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Full-Text Articles in Physical Sciences and Mathematics

Transmission Zeros With Topological Symmetry In Complex Systems, Yuhao Kang, Azriel Genack Jan 2021

Transmission Zeros With Topological Symmetry In Complex Systems, Yuhao Kang, Azriel Genack

Publications and Research

Understanding vanishing transmission in Fano resonances in quantum systems and metamaterials and perfect and ultralow transmission in disordered media, has advanced the understanding and applications of wave interactions. Here we use analytic theory and numerical simulations to understand and control the transmission and transmission time in complex systems by deforming a medium and by adjusting the level of gain or loss. Unlike the zeros of the scattering matrix, the position and motion of the zeros of the determinant of the transmission matrix in the complex plane of frequency and field decay rate have robust topological properties. In systems without loss …


Potential Solar Replacement Of Hydroelectricity To Reopen Rivers: Maine As A Case Example, Shailesh Sharma, John Waldman Jan 2021

Potential Solar Replacement Of Hydroelectricity To Reopen Rivers: Maine As A Case Example, Shailesh Sharma, John Waldman

Publications and Research

Hydroelectricity provides 6% of U.S. electrical power needs, but hydro-dams also cause environmental harm, including the retardation or complete blockage of spawning runs of anadromous fishes. To facilitate fish movements, engineered-fishways have long been used but many have performed poorly. Dam-removal is the most effective way of restoring dwindling migratory fish populations by allowing unrestricted pathways to their spawning areas and for the downstream migrations of post-spawning adults and juveniles. However, removals of hydro-dams result in a loss of electricity production. For the replacement of energy foregone from hydro-dam removals, various alternative energy installations are now feasible. We present one-to-one …


Exclusion Statistics For Particles With A Discrete Spectrum, Stéphane Ouvry, Alexios P. Polychronakos Jan 2021

Exclusion Statistics For Particles With A Discrete Spectrum, Stéphane Ouvry, Alexios P. Polychronakos

Publications and Research

We formulate and study the microscopic statistical mechanics of systems of particles with exclusion statistics in a discrete one-body spectrum. The statistical mechanics of these systems can be expressed in terms of effective single-level grand partition functions obeying a generalization of the standard thermodynamic exclusion statistics equation of state. We derive explicit expressions for the thermodynamic potential in terms of microscopic cluster coefficients and show that the mean occupation numbers of levels satisfy a nesting relation involving a number of adjacent levels determined by the exclusion parameter. We apply the formalism to the harmonic Calogero model and point out a …


Three Imprimitive Character Sums, Brad Isaacson Jan 2021

Three Imprimitive Character Sums, Brad Isaacson

Publications and Research

We express three imprimitive character sums in terms of generalized Bernoulli numbers. These sums are generalizations of sums introduced and studied by Arakawa, Berndt, Ibukiyama, Kaneko and Ramanujan in the context of modular forms and theta function identities. As a corollary, we obtain a formula for cotangent power sums considered by Apostol.


Discrete Mathematical Structures, Tugce Ozdemir Jan 2021

Discrete Mathematical Structures, Tugce Ozdemir

Open Educational Resources

No abstract provided.


Topological Terms And Diffeomorphism Anomalies In Fluid Dynamics And Sigma Models, V. Parameswaran Nair Jan 2021

Topological Terms And Diffeomorphism Anomalies In Fluid Dynamics And Sigma Models, V. Parameswaran Nair

Publications and Research

The requirement of diffeomorphism symmetry for the target space can lead to anomalous commutators for the energy-momentum tensor for sigma models and for fluid dynamics, if certain topological terms are added to the action. We analyze several examples . A particular topological term is shown to lead to the known effective hydrodynamics of a dense collection of vortices, i.e. the vortex fluid theory in 2+1 dimensions. The possibility of a similar vortex fluid in 3+1 dimensions, as well as a fluid of knots and links, with possible extended diffeomorphism algebras is also discussed.


Distributed Cross-Community Collaboration For The Cloud-Based Energy Management Service, Yu-Wen Chen, J. Morris Chang Jan 2021

Distributed Cross-Community Collaboration For The Cloud-Based Energy Management Service, Yu-Wen Chen, J. Morris Chang

Publications and Research

Customers’ participation is a critical factor for inte-grating the distributed energy resources via demand response and demand-side management programs, especially when customers become prosumers. Incentives need to be delivered by the energy management service to attract prosumers to operate their distributed energy resources and electricity loads grid-friendly actively. The cloud-based energy management service enables virtual trading for customers within the same community to minimize cost and smooth the fluctuation. With the potential fast-growing number of service providers and customers, the needs exist for efficiently collaborating across multiple service providers and customers. This paper proposes the distributed cross-community collaboration (XCC) for …


Amm Problem #12219, Brad Isaacson Jan 2021

Amm Problem #12219, Brad Isaacson

Publications and Research

No abstract provided.


A Twisted Generalization Of The Classical Dedekind Sum, Brad Isaacson Jan 2021

A Twisted Generalization Of The Classical Dedekind Sum, Brad Isaacson

Publications and Research

In this paper, we express three different, yet related, character sums in terms of generalized Bernoulli numbers. Two of these sums are generalizations of sums introduced and studied by Berndt and Arakawa–Ibukiyama–Kaneko in the context of the theory of modular forms. A third sum generalizes a sum already studied by Ramanujan in the context of theta function identities. Our methods are elementary, relying only on basic facts from algebra and number theory.