1,646 research outputs found
Quark-hadron phase transition with surface fluctuation
The effect of surface fluctuation on the observables of quark-hadron phase
transition is studied. The Ginzburg-Landau formalism is extended by the
inclusion of an extra term in the free energy that depends on the vertical
displacements from a flat surface. The probability that a bin has a particular
net displacement is determined by lattice simulation, where the physics input
is color confinement. The surface fluctuation from bin to bin is related to
multiplicity fluctuation, which in turn is measured by the factorial moments.
It is found that both the F-scaling behavior and the scaling exponent are
essentially unaffected by the inclusion of surface fluctuation.Comment: 9 pages, LaTex, 7 figures in a single postscript file, submitted to
Phys. Rev.
Universal behavior of multiplicity differences in quark-hadron phase transition
The scaling behavior of factorial moments of the differences in
multiplicities between well separated bins in heavy-ion collisions is proposed
as a probe of quark-hadron phase transition. The method takes into account some
of the physical features of nuclear collisions that cause some difficulty in
the application of the usual method. It is shown in the Ginzburg-Landau theory
that a numerical value of the scaling exponent can be determined
independent of the parameters in the problem. The universality of
characterizes quark-hadron phase transition, and can be tested directly by
appropriately analyzed data.Comment: 15 pages, including 4 figures (in epsf file), Latex, submitted to
Phys. Rev.
Similarity-Detection and Localization
The detection of similarities between long DNA and protein sequences is
studied using concepts of statistical physics. It is shown that mutual
similarities can be detected by sequence alignment methods only if their amount
exceeds a threshold value. The onset of detection is a continuous phase
transition which can be viewed as a localization-delocalization transition. The
``fidelity'' of the alignment is the order parameter of that transition; it
leads to criteria for the selection of optimal alignment parameters.Comment: 4 pages including 4 figures (308kb post-script file
Higher rank numerical ranges of normal matrices
The higher rank numerical range is closely connected to the construction of
quantum error correction code for a noisy quantum channel. It is known that if
a normal matrix has eigenvalues , then its higher
rank numerical range is the intersection of convex polygons with
vertices , where . In this paper, it is shown that the higher rank numerical range of a
normal matrix with distinct eigenvalues can be written as the intersection
of no more than closed half planes. In addition, given a convex
polygon a construction is given for a normal matrix
with minimum such that . In particular, if
has vertices, with , there is a normal matrix with such that .Comment: 12 pages, 9 figures, to appear in SIAM Journal on Matrix Analysis and
Application
Determination of direction of littoral transport along the north shore of Santa Rosa Island, Florida
The purpose of this study was to determine
the actual direction of littoral transport along the north shore of Santa
Rosa Island in the vicinity of Pensacola Beach, Florida. To accomplish this
objective the sand tracer method was used for the study. Visual observations
and instrument recordings of the environment factors were also made during
the tracing operations. The investigation covered a time span from September
14, 1976 to March 12, 1977.
(PDF contains 68 pages.
Novel Scaling Behavior for the Multiplicity Distribution under Second-Order Quark-Hadron Phase Transition
Deviation of the multiplicity distribution in small bin from its
Poisson counterpart is studied within the Ginzburg-Landau description for
second-order quark-hadron phase transition. Dynamical factor for the distribution and ratio are defined, and
novel scaling behaviors between are found which can be used to detect the
formation of quark-gluon plasma. The study of and is also very
interesting for other multiparticle production processes without phase
transition.Comment: 4 pages in revtex, 5 figures in eps format, will be appeared in Phys.
Rev.
Thermodynamics of Mesoscopic Vortex Systems in 1+1 Dimensions
The thermodynamics of a disordered planar vortex array is studied numerically
using a new polynomial algorithm which circumvents slow glassy dynamics. Close
to the glass transition, the anomalous vortex displacement is found to agree
well with the prediction of the renormalization-group theory. Interesting
behaviors such as the universal statistics of magnetic susceptibility
variations are observed in both the dense and dilute regimes of this mesoscopic
vortex system.Comment: 4 pages, REVTEX, 6 figures included. Comments and suggestions can be
sent to [email protected]
Disorder-Induced Depinning Transition
The competition in the pinning of a directed polymer by a columnar pin and a
background of random point impurities is investigated systematically using the
renormalization group method. With the aid of the mapping to the noisy-Burgers'
equation and the use of the mode-coupling method, the directed polymer is shown
to be marginally localized to an arbitrary weak columnar pin in 1+1 dimensions.
This weak localization effect is attributed to the existence of large scale,
nearly degenerate optimal paths of the randomly pinned directed polymer. The
critical behavior of the depinning transition above 1+1 dimensions is obtained
via an -expansion.Comment: 47 pages in revtex; postscript files of 6 figures include
Localization of Denaturation Bubbles in Random DNA Sequences
We study the thermodynamic and dynamic behaviors of twist-induced
denaturation bubbles in a long, stretched random sequence of DNA. The small
bubbles associated with weak twist are delocalized. Above a threshold torque,
the bubbles of several tens of bases or larger become preferentially localized
to \AT-rich segments. In the localized regime, the bubbles exhibit ``aging''
and move around sub-diffusively with continuously varying dynamic exponents.
These properties are derived using results of large-deviation theory together
with scaling arguments, and are verified by Monte-Carlo simulations.Comment: TeX file with postscript figure
Ground state and glass transition of the RNA secondary structure
RNA molecules form a sequence-specific self-pairing pattern at low
temperatures. We analyze this problem using a random pairing energy model as
well as a random sequence model that includes a base stacking energy in favor
of helix propagation. The free energy cost for separating a chain into two
equal halves offers a quantitative measure of sequence specific pairing. In the
low temperature glass phase, this quantity grows quadratically with the
logarithm of the chain length, but it switches to a linear behavior of entropic
origin in the high temperature molten phase. Transition between the two phases
is continuous, with characteristics that resemble those of a disordered elastic
manifold in two dimensions. For designed sequences, however, a power-law
distribution of pairing energies on a coarse-grained level may be more
appropriate. Extreme value statistics arguments then predict a power-law growth
of the free energy cost to break a chain, in agreement with numerical
simulations. Interestingly, the distribution of pairing distances in the ground
state secondary structure follows a remarkable power-law with an exponent -4/3,
independent of the specific assumptions for the base pairing energies
- âŠ