The Kardar-Parisi-Zhang equation with spatially correlated noise: a unified picture from nonperturbative renormalization group

We investigate the scaling regimes of the Kardar-Parisi-Zhang equation in the presence of spatially correlated noise with power law decay $D(p) \sim p^{-2\rho}$ in Fourier space, using a nonperturbative renormalization group approach. We determine the full phase diagram of the system as a function of $\rho$ and the dimension $d$. In addition to the weak-coupling part of the diagram, which agrees with the results from Refs. [Europhys. Lett. 47, 14 (1999), Eur. Phys. J. B 9, 491 (1999)], we find the two fixed points describing the short-range (SR) and long-range (LR) dominated strong-coupling phases. In contrast with a suggestion in the references cited above, we show that, for all values of $\rho$, there exists a unique strong-coupling SR fixed point that can be continuously followed as a function of $d$. We show in particular that the existence and the behavior of the LR fixed point do not provide any hint for 4 being the upper critical dimension of the KPZ equation with SR noise.Comment: 13 pages, 5 figures, final versio

High School Band Students’ Perspectives of Teacher Turnover

Teacher turnover remains an important issue in education. The least researched perspectives, though, are those of the students who experience teacher turnover. The purpose of this study was to examine how high school band students experience teacher turnover. A total of twelve students were interviewed, representing three schools that experienced a teacher turnover that year. Students were asked to give advice to teachers leaving a program, teachers coming to a new program, and for students who learn that their teacher is leaving. The study shows that reactions to teacher change vary, and that there is more to the turnover process than just the teacher leaving or a new one arriving. Students make connections with their teachers, and when a turnover takes place, they experience a full range of emotions

Strong competition between ΘII\Theta_{II}-loop-current order and dd-wave charge order along the diagonal direction in a two-dimensional hot spot model

We study the fate of the so-called $\Theta_{II}$-loop-current order that breaks both time-reversal and parity symmetries in a two-dimensional hot spot model with antiferromagnetically mediated interactions, using Fermi surfaces relevant to the phenomenology of the cuprate superconductors. We start from a three-band Emery model describing the hopping of holes in the CuO$_{2}$ plane that includes two hopping parameters $t_{pp}$ and $t_{pd}$, local on-site Coulomb interactions $U_{d}$ and $U_{p}$ and nearest-neighbor $V_{pd}$ couplings between the fermions in the copper [Cu$(3d_{x^{2}-y^{2}})$] and oxygen [O$(2p_{x})$ and O$(2p_{y})$] orbitals. By focusing on the lowest-energy band, we proceed to decouple the local interaction $U_{d}$ of the Cu orbital in the spin channel using a Hubbard-Stratonovich transformation to arrive at the interacting part of the so-called spin-fermion model. We also decouple the nearest-neighbor interaction $V_{pd}$ to introduce the order parameter of the $\Theta_{II}$-loop-current order. In this way, we are able to construct a consistent mean-field theory that describes the strong competition between the composite order parameter made of a quadrupole-density-wave and $d$-wave pairing fluctuations proposed in Efetov \emph{et al.} [Nat. Phys. \textbf{9}, 442 (2013)] with the $\Theta_{II}$-loop-current order parameter that is argued to be relevant for explaining important aspects of the physics of the pseudogap phase displayed in the underdoped cuprates.Comment: 16 pages, 5 figures. v2: minor revisions, references added. The magnetic moment per unit-cell associated with the $\Theta_{II}$-loop-current-phase is calculated and compared with experimental results. Accepted for publication in Physical Review

Parscale - an open-source library for the simulation of intra-particle heat and mass transport processes in coupled simulations

We introduce the open-source library ParScale for the modeling of intra-particle transport processes in non-isothermal reactive fluid-particle flows. The underlying equations, the code architecture, as well as the coupling strategy to the widely-used DEM solver LIGGGHTS is presented. A set of verification cases, embedded into an automated test harness, is presented that proofs the functionality of ParScale. To demonstrate the capabilities of ParScale, we perform simulations of a non-isothermal granular shear flow including heat transfer to the surrounding fluid. We present results for the conductive heat flux through the particle bed for a wide range of dimensionless cooling rates and particle volume fractions. Our data suggests that intra-particle temperature gradients need to be considered for an accurate prediction of the conductive flux in case of (i) a dense particle bed and (ii) for large cooling rates characterized by a critical Biot number of ca Bicrit ≈ 0.1

Thermalization of magnons in yttrium-iron garnet: nonequilibrium functional renormalization group approach

Using a nonequilibrium functional renormalization group (FRG) approach we calculate the time evolution of the momentum distribution of a magnon gas in contact with a thermal phonon bath. As a cutoff for the FRG procedure we use a hybridization parameter {\Lambda} giving rise to an artificial damping of the phonons. Within our truncation of the FRG flow equations the time evolution of the magnon distribution is obtained from a rate equation involving cutoff-dependent nonequilibrium self-energies, which in turn satisfy FRG flow equations depending on cutoff-dependent transition rates. Our approach goes beyond the Born collision approximation and takes the feedback of the magnons on the phonons into account. We use our method to calculate the thermalization of a quasi two-dimensional magnon gas in the magnetic insulator yttrium-iron garnet after a highly excited initial state has been generated by an external microwave field. We obtain good agreement with recent experiments.Comment: 16 pages, 6 figures, final versio