CMSP Seminar @ICTP BUDINICH HALL: Sir M. BERRY on Tuesday 27 June at 11:00

[Condensed Matter Section]

Special Condensed Matter Seminar
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Tuesday 27 June at 11:00 - ICTP Budinich Lecture Hall

Speaker:Sir Michael BERRY (H H Wills Physics Lab., Bristol University, U.K.)

"Variations on a Theme of Aharonov and Bohm"

Abstract:
The Aharonov-Bohm effect (AB) concerns the role in quantum physics of 
the magnetic vector potential of an impenetrable line of magnetic flux. 
Its partial anticipation by Ehrenberg and Siday, in terms of 
interference, was an approximation whose wavefunction was not 
singlevalued. Its connection with the singlevalued AB wave involves 
topology: ‘whirling waves’ winding round the flux. AB is a fine 
illustration of idealization in physics. There are four AB effects, 
depending on whether the waves and the flux are classical or quantum. In 
the classical-classical case, many details of the AB wavefunction have 
been explored experimentally in ripples scattered by a water vortex, 
where the flow velocity of the water corresponds to the vector 
potential; this analogy has recently been extended to include 
superradiance. The AB wave possesses a phase singularity, and there is a 
similar phenomenon in general interferometers. Connections between the 
AB wave and the Cornu spiral describing edge diffraction lead to very 
accurate approximations.


All are welcome to attend.
http://indico.ictp.it/event/8247/