36,333 research outputs found
Dynamical scaling in Ising and vector spin glasses
We have studied numerically the dynamics of spin glasses with Ising and XY
symmetry (gauge glass) in space dimensions 2, 3, and 4. The nonequilibrium
spin-glass susceptibility and the nonequilibrium energy per spin of samples of
large size L_b are measured as a function of anneal time t_w after a quench to
temperatures T. The two observables are compared to the equilibrium spin-glass
susceptibility and the equilibrium energy, respectively, measured as functions
of temperature T and system size L for a range of system sizes. For any time
and temperature a nonequilibrium time-dependent length scale L*(t_w,T) can be
defined by comparing equilibrium and nonequilibrium quantities. Our analysis
shows that for all systems studied, an "effective dynamical critical exponent"
parametrization L*(t_w,T) = A(T) t^(1/z(T)) fits the data well at each
temperature within the whole temperature range studied, which extends from well
above the critical temperature to near T = 0 for dimension 2, or to well below
the critical temperature for the other space dimensions studied. In addition,
the data suggest that the dynamical critical exponent z varies smoothly when
crossing the transition temperature.Comment: 14 pages, 13 figures, 9 table
Design and standalone characterisation of a capacitively coupled HV-CMOS sensor chip for the CLIC vertex detector
The concept of capacitive coupling between sensors and readout chips is under
study for the vertex detector at the proposed high-energy CLIC electron
positron collider. The CLICpix Capacitively Coupled Pixel Detector (C3PD) is an
active High-Voltage CMOS sensor, designed to be capacitively coupled to the
CLICpix2 readout chip. The chip is implemented in a commercial nm HV-CMOS
process and contains a matrix of square pixels with m
pitch. First prototypes have been produced with a standard resistivity of
cm for the substrate and tested in standalone mode. The
results show a rise time of ns, charge gain of mV/ke and
e RMS noise for a power consumption of W/pixel. The
main design aspects, as well as standalone measurement results, are presented.Comment: 13 pages, 13 figures, 2 tables. Work carried out in the framework of
the CLICdp collaboratio
Legal Writing
This issue of the Victoria University of Wellington Law Review provides an opportunity for students to develop their skill in written analysis and argument. In turn, the author uses this issue as an opportunity to consider the standards by which a writer should be guided both in their own creative work and in assessing the work of others by using Professor W Friedmann's Law and Social Change in Contemporary Britain as a framework. According to the author, legal writing requires absolute integrity to the facts, full candour as to the facts, avoiding distortion and straw-men targets in arguments, consistency, and clarity and accuracy
Kink-antikink interactions in the double sine-Gordon equation and the problem of resonance frequencies
We studied the kink-antikink collision process for the "double sine-Gordon"
(DSG) equation in 1+1 dimensions at different values of the potential parameter
. For small values of we discuss the problem of resonance frequencies.
We give qualitative explanation of the frequency shift in comparison with the
frequency of the discrete level in the potential well of isolated kink. We show
that in this region of the parameter the effective long-range interaction
between kink and antikink takes place.Comment: 9 pages, LaTeX, 4 figures (eps
Effect of Disorder in the Frustrated Ising FCC Antiferromagnet: Phase Diagram and Stretched Exponential Relaxation
We study the phase transition in a face-centered-cubic antiferromagnet with
Ising spins as a function of the concentration of ferromagnetic bonds
randomly introduced into the system. Such a model describes the spin-glass
phase at strong bond disorder. Using the standard Monte Carlo simulation and
the powerful Wang-Landau flat-histogram method, we carry out in this work
intensive simulations over the whole range of . We show that the first-order
transition disappears with a tiny amount of ferromagnetic bonds, namely , in agreement with theories and simulations on other 3D models. The
antiferromagnetic long-range order is also destroyed with a very small
(). With increasing , the system changes into a spin glass and
then to a ferromagnetic phase when . The phase diagram in the space
() shows an asymmetry, unlike the case of the Ising spin glass
on the simple cubic lattice. We calculate the relaxation time around the
spin-glass transition temperature and we show that the spin autocorrelation
follows a stretched exponential relaxation law where the factor is equal to
at the transition as suggested by the percolation-based theory.
This value is in agreement with experiments performed on various spin glasses
and with Monte Carlo simulations on different SG models
Kinetics of viral self-assembly: the role of ss RNA antenna
A big class of viruses self-assemble from a large number of identical capsid
proteins with long flexible N-terminal tails and ss RNA. We study the role of
the strong Coulomb interaction of positive N-terminal tails with ss RNA in the
kinetics of the in vitro virus self-assembly. Capsid proteins stick to
unassembled chain of ss RNA (which we call "antenna") and slide on it towards
the assembly site. We show that at excess of capsid proteins such
one-dimensional diffusion accelerates self-assembly more than ten times. On the
other hand at excess of ss RNA, antenna slows self-assembly down. Several
experiments are proposed to verify the role of ss RNA antenna.Comment: 4 pages, 3 figures, several experiments are proposed, a new idea of
experiment is adde
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