reminder: AMPQ Seminar with BALAZS HETENYI

[Emanuele Tuillier Illingworth]

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*ANALYSIS, MATH-PHYS, AND QUANTUM SEMINAR 
<http://people.sissa.it/%7Ealemiche/qm-seminar>*
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*Today*
Thursday 19 March 2015, 16:15
SISSA main building, lecture room A-136


*Balázs Hetényi 
<http://www.physics.bilkent.edu.tr/index.php/people/faculty-members/balazs-hetenyi>* 
(Bilkent University Ankara)
*The topology of ideal conduction*


*Summary*: One of the most interesting recent discoveries in physics is 
topological insulation. Topological insulation can be viewed as an 
extension of the quantum Hall effect. The Hall conductance in a quantum 
system is characterised by a topological invariant, which arises upon 
integrating around the Brillouin zone of a two-dimensional system. A 
non-trivial behaviour results from application of an external magnetic 
field but it can also arise from magnetic impurities without an external 
field. Similarly, topological insulators are characterised by 
topological invariants which display non-trivial behaviour in particular 
cases, for example in spin-orbit coupled systems.  A common feature of 
topological insulators and quantum Hall systems is that they display 
particular behaviour at their boundaries, where the topological 
invariant changes from a trivial to a non-trivial value (principle of 
bulk-boundary correspondence). In this talk an overview of the quantum 
Hall effect and topological insulation will be given. Subsequently it 
will be shown that ideal conduction is also a topological physical 
effect. The topological invariant associated with the Drude weight will 
be derived.  This invariant is similar in form to the Hall conductance, 
however it arises upon integrating around a rectangle one of whose sides 
is the crystal momentum in some direction, the other being the total 
position in the same direction. It will be argued that the Drude weight, 
as well as related transport quantities (Meissner weight in 
superconductors, superfluid weight in superfluid 4He) can in principle 
exhibit quantization both integer and fractional. Indeed, 
superconductors exhibit flux quantization in cavities, superfluids give 
rise to vortex quantization. If time permits then also the analog of the 
bulk-boundary correspondence principle for ideal conduction and its 
relation to the Meissner effect will be discussed.


*AMPQ Seminar's following meetings:*


Thursday 19 March 2015
Speaker: *Andrea Trombetton <http://people.sissa.it/%7Eandreatr/>*i 
<http://people.sissa.it/%7Eandreatr/> (DEMOCRITOS Trieste)
Title: *Suppression of Landau instability for supersonic superfluid flows*


Monday 27 April 2015
Speaker: *Giuseppe De Nittis <https://gdenittis.wordpress.com/>* (Erlangen)
Title: *The topology of chiral vector bundles*


(/date to be confirmed/)
Speaker: *Fabio Benatti <http://www-dft.ts.infn.it/%7Ebenatti/>* 
(University of Trieste)
Title: *Quantum fluctuations, dissipation, and mesoscopic entanglement*


*for the complete schedule visit the AMPQ Seminar webpage*
http://www.sissa.it/~alemiche/ 
<http://people.sissa.it/%7Ealemiche/qm-seminar>qm- 
<http://people.sissa.it/%7Ealemiche/qm-seminar>seminar 
<http://people.sissa.it/%7Ealemiche/qm-seminar>


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