TITLE:

Generating and shepherding intrinsic localized modes in nonlinear macroscopic and microscopic lattices

DATE:

Friday, February 7th, 2014

TIME:

3:30 PM

LOCATION:

GMCS 214

SPEAKER:

Dr. Al Sievers. Cornell University

ABSTRACT:

It had been known for some time that nonlinearity and discreteness play important roles in many

branches of condensed matter physics as evidenced by the appearance of domain walls, kinks

and solitons. A more recent discovery is that localized dynamical energy in a perfect nonlinear

lattice can be stabilized by lattice discreteness. Intrinsic localized modes (ILMs) are the resulting

feature. Their energy profiles resemble those of localized modes at defects in a harmonic lattice

but, like solitons, they can propagate; however, in contrast with solitons, collisions between

such excitations result in energy transfer between them with the more localized excitations

stealing energy from the less localized ones. I begin this talk with a mechanical demonstration

of this localization process using coupled pendula. Our experimental studies involve steady state

locking of ILMs and their interactions with impurities. We demonstrate both the manipulation of

localized energy along micromechanical arrays and also the generation of countable ILMs and

their controlled switching in an atomic lattice.

HOST:

Dr. Jose Castillo

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