Finite baryon density effects on gauge field dynamics

We discuss the effective action for QCD gauge fields at finite temperatures and densities, obtained after integrating out the hardest momentum scales from the system. We show that a non-vanishing baryon density induces a charge conjugation (C) odd operator to the gauge field action, proportional to the chemical potential. Even though it is parametrically smaller than the leading C even operator, it could have an important effect on C odd observables. The same operator appears to be produced by classical kinetic theory, allowing in principle for a non-perturbative study of such processes.Comment: 20 page

Plasmon properties in classical lattice gauge theory

In order to investigate the features of the classical approximation at high temperatures for real time correlation functions, the plasmon frequencies and damping rates were recently computed numerically in the SU(2)+Higgs model and in the pure SU(2) theory. We compare the lattice results with leading order hard thermal loop resummed perturbation theory. In the broken phase of the SU(2)+Higgs model, we show that the lattice results can be reproduced and that the lattices used are too coarse to observe some important plasmon effects. In the symmetric phase, the main qualitative features of the lattice results can also be understood. In the pure SU(2) theory, on the other hand, there are discrepancies which might point to larger Landau and plasmon damping effects than indicated by perturbation theory.Comment: 17 pages, 5 figures. A few points written more clearly (e.g., in the abstract). A note added concerning two recent papers. Conclusions unchanged. To appear in Phys.Lett.

Trauma Prevention & Best Practices in Performance Classrooms

Abstract This thesis has been constructed to create a trauma-informed teaching method to be used within performance classrooms at the college level. The first chapter starts by defining trauma and walking the reader through the neuroscience behind trauma. Next, the code of ethics created by the National Educational Association is examined and a definition for best practices within the classroom is outlined. Finally, this chapter concludes with a definition of emotional abuse that brings all the concepts together and explains how they are interlaced. The next chapter is dedicated to learning more about the percentage of actors who have experienced childhood trauma. The two studies in this section show us that performers are more fantasy-prone, dissociate more, and tend to have more traumatic childhood experiences. From here this chapter then moves into exploring already established and successful trauma-informed teaching models outside of the performance classroom. Chapter three then dives into the differences between teaching, therapy, and dramatherapy. After these three vocations have been explored, the six beliefs at the core of my trauma-informed model are presented and justified. Chapter four then investigates different established acting pedagogies and pairs them with the six core beliefs established at the end of chapter three. Six theatre practitioners techniques are explored and discussed, with multiple acting exercises explained in-depth for each practitioner. Chapter five takes a brief moment to bring light to generational trauma and trauma of marginalized groups. Concluding with a summarization of my personal process constructing this thesis. Finally, chapter six serves as a conclusion where all the research conducted above comes together to create a visual acting trajectory, syllabus, and lesson plan for a new trauma-informed performance pedagogy

A way to estimate the heavy quark thermalization rate from the lattice

The thermalization rate of a heavy quark is related to its momentum diffusion coefficient. Starting from a Kubo relation and using the framework of the heavy quark effective theory, we argue that in the large-mass limit the momentum diffusion coefficient can be defined through a certain Euclidean correlation function, involving color-electric fields along a Polyakov loop. Furthermore, carrying out a perturbative computation, we demonstrate that the spectral function corresponding to this correlator is relatively flat at small frequencies. Therefore, unlike in the case of several other transport coefficients, for which the narrowness of the transport peak makes analytic continuation from Euclidean lattice data susceptible to severe systematic uncertainties, it appears that the determination of the heavy quark thermalization rate could be relatively well under control.Comment: 17 pages. v2: clarifications and references added, published versio

Heavy Quark Thermalization in Classical Lattice Gauge Theory: Lessons for Strongly-Coupled QCD

Thermalization of a heavy quark near rest is controlled by the correlator of two electric fields along a temporal Wilson line. We address this correlator within real-time, classical lattice Yang-Mills theory, and elaborate on the analogies that exist with the dynamics of hot QCD. In the weak-coupling limit, it can be shown analytically that the dynamics on the two sides are closely related to each other. For intermediate couplings, we carry out non-perturbative simulations within the classical theory, showing that the leading term in the weak-coupling expansion significantly underestimates the heavy quark thermalization rate. Our analytic and numerical results also yield a general understanding concerning the overall shape of the spectral function corresponding to the electric field correlator, which may be helpful in subsequent efforts to reconstruct it from Euclidean lattice Monte Carlo simulations.Comment: 22 pages. v2: a reference and clarifications added; published versio

CO Distribution and Kinematics Along the Bar in the Strongly Barred Spiral NGC 7479

We report on the 2.5 arcsec (400 pc) resolution CO (J = 1 -> 0) observations covering the whole length of the bar in the strongly barred late-type spiral galaxy NGC 7479. CO emission is detected only along a dust lane that traverses the whole length of the bar, including the nucleus. The emission is strongest in the nucleus. The distribution of emission is clumpy along the bar outside the nucleus, and consists of gas complexes that are unlikely to be gravitationally bound. The CO kinematics within the bar consist of two separate components. A kinematically distinct circumnuclear disk, < 500 pc in diameter, is undergoing predominantly circular motion with a maximum rotational velocity of 245 km/s at a radius of 1 arcsec (160 pc). The CO-emitting gas in the bar outside the circumnuclear disk has substantial noncircular motions which are consistent with a large radial velocity component, directed inwards. The CO emission has a large velocity gradient across the bar dust lane, ranging from 0.5 to 1.9 km/s/pc after correcting for inclination, and the projected velocity change across the dust lane is as high as 200 km/s. This sharp velocity gradient is consistent with a shock front at the location of the bar dust lane. A comparison of H-alpha and CO kinematics across the dust lane shows that although the H-alpha emission is often observed both upstream and downstream from the dust lane, the CO emission is observed only where the velocity gradient is large. We also compare the observations with hydrodynamic models and discuss star formation along the bar.Comment: 16 pages, including 10 figures. Accepted for publication in Ap

Lattice study of a magnetic contribution to heavy quark momentum diffusion

Heavy quarks placed within a hot QCD medium undergo Brownian motion, characterized by specific transport coefficients. Their determination can be simplified by expanding them in T/M, where T is the temperature and M is a heavy quark mass. The leading term in the expansion originates from the colour-electric part of a Lorentz force, whereas the next-to-leading order involves the colour-magnetic part. We measure a colour-magnetic 2-point correlator in quenched QCD at T ∼ (1.2 − 2.0)Tc. Employing multilevel techniques and non-perturbative renormalization, a good signal is obtained, and its continuum extrapolation can be estimated. Modelling the shape of the corresponding spectral function, we subsequently extract the momentum diffusion coefficient, κ. For charm (bottom) quarks, the magnetic contribution adds ∼ 30% (10%) to the electric one. The same increases apply also to the drag coefficient, η. As an aside, the colour-magnetic spectral function is computed at NLO

Quarkonium in Hot Medium

I review recent progress in studying quarkonium properties in hot medium as well as possible consequences for quarkonium production in heavy ion collisions.Comment: Invited talk at SQM 2009, Buzios, Brazil, Sep. 27 -Oct. 2 2009, LaTeX, 8 pages,3 figures; typos corrected, references adde

O(a) errors in 3-D SU(N) Higgs theories

We compute the matching conditions between lattice and continuum 3-D SU(N) Higgs theories, with both adjoint and fundamental scalars, at O(a), except for additive corrections to masses and Higgs field operator insertions.Comment: 23 pages with two figures. Added references, a few typos correcte