93 research outputs found
Polarity-directed analog electro-optic switching in a low-polarization chiral smectic liquid crystal with positive dielectric anisotropy
Fluctuation - induced forces in critical fluids
The current knowledge about fluctuation - induced long - ranged forces is
summarized. Reference is made in particular to fluids near critical points, for
which some new insight has been obtained recently. Where appropiate, results of
analytic theory are compared with computer simulations and experiments.Comment: Topical review, 24 pages RevTeX, 6 figure
Bulk and Boundary Critical Behavior at Lifshitz Points
Lifshitz points are multicritical points at which a disordered phase, a
homogeneous ordered phase, and a modulated ordered phase meet. Their bulk
universality classes are described by natural generalizations of the standard
model. Analyzing these models systematically via modern
field-theoretic renormalization group methods has been a long-standing
challenge ever since their introduction in the middle of the 1970s. We survey
the recent progress made in this direction, discussing results obtained via
dimensionality expansions, how they compare with Monte Carlo results, and open
problems. These advances opened the way towards systematic studies of boundary
critical behavior at -axial Lifshitz points. The possible boundary critical
behavior depends on whether the surface plane is perpendicular to one of the
modulation axes or parallel to all of them. We show that the semi-infinite
field theories representing the corresponding surface universality classes in
these two cases of perpendicular and parallel surface orientation differ
crucially in their Hamiltonian's boundary terms and the implied boundary
conditions, and explain recent results along with our current understanding of
this matter.Comment: Invited contribution to STATPHYS 22, to be published in the
Proceedings of the 22nd International Conference on Statistical Physics
(STATPHYS 22) of the International Union of Pure and Applied Physics (IUPAP),
4--9 July 2004, Bangalore, Indi
Self-assembly of colloid-cholesteric composites provides a possible route to switchable optical materials
Colloidal particles dispersed in liquid crystals can form new materials with
tunable elastic and electro-optic properties. In a periodic `blue phase' host,
particles should template into colloidal crystals with potential uses in
photonics, metamaterials, and transformational optics. Here we show by computer
simulation that colloid/cholesteric mixtures can give rise to regular crystals,
glasses, percolating gels, isolated clusters, twisted rings and undulating
colloidal ropes. This structure can be tuned via particle concentration, and by
varying the surface interactions of the cholesteric host with both the
particles and confining walls. Many of these new materials are metastable: two
or more structures can arise under identical thermodynamic conditions. The
observed structure depends not only on the formulation protocol, but also on
the history of an applied electric field. This new class of soft materials
should thus be relevant to design of switchable, multistable devices for
optical technologies such as smart glass and e-paper.Comment: Manuscript with 3 figures plus supporting text and figure
Ferroelectric Liquid-Crystals - from the Plane-Wave to the Multisoliton Limit
Contains fulltext :
27864.pdf (publisher's version ) (Open Access
Slow mode of the smectic-A-smectic-C-alpha(*) phase transition
Contains fulltext :
92658.pdf (publisher's version ) (Open Access
Order-Parameter Dynamics near the Lifshitz Point in a Ferroelectric Liquid-Crystal
Contains fulltext :
27865.pdf (publisher's version ) (Open Access
Phase Diagram of a Ferroelectric Chual Smectic Liquid Crystal near the Lifshitz Point
Contains fulltext :
92722.pdf (publisher's version ) (Open Access
Thickness-dependent phase transition in thin nematic films
Contains fulltext :
28882.pdf (publisher's version ) (Open Access
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