quantities taken as input by many-body methods. To quantify both
types of uncertainty, we compute flux-averaged double-differential cross
sections using the Green's function Monte Carlo and spectral function methods
as well as different parameterizations of the nucleon axial form factors based
on either deuterium bubble-chamber data or lattice quantum chromodynamics
calculations. The cross-section results are compared with available
experimental data from the MiniBooNE and T2K collaborations. We also discuss
the uncertainties associated with transition form factors
that enter the two-body current operator. We quantify the relations between
neutrino-nucleus cross section and nucleon form factor uncertainties. These
relations enable us to determine the form factor precision targets required to
achieve a given cross-section precision.Comment: Minor changes to text and figure label
Negative quasiprobabilities enhance phase estimation in quantum-optics experiment
Operator noncommutation, a hallmark of quantum theory, limits measurement
precision, according to uncertainty principles. Wielded correctly, though,
noncommutation can boost precision. A recent foundational result relates a
metrological advantage with negative quasiprobabilities -- quantum extensions
of probabilities -- engendered by noncommuting operators. We crystallize the
relationship in an equation that we prove theoretically and observe
experimentally. Our proof-of-principle optical experiment features a filtering
technique that we term partially postselected amplification (PPA). Using PPA,
we measure a waveplate's birefringent phase. PPA amplifies, by over two orders
of magnitude, the information obtained about the phase per detected photon. In
principle, PPA can boost the information obtained from the average filtered
photon by an arbitrarily large factor. The filter's amplification of systematic
errors, we find, bounds the theoretically unlimited advantage in practice. PPA
can facilitate any phase measurement and mitigates challenges that scale with
trial number, such as proportional noise and detector saturation. By
quantifying PPA's metrological advantage with quasiprobabilities, we reveal
deep connections between quantum foundations and precision measurement.Comment: 5 pages, 4 figures in main text; 8 pages, 1 figure in appendice
Generating a 4-photon Tetrahedron State: Towards Simultaneous Super-sensitivity to Non-commuting Rotations
It is often thought that the super-sensitivity of a quantum state to an
observable comes at the cost of a decreased sensitivity to other non-commuting
observables. For example, a squeezed state squeezed in position quadrature is
super-sensitive to position displacements, but very insensitive to momentum
displacements. This misconception was cleared with the introduction of the
compass state, a quantum state equally super-sensitive to displacements in
position and momentum. When looking at quantum states used to measure spin
rotations, N00N states are known to be more advantageous than classical methods
as long as they are aligned to the rotation axis. When considering the
estimation of a rotation with unknown direction and amplitude, a certain class
of states stands out with interesting properties. These states are equally
sensitive to rotations around any axis, are second-order unpolarized, and can
possess the rotational properties of platonic solids in particular dimensions.
Importantly, these states are optimal for simultaneously estimating the three
parameters describing a rotation. In the asymptotic limit, estimating all d
parameters describing a transformation simultaneously rather than sequentially
can lead to a reduction of the appropriately-weighted sum of the measured
parameters' variances by a factor of d. We report the experimental creation and
characterization of the lowest-dimensional such state, which we call the
"tetrahedron state" due to its tetrahedral symmetry. This tetrahedron state is
created in the symmetric subspace of four optical photons' polarization in a
single spatial and temporal mode, which behaves as a spin-2 particle. While
imperfections due to the hardware limit the performance of our method, we argue
that better technology can improve our method to the point of outperforming any
other existing strategy in per-photon comparisons.Comment: 13 pages, 6 figure
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