Speaker
Prof.
Lamberto Rondoni
(Politecnico di Torino)
Description
The time-reversal properties of charged systems in a
constant external magnetic field are reconsidered, showing
that the evolution equations are invariant under novel
symmetry operations that imply new signature properties for
time-correlation functions under time reversal. Such
symmetry relations do not require that the magnetic field be
reversed, which makes them applicable to material properties
of a single system, rather than of two distinct physical
situations. This implies, that Onsager-Casimir relations may
be replaced by Onsager reciprocal relations even in the
presence of a constant magnetic field, or of mechanically
analogous situations. These findings determine, for example,
null components of the correlation functions of velocities
and currents and of the associated transport coefficients.
The theory is developed for both classical and quantum systems,
in analogy to Kubo's approach, but the quantum mechanical
version leads to new intriguing questions. The theoretical
predictions are then illustrated by molecular dynamics
simulations of superionic AgI.
