376 research outputs found
Collective Almost Synchronization in Complex Networks
This work introduces the phenomenon of Collective Almost Synchronization
(CAS), which describes a universal way of how patterns can appear in complex
networks even for small coupling strengths. The CAS phenomenon appears due to
the existence of an approximately constant local mean field and is
characterized by having nodes with trajectories evolving around periodic stable
orbits. Common notion based on statistical knowledge would lead one to
interpret the appearance of a local constant mean field as a consequence of the
fact that the behavior of each node is not correlated to the behaviors of the
others. Contrary to this common notion, we show that various well known weaker
forms of synchronization (almost, time-lag, phase synchronization, and
generalized synchronization) appear as a result of the onset of an almost
constant local mean field. If the memory is formed in a brain by minimising the
coupling strength among neurons and maximising the number of possible patterns,
then the CAS phenomenon is a plausible explanation for it.Comment: 3 figure
Direct Visualization of Single Nuclear Pore Complex Proteins Using Genetically-Encoded Probes for DNA-PAINT
The nuclear pore complex (NPC) is one of the largest and most complex protein assemblies in the cell and, among other functions, serves as the gatekeeper of nucleocytoplasmic transport. Unraveling its molecular architecture and functioning has been an active research topic for decades with recent cryogenic electron microscopy and super-resolution studies advancing our understanding of the architecture of the NPC complex. However, the specific and direct visualization of single copies of NPC proteins is thus far elusive. Herein, we combine genetically-encoded self-labeling enzymes such as SNAP-tag and HaloTag with DNA-PAINT microscopy. We resolve single copies of nucleoporins in the human Y-complex in three dimensions with a precision of circa 3 nm, enabling studies of multicomponent complexes on the level of single proteins in cells using optical fluorescence microscopy
A reduced complexity numerical method for optimal gate synthesis
Although quantum computers have the potential to efficiently solve certain
problems considered difficult by known classical approaches, the design of a
quantum circuit remains computationally difficult. It is known that the optimal
gate design problem is equivalent to the solution of an associated optimal
control problem, the solution to which is also computationally intensive.
Hence, in this article, we introduce the application of a class of numerical
methods (termed the max-plus curse of dimensionality free techniques) that
determine the optimal control thereby synthesizing the desired unitary gate.
The application of this technique to quantum systems has a growth in complexity
that depends on the cardinality of the control set approximation rather than
the much larger growth with respect to spatial dimensions in approaches based
on gridding of the space, used in previous literature. This technique is
demonstrated by obtaining an approximate solution for the gate synthesis on
- a problem that is computationally intractable by grid based
approaches.Comment: 8 pages, 4 figure
Ferromagnetic phase transition in a Heisenberg fluid: Monte Carlo simulations and Fisher corrections to scaling
The magnetic phase transition in a Heisenberg fluid is studied by means of
the finite size scaling (FSS) technique. We find that even for larger systems,
considered in an ensemble with fixed density, the critical exponents show
deviations from the expected lattice values similar to those obtained
previously. This puzzle is clarified by proving the importance of the leading
correction to the scaling that appears due to Fisher renormalization with the
critical exponent equal to the absolute value of the specific heat exponent
. The appearance of such new corrections to scaling is a general
feature of systems with constraints.Comment: 12 pages, 2 figures; submitted to Phys. Rev. Let
Monte Carlo study of the magnetic critical properties of the two-dimensional Ising fluid
A two-dimensional fluid of hard spheres each having a spin and
interacting via short-range Ising-like interaction is studied near the second
order phase transition from the paramagnetic gas to the ferromagnetic gas
phase. Monte Carlo simulation technique and the multiple histogram data
analysis were used. By measuring the finite-size behaviour of several different
thermodynamic quantities,we were able to locate the transition and estimate
values of various static critical exponents. The values of exponents
and are close to the ones for the two-dimensional
lattice Ising model. However, our result for the exponent is very
different from the one for the Ising universality class.Comment: 6 pages, 8 figures. To appear in Phys. Rev.
- …