A mathematical formalism for the Kondo effect in WZW branes

In this paper, we show how to adapt our rigorous mathematical formalism for closed/open conformal field theory so that it captures the known physical theory of branes in the WZW model. This includes a mathematically precise approach to the Kondo effect, which is an example of evolution of one conformally invariant boundary condition into another through boundary conditions which can break conformal invariance, and a proposed mathematical statement of the Kondo effect conjecture. We also review some of the known physical results on WZW boundary conditions from a mathematical perspective.Comment: Added explanations of the settings and main result

Beam-Breakup Instability Theory for Energy Recovery Linacs

Here we will derive the general theory of the beam-breakup instability in recirculating linear accelerators, in which the bunches do not have to be at the same RF phase during each recirculation turn. This is important for the description of energy recovery linacs (ERLs) where bunches are recirculated at a decelerating phase of the RF wave and for other recirculator arrangements where different RF phases are of an advantage. Furthermore it can be used for the analysis of phase errors of recirculated bunches. It is shown how the threshold current for a given linac can be computed and a remarkable agreement with tracking data is demonstrated. The general formulas are then analyzed for several analytically solvable cases, which show: (a) Why different higher order modes (HOM) in one cavity do not couple so that the most dangerous modes can be considered individually. (b) How different HOM frequencies have to be in order to consider them separately. (c) That no optics can cause the HOMs of two cavities to cancel. (d) How an optics can avoid the addition of the instabilities of two cavities. (e) How a HOM in a multiple-turn recirculator interferes with itself. Furthermore, a simple method to compute the orbit deviations produced by cavity misalignments has also been introduced. It is shown that the BBU instability always occurs before the orbit excursion becomes very large.Comment: 12 pages, 6 figure

Virasoro constraints in Drinfeld-Sokolov hierarchies

We describe a geometric theory of Virasoro constraints in generalized Drinfeld-Sokolov hierarchies. Solutions of Drinfeld-Sokolov hierarchies are succinctly described by giving a principal bundle on a complex curve together with the data of a Higgs field near infinity. String solutions for these hierarchies are defined as points having a big stabilizer under a certain Lie algebra action. We characterize principal bundles coming from string solutions as those possessing connections compatible with the Higgs field near infinity. We show that tau-functions of string solutions satisfy second-order differential equations generalizing the Virasoro constraints of 2d quantum gravity.Comment: 28 page

Estimation of parameters in a structured SIR model

[EN] In this paper, an age-structured epidemiological process is considered. The disease model is based on a SIR model with unknown parameters. We addressed two important issues to analyzing the model and its parameters. One issue is concerned with the theoretical existence of unique solution, the identifiability problem. The second issue is how to estimate the parameters in the model. We propose an iterative algorithm to study the identifiability of the system and a method to estimate the parameters which are identifiable. A least squares approach based on a finite set of observations helps us to estimate the initial values of the parameters. Finally, we test the proposed algorithms.The authors would like to thank the referees and the editor for their comments and useful suggestions for improvement of the manuscript. This work has been partially supported by Spanish Grant MTM2013-43678-P.Cantó Colomina, B.; Coll, C.; Sánchez, E. (2017). Estimation of parameters in a structured SIR model. Advances in Difference Equations. 33:1-13. https://doi.org/10.1186/s13662-017-1078-5S11333Strogatz, S, Friedman, M, Mallinck-Rodt, AJ, McKay, S: Nonlinear Dynamics and Chaos: With Applications to Physics, Biology, Chemistry, and Engineering. Perseus Books, Washington (1994)De La Sen, M, Quesada, A: Some equilibrium, stability, instability and oscillatory results for an extended discrete epidemic model with evolution memory. Adv. Differ. Equ. 2013, 234 (2013)Han, Q, Wang, Z: On extinction of infectious diseases for multi-group SIRS models with satured incidence rate. Adv. Differ. Equ. 2015, 333 (2015)Cantó, B, Coll, C, Sánchez, E: Structural identifiability of a model of dialysis. Math. Comput. Model. 50, 733-737 (2009)Cantó, B, Coll, C, Sánchez, E: Identifiability of a class of discretized linear partial differential algebraic equations. Math. Probl. Eng., 1-12 (2011)Craciun, G, Pantea, C: Identifiability of chemical reaction networks. J. Math. Chem. 44, 244-259 (2008)Malik, MB, Salman, M: State-space least mean square. Digit. Signal Process. 18, 334-345 (2008)Ding, F, Liu, PX, Liu, G: Multiinnovatiovation least-squares identification for system modeling. IEEE Trans. Syst. Man Cybern., Part B, Cybern. 18(3), 767-778 (2010)Ben-Zvi, A, McLellan, PJ, McAuley, KB: Identifiability of linear time-invariant differential-algebraic systems, I. The generalized Markov parameter approach. Ind. Eng. Chem. Res. 42, 6607-6618 (2003)Boyadjiev, C, Dimitrova, E: An iterative method for model parameter identification. Comput. Chem. Eng. 29, 941-948 (2005)Ben-Zvi, A, McLellan, PJ, McAuley, KB: Identifiability of linear time-invariant differential-algebraic systems, 2. The differential-algebraic approach. Ind. Eng. Chem. Res. 43, 1251-1259 (2004)Dion, JM, Commault, C, van der Woude, J: Generic properties and control of linear structured systems: a survey. Automatica 39, 1125-1144 (2003)Chou, IC, Voit, EO: Recent developments in parameter estimation and structure identification of biochemical and genomic systems. Math. Biosci. 219, 57-83 (2009)Schmitz, OJ: Ecology and Ecosystems Conservation. Island Press, Washington (2013

