Fundamental scientific research, as a majority federally funded initiative, is becoming more deeply embedded in politics. Since the end of the Space Race, funding of basic physical sciences research as a percent GDP has continuously declined, indicating that policy makers see funding scientific research as less of a priority than they once did. Indeed, a lack of understanding about both science and how science is done amongst members of Congress has led to both reduced prioritization and also to misguided attempts at regulation, such as making peer review a public process and considering Congressional oversight for specific grants. Here we will examine a few current issues in science policy and the need for physicists to effectively weigh in on such policy issues. We will also consider the positive or negative effects such public engagement may have on our scientific careers and ways in which you can get involved.

 

Refreshments will be served in CP 179 at 3:15 PM

   The disk of the Milky Way beyond the solar circle is not open to simple

interpretations. In short, it is a mess. From observations of interstellar

gas it is clear that the disk has both a warp and a flare.

The stellar component is riddled with stellar over-densities and/or streams,

the largest of which is the Monoceros stream. It is unclear whether gas

is in-falling and still building the outer disk, whether the distribution

of dark matter inflates the outer disk, if interactions with satellite

galaxies are perturbing the disk or if disrupted satellites are adding

to the disk. It is possible that all of these effects are contributing.

What is clear is that the outer disk of the Galaxy holds many clues as to

how galaxies form and evolve.



   Studying stellar populations in the outer disk is useful but currently has

limitations because spatial and kinematic distributions are not uniquely

described by the various Galactic models. I will discuss our current

attempts at helping to constrain properties of the outer disk using

spectroscopic analysis of A-star samples. Most of the talk will be dedicated

to our analysis of chemically peculiar A-stars in the SDSS DR8 sample and

whether the distribution of these stars indicate that the Monoceros stream

contains ancient blue stragglers or younger A-stars. The latter conclusion

might suggest that the stream is a component of disk of the Galaxy, while the

former might indicate dwarf disruption. I will conclude the talk by showing

our current work on the Canis Major Over-density and our future goal to explore

dust distribution in the disk using A-stars

 

Despite its apparent simplicity, the idealized model of a particle constrained to move on a circle has intriguing dynamic properties and immediate experimental relevance. While a rotor is rather easy to set up classically, the quantum regime is harder to realize and investigate. Here we demonstrate that the quantum dynamics of quasiparticles in certain classes of nanostructured superconductors can be mapped onto a quantum rotor. Furthermore, we provide a straightforward experimental procedure to convert this nanoscale superconducting rotor into a regular or inverted quantum pendulum with tunable gravitational field, inertia, and drive. We detail how these novel states can be detected via scanning tunneling spectroscopy. The proposed experiments will provide insights into quantum dynamics and quantum chaology.



Reference: S.H. Lin, M. Milosevic, L. Covaci, F. Peeters, B. Janko, Nature Sci. Rep. 4, 4542 (2014).

All are welcome to come to mingle over coffee, tea, and cookies.

Happ Title:  "Generalized Abel-Rothe Polynomials" 

Happ Abstract:  This sequence of polynomials is conjectured to be of a "multi" binomial type, and we will discuss how they count certain trees and generalized parking functions.

Hedmark Title:  TBA

Hedmark Abstract:  TBA

Title:  Introduction to Linkage

Abstract:  Liaison theory studies ideals by "linking" them to nicer ideals that are well understood, and so gaining some interesting information about the original ideals.  In this talk we will introduce some key ideas in liaison theory and apply them to the study of ideals generated by minors in a symmetric skew tableau. This will include some recent work with Uwe Nagel.

Title:  On a generalized Derivative Nonlinear SchrÖdinger equation

Abstract:  The Derivative Nonlinear SchrÖdinger equation (DNLS) equation iψt + ψxx + i |ψ|2 ψx = 0 is a canonical equation obtained from the Hall-MHD equations in a long-wave scaling, in the context of weakly nonlinear Alfvén waves propagating along an ambient magnetic field. It has the same scaling properties as the Nonlinear SchrÖdinger equation with quantic power law nonlinearity (L2-critical) that develop singularities in a finite time.  It also has the property of being completely integrable by the inverse scattering transform and has soliton solutions. In an effort to address the open question of long-time existence, we introduced recently an L2 -supercritical version of the DNLS equation by modifying the nonlinearity |ψ|2ψx to |ψ|2σψx (σ > 1). Numerical simulations indicate that a finite time singularity may occur, and provide a precise description of the local structure of the solution in terms of blowup rate and asymptotic profile. The (complex valued) profile satisfies a nonlinear elliptic equation Qξξ −Q+ia(1/2σQ+ξQξ) − ibQξ + i |Q|2σQξ = 0, where the (real) coefficients a and b depend on σ (but not on the initial condition). Using methods of asymptotic analysis, we study the deformation of the functions Q, and parameters a, b as the nonlinearity σ tends to 1. We also check our analysis against a numerical integration of the profile equation with continuation type methods. This is an ongoing work with G. Simpson and Y. Cher.

Title:  An approach to enumerating lecture hall partitions.

Abstract:  We will introduce and define lecture hall partitions.  We will then investigate two different proofs of the Lecture Hall Theorem.