Search results for "GLASS"
showing 10 items of 1153 documents
Finite-Size Scaling Study of the Simple Cubic Three-State Potts Glass
1991
During the last few years the Potts glass model has attracted more and more attention. It is considered as a first step towards modelling the phase transition of structural and orientational glasses. A mean-field approach /1/ predicts a low temperature behavior completely different from what is known from Ising spin glasses /2/. But short range models differ markedly from mean-field-predictions. So it is natural to ask, how the short range Potts glass behaves. Especially the question of the lower critical dimension d l is important, below which a finite temperature transition ceases to occur. We tried to answer this by combining Monte-Carlo simulations with a finite-size scaling analysis. T…
Relaxation times at the rate-dependent glass transition
1997
The structural relaxation time near the cooling rate dependent glass transition is determined self-consistently within the Moynihan-Narayanaswami formalism. In order to illustrate the method we analyze scanning calorimetry data from amorphous calcium-rubidium nitrate. A characteristic time scale of about 250 s is obtained at the conventionally defined glass transition. The occurrence of decoupled, faster relaxation modes is briefly discussed.
Domain-wall excitations in the two-dimensional Ising spin glass
2018
The Ising spin glass in two dimensions exhibits rich behavior with subtle differences in the scaling for different coupling distributions. We use recently developed mappings to graph-theoretic problems together with highly efficient implementations of combinatorial optimization algorithms to determine exact ground states for systems on square lattices with up to $10\,000\times 10\,000$ spins. While these mappings only work for planar graphs, for example for systems with periodic boundary conditions in at most one direction, we suggest here an iterative windowing technique that allows one to determine ground states for fully periodic samples up to sizes similar to those for the open-periodic…
Predictions for low-pTand high-pThadron spectra in nearly central Pb+Pb collisions atsNN=5.5TeV tested atsNN=130and 200 GeV
2005
We study the hadron spectra in nearly central $A+A$ collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) in a broad transverse momentum range. We cover the low-${p}_{T}$ spectra using longitudinally boost-invariant hydrodynamics with initial energy and net-baryon number densities from the perturbative QCD (pQCD)+saturation model. Buildup of the transverse flow and sensitivity of the spectra to a single decoupling temperature ${T}_{\mathrm{dec}}$ are studied. Comparison with RHIC data at $\sqrt{{s}_{\mathit{NN}}}=130$ and 200 GeV suggests a rather high value ${T}_{\mathrm{dec}}=150$ MeV. The high-${p}_{T}$ spectra are computed using factorized pQCD cro…
Forward J / ψ and D meson nuclear suppression at the LHC
2017
Abstract Using the color glass condensate formalism, we study the nuclear modification of forward J/ψ and D meson production in high energy proton-nucleus collisions at the LHC. We show that relying on the optical Glauber model to obtain the dipole cross section of the nucleus from the one of the proton fitted to HERA DIS data leads to a smaller nuclear suppression than in the first study of these processes in this formalism and a better agreement with experimental data.
Renormalization group evolution of multi-gluon correlators in high energy QCD
2011
Many-body QCD in leading high energy Regge asymptotics is described by the Balitsky-JIMWLK hierarchy of renormalization group equations for the x evolution of multi-point Wilson line correlators. These correlators are universal and ubiquitous in final states in deeply inelastic scattering and hadronic collisions. For instance, recently measured di-hadron correlations at forward rapidity in deuteron-gold collisions at the Relativistic Heavy Ion Collider (RHIC) are sensitive to four and six point correlators of Wilson lines in the small x color fields of the dense nuclear target. We evaluate these correlators numerically by solving the functional Langevin equation that describes the Balitsky-…
Experimental Evidence for a Structural-Dynamical Transition in Trajectory Space.
2016
Among the key insights into the glass transition has been the identification of a non-equilibrium phase transition in trajectory space which reveals phase coexistence between the normal supercooled liquid (active phase) and a glassy state (inactive phase). Here we present evidence that such a transition occurs in experiment. In colloidal hard spheres we find a non-Gaussian distribution of trajectories leaning towards those rich in locally favoured structures (LFS), associated with the emergence of slow dynamics. This we interpret as evidence for an non-equilibrium transition to an inactive LFS-rich phase. Reweighting trajectories reveals a first-order phase transition in trajectory space be…
Forward quark jet-nucleus scattering in a light-front Hamiltonian approach
2020
We investigate the scattering of a quark jet on a high-energy heavy nucleus using the time-dependent light-front Hamiltonian approach. We simulate a real-time evolution of the quark in a strong classical color field of the relativistic nucleus, described as the Color Glass Condensate. We study the sub-eikonal effect by letting the quark jet carry realistic finite longitudinal momenta, and we find sizeable changes on the transverse coordinate distribution of the quark. We also observe the energy loss of the quark through gluon emissions in the $\ket{q}+\ket{qg}$ Fock space. This approach provides us with an opportunity to study scattering processes from non-perturbative aspects.
Four-time rotational correlation functions
1998
A scheme to analyze four-time rotational correlation functions of any rank is developed and details for rank L = 1 and 2 are given. The scheme provides a transparent way for identifying deviations from simple Markovian dynamics as observed, e.g., in complex liquids close to the glass transition. The method should be applicable to NMR and optical multiple-pulse techniques as well as to photon correlation spectroscopy. Results are given for 2H-NMR multiple-pulse data in supercooled glycerol. We identify and analyze the dynamical heterogeneity of molecular reorientation in a range of 205 − 215 K close to the glass temperature Tg = 190 K.
Dynamics of Uniaxial Hard Ellipsoids
2007
We study the dynamics of monodisperse hard ellipsoids via a new event-driven molecular dynamics algorithm as a function of volume fraction $\phi$ and aspect ratio $X_0$. We evaluate the translational $D_{trans}$ and the rotational $D_{rot}$ diffusion coefficient and the associated isodiffusivity lines in the $\phi-X_0$ plane. We observe a decoupling of the translational and rotational dynamics which generates an almost perpendicular crossing of the $D_{trans}$ and $D_{rot}$ isodiffusivity lines. While the self intermediate scattering function exhibits stretched relaxation, i.e. glassy dynamics, only for large $\phi$ and $X_0 \approx 1$, the second order orientational correlator $C_2(t)$ sho…