Coupled-Bunch Beam Breakup due to Resistive-Wall Wake

The coupled-bunch beam breakup problem excited by the resistive wall wake is formulated. An approximate analytic method of finding the asymptotic behavior of the transverse bunch displacement is developed and solved.Comment: 8 page

Collective Effects in the Rhic-Ii Electron Cooler

Electron cooling at RHIC-I1 upgrade imposes strict requirements on the quality of the electron beam at the cooling section. Beam current dependent effects such as the space charge, wake fields, CSR in bending magnets, trapped ions, etc., will tend to spoil the beam quality and decrease the cooling efficiency. In this paper, we estimate the defocusing effect of the space charge at the cooling section and describe our plan to compensate the defocusing space charge force by focusing solenoids. We also estimate the energy and emittance growth cased by wake fields. Finally, we discuss ion trapping in the electron cooler and consider different techniques to minimize the effect of ion trapping

VORPAL simulations relevant to coherent electron cooling

Coherent electron cooling (CEC) [1] combines the best features of electron cooling and stochastic cooling, via free-electron laser technology [2], to offer the possibility of cooling high-energy hadron beams with order-of-magnitude shorter cooling times. Many technical difficulties must be resolved via full-scale 3D simulations, before the CEC concept can be validated experimentally. VORPAL is the ideal code for simulating the modulator and kicker regions, where the electron and hadron beams will co-propagate as in a conventional electron cooling section. Unlike previous VORPAL simulations [3] of electron cooling physics, where dynamical friction on the ions was the key metric, it is the details of the electron density wake driven by each ion in the modulator section that must be understood, followed by strong amplification in the FEL. We present some initial simulation results

Blueberries infected with the fungal pathogen Colletotrichum fioriniae release odors that repel Drosophila suzukii

Spotted-wing drosophila, Drosophila suzukii, is a serious pest of thin-skinned fruits. Alternative methods to control this pest are needed to reduce insecticide use, including new repellents. Previous research demonstrated that D. suzukii adults use odor cues to avoid blueberries infected with the fungal pathogen Colletotrichum fioriniae, which causes the disease anthracnose. To identify novel D. suzukii repellents, we investigated the volatile emission from experimentallyinfected fruit, which were inoculated with C. fioriniae isolates in the laboratory, and from field-collected fruit, which were naturally infected and harvested from a field. We then tested the pathogen-induced volatiles on D. suzukii adult behavior.hanks to Arthur Rudolph for his help operating the GC–MS during pandemic work restrictions, Chelsea Abegg for providing field-collected blueberry fruit infected with anthracnose, to Mustafa Wasti, Robert Holdcraft, and Vera Kyryczenko-Roth for technical assistance. Authors CCR and JJB were supported by USDA ARS CRIS 6036-224300-001-000D and CR-S and AQ were supported by USDA SCRI 2020-51181-32140, The Sridhar Polavarapu Memorial Endowment for Vaccinium Research, and USDA Sustainable Agriculture Research and Education (grant no. LNE22-455R).info:eu-repo/semantics/publishedVersio

Fundamental damper power calculation of the 56MHz SRF cavity for RHIC

At each injection period during RHIC's operation, the beam's frequency sweeps across a wide range, and some of its harmonics will cross the frequency of the 56MHz SRF cavity. To avoid excitation of the cavity at these times, we designed a fundamental damper for the quarter-wave resonator to damp the cavity heavily. The power extracted by the fundamental damper should correspond to the power handling ability of the system at all stages. In this paper, we discuss the power output from the fundamental damper when it is fully extracted, inserted, and any intermediate point. A Fundamental Damper (FD) will greatly reduce the cavity's Q factor to {approx}300 during the acceleration phase of the beam. However, when the beam is at store and the FD is removed, the cavity is excited by both the yellow and the blue beams at 2 x 0.3A to attain the required 2MV voltage across its gap. The cavity then is operated to increase the luminosity of the RHIC experiments. Table 1 lists the parameters of the FD. Figure 1 shows the configuration of the FD fully inserted into the 56MHz SRF cavity; this complete insertion is defined as the start location (0cm) of FD simulation, an assumption we make throughout this paper. The power consumed by the cavity while maintaining the beam's energy and its orbit is compensated by the 28MHz accelerating cavities in the storage ring. The power dissipation of the external load is dynamic with respect to the position of the FD during its extraction. As a function of the external Q and the EM field in the cavity, the power should peak with the FD at a certain vertical location. Our calculation of the power extracted is detailed in the following sections. Figure 2 plots the frequency change in the cavity, and the external Q against the changes in position of the FD. The location of the FD is selected carefully such that the frequency will approach the designed working point from the lower side only. The loaded Q of the cavity is 223 when the FD is fully inserted. The simulation was carried out with Microwave Studio 2010

Proposed UV-FEL user facility at BNL

The NSLS at Brookhaven National Laboratory is proposing the construction of a UV-FEL operating in the wavelength range from visible to 1000{angstrom}. Nano-Coulomb electron pulses will be generated at a laser photo-cathode RF gun at a repetition rate of 10 KHz. The 6 ps pulses will be accelerated to 250 MeV in a superconducting linac. The FEL consists of an exponential growth section followed by a tapered section. The amplifier input is a harmonic of a tunable visible laser generated either by nonlinear optical material or the non-linearity of the FEL itself. The FEL output in 10{sup {minus}4} bandwidth is 1 mJ per pulse, resulting in an average power of 10 watts. The availability of radiation with these characteristics would open up new opportunities in photochemistry, biology and non linear optics, as discussed in a recent workshop held at BNL. 10 refs., 4 figs., 1 tab