3,821 research outputs found
Supersymmetric Localization in GLSMs for Supermanifolds
In this paper we apply supersymmetric localization to study gauged linear
sigma models (GLSMs) describing supermanifold target spaces. We use the
localization method to show that A-twisted GLSM correlation functions for
certain supermanifolds are equivalent to A-twisted GLSM correlation functions
for hypersurfaces in ordinary spaces under certain conditions. We also argue
that physical two-sphere partition functions are the same for these two types
of target spaces. Therefore, we reproduce the claim of arXiv:hep-th/9404186,
arXiv:hep-th/9506070. Furthermore, we explore elliptic genera and (0,2)
deformations and find similar phenomena.Comment: 31 pages, no figure
Quantum K theory of Grassmannians, Wilson line operators, and Schur bundles
We prove a `Whitney' presentation, and a `Coulomb branch' presentation, for
the torus equivariant quantum K theory of the Grassmann manifold
, inspired from physics, and stated in an earlier paper. The
first presentation is obtained by quantum deforming the product of the
Hirzebruch classes of the tautological bundles. In physics, the
classes appeared as certain Wilson line operators. The second
presentation is obtained from the Coulomb branch equations involving the
partial derivatives of a twisted superpotential from supersymmetric gauge
theory. This is closest to a presentation obtained by Gorbounov and Korff,
utilizing integrable systems techniques. Algebraically, we relate the Coulomb
and Whitney presentations utilizing transition matrices from the (equivariant)
Grothendieck polynomials to the (equivariant) complete homogeneous symmetric
polynomials. The calculations of K-theoretic Gromov-Witten invariants of wedge
powers of the tautological subbundles on the Grassmannian utilize the
`quantum=classical' statement.Comment: 39 page
Quantum K Whitney relations for partial flag varieties
In a recent paper, we stated conjectural presentations for the equivariant
quantum K ring of partial flag varieties, motivated by physics considerations.
In this companion paper, we analyze these presentations mathematically. We
prove that if the conjectured relations hold, then they must form a complete
set of relations. Our main result is a proof of the conjectured presentation in
the case of the incidence varieties. We also show that if a quantum K divisor
axiom holds (as conjectured by Buch and Mihalcea), then the conjectured
presentation also holds for the complete flag variety.Comment: 25 pages; revised Remark 5.9 and added Example 5.1
One-off and Repeating Fast Radio Bursts: A Statistical Analysis
According to the number of detected bursts, fast radio bursts (FRBs) can be
classified into two categories, i.e., one-off FRBs and repeating ones. We make
a statistical comparison of these two categories based on the first FRB catalog
of the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst Project.
Using the Anderson-Darling, Kolmogrov-Smirnov, and Energy statistic tests, we
find significant statistical differences (-value 0.001) of the burst
properties between the one-off FRBs and the repeating ones. More specifically,
after controlling for distance, we find that the peak luminosities of one-off
FRBs are, on average, higher than the repeating ones; the pulse temporal widths
of repeating FRBs are, on average, longer than the one-off ones. The
differences indicate that these two categories could have distinct physical
origins. Moreover, we discuss the sub-populations of FRBs and provide
statistical evidence to support the existence of sub-populations in one-off
FRBs and in repeating ones.Comment: 10 pages, 6 figures, accepted for publication in Ap
Research on sound radiation characteristics of the high-speed train wheel
Taking the standard wheel model as an example, the radiation noise of a single wheel under excitation force which is computed by multi-body dynamics model is computed by acoustic boundary element method (BEM). Then, the damped wheel is proposed, and the sound radiation characteristics of both wheels are analyzed and compared. The results show that sound field of a single wheel presents an obvious directivity with petaloid change and continuous decrease, and the wheel tread and web contribute the most rolling noise. Compared with the standard wheel, the acoustic radiation power of the damped wheel decreased significantly, especially at the peak frequency. After that, the radiation noise generated by the wheel in the train is researched. The results show that the radiation noise generated by the wheel in the train is a complex sound field after the superposition and interference of multiple wheel noises, which are mainly in the bogies at both ends and its vicinity region. Meanwhile, the basic directivity characteristics of the petaloid change and continuous reduction are remained. The radiation noise which is generated by the wheel in the train has obvious peak characteristic, whose corresponding peak noises are below 110Â dB. The radiation noise of the damped wheel is significantly smaller than that of the standard wheel at most frequency bands, and the total SPL at the observation point has decreased by 14.5Â dB with obvious noise reduction effect. In order to further research the radiation noise of the damping wheel, influence factors on the noise reduction are analyzed. Finally, these parameters such as thickness and material should be considered comprehensively during designing the damping wheel, in order to find the optimal combination of all parameters
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