14 research outputs found
Fluctuations of the Color-superconducting Order Parameter in Heated and Dense Quark Matter
Fluctuations of the color superconducting order parameter in dense quark
matter at finite temperatures are investigated in terms of the phenomenological
Ginzburg - Landau approach. Our estimates show that fluctuations of the
di-quark gap may strongly affect some of thermodynamic quantities even far
below and above the critical temperature. If the critical temperature of the
di-quark phase transition were rather high one could expect a manifestation of
fluctuations of the di-quark gap in the course of heavy ion collisions.Comment: 12
Properties of A Class of Topological Phase Transition
The properties of a class of topological quantum phase transition (TQPT) are
analyzed based on a model proposed by Haldane. We study the effect of finite
temperature on this phase transition. We have found that finite temperature
would drive this TQPT to be a crossover, while it is stable against the weak
short range interaction. When the interaction is strong enough, however, this
TQPT is unstable and other states would emerge. Then we investigate the effect
of the on-site energy in the original haldane model. The critical difference
between our TQPT and the topological phase transition in conventional quantum
Hall system is discussed. Finally, we discuss the potential application of our
analysis to a topological phase transition proposed in a realistic system.Comment: 7 pages, 7 figures. Accepted by Phys. Rev.
Dynamics of Resonances in Strongly Interacting Systems
The effects of the propagation of particles which have a finite life-time and
an according broad distribution in their mass spectrum are discussed in the
context of a transport descriptions. In the first part some example cases of
mesonic modes in nuclear matter at finite densities and temperatures are
presented. These equilibrium calculations illustrate the dynamical range of
spectral distributions to be adequately covered by non-equilibrium description
of the dynamics of two nuclei colliding at high energies. The second part
addresses the problem of transport descriptions which properly account for the
damping width of the particles. A systematic and general gradient approximation
is presented in the form of diagrammatic rules which permit to derive a
self-consistent transport scheme from the Kadanoff--Baym equation. The scheme
is conserving and thermodynamically consistent provided the self-energies are
obtained within the Phi-derivable two-particle irreducible (2PI) method of
Baym. The merits, the limitations and partial cures of the limitations of this
transport scheme are discussed in detail.Comment: To appear in the proceedings of the International Conference
"Progress in Nonequilibrium Green's Functions III", Kiel, 22.-26. August 200
Possible experiment for determination of the role of microscopic vortex rings in the \lambda-transition in He-II
It is suggested that microscopic vortex rings (MVR) play an important role in
the \lambda-transition in helium-II and substantially determine the value of
T_{\lambda}. For very thin films of He-II, with thickness d less than the size
of the smallest MVR, the rings do not fit in and, therefore, do not exist in
such films. Consequently, for superfluid films of He-II, a peculiarity in the
form of a smoothed-out jump should be observed in the curve T_{m}(d) at the
values of thickness approximately equal to the size of the smallest MVR, d= 3 -
9 A (T_{m} is the temperature of the maximum of the broad peak on the curve of
the dependence of the specific heat on temperature). The absence of a similar
peculiarity will be an evidence that MVR do not influence the values of
T_{\lambda} and T_{m}, and do not play any key role in the \lambda-transition.
The currently available experimental data are insufficient for revealing the
predicted peculiarity.Comment: 6 pages, 2 figure
STM-induced light emission from thin films of perylene derivatives on the HOPG and Au substrates
We have investigated the emission properties of N,N'-diheptyl-3,4,9,10-perylenetetracarboxylic diimide thin films by the tunneling-electron-induced light emission technique. A fluorescence peak with vibronic progressions with large Stokes shifts was observed on both highly ordered pyrolytic graphite (HOPG) and Au substrates, indicating that the emission was derived from the isolated-molecule-like film condition with sufficient π-π interaction of the perylene rings of perylenetetracarboxylic diimide molecules. The upconversion emission mechanism of the tunneling-electron-induced emission was discussed in terms of inelastic tunneling including multiexcitation processes. The wavelength-selective enhanced emission due to a localized tip-induced surface plasmon on the Au substrate was also obtained