Eric Sembrat's Test Bonanza

The 1:1 forced complex Ginzburg-Landau equation (FCGL) is a non-variational system that exhibits bistability between equilibria and thus admits traveling front solutions. A localized state consisting of an inner equilibrium embedded in an outer equilibrium can be formed by assembling two identical fronts back-to-back. In this talk, I will first describe the bifurcation structure of 1D steady localized states that takes the form of collapsed snaking (CS) if the inner equilibrium is temporally stable, and defect-mediated snaking (DMS) if the inner equilibrium is modulationally unstable. Outside their existence ranges, the steady localized states undergo time evolutions collectively referred to as depinning dynamics. Moving on to 2D, I will first introduce the temporal dynamics of quasi-1D periodic stripes leading to planar localized hexagons. In exploring fully 2D steady solutions, the bifurcation structure of radially symmetric localized states again depends on whether the inner equilibrium is temporally stable or modulationally unstable. The time evolution of these fully 2D localized states leads to either radially expanding or contracting fronts or to localized hexagons bounded by an axisymmetric front. At the end, I will describe the case when the inner equilibrium becomes Hopf unstable in time, which in turn yields localized spatiotemporal chaos that bears some resemblance to turbulent spots in shear flows.

We consider dynamics of Bose-Einstein condensates with long-range attractive interaction proportional to 1/r^b and arbitrary angular dependence. It is shown exactly that collapse of Bose-Einstein condensate without contact interactions is possible only for b greater or equal to 2. Case b=2 is critical and requires number of particles to exceed critical value to allow collapse. Case b>2 is supercritical with expected weak collapse which traps rapidly decreasing number of particles during approach to collapse. For b<2 singularity at r=0 is not strong enough to allow collapse but attractive 1/r^b interaction admits stable self-trapping even in absence of external trapping potential.

In this talk we will discuss a relaxation of high-energy quasiparticles in a weakly interacting one-dimensional Bose liquid. Unlike in higher dimensions, the rate is a nonmonotonic function of temperature. Moreover, it turns out that the inelastic scattering due to deviations from the integrability occurs at a much higher rate than three-body recombination processes, which is the main mechanism of losses in cold-atom-based realizations of 1D Bose liquids.

In theory, quantum computers can solve certain problems much more efficiently than classical computers. This possibility has motivated experimental efforts to construct devices that manipulate quantum bits (qubits) in a variety of physical systems. One such system is composed of atomic ions confined by electric fields in a rf Paul trap. The motions of such ions can be modeled to a very good approximation as harmonic oscillators, and with suitable laser cooling techniques they can be cooled to the harmonic oscillator ground state. When trapped within the same potential minimum, ions interact strongly via the Coulomb force, thereby enabling multiple-qubit quantum gates that are routinely used in ion trap quantum information experiments. However, a similar interaction between ions held in separate trapping potentials (where the force is much weaker) has not been observed until now. I will discuss an experiment demonstrating coupling, at the quantum level, between two ions trapped in separate potential minima. The ions are confined to independent regions above a microfabricated, surface-electrode trap held at 4.2 K by a helium bath cryostat. This represents the first observation of coupling between quantized harmonic oscillators held in separate locations. Such an interaction may prove useful for quantum information processing, simulations, and metrology. The experiment also represents a first step toward hybrid quantum systems, such as coupling a trapped ion to a quantized mechanical oscillator. If time permits, I will also present very recent results verifying the exquisite level of control we have over single-qubit gates in this system.

I briefly review the formation of color superconductivity which happens in compact stars. Below the temperature scale set by the gap in the quark spectrum, transport properties are determined by collective modes. We compute the thermal conductivity, $\kappa$, of color-flavor locked (CFL) quark matter in the frame of kinetics theory. We present and compare the result with previous estimates. We also conclude a CFL quark matter core of
the compact star becomes isothermal on a timescale of a few seconds.  Moreover, we compute the thermal conductivity and sound attenuation length of a dilute Fermi gas, which help us comment on the possibility of extracting the shear viscosity of the dilute Fermi gas at unitarity using measurements of the sound absorption length.

Doug Osheroff, professor of physics at Stanford University and a Nobel Laureate in Physics, will present a lecture on "How Advances in Science Are Made."

ABSTRACT: 

How advances in science are made and how they may come to benefit mankind at large are complex issues. The discoveries that most influence the way we think about nature seldom can be anticipated, and frequently the applications for new technologies developed to probe a specific characteristic of nature are also seldom clear, even to the inventors of these technologies. One thing is clear: Seldom are such advances made by individuals alone. Rather, they result from the progress of the scientific community asking questions, developing new technologies to answer those  questions and sharing their results and their ideas with others. However,  there are indeed research strategies that can substantially increase the probability of one's making a discovery. Osheroff will illustrate some of these strategies in the context of a number of well-known discoveries, including the work he did as a graduate student, for which he shared the Nobel Prize for Physics in 1996.

Albert Fert, who shared the 2007 Nobel Prize in Physics, delivers his talk "Spintronics: Electrons, Spins Computers and Telephones. 

Spintronics exploits the influence of the electron spin orientation on electronic transport. It is mainly known for the “giant magnetoresistance” (GMR) and the large increase of the hard disc capacity obtained with read heads based on the GMR, but it has also revealed many other interesting effects. 

Today spintronics is developing along many novel directions with promising prospects as well for short term applications as for the “beyond CMOS” perspective.

After an introduction on the fundamentals of spintronics, Fert will review some of the most interesting emerging directions of today: spin transfer and its applications to STT-RAMs or to microwave generation, spintronics with semiconductors, graphene and carbon nanotubes, Spin Hall Effects, neuromorphic devices etc.