1,519 research outputs found
Spectral gaps for periodic Schr\"odinger operators with strong magnetic fields
We consider Schr\"odinger operators
with the periodic magnetic field on covering spaces of
compact manifolds. Under some assumptions on , we prove that there are
arbitrarily large number of gaps in the spectrum of these operators in the
semiclassical limit of strong magnetic field .Comment: 14 pages, LaTeX2e, xypic, no figure
Lifshitz fermionic theories with z=2 anisotropic scaling
We construct fermionic Lagrangians with anisotropic scaling z=2, the natural
counterpart of the usual z=2 Lifshitz field theories for scalar fields. We
analyze the issue of chiral symmetry, construct the Noether axial currents and
discuss the chiral anomaly giving explicit results for two-dimensional case. We
also exploit the connection between detailed balance and the dynamics of
Lifshitz theories to find different z=2 fermionic Lagrangians and construct
their supersymmetric extensions.Comment: Typos corrected, comment adde
Non-catalytic bromination of benzene: a combined computational and experimental study
The non-catalytic bromination of benzene is shown experimentally to require high 5-14M concentrations of bromine in order to proceed at ambient temperatures to form predominantly bromobenzene, along with detectable (The non-catalytic bromination of benzene is shown experimentally to require high 5-14M concentrations of bromine in order to proceed at ambient temperatures to form predominantly bromobenzene, along with detectable (The non-catalytic bromination of benzene is shown experimentally to require high 5-14M concentrations of bromine in order to proceed at ambient temperatures to form predominantly bromobenzene, along with detectable
The order of curvature operators on loop groups
For loop groups (free and based), we compute the exact order of the curvature
operator of the Levi-Civita connection depending on a Sobolev space parameter.
This extends results of Freed and Maeda-Rosenberg-Torres.Comment: to appear in Letters in Mathematical Physic
Numerical model of ultrasonic multi-channel data transfer for servicing subsea production complex
Various researchers focused on different problems, and we can conclude that a single effective communication design with a specific algorithm that could be used in all types of underwater channels was not found. The design of the transmission is highly dependent on the conditions of the canal, as various schemes are used in shallow and deep water, and various algorithms in turbulent and calm waters. The type of channel alignment also depends on parameters such as channel estimation and coding. The ever-growing demand for bandwidth, efficiency, spatial diversity and the performance of underwater acoustic communications has opened the door to using Multiple Input Multiple Output (MIMO) technology. In this paper, we propose a method of ultrasonic data transmission under water based on the MIMO technology (Many emitters, many receivers, or MIMO - Multilpe Input - Multiple Output). This approach will allow for multi-channel data transmission in water and significantly increase the speed of information transfer
Yang-Mills action from minimally coupled bosons on R^4 and on the 4D Moyal plane
We consider bosons on Euclidean R^4 that are minimally coupled to an external
Yang-Mills field. We compute the logarithmically divergent part of the cut-off
regularized quantum effective action of this system. We confirm the known
result that this term is proportional to the Yang-Mills action.
We use pseudodifferential operator methods throughout to prepare the ground
for a generalization of our calculation to the noncommutative four-dimensional
Moyal plane (also known as noncommutative flat space). We also include a
detailed comparison of our cut-off regularization to heat kernel techniques.
In the case of the noncommutative space, we complement the usual technique of
asymptotic expansion in the momentum variable with operator theoretic arguments
in order to keep separated quantum from noncommutativity effects. We show that
the result from the commutative space R^4 still holds if one replaces all
pointwise products by the noncommutative Moyal product.Comment: 37 pages, v2 contains an improved treatment of the theta function in
Appendix A.
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