ELFT HÍRADÓ

[Janos Asboth <asboth.janos AT wigner.mta.hu>]

Kedves Mindenki,


Wigner SZFI Kvantumoptika és Kvantuminformatika Osztály szemináriumára
szeretettel várunk minden érdeklődőt. Aki nem az Intézet munkatársa, legyen
szíves jelezni egy emailben 
(asboth.janos AT wigner.mta.hu)
 a részvételi
szándékot, hogy a portán beengedjék.

Tuesday, 16 Feb, 1:00pm
Wigner SZFI Building 1, Room 123
From Casimir-Polder force between an atom and a topological insulator to
Dicke physics
Sebastian Fuchs
<http://www.quantum.uni-freiburg.de/pages/people/team/sebastian-fuchs.php>
(Physikalisches Institut, Albert-Ludwigs University of Freiburg)

In the first part of the talk I am going to discuss how the theory of
macroscopic quantum electrodynamics in dispersing and absorbing media is
applied to study the Casimir-Polder force between an atom and a topological
insulator [1]. The electromagnetic response of a topological insulator
surface leads to a mixing of electric and magnetic fields, breaking the
time-reversal symmetry [2, 3]. The coupling of these fields to an atom
causes shifts of the atom’s eigenenergies and modified decay rates near the
surface of the topological insulator.

In the second part we study superradiance that is associated with two
physical effects: Firstly, the cooperative emission of radiation of a large
number of excited atoms into free space in a quick, strong 'superradiant
burst'. Secondly, fur sufficiently strong coupling of many atoms to an
electromagnetic cavity mode, modeled with the Dicke Hamiltonian, a
'superradiant phase' is found, which shows macroscopic photon occupation
and atomic excitation. The two facets of superradiance can be combined in
studying the dissipative dynamics of an initially excited state of a
mesoscopic number of atoms towards equilibrium [4].

Combining macroscopic QED and Dicke physics opens the door to the
investigation of cooperative atom-surface interactions.

[1] S. Y. Buhmann, Dispersion Forces II, Springer-Verlag Berlin Heidelberg
(2012).
[2] S. Y. Buhmann, D. T. Butcher, and S. Scheel, New Journal of Physics 14,
083034 (2012).
[3] J. A. Crosse, S. Fuchs, and S. Y. Buhmann, Physical Review A 92, 063831
(2015).
[4] S. Fuchs, J. Ankerhold, M. Blencowe, and B. Kubala, Journal of Physics
B 49, 035501 (2016).

Minden érdeklődőt szívesen látunk.

Asbóth János