644 research outputs found
Irreducible free energy expansion and overlaps locking in mean field spin glasses
We introduce a diagrammatic formulation for a cavity field expansion around
the critical temperature. This approach allows us to obtain a theory for the
overlap's fluctuations and, in particular, the linear part of the
Ghirlanda-Guerra relationships (GG) (often called Aizenman-Contucci polynomials
(AC)) in a very simple way. We show moreover how these constraints are
"superimposed" by the symmetry of the model with respect to the restriction
required by thermodynamic stability. Within this framework it is possible to
expand the free energy in terms of these irreducible overlaps fluctuations and
in a form that simply put in evidence how the complexity of the solution is
related to the complexity of the entropy.Comment: 19 page
Chirality transfer and stereo-selectivity of imprinted cholesteric networks
Imprinting of cholesteric textures in a polymer network is a method of
preserving a macroscopically chiral phase in a system with no molecular
chirality. By modifying the elastics properties of the network, the resulting
stored helical twist can be manipulated within a wide range since the
imprinting efficiency depends on the balance between the elastics constants and
twisting power at network formation. One spectacular property of phase
chirality imprinting is the created ability of the network to adsorb
preferentially one stereo-component from a racemic mixture. In this paper we
explore this property of chirality transfer from a macroscopic to the molecular
scale. In particular, we focus on the competition between the phase chirality
and the local nematic order. We demonstrate that it is possible to control the
subsequent release of chiral solvent component from the imprinting network and
the reversibility of the stereo-selective swelling by racemic solvents
On the Microscopic Origin of Cholesteric Pitch
We present a microscopic analysis of the instability of the nematic phase to
chirality when molecular chirality is introduced perturbatively. We show that
previously neglected short-range biaxial correlations play a crucial role in
determining the cholesteric pitch. We propose an order parameter which
quantifies the chirality of a molecule.Comment: RevTeX 3.0, 4 pages, one included eps figure. Published versio
Probing molecular chirality by coherent optical absorption spectra
We propose an approach to sensitively probe the chirality of molecules by
measuring their coherent optical absorption spectra. It is shown that quantum
dynamics of the cyclic three-level chiral molecules driven by
appropriately-designed external fields is total-phase dependent. This will
result in chirality-dependent absorption spectra for the probe field. As a
consequence, these absorption spectra can be utilized to identify molecular
chirality and determinate enantiomer excess. The feasibility of the proposal
with chiral molecules confined in hollow-core photonic crystal fiber (HC-PCF)
is also discussed.Comment: 4 pages, 4 figure
Observation of a Chiral State in a Microwave Cavity
A microwave experiment has been realized to measure the phase difference of
the oscillating electric field at two points inside the cavity. The technique
has been applied to a dissipative resonator which exhibits a singularity --
called exceptional point -- in its eigenvalue and eigenvector spectrum. At the
singularity, two modes coalesce with a phase difference of We
conclude that the state excited at the singularity has a definitiv chirality.Comment: RevTex 4, 5 figure
Interdisciplinary Teaching and Research at a Liberal Arts College on Computational Biology
ABSTRACT This paper focuses in presenting several aspects of the interdisciplinary collaboration in teaching and research at a liberal arts college. In particular, it presents courses and research projects in the computational biology area, which naturally call for collaborative work between faculty members from mathematics & computer science and biology departments. It further discusses (1) challenges arising when doing interdisciplinary work, (2) the interaction between interdisciplinary teaching, research, and communication, (3) possible outcomes of such interdisciplinary training for both students and faculty members, and (4) how interdisciplinary training fits within the liberal arts philosophy
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