microseminar

informal seminar of Doppler Institute
on quantum theory and related topics and methods,

usually on Thursdays at 10.30 a.m. in Rez, on the territory of the
Department of Theoretical Physics of the Nuclear Physics Institute.

Enthusiastic visitors and/or speakers are always welcome.

Place:	NPI seminar room (ground floor)
Date:	Wednesday, February 8th, 2012
Time:	10.30 a. m.
Speaker:	Stephan Schmitz (IfM, JGU Meinz)
Title:	On indefinite Differential Operators of second order
Abstract:	Let \(\Omega\subset \mathbb{R}^n\) be a bounded open set with \(C^2\) boundary. Let \(A(\cdot)\) be a symmetric, not necessarily definite \(n\times n\) matrix with entries in \( L^\infty(\Omega)\), such that the inverse \(A(\cdot)^{-1}\) has entries in \( L^\infty(\Omega)\) again and \(\int_\Omega A(x)^{-1}dx\) is invertible. We show, that under these assumptions, there is a unique self-adjoint operator associated with the indefinite quadratic form \[\left\langle \grad u, A(\cdot) \grad u\right\rangle_{L^2(\Omega)^n}\] with domain lying in the domain of the gradient. This operator has a compact resolvent and its spectral properties are studied as well. The talk is based on a joint work with A. Hussein, D. Krejcirik and V. Kostrykin.

Date and time:	Tuesday, January 3rd, 2012, 10:30 a. m.
Speaker:	Tomas Brauner (Universitaet Bielefeld )
Title and abstract:	Number of Nambu-Goldstone bosons and its relation to charge densities
	I review some recent results concerning the counting of Nambu-Goldstone bosons in norelativistic system. Further details can be found in the papers 1109.6327 and 1112.3890 written together with Haruki Watanabe.

you would be always welcome by:	all of us
you may choose any date and time	though Thursdays on 10.30 are preferred
and any subject related to analytic and algebraic methods constructive Quantum Mechanics exactly solvable problems perturbation expansions non-Hermitian quantum models computer tricks relativistic equations and so on.
you should book your term of talk:	not later than 2 or 3 days in advance
your talk's length should be	20 minutes
time for subsequent questions:	unlimited

Stephan Schmitz (IfM, JGU Meinz)